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1

Glow and arc modes in field emission driven microplasmas  

NASA Astrophysics Data System (ADS)

Field emission plays a major role in determining the dynamics of charged particles in microgaps ˜ 10 ?m. While characteristics of positively charged direct current Townsend microdischarges are relatively well-studied, post-breakdown modes have received limited attention in the past. In this work, PIC/MCC simulations are used to model field emission driven microplasmas operating at current densities higher than those encountered before gas breakdown occurs. A quasi-neutral region is shown to exist even in gaps as small 5 ?m with plasma number densities ˜ 1022 1/m3. A simple sheath model is derived and validated using PIC/MCC simulations. Current voltage characteristics obtained using the model display two branches with positive and negative slopes similar to the abnormal glow and arc modes encountered in traditional macroscale plasmas. Field emission can hence potentially be used to confine plasmas in extremely small gaps thereby paving the way for their use in certain unique applications such as microscale etching.

Venkattraman, Ayyaswamy

2014-12-01

2

Array of surface-confined glow discharges in atmospheric pressure helium: Modes and dynamics  

SciTech Connect

Array of atmospheric pressure surface discharges confined by a two-dimensional hexagon electrode mesh is studied for its discharge modes and temporal evolution so as to a theoretical underpinning to their growing applications in medicine, aerodynamic control, and environmental remediation. Helium plasma surface-confined by one hexagon-shaped rim electrode is shown to evolve from a Townsend mode to a normal and abnormal glow mode, and its evolution develops from the rim electrodes as six individual microdischarges merging in the middle of the hexagon mesh element. Within one hexagon element, microdischarges remain largely static with the mesh electrode being the instantaneous cathode, but move towards the hexagon center when the electrode is the instantaneous anode. On the entire array electrode surface, plasma ignition is found to beat an unspecific hexagon element and then spreads to ignite surrounding hexagon elements. The spreading of microdischarges is in the form of an expanding circle at a speed of about 3?×?10{sup 4} m/s, and their quenching starts in the location of the initial plasma ignition. Plasma modes influence how input electrical power is used to generate and accelerate electrons and as such the reaction chemistry, whereas plasma dynamics are central to understand and control plasma instabilities. The present study provides an important aspect of plasma physics of the atmospheric surface-confined discharge array and a theoretical underpinning to its future technological innovation.

Li, D.; Liu, D. X., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi (China); Nie, Q. Y.; Li, H. P. [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Chen, H. L. [Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Kong, M. G., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi (China); Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

2014-05-19

3

Array of surface-confined glow discharges in atmospheric pressure helium: Modes and dynamics  

NASA Astrophysics Data System (ADS)

Array of atmospheric pressure surface discharges confined by a two-dimensional hexagon electrode mesh is studied for its discharge modes and temporal evolution so as to a theoretical underpinning to their growing applications in medicine, aerodynamic control, and environmental remediation. Helium plasma surface-confined by one hexagon-shaped rim electrode is shown to evolve from a Townsend mode to a normal and abnormal glow mode, and its evolution develops from the rim electrodes as six individual microdischarges merging in the middle of the hexagon mesh element. Within one hexagon element, microdischarges remain largely static with the mesh electrode being the instantaneous cathode, but move towards the hexagon center when the electrode is the instantaneous anode. On the entire array electrode surface, plasma ignition is found to beat an unspecific hexagon element and then spreads to ignite surrounding hexagon elements. The spreading of microdischarges is in the form of an expanding circle at a speed of about 3 × 104 m/s, and their quenching starts in the location of the initial plasma ignition. Plasma modes influence how input electrical power is used to generate and accelerate electrons and as such the reaction chemistry, whereas plasma dynamics are central to understand and control plasma instabilities. The present study provides an important aspect of plasma physics of the atmospheric surface-confined discharge array and a theoretical underpinning to its future technological innovation.

Li, D.; Liu, D. X.; Nie, Q. Y.; Li, H. P.; Chen, H. L.; Kong, M. G.

2014-05-01

4

A method of identification of abnormal glow curves in individual monitoring using CaSO4:Dy teflon TLD and hot gas reader.  

PubMed

In the present study, a method of identifying abnormal glow curves to electronically screen the glow curves of TL readout is presented. The method is based on the fact that the shape of an abnormal glow curve differs from the shape of a normal one. A few criteria for defining the normal shape of glow curves are arrived at by analysing the glow curves of dosemeters exposed to various doses in laboratory conditions and read at different elapsed time post irradiation. About 300 glow curves of dosemeters used for monthly monitoring were analysed as per these criteria and the effectiveness of the method is observed for total counts as low as 150 µSv equivalent. PMID:21186222

Pradhan, S M; Sneha, C; Adtani, M M

2011-03-01

5

Electrical and photoelectric properties of polycrystalline diamond films deposited from an abnormal glow discharge  

NASA Astrophysics Data System (ADS)

Electrical and photovoltaic properties of polycrystalline diamond films (PDF), deposited from the abnormal glow discharge were analysed. Features of charge carrier transfer in PDF are determined by continuous energy distribution in the band gap of defect states of different nature. Dominated n-type conductivity activation component of electrical conduction and photoconductivity is complemented by a hopping mechanism with the participation of states near the Fermi level with a density 5.6·1017–2.1·1021 eV?1 cm?3. Activation transfer is realized in the exchange of charge carriers between the allowed bands and donor levels with the activation energy 0.007-0.21 eV, which are sparsely populated and have wide variation in their parameters. Trapping centers and carriers recombination are heterogeneously distributed in grain boundaries. Under lighting, the state density increases 3-5 times and probable jump length decreases by 1-3 nm. Spectral distribution centers of photosensitivity are correlated with the distribution of deep-level defects, determining the absorption spectra.

Konusov, F. V.; Kabyshev, A. V.; Linnik, S. A.; Gaydaychuk, A. V.; Remnev, G. E.

2014-11-01

6

On the Discharge Parameters of a Glow-Mode DBD at Medium and Atmospheric Pressure  

Microsoft Academic Search

In this paper, we report on the behavior of a glow-mode pulsed barrier discharge working at different gas pressure (25-760 torr) in helium and helium-oxygen gas mixture. The experimental setup consists of a plane-parallel geometry of a dielectric barrier discharge (DBD) system, excited by positive monopolar voltage pulses. The discharge properties were characterized by electrical measurements and emission spectroscopy. Our

Alina Silvia Chiper; Bogdan George Rusu; Andrei Vasile Nastuta; Gheorghe Popa

2009-01-01

7

Cathode fall thickness of abnormal glow discharges between parallel-plane electrodes in different radii at low pressure  

NASA Astrophysics Data System (ADS)

In order to investigate the influence of electrode radius on the characteristics of cathode fall thickness, experiments of low-pressure (20 Pa ? p ? 30 Pa) abnormal glow discharge were carried out between parallel-plane electrodes in different radii keeping gap distance unchanged. Axial distributions of light intensity were obtained from the discharge images captured using a Charge Coupled Device camera. The assumption that the position of the negative glow peak coincides with the edge of cathode fall layer was verified based on a two-dimensional model, and the cathode fall thicknesses, dc, were calculated from the axial distributions of light intensity. It was observed that the position of peak emission shifts closer to the cathode as current or pressure grows. The dependence of cathode fall thickness on the gas pressure and normalized current J/p2 was presented, and it was found that for discharges between electrodes in large radius the curves of pdc against J/p2 were superimposed on each other, however, this phenomenon will not hold for discharges between the smaller electrodes. The reason for this phenomenon is that the transverse diffusions of charged particles are not the same in two gaps between electrodes with different radii.

Fu, Yangyang; Luo, Haiyun; Zou, Xiaobing; Wang, Xinxin

2015-02-01

8

Default mode network abnormalities in idiopathic generalized epilepsy  

PubMed Central

Idiopathic Generalized Epilepsy (IGE) is associated with widespread cortical network abnormalities on electroencephalography. Resting state functional connectivity (RSFC), based on fMRI, can assess the brain’s global functional organization and its disruption in clinical conditions. We compared RSFC associated with the ‘default mode network’ (DMN) between people with IGE and healthy controls. Strength of functional connectivity within the DMN associated with seeds in the posterior cingulate cortex (PCC) and medial prefrontal cortices (MPFC) was compared between people with IGE and normal controls and was correlated with seizure duration, age of seizure onset and age at scan. Those with IGE showed markedly reduced functional network connectivity between anterior and posterior cortical seed regions. Seizure duration positively correlates with RSFC between parahippocampal gyri and the PCC but negatively correlates with connectivity between the PCC and frontal lobe. The observed pattern of disruption provides evidence for integration and segregation-type network abnormalities and supports aberrant network organization among people with IGE. PMID:22381387

McGill, Megan L.; Devinsky, Orrin; Kelly, Clare; Milham, Michael; Castellanos, F. Xavier; Quinn, Brian T.; DuBois, Jonathan; Young, Jonathan; Carlson, Chad; French, Jacqueline; Kuzniecky, Ruben; Halgren, Eric; Thesen, Thomas

2014-01-01

9

Monte Carlo simulation for excessive Balmer line broadening generated by transport of fast H Atoms in an abnormal glow discharge  

SciTech Connect

Monte Carlo code for fast hydrogen atom transport and generating of excessively Doppler broadened profiles based on the collision model is presented. Results for the initial monoenergetic atom beam and for a more realistic energy distribution of H atoms are reported. Line profiles obtained from the simulation are compared to our experimentally obtained data. Initial energy distribution for atoms is approximately calculated from the measured line profiles while the initial angle distribution was taken to be cosine. Balmer alpha intensity was found to exponentially decay in the negative glow region, which concurs with the experimental results. These agreements between the simulation and experiment support the collision model for excessive line broadening.

Cvetanovic, N. [Faculty of Transport and Traffic Engineering, University of Belgrade, Vojvode Stepe 305, Belgrade (Serbia); Obradovic, B. M.; Kuraica, M. M. [Faculty of Physics, University of Belgrade, P.O. Box 368, Belgrade (Serbia)

2009-02-15

10

Glow Dog Glow  

E-print Network

Broadcast Transcript: South Korean researchers, ever striving to be top in science, have cloned a glow-in-the-dark dog. The little beagle was engineered by inserting genes from species--like jellyfish--that produce fluorescent proteins. The gene...

Hacker, Randi

2011-08-17

11

Glowing Pickle  

NSDL National Science Digital Library

In this activity, high voltage is applied across a pickle to emit a yellow glow. This activity should only be conducted by skilled adults and is best suited as a demonstration. Optional extensions to this activity include soaking the pickle for week in brine to emit a pink glow and using several pickles at once.

Paul Doherty

2001-01-01

12

Modifying argon glow discharges by hydrogen addition: effects on analytical characteristics of optical emission and mass spectrometry detection modes  

Microsoft Academic Search

An overview of the effects produced by the presence of hydrogen in a glow discharge (GD), generated either in argon or in\\u000a neon, is given. Extensive work related to the addition of hydrogen to GDs, coupled with optical emission spectrometry (OES)\\u000a and mass spectrometry (MS), has been published in the last few years in an attempt to explain the processes

A. Martín; A. Menéndez; R. Pereiro; N. Bordel; A. Sanz-Medel

2007-01-01

13

Glowing tags  

Microsoft Academic Search

Tagging physical objects to get a link from the physical world into some kind of technology has been done for a long time. The most commonly known is probably the barcodes that is used in five billion scans every day. During a project at Xerox Research Centre Europe in Cambridge, we came across the concept of Glow Tags. It is

Hans Tap

14

Abnormal lateralization of functional connectivity between language and default mode regions in autism  

PubMed Central

Background Lateralization of brain structure and function occurs in typical development, and abnormal lateralization is present in various neuropsychiatric disorders. Autism is characterized by a lack of left lateralization in structure and function of regions involved in language, such as Broca and Wernicke areas. Methods Using functional connectivity magnetic resonance imaging from a large publicly available sample (n?=?964), we tested whether abnormal functional lateralization in autism exists preferentially in language regions or in a more diffuse pattern across networks of lateralized brain regions. Results The autism group exhibited significantly reduced left lateralization in a few connections involving language regions and regions from the default mode network, but results were not significant throughout left- and right-lateralized networks. There is a trend that suggests the lack of left lateralization in a connection involving Wernicke area and the posterior cingulate cortex associates with more severe autism. Conclusions Abnormal language lateralization in autism may be due to abnormal language development rather than to a deficit in hemispheric specialization of the entire brain. PMID:24502324

2014-01-01

15

Abnormal Default-Mode Network Homogeneity in First-Episode, Drug-Naive Major Depressive Disorder  

PubMed Central

Background Default mode network (DMN) is one of the most commonly recognized resting-state networks in major depressive disorder (MDD). However, the homogeneity of this network in MDD is poorly understood. As such, this study was conducted to determine whether or not an abnormal network homogeneity (NH) of DMN is observed in patients with first-episode and drug-naive MDD. Methods Twenty-four first-episode drug-naive patients with MDD and twenty-four healthy control subjects participated in the study. NH and independent component analysis (ICA) methods were used to analyze data. Results Depressed patients exhibited a significantly increased NH in the left dorsal medial prefrontal cortex (MPFC) and decreased NH in the right inferior temporal gyrus (ITG) compared with the healthy control subjects. Receiver operating characteristic curves (ROC) were analyzed and results revealed that the NH values of MPFC and ITG could be applied as candidate markers with relatively high sensitivity and specificity to distinguish patients from healthy control subjects. No correlation was observed between the NH values of the two regions and clinical variables. Conclusions Our findings suggested that an abnormal DMN homogeneity could be observed in MDD, which highlight the importance of the DMN in the pathophysiology of MDD. PMID:24609111

Guo, Wenbin; Liu, Feng; Zhang, Jian; Zhang, Zhikun; Yu, Liuyu; Liu, Jianrong; Chen, Huafu; Xiao, Changqing

2014-01-01

16

The Effect of Abnormal Granulation on Acoustic Wave Travel Times and Mode Frequencies  

E-print Network

Observations indicate that in plage areas (i.e. in active regions outside sunspots) acoustic waves travel faster than in quiet sun, leading to shortened travel times and higher p-mode frequencies. While it is clear that the ultimate cause of any difference between quiet sun and plage is the presence of magnetic fields of order 100 G in the latter, the mechanism by which the magnetic field exerts its influence has not yet been conclusively identified. One possible such mechanism is suggested by the observation that granular motions in plage areas tend to be slightly ``abnormal'', dampened compared to quiet sun. In this paper we consider the effect that abnormal granulation observed in active regions should have on the propagation of acoustic waves. Any such effect is found to be limited to a shallow surface layer where sound waves propagate nearly vertically. The magnetically suppressed turbulence implies higher sound speeds, leading to shorter travel times. This time shift Dt is independent of the travel distance, while it shows a characteristic dependence on the assumed plage field strength. As a consequence of the variation of the acoustic cutoff with height, Dt is expected to be significantly higher for higher frequency waves within the observed regime of 3-5 mHz. The lower group velocity near the upper reflection point further leads to an increased envelope time shift, as compared to the phase shift. $p$-mode frequencies in plage areas are increased by a corresponding amount, Dnu/nu = nu*Dt. These characteristics of the time and frequency shifts are in accordance with observations. The calculated overall amplitude of the time and frequency shifts are comparable to, but still significantly (factor of 2 to 5) less than suggested by measurements.

K. Petrovay; R. Erdelyi; M. J. Thompson

2007-02-02

17

Thar She Glows!  

NSDL National Science Digital Library

Learners observe glow-in-the-dark objects in a homemade light-proof box. Objects can include glow sticks, glow-in-the-dark toys, and toys with fluorescent paint. The box is built with a black light installed, which can be controlled with a switch outside the box. Background information is provided about the difference between fluorescence (glows only when light is shined on it) and phosphorescence (continues to glow after light is removed), and an electron-level explanation is also provided.

Oregon Museum of Science and Industry

1997-01-01

18

The effect of power balance on the heating mode transition in micro-dielectric barrier helium glow discharges  

NASA Astrophysics Data System (ADS)

A particle-in-cell simulation has been adapted to analyze the helium discharge characteristics of a planar micro-dielectric barrier discharge with a gap distance less than 100 µm for variation of driving frequency from 10 to 500 MHz. Two scaling laws for the breakdown voltage were obtained with the change in heating mechanism from the ?- to the ?-mode with increasing frequency. The optimal condition for the efficient generation of high-density plasmas with minimized power is obtained when the ratio of ion transit time to the RF period is about 1/4, so that the secondary electrons emitted by ion bombardment on the dielectric-gap boundary are accelerated in phase with the sheath potential. Under this condition, the plasma density as well as the ion current is maximum, the displacement current and the electron current are almost the same, and the ratio of the power delivered to the plasma is 50% of the total power. At high frequencies, the collisional electron heating increases by the induced bulk electric field, enhancing excitation and elastic collisions, and thus ionization efficiency decreases while excitation efficiency increases.

Lee, Jung Yeol; Bae, Hyo Won; Lee, Hae June; Verboncoeur, John P.

2014-06-01

19

Abnormal electron-heating mode and formation of secondary-energetic electrons in pulsed microwave-frequency atmospheric microplasmas  

SciTech Connect

The formation of secondary energetic electrons induced by an abnormal electron-heating mode in pulsed microwave-frequency atmospheric microplasmas was investigated using particle-in-cell simulation. We found that additional high electron heating only occurs during the first period of the ignition phase after the start of a second pulse at sub-millimeter dimensions. During this period, the electrons are unable to follow the abruptly retreating sheath through diffusion alone. Thus, a self-consistent electric field is induced to drive the electrons toward the electrode. These behaviors result in an abnormal electron-heating mode that produces high-energy electrons at the electrode with energies greater than 50?eV.

Kwon, H. C. [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of) [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Research and Development Division, SK Hynix Semiconductor Inc., Icheon 467-701 (Korea, Republic of); Jung, S. Y. [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of)] [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Kim, H. Y.; Won, I. H.; Lee, J. K., E-mail: jkl@postech.ac.kr [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2014-03-15

20

Phenomena of oscillations in atmospheric pressure direct current glow discharges  

SciTech Connect

Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transform spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.

Liu, Fu-cheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yan, Wen; Wang, De-zhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2013-12-15

21

Glow in the Dark  

NSDL National Science Digital Library

Learners experiment to see which colors of light will cause a phosphorescent (glow-in-the-dark) material to glow. Different colors of light have different wavelengths, and different amounts of energy. Only the colors which shine with sufficient energy can charge up the phosphorescent material enough to glow in the dark. This activity starts on p.26 of the manual. This manual contains four activities related to the Spectra: The Original Laser Superhero Force comic book published by the American Physical Society.

Rebecca Thompson-Flagg

2010-01-01

22

Glowing in the Dark  

NSDL National Science Digital Library

In this activity, learners explore phosphorescence and how certain materials can absorb and store energy from a light source. Learners use critical thinking skills to hypothesize which type of light -- incandescent, ultraviolet, infrared or fluorescent -- will produce the brightest glow from a glow-in-the-dark star. Learners perform an experiment using cameras to observe the intensity of the resulting glow from each type of light source.

Science Friday

2011-01-01

23

Numerical Study on Glow Discharge of IEC Fusion  

SciTech Connect

An inertial electrostatic confinement (IEC) fusion device is possibly used for the neutron source that has the ability to produce the neutrons of 10{sup 5}-10{sup 8}/s by the glow discharge. It works more efficiently at the condition of the high voltage and the low pressure. It, however, is difficult to keep the continuous operation at the low-pressure because the glow discharge is apt to be unstable. We have made the three-dimensional Monte Carlo PIC code including atomic processes to investigate the glow discharge. The study reveals the spatial position where the ionization occurs and numerically reproduces the discharge called 'star mode'.

Osawa, Hodaka; Tabata, Takehiro; Ohnishi, Masami [Kansai University (Japan)

2005-05-15

24

Stable glow discharge detector  

DOEpatents

A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

Koo, Jackson C.; Yu, Conrad M.

2004-05-18

25

Glowing Bacteria: Transformation Efficiency  

E-print Network

1 Glowing Bacteria: Transformation Efficiency Purpose: To determine how well your E. coli cells took up and expressed GFP after transformation. Background: Transformation efficiency is a quantitative)______ (Fraction of DNA spread on plate) = ______ µg plasmid DNA spread on plate #12;2 5. Transformation efficiency

Rose, Michael R.

26

The Glow-worm  

NSDL National Science Digital Library

A general audience discussion of the natural history of Glow Worms of Britain. This well illustrated page also provides tips for venturing out and seeing them for yourself. The author is a lifetime naturalist and fellow of the Royal Entomological Society.

0000-00-00

27

Science Nation: Glowing Squid  

NSDL National Science Digital Library

In deep ocean waters, it's sometimes difficult to hide from predators. That's why so many sea creatures have evolved extraordinary methods of disguise. Cephalopods, such as octopus, squid and cuttlefish, are big on camouflage, by day or night. In fact, the Hawaiian bobtail squid has several means of stealthy self- preservation. With support from the National Science Foundation (NSF), a team from the University of Wisconsin-Madison study one bobtail squid camouflage scheme; one that glows in the dark!

28

Detection of surface glow related to spacecraft glow phenomenon  

SciTech Connect

We have developed a high flux source of low energy neutral beams to study the spacecraft glow phenomena by using a biased limiter to neutralize plasma in ACT-1. Beams of nitrogen and nitrogen-oxygen mixtures with energies of 1 to 15 eV and fluxes greater than or equal to 10/sup 14//cm/sup 2//s were directed on target surfaces consisting of Z-302 and Z-306 paints. With the nitrogen beams we successfully detected a glow due to beam-surface interactions. In addition, we discovered a volume glow effect due to beam-gas interactions which may also play a role in spacecraft glow. 11 refs., 14 figs.

Langer, W.D.; Cohen, S.A.; Manos, D.M.; Motley, R.W.; Ono, M.; Paul, S.; Roberts, D.; Selberg, H.

1986-02-01

29

Modeling of asymmetric pulsed phenomena in dielectric-barrier atmospheric-pressure glow discharges  

SciTech Connect

Asymmetric current pulses in dielectric-barrier atmospheric-pressure glow discharges are investigated by a self-consistent, one-dimensional fluid model. It is found that the glow mode and Townsend mode can coexist in the asymmetric discharge even though the gas gap is rather large. The reason for this phenomenon is that the residual space charge plays the role of anode and reduces the gap width, resulting in the formation of a Townsend discharge.

Ha Yan [College of Mathematics and Computer Science, Hebei University, Baoding 071002 (China); Wang Huijuan [School of Mathematics and Physics, North China Electric Power University, Baoding 071003 (China); Wang Xiaofei [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

2012-01-15

30

Structural and Functional Abnormalities of Default Mode Network in Minimal Hepatic Encephalopathy: A Study Combining DTI and fMRI  

Microsoft Academic Search

Background and PurposeLive failure can cause brain edema and aberrant brain function in cirrhotic patients. In particular, decreased functional connectivity within the brain default-mode network (DMN) has been recently reported in overt hepatic encephalopathy (HE) patients. However, so far, little is known about the connectivity among the DMN in the minimal HE (MHE), the mildest form of HE. Here, we

Rongfeng Qi; Qiang Xu; Long Jiang Zhang; Jianhui Zhong; Gang Zheng; Shengyong Wu; Zhiqiang Zhang; Wei Liao; Yuan Zhong; Ling Ni; Qing Jiao; Zongjun Zhang; Yijun Liu; Guangming Lu

2012-01-01

31

Simulation of stationary glow patterns in dielectric barrier discharges at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Self-organized stationary patterns in dielectric barrier discharges operating in glow regime at atmospheric pressure are investigated by a self-consistent two-dimensional fluid model. The simulation results show that two different modes, namely, the diffuse mode and the static patterned mode, can be formed in different ranges of the driving frequency. The discharge operates in Townsend regime in the diffuse mode, while it operates in a glow regime inside the filaments and in a Townsend regime outside the filaments in the stable pattered mode. The forming process of the stationary filaments can be divided into three stages, namely, destabilizing stage, self-assembling stage, and stable stage. The space charge associated with residual electron density and surface charge is responsible for the formation of these stationary glow patterns.

Liu, Fucheng; He, Yafeng; Dong, Lifang

2014-12-01

32

Second Workshop on Spacecraft Glow  

NASA Technical Reports Server (NTRS)

Various aspects of space glow were considered. Results of a workshop held on May 6 to 7, 1985, at the Space Science Laboratory of NASA/Marshall Space Flight Center, Huntsville, Alabama are presented. The topics of discussion are divided as follows: (1) in situ observations; (2) theoretical calculations; (3) laboratory measurements; and (4) future experiments.

Waite, J. H., Jr. (editor); Moorehead, T. W. (editor)

1985-01-01

33

DC Corona and Glow Discharges Generated along the Intersecting Axial Miniature Gas Flows under Atmospheric Pressure Air  

Microsoft Academic Search

We discussed the corona-to-glow transition of DC discharges using intersecting axial miniature gas flows under atmospheric pressure. The stable dc discharges generated along the intersecting two axial miniature helium flows were operated from low current of 0.1 mA to high current of 20 mA. With increasing the discharge current, the discharges appeared as corona-mode and then developed to glow-mode. The

Naoki Shirai; Hiroaki Shito; Shinji Ibuka; Shozo Ishii

2009-01-01

34

Constricted glow discharge plasma source  

DOEpatents

A constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The source is suitable for applying films of nitrides such as gallium nitride and oxides such as tungsten oxide and for enriching other substances in material surfaces such as oxygen and water vapor, which are difficult process as plasma in any known devices and methods. The source can also be used to assist the deposition of films such as metal films by providing low-energy ions such as argon ions.

Anders, Andre (Albany, CA); Anders, Simone (Albany, CA); Dickinson, Michael (San Leandro, CA); Rubin, Michael (Berkeley, CA); Newman, Nathan (Winnetka, IL)

2000-01-01

35

Glow Discharge Cleaning for LDX  

NASA Astrophysics Data System (ADS)

The Levitated Dipole Experiment (LDX) has completed construction of its glow discharge cleaning (GDC) system. GDC will be used before first plasmas in LDX, as well as between experimental operations, to eliminate all impurities from the vacuum vessel. The glow is created by a movable anode probe inserted through a flange on the underside of the vessel. The anode is biased with up to 1kV with respect to the vessel wall with 12kW DC power available for plasma formation. Away from the anode, a biased tungsten filament will be installed to aid in discharge breakdown and reduce the likelihood of arcing[1]. The filament may also be used for preionization during experimental operations. GDC will be implemented with deuterium gas followed by a shorter period of helium gas. A reduced conductance pumping path will be incorporated into the vacuum system in order to better control pressure during GDC operation. The completed design and initial tests of the GDC system will be presented. [1] H.W Kugel, W. Blanchard, G. D'Amico, R. Gernhardt, and T. Provost, "NSTX Filament Preionization And Glow Discharge Cleaning Systems", PPPL Report (2000).

Dagen, Sarah; Garnier, Darren; Ortiz, Eugenio

2002-11-01

36

Common Gamma-ray Glows above Thunderclouds  

NASA Astrophysics Data System (ADS)

Gamma-ray glows are continuous, long duration gamma- and x-ray emission seen coming from thunderclouds. The Airborne for Energetic Lightning Emissions (ADELE) observed 12 gamma-ray glows during its summer 2009 flight campaign over the areas of Colorado and Florida in the United States. For these glows we shall present their spectra, relationship to lightning activity and how their duration and size changes as a function of distance. Gamma-ray glows follow the relativistic runaway electron avalanche (RREA) spectrum and have been previously measured from the ground and inside the cloud. ADELE measured most glows as it flew above the screening layer of the cloud. During the brightest glow on August 21, 2009, we can show that we are flying directly into a downward facing relativistic runaway avalanche, indicative of flying between the upper positive and negative screening layer of the cloud. In order to explain the brightness of this glow, RREA with an electric field approaching the limit for relativistic feedback must be occurring. Using all 12 glows, we show that lightning activity diminishes during the onset of the glow. Using this along with the fact that glows occur as the field approaches the level necessary for feedback, we attempt to distinguish between two possibilities: that glows are evidence that RREA with feedback, rather than lightning, is sometimes the primary channel for discharging the cloud, or else that the overall discharging is still controlled by lightning, with glows simply appearing during times when a subsidence of lightning allows the field to rise above the threshold for RREA.

Kelley, Nicole; Smith, David; Dwyer, Joseph; Hazelton, Bryna; Grefenstette, Brian; Lowell, Alex; Splitt, Michael; Lazarus, Steven; Rassoul, Hamid

2013-04-01

37

ADELE's Common Gamma-Ray Glows  

NASA Astrophysics Data System (ADS)

Gamma-ray glows have been observed for the first time as a common, long duration phenomenon from the tops of thunderclouds. The Airborne Detector for Energetic Lightning Emissions (ADELE) observed 12 gamma-ray glows during its Summer 2009 flight campaign. We present their spectra, their relationship to lightning activity and show how the duration and size of a glow changes with distance from the glow. Since glows have a very hard spectrum, with many counts above 5 MeV, they may be evidence of a continual relativistic runaway process with positron feedback. We compare our spectra with simulations of relativistic runaway in the atmosphere with all effects of feedback included. We show that the lightning activity diminishes during the onset of a glow. From our simulations we attempt to distinguish between the two possibilities for this decrease: the mechanism responsible for glows is only able to become significant when lightning activity subsides or glows are actually stifling the lightning activity and considerably limiting the charging of the cloud. Comparison of the data with our simulations will determine if runaway or feedback are necessary to explain the glow brightness and if these mechanisms have significant effects on the total charging of the cloud.

Kelley, N. A.; Smith, D. M.; Dwyer, J. R.; Hazelton, B. J.; Grefenstette, B. W.; Lowell, A.; Splitt, M. E.; Lazarus, S. M.; Rassoul, H. K.

2012-12-01

38

Glow Sticks: Spectra and Color Mixing  

NASA Astrophysics Data System (ADS)

Glow sticks are a popular Halloween staple familiar to most of our students. The production of light via a chemical reaction is called "chemiluminescence," and glow sticks are often used as demonstrations and experiments in the chemistry classroom to study reaction rates as a function of temperature.1-3 A black light can be used to illuminate glow sticks that have not been cracked or those that are "dead" in order to demonstrate fluorescence in liquid chemicals.4 In this article, we present the use of glow sticks as an inexpensive demonstration of spectra and color addition.

Birriel, Jennifer; Birriel, Ignacio

2014-10-01

39

Spacecraft ram glow and surface temperature  

NASA Technical Reports Server (NTRS)

Space shuttle glow intensity measurements show large differences when the data from different missions are compared. In particular, on the 41-G mission the space shuttle ram glow was observed to display an unusually low intensity. Subsequent investigation of this measurement and earlier measurements suggest that there was a significant difference in temperature of the glow producing ram surfaces. The highly insulating properties coupled with the high emissivity of the shuttle tile results in surfaces that cool quickly when exposed to deep space on the night side of the orbit. The increased glow intensity is consistent with the hypothesis that the glow is emitted from excited NO2. The excited NO2 is likely formed through three body recombination (OI + NO + M = NO2*) where ramming of OI interacts with weakly surface bound NO. The NO is formed from atmospheric OI and NI which is scavenged by the spacecraft moving through the atmosphere. It is postulated that the colder surfaces retain a thicker layer of NO thereby increasing the probability of the reaction. It has been found from the glow intensity/temperature data that the bond energy of the surface bound precursor, leading to the chemical recombination producing the glow, is approximately 0.14 eV. A thermal analysis of material samples of STS-8 was made and the postulated temperature change of individual material samples prior to the time of glow measurements above respective samples are consistent with the thermal effect on glow found for the orbiter surface.

Swenson, G. R.; Mende, S. B.; Llewellyn, E. J.

1987-01-01

40

Gas flow effects on the submicrosecond pulsed atmospheric pressure glow discharges  

SciTech Connect

The influence of gas flow on the discharge characteristics in the submicrosecond pulsed dielectric barrier discharge at atmospheric pressure was investigated by a one-dimensional self-consistent kinetic model. The convection-transport mechanism of the plasma species caused by a longitudinal gas flow was integrated into flux equation. Two discharge current pulses, the positive one and the negative one, are operated in a normal glow mode and a subnormal glow mode, respectively. It is shown that the gas flow has a significant impact on the discharge characteristics, especially on the positive discharge pulse. The spatial distribution of electrons is affected by the gas flow through the convection transport mechanism.

Liu Fucheng; Zhang Dingzong; Wang Dezhen [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2010-10-15

41

Meiotic abnormalities  

SciTech Connect

Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

NONE

1993-12-31

42

Glow Fast, Glow Slow: Alter the Rate of a Reaction!  

NSDL National Science Digital Library

Learners investigate one factor affecting reaction rates: temperature. In a darkened room, two identical lightsticks are placed in water -- one in hot water and one in cold water. The lightstick in the hot water glows brighter than the lightstick in the cold water since the light-producing reaction is faster in hot water. This activity, located on page 2 of the PDF, is one of three activities in the Take Home guide for the Chemical Reactions unit in OMSI's Chemistry Lab. Also included on the PDF are two additional activities: Cloudy Globs and Gas Production.

Oregon Museum of Science and Industry

1997-01-01

43

Glow Sticks: Spectra and Color Mixing  

ERIC Educational Resources Information Center

Glow sticks are a popular Halloween staple familiar to most of our students. The production of light via a chemical reaction is called "chemiluminescence," and glow sticks are often used as demonstrations and experiments in the chemistry classroom to study reaction rates as a function of temperature. A black light can be used to…

Birriel, Jennifer; Birriel, Ignacio

2014-01-01

44

APEX reveals glowing stellar nurseries  

NASA Astrophysics Data System (ADS)

Illustrating the power of submillimetre-wavelength astronomy, an APEX image reveals how an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars. Submillimetre light is the key to revealing some of the coldest material in the Universe, such as these cold, dense clouds. Glowing Stellar Nurseries ESO PR Photo 40/08 Glowing Stellar Nurseries The region, called RCW120, is about 4200 light years from Earth, towards the constellation of Scorpius. A hot, massive star in its centre is emitting huge amounts of ultraviolet radiation, which ionises the surrounding gas, stripping the electrons from hydrogen atoms and producing the characteristic red glow of so-called H-alpha emission. As this ionised region expands into space, the associated shock wave sweeps up a layer of the surrounding cold interstellar gas and cosmic dust. This layer becomes unstable and collapses under its own gravity into dense clumps, forming cold, dense clouds of hydrogen where new stars are born. However, as the clouds are still very cold, with temperatures of around -250? Celsius, their faint heat glow can only be seen at submillimetre wavelengths. Submillimetre light is therefore vital in studying the earliest stages of the birth and life of stars. The submillimetre-wavelength data were taken with the LABOCA camera on the 12-m Atacama Pathfinder Experiment (APEX) telescope, located on the 5000 m high plateau of Chajnantor in the Chilean Atacama desert. Thanks to LABOCA's high sensitivity, astronomers were able to detect clumps of cold gas four times fainter than previously possible. Since the brightness of the clumps is a measure of their mass, this also means that astronomers can now study the formation of less massive stars than they could before. The plateau of Chajnantor is also where ESO, together with international partners, is building a next generation submillimetre telescope, ALMA, the Atacama Large Millimeter/submillimeter Array. ALMA will use over sixty 12-m antennas, linked together over distances of more than 16 km, to form a single, giant telescope. APEX is a collaboration between the Max-Planck-Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The telescope is based on a prototype antenna constructed for the ALMA project. Operation of APEX at Chajnantor is entrusted to ESO.

2008-11-01

45

Enhancement in ion beam current with layered-glows in a constricted dc plasma ion source.  

PubMed

High current mode has been discovered and investigated in a constricted dc plasma ion source. As discharge currents exceed a certain threshold, voltage to sustain the constricted dc plasma suddenly falls down to almost half of the value. In this sense, constricted dc plasmas can be sustained at much higher current than in conventional mode operation at a fixed discharge voltage. Phenomenally, several discrete layered-glows are created between an anode glow and a cathode glow. The layers are thin and divided by dark spaces where charged particles can be accelerated. In this high current mode, ion beam current density is about 100 times higher than in conventional mode at the same voltage. It is noteworthy that lower gas pressure is desirable to sustain the layered-glow mode, which is also profitable for ion source in terms of differential pumping. Ion current density exceeds 300 mA/cm(2) at low discharge power of 175 W where ion density of plasma ball is estimated to be over 3.7x10(12) cm(-3). PMID:20192432

Park, Yeong-Shin; Hwang, Y S

2010-02-01

46

Atmospheric sampling glow discharge ionization source  

DOEpatents

An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

McLuckey, S.A.; Glish, G.L.

1989-07-18

47

Atmospheric sampling glow discharge ionization source  

DOEpatents

An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above.

McLuckey, Scott A. (Oak Ridge, TN); Glish, Gary L. (Oak Ridge, TN)

1989-01-01

48

Nail abnormalities  

MedlinePLUS

Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails. ... Infection: Fungus or yeast cause changes in the color, texture, and shape of the nails. Bacterial infection may cause a ...

49

Chromosomal abnormalities  

Microsoft Academic Search

Cytogenetic studies from the peripheral blood of a patient with malignant lymphoma and rhematoid arthritis who was treated with intra-articular gold Au 198 revealed mosaicism with a normal female metaphase and a 43-chromosome metaphase. The abnormal cell line showed six missing normal chromosomes and three morphologically abnormal chromosomes. The trypsin-digested G-banding metaphases showed that the marker chromosomes were an isochromosome

K. Goh; R. F. Jacox; F. W. Anderson

1980-01-01

50

Is the negative glow plasma of a direct current glow discharge negatively charged?  

NASA Astrophysics Data System (ADS)

A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculation of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge.

Bogdanov, E. A.; Demidov, V. I.; Kudryavtsev, A. A.; Saifutdinov, A. I.

2015-02-01

51

Chromosomal abnormalities  

SciTech Connect

Cytogenetic studies from the peripheral blood of a patient with malignant lymphoma and rhematoid arthritis who was treated with intra-articular gold Au 198 revealed mosaicism with a normal female metaphase and a 43-chromosome metaphase. The abnormal cell line showed six missing normal chromosomes and three morphologically abnormal chromosomes. The trypsin-digested G-banding metaphases showed that the marker chromosomes were an isochromosome of the long arm of chromosome 17, a translocated chromosome that involved the long arm of chromosome 4 and a chromosome 16, and a translocated chromosome that involved the long arm of chromosome 4 and a chromosome 5. It is tempting to conclude that these abnormalities were due to the gold Au 198 treatment, but we cannot exclude other possibilities.

Goh, K.; Jacox, R.F.; Anderson, F.W.

1980-09-01

52

Probiotic Bacteria Induce a ‘Glow of Health’  

E-print Network

Radiant skin and hair are universally recognized as indications of good health. However, this ‘glow of health’ display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary ...

Levkovich, Tatiana

53

Glow discharge plasma deposition of thin films  

DOEpatents

A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

Weakliem, Herbert A. (Pennington, NJ); Vossen, Jr., John L. (Bridgewater, NJ)

1984-05-29

54

Mass dependency of turbulent parameters in stationary glow discharge plasmas  

SciTech Connect

A direct current glow discharge tube is used to determine how mass changes the effects of certain turbulence characteristics in a weakly ionized gas. Helium, neon, argon, and krypton plasmas were created, and an axial magnetic field, varied from 0.0 to 550.0 Gauss, was used to enhance mass dependent properties of turbulence. From the power spectra of light emission variations associated with velocity fluctuations, determination of mass dependency on turbulent characteristic unstable modes, energy associated with turbulence, and the rate at which energy is transferred from scale to scale are measured. The magnetic field strength is found to be too weak to overcome particle diffusion to the walls to affect the turbulence in all four types of plasmas, though mass dependency is still detected. Though the total energy and the rate at which the energy moves between scales are mass invariant, the amplitude of the instability modes that characterize each plasma are dependent on mass.

Titus, J. B.; Alexander, A. B. [Florida A and M University, Tallahassee, Florida 32310 (United States)] [Florida A and M University, Tallahassee, Florida 32310 (United States); Wiggins, D. L. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53703 (United States)] [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53703 (United States); Johnson, J. A. III [Pyramid Plasmas LLC, Lawrenceville, Georgia 30043 (United States)] [Pyramid Plasmas LLC, Lawrenceville, Georgia 30043 (United States)

2013-05-15

55

Io Glowing in the Dark  

NASA Technical Reports Server (NTRS)

Volcanic hot spots and auroral emissions glow on the darkside of Jupiter's moon Io in the image at left. The image was taken by the camera onboard NASA's Galileo spacecraft on 29 June, 1996 UT while Io was in Jupiter's shadow. It is the best and highest-resolution image ever acquired of hot spots or auroral features on Io. The mosaic at right of 1979 Voyager images is shown with an identical scale and projection to identify the locations of the hot spots seen in the Galileo image. The grid marks are at 30 degree intervals of latitude and longitude. North is to the top.

In the nighttime Galileo image, small red ovals and perhaps some small green areas are from volcanic hot spots with temperatures of more than about 700 kelvin (about 1000 degrees Fahrenheit). Greenish areas seen near the limb, or edge of the moon, are probably the result of auroral or airglow emissions of neutral oxygen or sulfur atoms in volcanic plumes and in Io's patchy atmosphere. The image was taken from a range of 1,035,000 kilometers (about 643,000 miles).

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

1996-01-01

56

Saddle-field glow-discharge deposition of amorphous semiconductors  

SciTech Connect

The authors present a dc saddle-field glow-discharge deposition procedure which combines the positive attributes of the conventional dc and rf glow-discharge techniques. Preliminary mass spectra analyses of both silane and methane glow-discharges demonstrates that ions constitute a significant fraction of the species reaching the film surface. Growth rate analyses suggest that ions play a significant role in the saddle-field glow-discharge deposition of amorphous semiconducting films.

Gaspari, F.; Sidhu, L.S.; O`Leary, S.K.; Zukotynski, S. [Univ. of Toronto, Ontario (Canada). Dept. of Electrical and Computer Engineering

1996-12-31

57

The glow discharge as an atomization and ionization device  

SciTech Connect

All of our projects involve the glow discharge source as our basic research focus. Our primary effort is glow discharge mass spectrometry, but we frequently use complementary procedures such as atomic absorption and atomic emission in the glow discharge to obtain useful information about plasma processes. Our overall goal is to gain a better understanding of the glow discharge and to bring it to bear on real analytical problems.

Harrison, W.W.

1990-01-01

58

Normal glow discharge in axial magnetic field  

NASA Astrophysics Data System (ADS)

Theory and results of mathematical modeling of a glow discharge in a parallel-plate configuration with axial magnetic field is presented. The model consists of continuity equations for electron and ion fluids, the Poisson equation for the self-consistent electric field. Numerical simulation results are presented for two-dimensional glow discharge at various initial conditions. The results are obtained for molecular nitrogen at pressure 1–5 Torr, emf of power supply 1–2 kV, and magnetic field induction B = 0–0.5 T. It is shown that in the presence of the axial magnetic field the glow discharge is rotated around its axis of symmetry. Nevertheless it is shown that in the investigated range of discharge parameters in an axial magnetic field the law of the normal current density is retained.

Surzhikov, S.; Shang, J.

2014-10-01

59

Characterization of a Direct-Current Glow Discharge Plasma Actuator in Low-Pressure Supersonic Flow  

Microsoft Academic Search

DOI: 10.2514\\/1.27197 An experimental study of a direct-current, nonequilibrium glow plasma discharge in the presence of a Mach 2.85 supersonic flow is presented. The discharge is generated with pinlike electrodes flush-mounted on a plane surface with sustaining currents between 25 to 300 mA. In the presence of a supersonic flow, two distinct discharge modes (diffuse and constricted) are observed depending

Jichul Shin; V. Narayanaswamy; Laxminarayan L. Raja; Noel T. Clemens

2007-01-01

60

On the accuracy and limitations of fluid models of the cathode region of dc glow discharges  

NASA Astrophysics Data System (ADS)

This paper compares the performance and limitations of different models of the cathode region of cold-cathode low-pressure dc glow discharges: (i) we review known modelling approaches, (ii) develop our own simulation codes based on these approaches, (iii) perform calculations using these codes for reference sets of discharge conditions, which allows a critical comparison of the models and (iv) for a further check of the simulation results we carry out Langmuir probe measurements of electron densities in abnormal Ar glow discharges. The theoretical approaches include fluid models both neglecting and including the electron energy balance equation, as well as hybrid models, which combine the fluid treatment of slow plasma species with the kinetic simulation of fast electrons. We also test the effect of the choice of the ionization source term in fluid models. We find that the electron densities calculated from the fluid models are far (several orders of magnitude) below the experimental values even if the electron energy equation is considered in the calculations. This weakness of fluid models clearly points out the importance of an accurate calculation of the ionization source term, which can only be accomplished by a kinetic approach under the conditions of highly nonlocal electron transport in the cathode region of glow discharges. In hybrid models Monte Carlo simulation is used for this purpose, and indeed, this approach gives electron densities comparable to our experimental data.

Derzsi, A.; Hartmann, P.; Korolov, I.; Karácsony, J.; Bánó, G.; Donkó, Z.

2009-11-01

61

Specific features of radiation from a negative air corona operating in the Trichel-pulse mode  

Microsoft Academic Search

Experimental studies of spatiotemporal characteristics of radiation from a negative corona operating in the Trichel-pulse\\u000a mode in the point-to-sphere electrode geometry have revealed two emission zones. In addition to the well-known glow near the\\u000a point electrode, there is also an anode glow, whose intensity depends substantially on the shape of the anode. It is found\\u000a that the anode glow is

V. I. Karas; V. I. Golota; O. V. Bolotov; B. B. Kadolin; D. V. Kudin

2008-01-01

62

NASA CONNECT: 'Glow with the Flow'  

NASA Technical Reports Server (NTRS)

'Geometry and Algebra: Glow with the Flow' is the second of five programs in the 2000-2001 NASA CONNECT series. Produced by NASA Langley Research Center's Office of Education, NASA CONNECT is an award-winning series of instructional programs designed to enhance the teaching of math, science and technology in grades 5-8. NASA CONNECT establishes teh 'connection' between the mathematics, science, and tehcnology concepts taught in the classroom and NASA research. NASA CONNECT is FREE and the programs in the series are in the public domain. Visit our web site adn register http://connect.larc.nasa.gov In 'Geometry and Algebra: Glow with the Flow', students will learn about the force of drag and how NASA engineers use models and glowing paints to see how air flows over vehicles in a wind tunnel. Students will also discover how the blended wing body(BWB), a concept super jumbo jet that resembles a flying wing, will affect air travelers of the future. Students will observe NASA engineers using geometry and algebra when they measure and design models to be tested in wind tunnels. By conducting classroom and on-line activities, students will make connections between NASA research and the mathematics, science and technology they learn in their classroom.

1999-01-01

63

Skeletal limb abnormalities  

MedlinePLUS

Skeletal limb abnormalities may be due to: Cancer Genetic diseases and chromosomal abnormalities, including Marfan syndrome , Down syndrome, Apert syndrome , Basal cell nevus syndrome Improper position ...

64

Glowing Connection Experiments with Alternating Currents below 1 Arms  

Microsoft Academic Search

It was experimentally proven that a glowing connection can develop in an electrical switch at a terminal connection comprising of a connector that utilizes a spring action against a conductor to provide electrical contact in household electrical appliances where vibration exists. This can happen at a current flow such as 0.6 Arms at 120 V. Further, the glow can provide

Joe Urbas

2008-01-01

65

Identifying the warm glow effect in contingent valuation  

Microsoft Academic Search

This paper reports the results from a contingent valuation study designed to investigate the influence of warm glow in willingness to pay (WTP) responses. Interindividual differences in warm glow motivation are measured through a factor analysis, performed on a list of attitudinal items. The reported (WTP) measures fail to pass the scope test. Both socioeconomic variables and motivational factor scores

Paulo A. L. D. Nunesa; Erik Schokkaertd

66

The theory of positive glow corona  

NASA Astrophysics Data System (ADS)

A theory for the current and light pulses of positive glow corona from a point in air is presented; this phenomenon was first observed as an apparently continuous glow by Michael Faraday. Results are obtained, in concentric sphere geometry, for air at atmospheric pressure, by solving the continuity equations for electrons, positive ions, negative ions and metastable oxygen molecules, coupled with Poisson's equation. A series of `saw-toothed' current pulses of period about 0022-3727/30/22/008/img1 is predicted with a DC current level. Accompanying the current peaks are discrete pulses of light 30 ns wide. Successive `shells' of positive ions, from successive current pulses, carry 96% of the mean current. The mean current - voltage relationship has the classic square-law form. The seed electrons required for successive pulses are detached from negative ions by metastable oxygen molecules. Photo-ionization is crucial for the discharge at the anode and for the formation of negative ions throughout the gap. The pulse frequency varies with applied voltage and is found to be approximately proportional to the positive-ion mobility. The surface electric field at the central electrode remains close to Peek's onset field. The origin of onset streamers is explained and sub-microsecond voltage pulses are found to produce streamers. The results for concentric-cylinder electrodes are described briefly.

Morrow, R.

1997-11-01

67

Glow discharge based device for solving mazes  

SciTech Connect

A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center ? All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center ? All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

2014-09-15

68

Acting green elicits a literal warm glow  

NASA Astrophysics Data System (ADS)

Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

2015-01-01

69

Abnormal Uterine Bleeding  

MedlinePLUS

... abnormal uterine bleeding is caused by a hormone imbalance. When hormones are the problem, doctors call the ... bleeding, or DUB. Abnormal bleeding caused by hormone imbalance is more common in teenagers or in women ...

70

Abnormal Head Position  

MedlinePLUS

... cause. Can a longstanding head turn lead to any permanent problems? Yes, a significant abnormal head posture could cause permanent ... occipitocervical synostosis and unilateral hearing loss. Are there any ... postures? Yes. Abnormal head postures can usually be improved depending ...

71

Space vehicle glow measurements on STS 41-D  

NASA Technical Reports Server (NTRS)

A flight experiment using a hand-held, image-intensified spectrographic camera was performed on mission 41-D. The instrument enabled the photographic documentation of the position of the spectral slit on the image to be subjected to spectrographic analysis. Because of this instrument feature, the spectrum of the glow on the Shuttle tail pod could be clearly separated from spectrum of the scattered light from the Orbiter. From the measurements it is clear that the spectrum of the glow is a continuum in the passband of the instrument between 4200 A and 8000 A. The measured spectral resolution of the instrument was 35 A. The scattered light from the Orbiter surfaces distinctly show the components of the earth's airglow at 5577 A and 7620 A. On the same flight material samples were also carried by the Orbiter attached to the Remote Manipulating System arm. These samples were representative of the material overcoatings used on the space telescope. The altitude of the 41-D flight was 290 km, instead of the 220 km which was originally planned for this experiment. The signal to noise ratio in the material glow discrimination experiment was quite low. This made it difficult to draw strong conclusions regarding the glow propensity of the materials. Nevertheless it was clear that polyethylene produces a very weak glow, while most black overcoating materials produce significant glow. MgF2 was also found to produce a relatively intense glow.

Mende, S. B.; Swenson, G. R.; Clifton, K. S.; Gause, R.; Leger, L.; Garriott, O. K.

1985-01-01

72

Electron assisted glow discharges for conditioning fusion tokamak devices  

SciTech Connect

Glow discharge conditioning of tokamaks with graphite plasma-facing surfaces has been used to reduce impurities and obtain density control of the plasma discharge. However, a major operational disadvantage of glow conditioning is the high pressure required to initiate the glow discharge, e.g., {approx}70 mTorr for helium in DIII-D, which requires isolating auxiliary components that can not tolerate the high pressure. An electron-gun-assisted glow discharge can lower breakdown pressure, possibly eliminating the necessity of isolating these auxiliary systems during glow discharge conditioning and allowing glow discharge operation at lower pressures. An electron-assisted glow discharge experiment has been carried out in a small vacuum vessel to evaluate whether such a system can be employed in the DIII-D tokamak. With an electron gun to produce an initial source of electrons, the pressure at which a helium glow discharge can be initiated has been decreased by two orders of magnitude. The glow was produced in a 0.40 m{sup 3} Inconel test chamber (3.5 m{sup 2} surface area) and was pumped with a 330 l/s turbomolecular pump. The electron gun consists of a tungsten filament and grid assembly. An electron current of up to 18 mA with energies up to 1.6 kV has been used. The pressure is measured with a capacitance manometer, the gas composition with a residual gas analyzer and the electron temperature, density, and plasma floating potential with a Langmuir probe. With the addition of an electron current of 10 mA, the initiation pressure was reduced from 165 to 1.6 mTorr. The lowest sustaining pressure dropped from 3.0 mTorr in the absence of electron assist to 1.5 mTorr with 10 mA of electron current.

Schaubel, K.M.; Jackson, G.L. (General Atomics, San Diego, CA (USA))

1990-05-01

73

Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials  

NASA Astrophysics Data System (ADS)

Atmospheric pressure glow discharge plasma was used to modify spaceport materials to render them compliant with KSC ESD standards. The plasma treatment both inhibited and enhanced the recovery of adhered bacteria depending upon the material.

Trigwell, S.; Schuerger, A. C.; Buhler, C. R.; Calle, C. I.

2006-03-01

74

Vehicle/Atmosphere Interaction Glows: Far Ultraviolet, Visible, and Infrared  

NASA Technical Reports Server (NTRS)

Spacecraft glow information has been gathered from a number of spacecraft including Atmospheric and Dynamic satellites, and Space Shuttles (numerous flights) with dedicated pallet flow observations on STS-39 (DOD) and STS-62 (NASA). In addition, a larger number of laboratory experiments with low energy oxygen beam studies have made important contributions to glow understanding. The following report provides information on three engineering models developed for spacecraft glow including the far ultraviolet to ultraviolet (1400-4000 A), and infrared (0.9-40 microns) spectral regions. The models include effects resulting from atmospheric density/altitude, spacecraft temperature, spacecraft material, and ram angle. Glow brightness would be predicted as a function of distance from surfaces for all wavelengths.

Swenson, G.

1999-01-01

75

Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials  

Microsoft Academic Search

Atmospheric pressure glow discharge plasma was used to modify spaceport materials to render them compliant with KSC ESD standards. The plasma treatment both inhibited and enhanced the recovery of adhered bacteria depending upon the material.

S. Trigwell; A. C. Schuerger; C. R. Buhler; C. I. Calle

2006-01-01

76

Glow discharge techniques for conditioning high vacuum systems  

SciTech Connect

A review is given of glow discharge techniques which are useful for conditioning vacuum vessels for high vacuum applications. Substantial development of glow discharge techniques has been done for the purpose of in-situ conditioning of the large ultrahigh vacuum systems for particle accelerators and magnetic fusion devices. In these applications the glow discharge treatments remove impurities from vessel surfaces in order to minimize particle-induced desorption coefficients. Cleaning mechanisms involve a mixture of sputtering and ion- (or neutral) induced desorption effects depending on the gas mixture (ArO/sub 2/ vs. H/sub 2/) and excitation method (DC, RF, and ECR). The author will review the methodology of glow discharge conditioning, diagnostic measurements provided by residual gas and surface composition analysis, and applications to vessel conditioning and materials processing. 76 refs., 16 figs.

Dylla, H.F.

1988-03-01

77

Ram vehicle glow spectrum - Implication of NO2 recombination continuum  

NASA Technical Reports Server (NTRS)

An experiment was operated on several Space Shuttle missions to provide spatial and spectral distributions of a ram glow associated with the Orbiter. The most recent data featured resolved spectrum and imagery of the glow with spectroscopic resolution of 34 A FWHM between 4000 and 8000 A. The spectrum of the glow on the Shuttle tail pod could be clearly separated from spectrum of the reflected light from the Orbiter. Analysis and comparison have been performed which strongly suggest the emission originates from recombination continuum of NO2. Both fast recombination (high temperature) and the spectral dependence in lifetime can describe the spectral difference. If the recombined NO2 retains 25 percent of the kinetic energy of the ram OI, the thickness of the glow layer can be explained by the lifetime of NO2 (2B1) recombination emission.

Swenson, G. R.; Mende, S. B.; Clifton, K. S.

1985-01-01

78

Glow Discharge as a Tool for Surface and Interface Analysis  

Microsoft Academic Search

This review article focuses on the analytical capabilities of glow discharge optical emission spectrometry (GD?OES) and mass spectrometry (GD?MS) to perform compositional depth profiling (GD?CDP). The properties of the Grimm?type glow discharge as well as basic processes of sputtering are described and their influence on the GD as a surface and interface analytical tool are discussed. A series of examples

Thomas Nelis; Jozsef Pallosi

2006-01-01

79

Thermoluminescence glow curve analysis of natural onyx from Turkey.  

PubMed

In this study, the thermoluminesce (TL) properties of natural onyx were determined after ?-irradiation ((90)Sr/(90)Y) at room temperature. The effect of the additive dose and variable heating rate for TL glow peaks of the sample were investigated. Computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters related to the TL glow peaks in natural onyx from Turkey. It was also determined kinetic parameters of onyx by means of the variable heating rate (VHR) method. The sample was exposed to ?-irradiation between 2.4 Gy and 2.457 kGy. The CGCD methods showed that the glow curve of sample is the superposition of at least six first order components which were ascribed as P1-P6. The dose responses of some peaks have similar patterns and they follow linearity. The effect of heating rates on the response of dosimetric glow peaks of sample was studied. The maximum TL peak intensities of glow curve are decreasing with increasing heating rate and maximum TL peak intensities at 1 °C/s drops to 20% of the initial value when the sample is read at 6 °C/s. PMID:25474767

Dogan, Tamer; Toktam??, Hüseyin; Yüksel, Mehmet; Topaksu, Mustafa; Yazici, A Necmeddin

2015-02-01

80

Influence of cathode material on generation of energetic hydrogen atoms in a glow discharge  

SciTech Connect

In this paper influence of cathode material on formation of fast hydrogen atoms in an abnormal glow discharge is investigated using Balmer alpha emission spectroscopy. Energetic H atoms are generated in charge exchange reactions of hydrogen ions that are accelerated in the electric field, and also formed in the backscattering process at the cathode surface. Copper and graphite cathodes were used. Investigation was performed in two orthogonal directions of observation in pure hydrogen and argon-hydrogen mixture. The shapes of the profiles are examined together with the space intensity distribution of Balmer alpha line. Reduced atom reflection from graphite was manifested in the spectroscopic result, in accordance to the field acceleration model. The effect was evident only at high ion energies. This is explained by energy dependence of reflection coefficient for H atoms.

Cvetanovic, N. [Faculty of Transport and Traffic Engineering, University of Belgrade, Vojvode Stepe 305, Belgrade 11000 (Serbia); Obradovic, B. M.; Kuraica, M. M. [Faculty of Physics, University of Belgrade, P.O. Box 368, Belgrade 11000 (Serbia)

2011-01-01

81

Urine - abnormal color  

MedlinePLUS

The usual color of urine is straw-yellow. Abnormally colored urine may be cloudy, dark, or blood-colored. ... Abnormal urine color may be caused by infection, disease, medicines, or food you eat. Cloudy or milky urine is a sign ...

82

Observation of the glow-to-arc transitions  

NASA Astrophysics Data System (ADS)

Researches of the glow-to-arc transitions have been required for a new development of the welding technology in low current. It is important to clarify the characteristics of plasma in the transitions because there have been few reports investigated the transitions in detail. The glow-to-arc transitions were observed in argon at atmospheric pressure. The Th-W electrodes of 1 mm in a diameter are used. Both of the electrodes are needle-shaped and set in a quartz tube coaxially. Plasma is generated between the electrodes with the gap spacing of 1 mm. A DC power supply has been applying constant voltage of 600 V during the discharge. A high-speed camera is used to record the images of plasma in the transitions with the measurement of voltage and current between the electrodes. As a result, two things were confirmed for the behavior of the glow-to-arc transition. First, plasma extended over the cathode surface in the transition from the glow to the arc. Second, temperature in the tip of the cathode would increase gradually during the glow and decrease during the arc.

Watanabe, Shigeru; Saito, Shigeki; Takahashi, Kunio; Onzawa, Tadao

2002-10-01

83

Enhanced Glow Discharge Production of Oxygen  

NASA Technical Reports Server (NTRS)

Studies starting in late seventies have shown Mars atmosphere can be used as a feedstock for oxygen production using simple chemical processing systems during early phases of the Mars exploration program. This approach has been recognized as one of the most important in-situ resource utilization (ISRU) concepts for enabling future round trip Mars missions. It was determined a decade ago that separation of oxygen can be accomplished efficiently by permeation through a silver membrane at temperatures well below 1000 K. This process involves adsorption of atomic oxygen on the surface and its subsequent diffusion through a silver lattice via an oxygen concentration gradient. We have determined recently that glow discharge can be used to liberate atomic oxygen from Mars atmosphere and that the oxygen can be collected through a silver permeation membrane. Recently, we demonstrated a substantial increase in energy efficiency of the process by applying a radio frequency discharge in combination with a silver permeation membrane. The experiments were performed using pure carbon dioxide in the pressure range equal to Mars surface conditions. Energy efficiency was defined as the ratio of the energy required to dissociate a unit mass of oxygen from carbon dioxide to the (electrical) energy consumed by the overall system during the dissociation and collection process. The research effort, started at NASA Langley Research Center, continued with this project. Oxygen production apparatus, built and operated under the research grant NAG1-1140 was relocated to the Atomic Beams Laboratory at ODU in July 1996, being since then in fall operation.

Ash, Robert; Zhong, Shi

1998-01-01

84

Glow plug for an internal combustion engine  

SciTech Connect

A glow plug mounted in a combustion chamber of an internal combustion engine is described which consists of: (1) a heater support member projecting into the combustion chamber of the internal combustion engine, the heater support member being formed of a mixture containing alumina and silicon nitride; (2) a heater member affixed to the surface of the heater support member, the heater member being formed of a mixture containing molybdenum disilicate and silicon nitride, the heater support member and the heater member being integrally sintered; the heater support member being in the form of a rod, and the heater member covering in a U-shaped form the tip end face of the heater support member and the upper and lower face portions of the heater support member contiguous to the end face; (3) first, second and third lead wires for power supply embedded in the heater support member; one end of the first lead wire being connected embeddedly to one end portion of the heater member, one end of the second lead wire being connected embeddedly to the other end portion of the heater member and one end of the third lead wire being connected embeddedly to the central portion of the heater member, thereby forming two heater elements having substantially the same resistance value between the lead wires; (4) a power source; and (5) a power switching means for connecting the power source selectively between the lead wires for power supply according to the state of preheating in the combustion chamber, the power switching means having a switching relay contact for connecting the power source selectively between the third lead wire and the other two lead wires and between the other two lead wires.

Ito, N.; Atsumi, K.; Mizuno, N.; Kikuchi, T.

1986-07-08

85

Tooth - abnormal shape  

MedlinePLUS

... many different conditions. Specific diseases can affect tooth shape, tooth color, time of appearance, or absence of teeth. ... any medical conditions that may cause abnormal tooth shape? At what age ... spacing)? What other symptoms are also present? Fillings, ...

86

Abnormal Uterine Bleeding  

MedlinePLUS

... as cancer of the uterus, cervix, or vagina • Polycystic ovary syndrome How is abnormal bleeding diagnosed? Your health care ... before the fetus can survive outside the uterus. Polycystic Ovary Syndrome: A condition characterized by two of the following ...

87

Contact Glow Discharge Electrolysis in the presence of Organic Waste  

NASA Astrophysics Data System (ADS)

The present experimental study was conducted to analyze the interaction between contact glow discharge electrolysis and biomass. For comparison, two sets of tests were conducted, first in the absence of biomass and second in the presence of biomass. It was observed that when limited electrolyte was present in the liquid, the process of normal electrolysis did not transition to contact glow discharge electrolysis. Addition of biomass to the liquid, increased the overall concentration of electrolyte and the process transitioned to contact glow discharge electrolysis after a critical current density was reached near the electrode with smaller surface area. Further, it was observed that most of the energy was consumed in generating steam instead of performing gasification of biomass.

Sharma, Neeraj; Munoz-Hernandez, Andres; Diaz, Gerardo; Leal-Quiros, Edbertho

2015-03-01

88

Boundary Phenomena in RF and DC Glow Discharge Dusty Plasmas  

NASA Astrophysics Data System (ADS)

In experimental investigations of dusty or complex plasmas, studies have been performed primarily using dc or rf glow discharge plasmas. In spite of the similarity of the experimental parameters produced by each of these plasma generation techniques, the addition of charged microparticles to these plasmas often leads to different phenomena. This paper discusses the similarities and differences in particle transport observed at the boundary between the microparticle clouds and the surrounding plasma. Results will highlight experimental studies performed using two different dc glow discharge dusty plasma experiments - the Auburn Dusty Plasma Experiment (DPX) and the Naval Research Laboratory DUPLEX experiment - and an rf glow discharge dusty plasma experiment - the Plasma-Kristall Experiment (PKE-Nefedov) at Max-Planck-Institut für Extraterrestrische Physik. Sheath-like structures are observed at the particle cloud - plasma interface in all three cases.

Thomas, Edward; Amatucci, William E.; Morfill, Gregor E.

2002-12-01

89

Glow discharge conditioning of the PDX vacuum vessel  

SciTech Connect

A glow discharge technique has been developed and applied to the conditioning of the large (38 m/sup 3/) Poloidal Divertor Experiment (PDX) vacuum vessel. The discharge parameters and working gas (H/sub 2/) were chosen to maximize C and O removal and minimize metal sputtering. The glow discharge was produced by biasing one or two internal anodes at 400 V to sustain a discharge current of 2 to 4 A per anode. Purified H/sub 2/ at a pressure of 3 x 10/sup -2/ torr was flowed through PDX at approx. 10 t-l/s. The effectiveness of the glow discharge conditioning was monitored by measuring impurity gas (CH/sub 4/, C/sub 2/H/sub 4/, and CO) exhaust rates by mass spectrometry and C and O surface removal rates by in-situ AES and XPS.

Dylla, H.F.; Cohen, S.A.; Rossnagel, S.M.; McCracken, G.M.; Staib, P.

1980-03-01

90

High-Energy Radiation from Thunderstorms with ADELE: TGFs, Steps, and Glows  

NASA Technical Reports Server (NTRS)

The biggest challenge in the study of high-energy processes in thunderstorms is getting a detector to the vicinity of the electrically active regions of a storm. The Airborne Detector for Energetic Lightning Emissions (ADELE) has been used to detect gamma rays from aircraft above storms and from a storm-chasing van on the ground. In August 2009, ADELE flew above Florida storms in a Gulfstream V jet, detecting the first terrestrial gamma-ray flash (TGF) seen from a plane and continuous glows of high-energy emission above thunderclouds. The presence of these glows suggests that a gradual process of relativistic runaway and feedback may help limit the total amount of charging in thunderstorms, in contrast to the traditional view that only lightning discharges compete with the charging process. The upper limits on TGF emission from intracloud and cloud-to-ground lightning from the ADELE flights demonstrated conclusively that a TGF of the sort seen from space is not associated with most lightning and not necessary to trigger it. In August 2010, observations from a van detected stepped-leader x-ray emission from at least four lightning strikes in ten days of operations. This mode of operation is therefore promising for future observations of the stepping process, although a more varied suite of instrumentation, in particular a flash-distance detector, would be useful. We will report on these results and on future possibilities for ADELE campaigns.

Smith, David M.; Kelley, Nicole; Martinez-McKinney, Forest; Zhang, Zi Yan; Hazelton, Bryna; Grefenstette, Brian; Splitt, Michael; Lazarus, Steven; Ulrich, William; Levine, Steven; Dwyer, Joseph; Schaal, Meagan; Saleh, Ziad; Cramer, Eric; Rassoul, Hamid; Cummer, Steven; Lu, Gaopeng; Shao, Xuan-Min; Ho, Cheng; Blakeslee, Richard

2011-01-01

91

Influences of impedance matching network on pulse-modulated radio frequency atmospheric pressure glow discharges  

NASA Astrophysics Data System (ADS)

Pulse-modulated RF atmospheric pressure glow discharges (APDGs) were investigated in recent years to reduce the thermal accumulation and extend the operation region of the stable alpha glow mode. Different pulse-modulated voltage and current waveforms were acquired in previous experiments, but no attention was paid to the interpretation. We investigated this issue and associated phenomenon via positive and negative feedback effects derived from varying the series capacitor in the inversely L-shaped matching network used in our pulse-modulated RF APGD source. The evolutions of pulse-modulated RF waveforms were found to be associated with the feedback region and the pulsed plasma absorbed RF power. In the positive feedback region, pulse-modulated RF APGDs are relatively stable. In the negative feedback region, wide spikes as well as undershoots occur in RF voltage and current waveforms and the plasma absorbed RF power. In case of a high RF power discharge with a low modulation frequency, the pulse-modulated RF APGD is extinguished and re-ignited due to the enhanced undershoot during the initial pulse phase. The pulse-modulated RF APGD can transit from positive to negative feedback region in a range of series capacitance. Experimental results are discussed by the aid of equivalent circuit, negative and positive feedback effects.

Huo, W. G.; Xu, K.; Sun, B.; Ding, Z. F.

2012-08-01

92

Investigation of helium ion production in constricted direct current plasma ion source with layered-glows  

SciTech Connect

Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He{sup 2+} by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm{sup 2} and power density of 0.52 mA/cm{sup 2}/W. He{sup 2+} ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He{sup 2+} ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He{sup 2+} ions with the layered-glow DC discharge.

Lee, Yuna [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Yeong-Shin [Samsumg Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of)] [Samsumg Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2014-02-15

93

Influences of impedance matching network on pulse-modulated radio frequency atmospheric pressure glow discharges  

SciTech Connect

Pulse-modulated RF atmospheric pressure glow discharges (APDGs) were investigated in recent years to reduce the thermal accumulation and extend the operation region of the stable alpha glow mode. Different pulse-modulated voltage and current waveforms were acquired in previous experiments, but no attention was paid to the interpretation. We investigated this issue and associated phenomenon via positive and negative feedback effects derived from varying the series capacitor in the inversely L-shaped matching network used in our pulse-modulated RF APGD source. The evolutions of pulse-modulated RF waveforms were found to be associated with the feedback region and the pulsed plasma absorbed RF power. In the positive feedback region, pulse-modulated RF APGDs are relatively stable. In the negative feedback region, wide spikes as well as undershoots occur in RF voltage and current waveforms and the plasma absorbed RF power. In case of a high RF power discharge with a low modulation frequency, the pulse-modulated RF APGD is extinguished and re-ignited due to the enhanced undershoot during the initial pulse phase. The pulse-modulated RF APGD can transit from positive to negative feedback region in a range of series capacitance. Experimental results are discussed by the aid of equivalent circuit, negative and positive feedback effects.

Huo, W. G. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Xu, K.; Sun, B.; Ding, Z. F. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

2012-08-15

94

Investigation of helium ion production in constricted direct current plasma ion source with layered-glows.  

PubMed

Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He(2+) by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm(2) and power density of 0.52 mA/cm(2)/W. He(2+) ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He(2+) ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He(2+) ions with the layered-glow DC discharge. PMID:24593635

Lee, Yuna; Chung, Kyoung-Jae; Park, Yeong-Shin; Hwang, Y S

2014-02-01

95

Investigation of helium ion production in constricted direct current plasma ion source with layered-glows  

NASA Astrophysics Data System (ADS)

Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He2+ by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm2 and power density of 0.52 mA/cm2/W. He2+ ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He2+ ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He2+ ions with the layered-glow DC discharge.

Lee, Yuna; Chung, Kyoung-Jae; Park, Yeong-Shin; Hwang, Y. S.

2014-02-01

96

Role of trace impurities in large-volume noble gas atmospheric-pressure glow discharges  

E-print Network

Role of trace impurities in large-volume noble gas atmospheric-pressure glow discharges Xiaohui 2002 A computational study of capacitively coupled atmospheric-pressure glow discharges in high atmospheric-pressure glow discharges. © 2002 American Institute of Physics. DOI: 10.1063/1.1497445 Several

Raja, Laxminarayan L.

97

Glow discharge plasma deposited hexauoropropylene lms: surface chemistry and interfacial materials properties  

E-print Network

; accepted 10 November 1998 Abstract Fluoropolymer ®lms prepared by radio frequency glow discharge (RF: Fluoropolymer ®lms; RF-glow discharge; Scanning force microscopy; Electron spectroscopy for chemical analysis 1 reactor conditions. Fluoropolymer coatings produced by RF-glow discharge are attractive for industrial

98

A New Pulsed Glow Discharge Source With Enhanced Ion Extraction for Small Non-Conductive Samples or Atmospheric Sampling  

SciTech Connect

An ionization source designed to efficiently utilize sub-milligram quantities of electrically non-conducting compounds (i.e. oxides) for prolonged periods of mass spectrometric analysis is described. The source is coupled to a quadrupole ion trap mass spectrometer in this report, but could readily be modified for alternative types of mass spectrometers. The coaxial-design glow discharge ion source is unique in that it incorporates a focusing lens behind the discharge surface to steer ions towards the ion sampling plate and thereby improve sensitivity. Non-conducting oxide samples are infused in indium and set in one end of an electrically conductive rod, to which the voltage is applied. Transmission efficiency is sufficient to allow the measurement of isotopes of tungsten from a tungsten rod using glow discharge pulse widths as narrow as 2 {micro}s, which is on the order of single-atom layer sputtering. The sputtering and ionization processes occurring in the discharge produces mainly atomic metal ions, regardless of the chemical form of the metals in the samples. This latter aspect is particularly useful for intended applications involving actinide samples, and allows a minimal amount of sample handling. In a second application, a metal capillary is used in place of the rod to create an atmospheric sampling glow discharge. In this mode, the ion-focusing lens was also found to enhance ion signals arising from volatile vapors entering the discharge from the capillary.

Jackson, Glen P. [Ohio University, Athens; Haire, Richard {Dick} G [ORNL; Duckworth, Douglas {Doug} C [ORNL

2003-04-01

99

The influence of resonance radiation transport on the contraction of a glow discharge in argon  

NASA Astrophysics Data System (ADS)

The role of resonance radiation transport in the contraction of a positive column in an argon glow discharge is studied numerically. The theory is based on the self-consistent solution of the ambipolar diffusion equation for electrons, the diffusion equation for metastable atoms and the Biberman–Holstein equation for resonance atoms. To calculate the ionization and excitation rates, the Boltzmann equation is solved in a local approximation taking into account elastic, inelastic and electron–electron collisions. A solution method for a boundary problem is developed which allows one to obtain a hysteresis of the parameters during a continuous transition from a diffuse mode to a contracted mode through an unstable branch. At small currents there is a diffuse discharge where the role of radiation transport is inessential because the radial distributions of electrons and excited atoms are close to the fundamental modes of the corresponding equations. Under these conditions, the traditional approximation of ‘effective lifetime’ is accurate enough. For a contracted discharge, this approximation is not applicable because the higher diffusion and radiation modes play a notable role and a more strict description of radiation transport is required. It is shown that, when radiation transport is taken into account, the width of a filament in a contracted discharge significantly exceeds that obtained in the traditional ‘effective lifetime’ approximation. The critical current, when the discharge abruptly turns into a contracted mode, is shifted towards higher current values. The results obtained in this paper can also relate to a discharge in other inert gases.

Golubovskii, Yu B.; Maiorov, V. A.

2015-04-01

100

Introduction to plasma glow discharge treatment of dental implants.  

PubMed

As more practitioners are using implants in their practice, more questions have arisen regarding the use of these devices. One very important factor is the type of bone-implant interface obtained. The more inert and stable over time the metal is, the more we can control the overall success of the implant. Plasma glow discharge treatment is an ideal technique to increase the wettability of the metal and to insure a sound bone-implant interface. This article is an introduction to the use of plasma glow discharge treatment on dental implants. PMID:8148429

Linkow, L I; Giauque, F

1993-01-01

101

Degradation of Organics in a Glow Discharge Under Martian Conditions  

NASA Astrophysics Data System (ADS)

We present initial results on the degradation of organic material in a Mars gas glow discharge plasma. The plasma simulates the discharges that are likely to occur in Martian dust storms and may be a factor in the degradation of organic material.

Hintze, P. E.; Buhler, C. R.; Calle, L. M.; Calle, C. I.; Trigwell, S.; Starnes, J. W.; Schuerger, A. C.

2006-03-01

102

Degradation of Organics in a Glow Discharge Under Martian Conditions  

NASA Technical Reports Server (NTRS)

The primary objective of this project is to understand the consequences of glow electrical discharges on the chemistry and biology of Mars. The possibility was raised some time ago that the absence of organic material and carbonaceous matter in the Martian soil samples studied by the VikinG Landers might be due in part to an intrinsic atmospheric mechanism such as glow discharge. The high probability for dust interactions during Martian dust storms and dust devils, combined with the cold, dry climate of Mars most likely results in airborne dust that is highly charged. Such high electrostatic potentials generated during dust storms on Earth are not permitted in the low-pressure CO2 environment on Mars; therefore electrostatic energy released in the form of glow discharges is a highly likely phenomenon. Since glow discharge methods are used for cleaning and sterilizing surfaces throughout industry, the idea that dust in the Martian atmosphere undergoes a cleaning action many times over geologic time scales appears to be a plausible one.

Hintze, P. E.; Calle, L. M.; Calle, C. I.; Buhler, C. R.; Trigwell, S.; Starnes, J. W.; Schuerger, A. C.

2006-01-01

103

Nanosecond pulsed atmospheric glow discharges without dielectric barriers  

Microsoft Academic Search

Summary form only given. Pulsed excitation is widely believed to offer an additional option in the quest to achieve superior performance of atmospheric pressure glow discharges (APGD), compared to the mainstream sinusoidally excited APGD. For example, very large applied voltage can be used over very short period of time to produce abundant and highly energetic electrons. Yet inherently pulsed excitation

J. L. Walsh; J. J. Shi; M. G. Kong

2006-01-01

104

SkyGlowNet as a Vehicle for STEM Education  

NASA Astrophysics Data System (ADS)

SkyGlowNet is an emerging network of internet-enabled sky brightness meters (iSBM) that continuously record and log sky brightness at the zenith of each network node site. Also logged are time and weather information. These data are polled at a user-defined frequency, typically about every 45 seconds. The data are uploaded to the SkyGlowNet website, initially to a proprietary area where the data for each institution are embargoed for one or two semesters as students conduct research projects with their data. When released from embargo, the data are moved to another area where they can be accessed by all SkyGlowNet participants. Some of the data are periodically released to a public area on the website. In this presentation we describe the data formats and provide examples of both data content and the structure of the website. Early data from two nodes in the SkyGlowNet have been characterized, both quantitatively and qualitatively, by undergraduate students at NCAT. A summary of their work is presented here. These analyses are of utility in helping those new to looking at these data to understand how to interpret them. In particular, we demonstrate differences between effects on light at night and sky brightness due to astronomical cycles, atmospheric phenomena, and artificial lighting. Quantitative characterization of the data includes statistical analyses of parsed segments of the temporal data stream. An attempt is made to relate statistical metrics to specific types of phenomena.

Flurchick, K. M.; Craine, E. R.; Culver, R. B.; Deal, S.; Foster, C.

2013-06-01

105

Immobilization of proteins on glow discharge treated polymers  

NASA Astrophysics Data System (ADS)

Certain glow discharge-treated surfaces have been shown to enhance retention of adsorbed proteins. On the basis of this phenomenon, we have investigated the possibility of immobilizing (a) albumin for developing thromboresistant and non-fouling surfaces, (b) antibodies for immuno-diagnostic assays and (c) enzymes for various biosensors and industrial bioprocesses. Albumin retention was highest on surfaces treated with tetrafluoroethylene (TFE) compared to untreated surfaces or other glow discharge treatments studied. Preadsorption of albumin on TFE-treated surfaces resulted in low fibrinogen adsorption and platelet adhesion. IgG retention was also highest on TFE-treated surfaces. The lower detection limits of both malaria antigen and circulating anodic antigen of the schistosomiasis worm were enhanced following glow discharge treatment of the assay plates with TFE. Both TFE and tetrachloroethylene (TCE) glow discharge treated surfaces showed high retention of adsorbed horseradish peroxidase (HRP). However, the retained specific activity of HRP after adsorption on TCE-treated surfaces was remarkably higher than on TFE-treated surfaces.

Kiaei, D.; Safranj, A.; Chen, J. P.; Johnston, A. B.; Zavala, F.; Deelder, A.; Castelino, J. B.; Markovic, V.; Hoffman, A. S.

106

Metal Mesh Smear Sampling for Glow Discharge Analytical Spectroscopy  

SciTech Connect

Metal mesh smear sampling is being developed and evaluated for use in a number of glow discharge and other optical and mass spectrometric techniques. Sensitive elemental and isotopic analyses thus will be coupled with a convenient sampling scheme similar to one that is common for radiological surveys.

Shaw, R.W.; Barshick, C.M.; Ramsey, J.M.; Smith, D.H.

2000-06-01

107

Glowing Connection Experiments With Alternating Currents Below 1  

Microsoft Academic Search

It was experimentally shown that a glowing connection can develop in an electrical switch at a terminal connection comprised of a connector that utilizes a spring action against a conductor to provide electrical contact in household electrical appliances where vibration exists, and when the connection is loose. This can happen at a current flow such as 0.6 Arms at 120-V.

Joe Urbas

2010-01-01

108

A Microwave Spectrometer with an Internal Glow Discharge  

Microsoft Academic Search

A microwave spectrometer which utilizes the positive column of a dc glow discharge as its sample region has been constructed and operated successfully. This instrument employs free space microwave propagation through a large industrial Pyrex pipe, along with Zeeman modulation, and is intended for the study of transient paramagnetic molecules which are likely to be found in active discharges. This

R. Claude Woods

1973-01-01

109

Double glow plasma surface alloying and plasma nitriding  

Microsoft Academic Search

Based on plasma nitriding technique, Double Glow Plasma Surface Alloying Technology (DG Technique) was developed in 1980. This technique breaks the restriction of traditional plasma nitriding and successfully applies solid alloying elements, such as Ni, Cr, W, Mo, Ti, Al, Nb et al., to realize plasma surface alloying. Numerous experiment results concerning the DG technique have demonstrated that various alloys

Z. Xu; X. Liu; P. Zhang; Y. Zhang; G. Zhang; Z. He

2007-01-01

110

Langmuir-probe measurements of a pulsed and steady-state rf glow-discharge source and of an rf planar-magnetron source  

Microsoft Academic Search

Langmuir-probe measurements were made of a conventional radio-frequency glow-discharge source (in both pulsed and constant-power modes) and of a radio-frequency planar-magnetron source. The rf-driven oscillations of the plasma were neutralized by tuning the probe impedance with an external circuit. The conventional source, with a copper cathode, exhibited temperatures of roughly 2–5 eV and electron densities of 109–1010 cm?3, with the

M. J. Heintz; G. M. Hieftje

1996-01-01

111

Measurements of three-dimensional structures and transport in dc glow discharge dusty plasmas  

NASA Astrophysics Data System (ADS)

Dusty plasmas have recently become the subject of intense experimental and theoretical interest. Much of the recent research emphasis has focused on strong coupling effects and collective modes in dusty plasmas. This investigation focuses on the transport of dust particles within a plasma. Experiments are performed in the Dusty Plasma Experiment (DPX) device. Dust clouds of silica particles are suspended within the anode spots of dc glow discharge argon plasmas with pressures ranging from 90 to 400 mTorr. Through the use of particle image velocimetry (PIV) techniques, direct measurements of the dust particle transport are made. This presentation discusses measurements and numerical reconstructions of three-dimensional dust cloud structures that form in the DPX device. Detailed measurements of two-dimensional velocity profiles and the time evolution of the velocity profiles will be discussed. From these velocity profile measurements, a preliminary description of the three dimensional transport of dust particles will be given.

Thomas, Edward, Jr.; Watson, Michael

1999-11-01

112

Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol  

NASA Astrophysics Data System (ADS)

Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure ?-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images.

Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

2007-06-01

113

Preparation of carbonitride films in the active and afterglow phases of a glow discharge  

SciTech Connect

The formation of carbonitride (C{sub x}N{sub y}) films in the active and afterglow phases of a glow discharge in CH{sub 4}-N{sub 2} mixtures (as well in these mixtures diluted with argon and helium) was studied experimentally. The dependences of the film growth rate on the discharge current and gas pressure are obtained. The composition (the N/C ratio) and IR absorption spectra of the films are determined. Measurements of the absorption spectra made it possible to identify bonds between C and N atoms. A novel method of carbonitride film deposition in the 'double afterglow' mode was proposed. The use of this method appreciably increases the film deposition rate. Possible mechanisms of the formation and destruction of carbonitride films in the active and afterglow phases of the discharge are discussed.

Grigorian, G. M. [St. Petersburg State University (Russian Federation); Kochetov, I. V. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2013-05-15

114

Abnormal Psychology Psychology 280  

E-print Network

1 Abnormal Psychology Psychology 280 1st Summer Session 2013 May 13June 27, 2013 Tuesday" Kalibatseva, M.A. Office: 127B Psychology Building Email: kalibats@msu.edu Phone Psychology PhD program at Michigan State University. I completed my bachelor's dual degree in psychology

Liu, Taosheng

115

Abnormal Cats' Paws  

Microsoft Academic Search

ABNORMITIES in cats' paws occur rather frequently in Massachusetts. They are called mitten cats, and are much in demand because they are considered to be good mousers. The first I ever saw was a male yellow tiger, whose four paws had two extra toes strongly developed. A little stray female kitten which was brought up at my house had two

H. A. Hagen

1887-01-01

116

Abnormal Morphology Within Individuals  

Microsoft Academic Search

Semen from 15 healthy volunteers was assessed for basic semen measures every 2 weeks over a 6-month period to determine the relative stability of these factors. The parameters were: sperm count, semen volume, sperm motility, and normal morphology, along with the type of abnormal morphologic forms. Basic semen measures were generally more stable than the morphologic forms. Using three samples,

MARILYN L. POLAND; KAMRAN S. MOGHISSI; PAUL T. GIBLIN; JOEL W. AGER; JANE M. OLSON

117

Abnormal pressures as hydrodynamic phenomena  

USGS Publications Warehouse

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Neuzil, C.E.

1995-01-01

118

[Congenital foot abnormalities].  

PubMed

The foot may be the site of birth defects. These abnormalities are sometimes suspected prenatally. Final diagnosis depends on clinical examination at birth. These deformations can be simple malpositions: metatarsus adductus, talipes calcaneovalgus and pes supinatus. The prognosis is excellent spontaneously or with a simple orthopedic treatment. Surgery remains outstanding. The use of a pediatric orthopedist will be considered if malposition does not relax after several weeks. Malformations (clubfoot, vertical talus and skew foot) require specialized care early. Clubfoot is characterized by an equine and varus hindfoot, an adducted and supine forefoot, not reducible. Vertical talus combines equine hindfoot and dorsiflexion of the forefoot, which is performed in the midfoot instead of the ankle. Skew foot is suspected when a metatarsus adductus is resistant to conservative treatment. Early treatment is primarily orthopedic at birth. Surgical treatment begins to be considered after walking age. Keep in mind that an abnormality of the foot may be associated with other conditions: malposition with congenital hip, malformations with syndromes, neurological and genetic abnormalities. PMID:25524290

Delpont, M; Lafosse, T; Bachy, M; Mary, P; Alves, A; Vialle, R

2015-03-01

119

San Diego Natural History Museum: Glow: Living Lights  

NSDL National Science Digital Library

The San Diego Natural History Museum (SDNHM) has recently added a downloadable Teacher's Guide to its Web site for Glow: Living Lights -- "the first-ever museum exhibition to explore the phenomenon of bioluminescence." The 48-page Teacher's Guide is loaded with great lesson plans for grades 3-6. The activities may be used without a visit to the actual exhibit, although the Teacher's Guide also includes useful material for those lucky enough to make the trip. Glow: Living Lights "is an excellent platform for a number of scientific disciplines, including chemistry, biology, ecology, and oceanography." In addition to the Teacher's Guide, this Web site provides a fun, general guide to bioluminescence geared toward kids, which includes games, quick facts, a glossary, and related Web links.

120

Sensitive glow discharge ion source for aerosol and gas analysis  

DOEpatents

A high sensitivity glow discharge ion source system for analyzing particles includes an aerodynamic lens having a plurality of constrictions for receiving an aerosol including at least one analyte particle in a carrier gas and focusing the analyte particles into a collimated particle beam. A separator separates the carrier gas from the analyte particle beam, wherein the analyte particle beam or vapors derived from the analyte particle beam are selectively transmitted out of from the separator. A glow discharge ionization source includes a discharge chamber having an entrance orifice for receiving the analyte particle beam or analyte vapors, and a target electrode and discharge electrode therein. An electric field applied between the target electrode and discharge electrode generates an analyte ion stream from the analyte vapors, which is directed out of the discharge chamber through an exit orifice, such as to a mass spectrometer. High analyte sensitivity is obtained by pumping the discharge chamber exclusively through the exit orifice and the entrance orifice.

Reilly, Peter T. A. (Knoxville, TN)

2007-08-14

121

Abnormal human sex chromosome constitutions  

SciTech Connect

Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

NONE

1993-12-31

122

Effect of glow discharge air plasma on grain crops seed  

SciTech Connect

Oat and barley seeds have been exposed to both continuous and pulsed glow discharge plasmas in air to investigate the effects on germination and sprout growth. Statistical analysis was used to evaluate the effect of plasma exposure on the percentage germination and length of sprout growth. A stimulating effect of plasma exposure was found together with a strong dependence on whether continuous or pulsed discharges were used.

Dubinov, A.E.; Lazarenko, E.M.; Selemir, V.D.

2000-02-01

123

Preliminary Note on a Glow in Hydrogen at High Pressure  

Microsoft Academic Search

DURING an experiment in which an attempt was being made to get atomic hydrogen by means of an incandescent tungsten filament in wet hydrogen, a quite unexpected glow was discovered. The apparatus consisted of a three-litre bulb in the bottom of which there was sealed a tungsten filament from a 300-watt electric-light bulb. The pressures varied from 2 cm. to

Joseph Kaplan

1927-01-01

124

The Use of DC Glow Discharges as Undergraduate Educational Tools  

SciTech Connect

Plasmas have a beguiling way of getting students excited and interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. Our device, based on a direct current (DC) glow discharge tube, allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.

Stephanie A. Wissel and Andrew Zwicker, Jerry Ross, and Sophia Gershman

2012-10-09

125

Biological surface modification of titanium surfaces using glow discharge plasma  

Microsoft Academic Search

To improve the biological activity of titanium, by using of glow discharge plasma (GDP), albumin-grafted titanium disk have\\u000a been implemented and carefully studied. Titanium disks were pre-treated with GDP in an environment filled with argon and allylamine\\u000a gas. Glutaraldehyde was used as a cross-linking agent for albumin grafting. Then, the surface of the albumin-grafted titanium\\u000a was examined using scanning electron

Haw-Ming Huang; Sung-Chih Hsieh; Nai-Chia Teng; Sheng-Wei Feng; Ken-Liang Ou; Wei-Jen Chang

2011-01-01

126

Inception of Snapover and Gas Induced Glow Discharges  

NASA Technical Reports Server (NTRS)

Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. The average time constant for sample charging was estimated between 25 and 50 seconds for all samples. It appears that current drops off by approximately a factor of 3 over the charging time of the sample. All samples charged in the forward and reverse bias directions, demonstrated hysteresis. Current jumps were only observed in the forward or positive swept voltage direction. There is large dispersion in tile critical snapover potential when repeating sweeps on any one sample. The current ratio for the first snapover region jumps between 2 and 4.6 times, with a standard deviation less than 1.6. Two of the samples showed even larger current ratios. It is believed the second large snapover region is due to sample outgassing. Under certain preset conditions, namely at the higher neutral gas background pressures, a perceptible blue-green glow was observed around the conductor. The glow is believed to be a result of secondary electrons undergoing collisions with an expelled tenuous cloud of gas, that is outgassed from the sample. Spectroscopic measurements of the glow discharge were made in an attempt to identify specific lines contributing to the observed glow.

Galofaro, J. T.; Vayner, B. V.; Degroot, W. A.; Ferguson, D. C.; Thomson, C. D.; Dennison, J. R.; Davies, R. E.

2000-01-01

127

Analysis of thermoluminescent glow peaks of zoisite under beta irradiations  

SciTech Connect

In this study, the thermoluminescence (TL) properties of natural crystal of zoisite were investigated after beta ({sup 90}Sr) irradiation at room temperature (RT). Zoisite, of chemical formula Ca{sub 2}Al{sub 3}(SiO{sub 4})(Si{sub 2}O{sub 7})O(OH), is found in Minas Gerais State, Brazil as natural mineral of silicate, member of the epidote group. The glow curve of a natural sample submitted to a heat treatment at 600 deg. C is composed of two broad peaks, centered at about 110-130 deg. C and another one at about 205-210 deg. C. A heating rate of 4 deg. C s{sup -1} was used in the temperature range from RT to 300 deg. C. The additive dose, T{sub m}-T{sub STOP} thermal cleaning, initial rise, variable heating rate and computerized glow curve deconvolution methods have shown that the glow curve is a superposition of six peaks at 100, 130, 155, 175, 200 and 230 deg. C. The trapping parameters for the individual peaks have been calculated. The TL dose response of 130 and 200 deg. C peaks has a linear response. Zoisite is a candidate for a TL dosimeter because of its high sensitivity.

Ccallata, Henry Javier; Watanabe, Shigueo [Department of Nuclear Physics, Institute of Physics, University of Sao Paulo, CP: 66.318, Sao Paulo-SP 05315-970 (Brazil)

2010-08-04

128

Glow discharge optical emission of plutonium and plutonium waste  

SciTech Connect

The application of glow discharges to the analysis of nonconducting materials such as glasses and ceramics is of great interest due to the number of advantages afforded by their direct solids capabilities. These types of samples, by their chemical nature, pose difficulties in dissolution for their subsequent analysis by common spectroscopic instrumental methods such as inductively coupled plasma atomic emission (ICP-AES). The ability of the glow discharge to sputter-atomize and excite solid nonconducting materials greatly reduces sample preparation time, cost, and complexity of an analysis. In comparison with x-ray spectroscopies, GD also provides the advantage of a relatively uniform sample atomization rate, resulting in a lowering of matrix effects. In a traditional direct current glow discharge (dc-GD), the material to be analyzed must first be ground and thoroughly mixed with a conductive host matrix and pressed into a solid pellet. Additionally, atmospheric gases which are often trapped in the sample upon pressing can degrade the quality of the plasma and obscure analytical results by reducing sputtering rates and affecting excitation conditions. Internal standardization has been carried out in both atomic absorption and emission dc-GD analyses in order to improve precision and accuracy which are affected by these problems.

Marcus, R.K. [Clemson Univ., SC (United States); Spencer, W.A. [Westinghouse Savannah River Company Savannah River Site, Aiken, SC (United States)

1995-11-09

129

The One Atmosphere Glow Discharge in Air: Phenomenology and Applications  

NASA Astrophysics Data System (ADS)

The existence of an atmospheric pressure RF glow plasma with the characteristics of a classical low pressure DC glow discharge has been experimentally and theoretically demonstrated [1, 2]. At the UTK Plasma Sciences Laboratory, the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) in air has been applied to a wide range of plasma processing applications. The technology is simple, technically attractive, and suitable for online treatment of webs and 3-dimensional workpieces. A parallel plate reactor and a Remote Exposure Reactor (RER) have been developed for direct plasma immersion and remote exposure, respectively. The RER is based on generating active species capable of sterilization and surface treatment in a uniform surface layer of the OAUGDP on planar panels [3], and convecting the active species to a remote chamber where the workpiece is located. A related surface plasma has been developed for indoor air filtration systems. In addition, the surface plasma on flat panels modified the boundary layer in wind tunnel tests to produce electrohydrodynamic (EHD) flow effects that can be used to increase or decrease aerodynamic drag [3]. [1] Massines et al., J. Appl. Phys., Vol. 83, N 6, pp 2950-2957, Mar. 1998. [2] J. R. Roth, "Industrial Plasma Engineering" Vol. I: Principles. Inst. Phys. Pub., Bristol and philadelphia, ISBN 0-7503-0318-2, 1995. [3] Roth et al., AIAA Paper 98-0328, 36th AIAA Meeting, Reno NV, 1998, Jan. 12-15.

Ben Gadri, Rami; Sherman, Daniel M.; Chen, Zhiyu; Karakaya, Fuat; Reece Roth, J.

1999-10-01

130

Neurodevelopmental Abnormalities in ADHD  

PubMed Central

Structural and functional imaging studies in subjects with attention deficit hyperactivity disorder (ADHD) are reviewed with the goal of gleaning information about neurodevelopmental abnormalities characterizing the disorder. Structural imaging studies, particularly those with longitudinal designs, suggest that brain maturation is delayed by a few years in ADHD. However, a maturational delay model alone is incomplete: alternate courses are suggested by differences associated with phenotypic factors, such as symptom remission/persistence and exposure to stimulant treatment. Findings from functional imaging studies point to multiple loci of abnormalities that are not limited to frontal–striatal circuitry, which is important for executive and motivational function, but also include parietal, temporal and motor cortices, and the cerebellum. However, a definitive conclusion about maturational delays or alternate trajectories cannot be drawn from this work as activation patterns are influenced by task-specific factors that may induce variable performance levels and strategies across development. In addition, no studies have implemented cross-sectional or longitudinal designs, without which the developmental origin of differences in activation cannot be inferred. Thus, current task-evoked functional imaging provides information about dynamic or state-dependent differences rather than fixed or trait-related differences. In the future, task-free functional imaging holds promise for revealing neurodevelopmental information that is minimally influenced by performance/strategic differences. Further, studies using longitudinal designs that identify sources of phenotypic heterogeneity in brain maturation and characterize the relationship between brain function and underlying structural properties are needed to provide a comprehensive view of neurodevelopmental abnormalities in ADHD. PMID:21541845

Vaidya, Chandan J.

2012-01-01

131

Specific features of radiation from a negative air corona operating in the Trichel-pulse mode  

SciTech Connect

Experimental studies of spatiotemporal characteristics of radiation from a negative corona operating in the Trichel-pulse mode in the point-to-sphere electrode geometry have revealed two emission zones. In addition to the well-known glow near the point electrode, there is also an anode glow, whose intensity depends substantially on the shape of the anode. It is found that the anode glow is delayed with respect to the beginning of the Trichel pulse by a time that depends on the gap length and gap voltage. The emission spectrum of the anode glow in the wavelength range 300-400 nm is identified as the spectrum of the second positive system of nitrogen (the C{sup 3{Pi}}{sub u}-B{sup 3{Pi}}{sub g} transition).

Karas', V. I.; Golota, V. I.; Bolotov, O. V.; Kadolin, B. B.; Kudin, D. V. [National Academy of Sciences of Ukraine, National Science Center Kharkiv Institute of Physics and Technology (Ukraine)

2008-10-15

132

Specific features of radiation from a negative air corona operating in the Trichel-pulse mode  

NASA Astrophysics Data System (ADS)

Experimental studies of spatiotemporal characteristics of radiation from a negative corona operating in the Trichel-pulse mode in the point-to-sphere electrode geometry have revealed two emission zones. In addition to the well-known glow near the point electrode, there is also an anode glow, whose intensity depends substantially on the shape of the anode. It is found that the anode glow is delayed with respect to the beginning of the Trichel pulse by a time that depends on the gap length and gap voltage. The emission spectrum of the anode glow in the wavelength range 300 400 nm is identified as the spectrum of the second positive system of nitrogen (the C 3? u - B 3? g transition).

Karas', V. I.; Golota, V. I.; Bolotov, O. V.; Kadolin, B. B.; Kudin, D. V.

2008-10-01

133

Spirometric abnormalities among welders  

SciTech Connect

A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. (Industrial Toxicology Research Centre, Lucknow (India))

1991-10-01

134

Epilepsy and chromosomal abnormalities  

PubMed Central

Background Many chromosomal abnormalities are associated with Central Nervous System (CNS) malformations and other neurological alterations, among which seizures and epilepsy. Some of these show a peculiar epileptic and EEG pattern. We describe some epileptic syndromes frequently reported in chromosomal disorders. Methods Detailed clinical assessment, electrophysiological studies, survey of the literature. Results In some of these congenital syndromes the clinical presentation and EEG anomalies seems to be quite typical, in others the manifestations appear aspecific and no strictly linked with the chromosomal imbalance. The onset of seizures is often during the neonatal period of the infancy. Conclusions A better characterization of the electro clinical patterns associated with specific chromosomal aberrations could give us a valuable key in the identification of epilepsy susceptibility of some chromosomal loci, using the new advances in molecular cytogenetics techniques - such as fluorescent in situ hybridization (FISH), subtelomeric analysis and CGH (comparative genomic hybridization) microarray. However further studies are needed to understand the mechanism of epilepsy associated with chromosomal abnormalities. PMID:20438626

2010-01-01

135

Multiple solutions in the theory of dc glow discharges and cathodic part of arc discharges. Application of these solutions to the modeling of cathode spots and patterns: a review  

NASA Astrophysics Data System (ADS)

A new class of stationary solutions in the theory of glow discharges and plasma–cathode interaction in ambient-gas arc discharges has been found over the past 15 years. These solutions exist simultaneously with the solution given in textbooks, which describes a discharge mode with a uniform or smooth distribution of current over the cathode surface, and describes modes with various configurations of cathode spots: normal spots on glow cathodes, patterns of multiple spots recently observed on cathodes of glow microdischarges and spots on arc cathodes. In particular, these solutions show that cathode spots represent a manifestation of self-organization caused by basic mechanisms of the near-cathode space-charge sheath; another illustration of the richness of the gas discharge science. As far as arc cathodes are concerned, the new solutions have proved relevant for industrial applications. This work is dedicated to reviewing the multiple solutions obtained to date, their systematization, and analysis of their properties and physical meaning. The treatment is performed in the context of general trends of self-organization in bistable nonlinear dissipative systems, which allows one to consider glow discharges or arc–cathode interaction within a single physically transparent framework without going into mathematical details and offers a possibility of systematic computation of the multiple solutions. Relevant computational aspects and experimental data are discussed.

Benilov, M. S.

2014-10-01

136

Influence of driving frequency on discharge modes in a dielectric-barrier discharge with multiple current pulses  

SciTech Connect

A one-dimensional self-consistent fluid model was employed to investigate the effect of the driving frequency on the discharge modes in atmospheric-pressure argon discharge with multiple current pulses. The discharge mode was discussed in detail not only at current peaks but also between two adjacent peaks. The simulation results show that different transitions between the Townsend and glow modes during the discharge take place with the driving frequency increased. A complicated transition from the Townsend mode, through glow, Townsend, and glow, and finally back to the Townsend one is found in the discharge with the driving frequency of 8 kHz. There is a tendency of transition from the Townsend to glow mode for the discharge both at the current peaks and troughs with the increasing frequency. The discharge in the half period can all along operate in the glow mode with the driving frequency high enough. This is resulted from the preservation of more electrons in the gas gap and acquisition of more electron energy from the swiftly varying electric field with the increase in driving frequency. Comparison of the spatial and temporal evolutions of the electron density at different driving frequencies indicates that the increment of the driving frequency allows the plasma chemistry to be enhanced. This electrical characteristic is important for the applications, such as surface treatment and biomedical sterilization.

Jiang, Weiman; Tang, Jie; Wang, Yishan; Zhao, Wei [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China)] [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Duan, Yixiang [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China) [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Research Center of Analytical Instrumentation, Sichuan University, Chengdu 610064 (China)

2013-07-15

137

Glow-to-arc transition in plasma-assisted combustion at 100 MPa  

NASA Astrophysics Data System (ADS)

Electric energy can be added to the combustion of solid propellants in a gun in order to augment and to control parts of the internal ballistic cycle of the launch of a projectile. The pressure in the chamber and bore during launch is typically several hundred megapascal and the electric energy must be delivered to the flame at such a pressure level. To increase the understanding of the interaction between a flame and an electrical discharge at elevated pressure, experiments have been performed at 100 MPa in a combustion chamber where electric current has been conducted through the flame of a solid propellant. Pressure, voltage and current have been measured. The measured signals have been analysed and interpreted. The sequence of events has been interpreted as an initial formation of a glow-like discharge in the flame followed by a discharge mode transition to a filamentary arc discharge. The transition is shown to be dependent on the flame conductivity. For the test propellant used (Nzk5230 doped with 5% potassium nitrate), the flame conductivity is calculated to be 0.84 S m?1 and the discharge mode transition is found to occur after a dissipation of 0.2–0.4 kJ, or 11–22 kJ m?1 of electric energy, at an electric power of 0.1–0.5 MW.

Larsson, A.; Andreasson, S.

2015-04-01

138

A rare stapes abnormality.  

PubMed

The aim of this study is to increase awareness of rare presentations, diagnostic difficulties alongside management of conductive hearing loss and ossicular abnormalities. We report the case of a 13-year-old female reporting progressive left-sided hearing loss and high resolution computed tomography was initially reported as normal. Exploratory tympanotomy revealed an absent stapedius tendon and lack of connection between the stapes superstructure and footplate. The footplate was fixed. Stapedotomy and stapes prosthesis insertion resulted in closure of the air-bone gap by 50?dB. A review of world literature was performed using MedLine. Middle ear ossicular discontinuity can result in significant conductive hearing loss. This can be managed effectively with surgery to help restore hearing. However, some patients may not be suitable or decline surgical intervention and can be managed safely conservatively. PMID:25628909

Kanona, Hala; Virk, Jagdeep Singh; Kumar, Gaurav; Chawda, Sanjiv; Khalil, Sherif

2015-01-01

139

A Rare Stapes Abnormality  

PubMed Central

The aim of this study is to increase awareness of rare presentations, diagnostic difficulties alongside management of conductive hearing loss and ossicular abnormalities. We report the case of a 13-year-old female reporting progressive left-sided hearing loss and high resolution computed tomography was initially reported as normal. Exploratory tympanotomy revealed an absent stapedius tendon and lack of connection between the stapes superstructure and footplate. The footplate was fixed. Stapedotomy and stapes prosthesis insertion resulted in closure of the air-bone gap by 50?dB. A review of world literature was performed using MedLine. Middle ear ossicular discontinuity can result in significant conductive hearing loss. This can be managed effectively with surgery to help restore hearing. However, some patients may not be suitable or decline surgical intervention and can be managed safely conservatively. PMID:25628909

Kanona, Hala; Virk, Jagdeep Singh; Kumar, Gaurav; Chawda, Sanjiv; Khalil, Sherif

2015-01-01

140

Eye movement abnormalities.  

PubMed

Generation and control of eye movements requires the participation of the cortex, basal ganglia, cerebellum and brainstem. The signals of this complex neural network finally converge on the ocular motoneurons of the brainstem. Infarct or hemorrhage at any level of the oculomotor system (though more frequent in the brain-stem) may give rise to a broad spectrum of eye movement abnormalities (EMAs). Consequently, neurologists and particularly stroke neurologists are routinely confronted with EMAs, some of which may be overlooked in the acute stroke setting and others that, when recognized, may have a high localizing value. The most complex EMAs are due to midbrain stroke. Horizontal gaze disorders, some of them manifesting unusual patterns, may occur in pontine stroke. Distinct varieties of nystagmus occur in cerebellar and medullary stroke. This review summarizes the most representative EMAs from the supratentorial level to the brainstem. PMID:22377853

Moncayo, Jorge; Bogousslavsky, Julien

2012-01-01

141

Measurement of voltage and current in continuous and pulsed RF and DC glow discharges  

NASA Astrophysics Data System (ADS)

Electrical measurements are an important tool for the characterisation of glow discharges and have proved to be useful for a variety of needs in fundamental studies and as control parameter. Therefore, extensive hardware developments and studies of I-U characteristics in continuous and pulsed, dc and rf modes have been made (Wilken et al. 2007) and will be presented together with new results. In continuous dc mode, the I-U curves are non-linear and may be characterised by a threshold voltage U_0 and saturation current I_max (both cathode material and pressure dependent). On the other hand P-U curves are to a large extent linear and very similar in the continuous rf mode (Hoffmann et al. 1998). The ionic part of time resolved I-U curves of rf discharges however shows almost a linear behaviour and the capacitive component is small. No saturation current exists. This led to the assumption that gas heating is responsible for the non-linearity between U and I in continuous dc discharges. Consistent with this assumption, a dependence of the U-I curves of pulsed discharges on the duty cycle was found. The comparison of the curves with those at low duty cycle (cold) led to a rough estimation of the gas temperature. Owing to the large changes of current in a very short time, the measurement of the electronic part of the U-I curve in rf mode is far more difficult. If conducting samples are analysed, this electronic part contains extra information. For pulsed rf discharges the hysteresis of electronic part increased with decreasing duty cycle (lower gas temperature). In a study of the effect of the addition of small amounts of H_2 to the Ar discharge gas similar changes in the electronic part of the U-I curve were observed whereas the ionic part was identical. Further investigation and cooperation with modelling groups is needed and planned to explain these results.

Hoffmann, V.; Efimova, V. V.; Voronov, M. V.; Smid, P.; Steers, E. B. M.; Eckert, J.

2008-07-01

142

Dynamics of pulse phenomena in helium dielectric-barrier atmospheric-pressure glow discharges  

E-print Network

. A relatively simple zero-dimensional model that treats only the Paschen breakdown mechanism in the dischargeDynamics of pulse phenomena in helium dielectric-barrier atmospheric-pressure glow discharges of pulse phenomena in conventional parallel-plate dielectric-barrier controlled atmospheric-pressure glow

Raja, Laxminarayan L.

143

Method of inducing differential etch rates in glow discharge produced amorphous silicon  

DOEpatents

A method of inducing differential etch rates in glow discharge produced amorphous silicon by heating a portion of the glow discharge produced amorphous silicon to a temperature of about 365.degree. C. higher than the deposition temperature prior to etching. The etch rate of the exposed amorphous silicon is less than the unheated amorphous silicon.

Staebler, David L. (Lawrenceville, NJ); Zanzucchi, Peter J. (Lawrenceville, NJ)

1980-01-01

144

Effect of Glow Discharge Conditions on Structure and Thermal Properties of Polysilazane Thin Films  

Microsoft Academic Search

Polysilazane thin films were prepared by glow discharge polymerization of hexamethylcyclotrisilazane in mixture with various gases: argon, nitrogen, hydrogen and ammonia. The effect of gas type on thermal stability and chemical structure of glow discharge polysilazane was studied. Thermo-gravimetric measurements performed within a temperature range of 20–1000° C, showed that the best thermal stability was exhibited by polysilazane prepared at

A. M. Wróbel; M. Kryszewski

1978-01-01

145

LOX/Methane Main Engine Glow Plug Igniter Tests and Modeling  

NASA Technical Reports Server (NTRS)

Ignition data for tests with a LOX/methane igniter that utilized a glow plug as the ignition source are presented. The tests were conducted in a vacuum can with thermally conditioned (cold) hardware. Data showing the effects of glow plug geometry, type, and igniter operating conditions are discussed. Comparisons between experimental results and multidimensional, transient computer models are also made.

Breisacher, Kevin; Ajmani, Kumud

2009-01-01

146

Electron Trapping by the Electric Field Inversion Mechanism in a dc Glow Discharge  

Microsoft Academic Search

We investigate the existence of the electric field reversal in the negative glow of a dc discharge, its location, the width of the well trapping the electrons, the slow electrons scattering time as well the fraction of ions build up in the glow and returning to cathode. A simple analytical model is presented which includes a Boltzmann transport equations for

Mario J. Pinheiro

2000-01-01

147

Assessing the Warm Glow Effect in Contingent Valuations for Public Libraries  

ERIC Educational Resources Information Center

This article aims to present evidence of the warm glow effect in a public library setting. More specifically, it tests whether individual respondents with different values for the warm glow component report different values for their willingness to pay (WTP). The data come from a contingent valuation survey conducted on randomly selected citizens…

Lee, Soon-Jae; Chung, Hye-Kyung; Jung, Eun-Joo

2010-01-01

148

Persistence of phosphor glow in microchannel plate image intensifiers  

NASA Technical Reports Server (NTRS)

Image intensifier tubes using microchannel plate amplification stages and phosphor output stages are being increasingly used in various detection applications. In this paper, measurements of the decay times of what are attributed to be the P20 phosphors in various image intensifiers are reported. It is found that the long tail on the decay curve of the phosphor following illumination can be a limitation for certain observations. In addition, the background level of phosphor glow (which is seen by the subsequent detection system as a light signal) continues to build with continuing illumination.

Torr, M. R.

1985-01-01

149

Dusty plasma structures in He-Kr DC glow discharge  

SciTech Connect

Ion drift in gas mixtures has certain properties that can be used to generate ion flows with desired characteristics. For example, when the field is strong, ion heating is significant, and there is a large difference in atomic weight between ions and atoms, the ion velocity distribution can be highly anisotropic. Ion distribution anisotropy, in turn, can cause a substantial change in properties of dust structures in plasmas. Experiments on dusty plasma structures in glow discharge in mixtures of light and heavy gases (helium and krypton) are performed, and results of numerical simulations of ion and electron drift in the mixture are presented.

Antipov, S. N., E-mail: antipov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Vasil'ev, M. M., E-mail: mixxy@mail.ru; Maiorov, S. A., E-mail: mayorov_sa@mail.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Petrov, O. F.; Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2011-03-15

150

LANL Transfers Glowing Bio Technology to Sandia Biotech  

ScienceCinema

Partnering with Los Alamos National Laboratory, an Albuquerque-based company is seeking to transform the way protein and peptide analysis is conducted around the world. Sandia Biotech is using a biological technology licensed from Los Alamos called split green fluorescent protein (sGFP), as a detecting and tracking tool for the protein and peptide industry, valuable in the fields of Alzheimer's research, drug development and other biotechnology fields using protein folding to understand protein expression and mechanisms of action. http://www.lanl.gov/news/stories/glowing-future-for-los-alamos-and-sandia-b iotech-partnership.html

Rorick, Kevin

2012-08-02

151

Study of N2/He DC glow discharge  

NASA Astrophysics Data System (ADS)

Optical emission spectroscopy and mass spectrometry measurement were used to study a gas mixture glow discharge of He and N2 at total pressure of 2.0 Torr, a power of 10 W and a flow of 16.5 l/min. The emission bands were measured in the wavelength range of 200 to 1100 nm. The principal species observed were N2+ (B2?+u?X2?+g), N2 (C3?u?B3?g), and He, which agree with mass spectrometry measurement.

Villa, M.; Flores, O.; Castillo, F.; Reyes, P. G.; Martinez, H.

2015-03-01

152

Reproducing continuous radio blackout using glow discharge plasma  

SciTech Connect

A novel plasma generator is described that offers large-scale, continuous, non-magnetized plasma with a 30-cm-diameter hollow structure, which provides a path for an electromagnetic wave. The plasma is excited by a low-pressure glow discharge, with varying electron densities ranging from 10{sup 9} to 2.5 × 10{sup 11} cm{sup ?3}. An electromagnetic wave propagation experiment reproduced a continuous radio blackout in UHF-, L-, and S-bands. The results are consistent with theoretical expectations. The proposed method is suitable in simulating a plasma sheath, and in researching communications, navigation, electromagnetic mitigations, and antenna compensation in plasma sheaths.

Xie, Kai; Li, Xiaoping; Liu, Donglin; Shao, Mingxu [School of Aerospace Science and Technology, Xidian University, Xi'an 710071 (China)] [School of Aerospace Science and Technology, Xidian University, Xi'an 710071 (China); Zhang, Hanlu [School of Communication and Information Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121 (China)] [School of Communication and Information Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121 (China)

2013-10-15

153

Emission and fluorescence-spectroscopic investigation of a glow discharge plasma: Absolute number density of radiative and nonradiative atoms in the negative glow  

Microsoft Academic Search

The excited-state atom densities in the negative glow of a direct-current glow discharge are derived from the spectral-line intensity of radiative atoms and the resonance-fluorescence photon flux of nonradiative atoms. The discharge is operated in a helium-argon gas mixture (molar fraction ratio 91:9; total gas pressure 5 Torr) at a dc current of 0.7-1.2 mA. The observations are made in

Y. Takubo; T. Sato; N. Asaoka; K. Kusaka; T. Akiyama; K. Muroo; M. Yamamoto

2008-01-01

154

Long duration gamma-ray glows observed from the tops of thunderstorms  

NASA Astrophysics Data System (ADS)

The Airborne Detector for Energetic Lightning Emissions (ADELE) observed 12 ?-ray glows from thunderstorms near Montana and Florida during its Summer 2009 campaign. These glows have been observed from both the ground and air but this is the first evidence that they are a common, long duration occurrence at the tops of thunderclouds. Glows could be evidence that continuous relativistic runaway with feedback limits thunderstorm charging in a way that competes with lightning. We compare our observed glows to local lightning activity and find a slight but poor correlation, indicating that lightning and glows measure different aspects of cloud electrification. We have shown for all 11 of our observed glows in Florida that there is always an active cell nearby, but there were also many passes near active cells that had no observed glow. We will examine the meteorological differences between active lightning cells with and without glows. We have found the spectrum to be very hard for each glow, with a large fraction of the counts being above 5 MeV. Using a Monte Carlo simulation of relativistic runaway with positron feedback and a GEANT3 model of the atmosphere and instrument response from within a plane, we will distinguish between two different possibilities for a hard spectrum: an upward relativistic avalanche very deep in the atmosphere, so that most low energy photons have been removed via Compton scattering, and a downward relativistic avalanche between the upper positive and the screening layer, with the bremsstrahlung from the upward positron beam (a side-effect of feedback) producing the glow. If the latter model is correct, it demonstrates that positron feedback is indeed a common process in thunderclouds.

Kelley, N.; Smith, D. M.; Dwyer, J. R.; Hazelton, B. J.; Grefenstette, B. W.; Lowell, A.; Splitt, M. E.; Lazarus, S. M.; Rassoul, H. K.

2011-12-01

155

GCAFIT—A new tool for glow curve analysis in thermoluminescence nanodosimetry  

NASA Astrophysics Data System (ADS)

Glow curve analysis is widely used for dosimetric studies and applications. Therefore, a new computer program, GCAFIT, for deconvoluting first-order kinetics thermoluminescence (TL) glow curves and evaluating the activation energy for each glow peak in the glow curve has been developed using the MATLAB technical computing language. A non-linear function describing a single glow peak is fitted to experimental points using the Levenberg-Marquardt least-square method. The developed GCAFIT software was used to analyze the glow curves of TLD-100, TLD-600, and TLD-700 nanodosimeters. The activation energy E obtained by the developed GCAFIT software was compared with that obtained by the peak shape methods of Grossweiner, Lushchik, and Halperin-Braner. The frequency factor S for each glow peak was also calculated. The standard deviations are discussed in each case and compared with those of other investigators. The results show that GCAFIT is capable of accurately analyzing first-order TL glow curves. Unlike other software programs, the developed GCAFIT software does not require activation energy as an input datum; in contrast, activation energy for each glow peak is given in the output data. The resolution of the experimental glow curve influences the results obtained by the GCAFIT software; as the resolution increases, the results obtained by the GCAFIT software become more accurate. The values of activation energy obtained by the developed GCAFIT software a in good agreement with those obtained by the peak shape methods. The agreement with the Halperin-Braner and Lushchik methods is better than with that of Grossweiner. High E and S values for peak 5 were observed; we believe that these values are not real because peak 5 may in fact consist of two or three unresolved peaks. We therefore treated E and S for peak 5 as an effective activation energy, Eeff, and an effective frequency factor, Seff. The temperature value for peak 5 was also treated as an effective quantity, Tm eff.

Abd El-Hafez, A. I.; Yasin, M. N.; Sadek, A. M.

2011-05-01

156

Interaction of a surface glow discharge with a gas flow  

SciTech Connect

A surface glow discharge in a gas flow is of particular interest as a possible tool for controlling the flow past hypersonic aircrafts. Using a hydrodynamic model of glow discharge, two-dimensional calculations for a kilovolt surface discharge in nitrogen at a pressure of 0.5 Torr are carried out in a stationary gas, as well as in a flow with a velocity of 1000 m/s. The discharge structure and plasma parameters are investigated near a charged electrode. It is shown that the electron energy in a cathode layer reaches 250-300 eV. Discharge is sustained by secondary electron emission. The influence of a high-speed gas flow on the discharge is considered. It is shown that the cathode layer configuration is flow-resistant. The distributions of the electric field and electron energy, as well as the ionization rate profile in the cathode layer, do not change qualitatively under the action of the flow. The basic effect of the flow's influence is a sharp decrease in the region of the quasineutral plasma surrounding the cathode layer due to fast convective transport of ions.

Aleksandrov, A. L., E-mail: a_alex@itam.nsc.ru; Schweigert, I. V. [Russian Academy of Sciences, Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch (Russian Federation)

2010-05-15

157

Dust particle radial confinement in a dc glow discharge.  

PubMed

A self-consistent nonlocal model of the positive column of a dc glow discharge with dust particles is presented. Radial distributions of plasma parameters and the dust component in an axially homogeneous glow discharge are considered. The model is based on the solution of a nonlocal Boltzmann equation for the electron energy distribution function, drift-diffusion equations for ions, and the Poisson equation for a self-consistent electric field. The radial distribution of dust particle density in a dust cloud was fixed as a given steplike function or was chosen according to an equilibrium Boltzmann distribution. The balance of electron and ion production in argon ionization by an electron impact and their losses on the dust particle surface and on the discharge tube walls is taken into account. The interrelation of discharge plasma and the dust cloud is studied in a self-consistent way, and the radial distributions of the discharge plasma and dust particle parameters are obtained. It is shown that the influence of the dust cloud on the discharge plasma has a nonlocal behavior, e.g., density and charge distributions in the dust cloud substantially depend on the plasma parameters outside the dust cloud. As a result of a self-consistent evolution of plasma parameters to equilibrium steady-state conditions, ionization and recombination rates become equal to each other, electron and ion radial fluxes become equal to zero, and the radial component of electric field is expelled from the dust cloud. PMID:23410440

Sukhinin, G I; Fedoseev, A V; Antipov, S N; Petrov, O F; Fortov, V E

2013-01-01

158

On electron bunching and stratification of glow discharges  

SciTech Connect

Plasma stratification and excitation of ionization waves is one of the fundamental problems in gas discharge physics. Significant progress in this field is associated with the name of Lev Tsendin. He advocated the need for the kinetic approach to this problem contrary to the traditional hydrodynamic approach, introduced the idea of electron bunching in spatially periodic electric fields, and developed a theory of kinetic resonances for analysis of moving striations in rare gases. The present paper shows how Tsendin's ideas have been further developed and applied for understanding the nature of the well-known S-, P-, and R-striations observed in glow discharges of inert gases at low pressures and currents. We review numerical solutions of a Fokker-Planck kinetic equation in spatially periodic electric fields under the effects of elastic and inelastic collisions of electrons with atoms. We illustrate the formation of kinetic resonances at specific field periods for different shapes of injected Electron Distribution Functions (EDF). Computer simulations illustrate how self-organization of the EDFs occurs under nonlocal conditions and how Gaussian-like peaks moving along resonance trajectories are formed in a certain range of discharge conditions. The calculated EDFs agree well with the experimentally measured EDFs for the S, P, and R striations in noble gases. We discuss how kinetic resonances affect dispersion characteristics of moving striations and mention some non-linear effects associated with glow discharge stratification. We propose further studies of stratification phenomena combining physical kinetics and non-linear physics.

Golubovskii, Yuri B. [St. Petersburg State University, St. Petersburg 198504 (Russian Federation)] [St. Petersburg State University, St. Petersburg 198504 (Russian Federation); Kolobov, Vladimir I. [CFD Research Corporation, Huntsville, Alabama 35805 (United States)] [CFD Research Corporation, Huntsville, Alabama 35805 (United States); Nekuchaev, Vladimir O. [Ukhta State Technical University, Ukhta 169300 (Russian Federation)] [Ukhta State Technical University, Ukhta 169300 (Russian Federation)

2013-10-15

159

Ozone generation using atmospheric pressure glow discharge in air  

NASA Astrophysics Data System (ADS)

This paper presents results from a study into the generation of ozone by a stable atmospheric glow discharge, using dry air as the feeding gas for ozone generation. The power supply is 50 Hz ac, with the use of a perforated aluminium sheet for the electrodes and soda lime glass as a dielectric layer in a parallel-plate configuration, stabilizing the generation process and enabling ozone to be produced. The stable glow discharge spreads uniformly at a gas breakdown voltage below 4.8 kV and requires only 330 mW discharge power, with a limitation of 3 mm on the maximum gap spacing for the dry air. With the technique providing a high collision rate between the electrons and gas molecules during the discharge process, a high ozone yield is obtained. An analysis of the effect on the production rate of parameters such as the input voltage, gas flow rate and reaction chamber dimensions resulted in a highest efficiency of production of almost 350 g kWh-1 and confirms its potential as an important ozone generation technology.

Buntat, Z.; Smith, I. R.; Razali, N. A. M.

2009-12-01

160

abnormalities in infants and toddlers  

E-print Network

Cerebellar abnormalities in infants and toddlers with Williams syndrome Wendy Jones* PhD, The Salk-mail: jones@crl.ucsd.edu One commonly observed neuroanatomical abnormality in adults with Williams syndrome children with Williams syndrome. Clinical brain MRI was examined in nine young children with Williams

Bellugi, Ursula

161

Chromosomal abnormalities and mental illness  

Microsoft Academic Search

Linkage studies of mental illness have provided suggestive evidence of susceptibility loci over many broad chromosomal regions. Pinpointing causative gene mutations by conventional linkage strategies alone is problematic. The breakpoints of chromosomal abnormalities occurring in patients with mental illness may be more direct pointers to the relevant gene locus. Publications that describe patients where chromosomal abnormalities co-exist with mental illness

D J MacIntyre; D H R Blackwood; D J Porteous; B S Pickard; W J Muir

2003-01-01

162

Students' reactions to abnormal psychology  

Microsoft Academic Search

As a result of some concern about the effect of courses in abnormal psychology on students, a questionnaire was presented to several classes at the close of the course. The majority answering the questionnaire felt the course to be beneficial, giving evidence that the study of abnormal psychology need not be generally harmful, and may have a significant place in

W. S. Taylor

1932-01-01

163

Systemic abnormalities in liver disease  

PubMed Central

Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases. PMID:19554648

Minemura, Masami; Tajiri, Kazuto; Shimizu, Yukihiro

2009-01-01

164

Abnormal pressure in hydrocarbon environments  

USGS Publications Warehouse

Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

Law, B.E.; Spencer, C.W.

1998-01-01

165

On copper diffusion in silicon measured by glow discharge mass spectrometry.  

PubMed

Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ?0.5 ?m over a total sputtered depth of 8-30 ?m. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed. PMID:25146357

Modanese, Chiara; Gaspar, Guilherme; Arnberg, Lars; Di Sabatino, Marisa

2014-11-01

166

Echocardiographic abnormalities following cardiac radiation  

SciTech Connect

Five years or more after receiving cardiac radiation, 41 patients with Hodgkin's disease and seminoma in remission were subjected to echocardiography. The abnormalities detected included pericardial thickening in 70%, thickening of the aortic and/or mitral valves in 28%, right ventricular dilatation or hypokinesis in 39%, and left ventricular dysfunction in 39%. In the 23 patients treated by an upper mantle technique with shielding, the incidence of right ventricular abnormalities and valvular thickening was significantly lower than in patients treated with modified techniques. Although no symptoms were attributable to the observed abnormalities, longer follow-up time may reveal important functional implications.

Perrault, D.J.; Levy, M.; Herman, J.D.; Burns, R.J.; Bar Shlomo, B.Z.; Druck, M.N.; Wu, W.Q.; McLaughlin, P.R.; Gilbert, B.W.

1985-04-01

167

Medium resolution spectra of the shuttle glow in the visible region of the spectrum  

NASA Technical Reports Server (NTRS)

Recent spectral measurements of the visible shuttle glow (lambda = 400 - 800 nm) at medium resolution (1 nm) reveal the same featureless continuum with a maximum near 680 nm that was reported previously. This is also in good agreement with recent laboratory experiments that attribute the glow to the emissions of NO2 formed by the recombination of O + NO. The data that are presented were taken from the aft flight deck with a hand-held spectrograph and from the shuttle bay with a low-light-level television camera. Shuttle glow images and spectra are presented and compared with laboratory data and theory.

Viereck, R. A.; Murad, E.; Pike, C. P.; Mende, S. B.; Swenson, G. R.; Culbertson, F. L.; Springer, B. C.

1992-01-01

168

Flush-mounted probe diagnostics for argon glow discharge plasma.  

PubMed

A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on. PMID:25273724

Xu, Liang; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi; Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang

2014-09-01

169

Flush-mounted probe diagnostics for argon glow discharge plasma  

SciTech Connect

A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on.

Xu, Liang, E-mail: xld02345@mail.ustc.edu.cn; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang [Science and Technology on Space Physics Laboratory, Beijing 100076 (China)

2014-09-15

170

Gain characteristics of CO/sub 2/ supersonic mixing laser with N2 axial glow discharge  

SciTech Connect

An experimental and analytical study of a CO/sub 2/ supersonic mixing laser by N/sub 2/ axial glow discharge is presented. A cluster of supersonic and circular N/sub 2/ channels for axial glow discharge are employed to mix with CO/sub 2/ supersonic flow from conical screen nozzles. Small-signal gain measurement is conducted, together with monitoring discharge characteristics. Vibrationally nonequilibrium analysis of quasi-one-dimensional supersonic flow for the mixing laser is also presented, including N/sub 2/ collisional activation effects by electron impact in the glow discharge. Steady glow discharge in supersonic N/sub 2/ flow is obtained, and measured gain dependency on cavity flow distance, on plenum pressures, and on discharge power density in N/sub 2/ are discussed in comparison with numerically estimated characteristics. 11 references.

Maeno, K.; Hanaoka, Y.; Hirose, M.

1987-06-01

171

Potential industrial applications of the one atmosphere uniform glow discharge plasma operating in ambient air  

SciTech Connect

The majority of industrial plasma processing is conducted with glow discharges at pressures below 10 Torr. This tends to limit such applications to high value workpieces, as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharges would play a much larger industrial role if they could be generated at 1 atm and in air. The one atmosphere uniform glow discharge plasma (OAUGDP registered ) has these capabilities. As a normal glow discharge, the OAUGDP registered can operate with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum. This paper will survey exploratory investigations at the University of Tennessee's Plasma Sciences Laboratory of seven potential industrial applications of the OAUGDP registered which can be conducted at 1 atm and at room temperature with air as the working gas.

Roth, J. Reece [Plasma Sciences Laboratory, Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, Tennessee 37996-2100 (United States)

2005-05-15

172

How Things Work. Mystery Glow-Ball: When Is a Battery Not a Battery?  

ERIC Educational Resources Information Center

Examines the working mechanism of a commercial "Mystery Glow-Ball" by analyzing its electronic circuitry. Finds that the advertising for the ball is wrong; energy actually came from inserting a battery. (YP)

Crane, H. Richard, Ed.

1989-01-01

173

CO^+ and C_2 Spectra Generated by CO_2 Atmospheric Pressure Glow Discharges in Microchannels  

NASA Astrophysics Data System (ADS)

Intense emission in the near-ultraviolet and visible from the Comet Tail and Swan bands of CO^+ and C_2, respectively, has been observed from glow discharges produced in CO_2 at atmospheric pressure. Generated within 200--500 ?m microchannels fabricated in nanoporous alumina, the microchannel plasmas are spatially homogeneous, diffuse glows. As the CO_2 flow rate through the microchannels is varied, the visible/UV spectra change dramatically and the chemical kinetics of this fascinating spectrum will be discussed.

Shin, Chul; Dai, Zhen; Houlahan, Thomas J., Jr.; Park, Sung-Jin; Eden, Gary

2014-06-01

174

Binary and ternary gas mixtures for use in glow discharge closing switches  

DOEpatents

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue of the combined physio-electric properties of the mixture components.

Hunter, Scott R. (Oak Ridge, TN); Christophorou, Loucas G. (Oak Ridge, TN)

1990-01-01

175

The Effects of Lamp Spectral Distribution on Sky Glow over Observatories  

NASA Astrophysics Data System (ADS)

Using a wavelength-generalized version of the Garstang (1991) model, we evaluate overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED lamps. We conclude for both professional, and especially cultural (visual), astronomy, that low-pressure sodium and narrow-spectrum amber LED lamps cause much less sky glow than all broad-spectrum sources.

Luginbuhl, C. B.; Boley, P. A.; Davis, D. R.; Duriscoe, D. M.

2015-03-01

176

[Spatial distribution of electrons with high energy in atmospheric pressure glow discharge excited by DC voltage].  

PubMed

Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6 mm air gap by using a needle-water electrode discharge device. The atompheric pressure glow discharge has characteristic regions such as a cathode fall, a negative glow, a Faraday dark space, a positive column and an anode glow. The discharge is a normal glow through analyzing its voltage-current curve. The emission intensity of 337.1 nm spectral line from the second positive system of N2 was investigated because it can indicate the electron density with high energy. Results show that the maxima of high energy electrons appears in the vicinity of the needle tip, and it almost remains constant at other locations. The density of high energy electrons decreases with increasing the voltage. Similarly, it decreases with increasing the value of the ballast resistor. Oxygen atom is important for the sterilization and disinfection. The distribution of oxygen atom was also investigated by optical emission spectroscopy. It was found that the oxygen distribution is similar with the distribution of high energy electrons. These results are important for the application of atmospheric pressure glow discharge in environmental protection and biological treatment. PMID:24369623

Liu, Zhi-qiang; Jia, Peng-ying; Liu, Tie

2013-09-01

177

Effect of plasma-glow discharge as a sterilization of titanium surfaces.  

PubMed

In this study, in vitro osteoblast responses to glow-discharged, commercially pure titanium (Ti) surfaces were investigated. It was hypothesized that the glow-discharge treatment would be an effective sterilization procedure for Ti implantations before implantation. The Ti surfaces were prepared by grinding to 600 grits followed by cleaning. These were then divided into two groups, with one group being the control and the other group undergoing glow-discharge treatment using oxygen. Human embryonic palatal mesenchyme cells, an osteoblast precursor, were used to evaluate the cell responses to glow-discharged and control Ti surfaces. It was observed from this study that protein production and osteocalcin production on both surfaces exhibited no significant differences during the 10-day study. Similarly, no significant differences were observed for alkaline phosphatase (ALP) specific activity during the first 7 days of incubation. However, at day 10, the ALP specific activity for control Ti surfaces was significantly higher than the ALP activity for the glow-discharged surface. Overall, this study suggested that the use of glow discharge as an alternative sterilization procedure for medical and dental implants did not inhibit osteoblast phenotypic expression. PMID:12704957

Youngblood, T; Ong, J L

2003-01-01

178

Numerical analysis of two homogeneous discharge modes at atmospheric pressure with a self-consistent model  

SciTech Connect

Two homogeneous discharge modes, Townsend discharge and glow discharge, can be obtained in dielectric barrier discharges at atmospheric pressure when an external voltage with an appropriate frequency is applied to the electrodes. In this paper, a one-dimensional self-consistent model was used to investigate the transition and the difference in characteristics of these two modes. The simulation results showed that the spatiotemporal distributions of the electron temperature in the two discharge modes differed noticeably. In the glow discharge, the electron temperature in the cathode fall was several times higher than that in any of the other regions; in contrast, the electron temperature in the Townsend discharge was approximately spatially uniform. The electron energy distribution functions (EEDFs) at different locations in the discharge gap at the discharge current peaks were given and analyzed. In the glow discharge, the EEDF in the cathode fall region contained the largest percentage of high energy in all regions, and the majority of the electrons in the negative glow region possessed very low energy. However in the Townsend discharge, the EEDFs at different locations were similar to each other. In addition, both the discharge current density and the voltage drop on the discharge gas versus the applied voltage were also examined. It was found that when the applied voltage was over a critical value, the Townsend discharge turned into the glow discharge, the peak magnitude of the discharge current density increased abruptly. The maximum of the discharge current density was nearly a linear function of the applied voltage, while the voltage drop on the discharge gas was approximately a constant. Also, we found that there was a minimum of the applied voltage leading to the transition from the Townsend discharge to the glow discharge as the discharge gap spacing varied.

Wang Qi; Sun Jizhong; Wang Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

2009-04-15

179

Complex patterns of abnormal heartbeats  

NASA Technical Reports Server (NTRS)

Individuals having frequent abnormal heartbeats interspersed with normal heartbeats may be at an increased risk of sudden cardiac death. However, mechanistic understanding of such cardiac arrhythmias is limited. We present a visual and qualitative method to display statistical properties of abnormal heartbeats. We introduce dynamical "heartprints" which reveal characteristic patterns in long clinical records encompassing approximately 10(5) heartbeats and may provide information about underlying mechanisms. We test if these dynamics can be reproduced by model simulations in which abnormal heartbeats are generated (i) randomly, (ii) at a fixed time interval following a preceding normal heartbeat, or (iii) by an independent oscillator that may or may not interact with the normal heartbeat. We compare the results of these three models and test their limitations to comprehensively simulate the statistical features of selected clinical records. This work introduces methods that can be used to test mathematical models of arrhythmogenesis and to develop a new understanding of underlying electrophysiologic mechanisms of cardiac arrhythmia.

Schulte-Frohlinde, Verena; Ashkenazy, Yosef; Goldberger, Ary L.; Ivanov, Plamen Ch; Costa, Madalena; Morley-Davies, Adrian; Stanley, H. Eugene; Glass, Leon

2002-01-01

180

Columnar discharge mode between parallel dielectric barrier electrodes in atmospheric pressure helium  

SciTech Connect

Using a fast-gated intensified charge-coupled device, end- and side-view photographs were taken of columnar discharge between parallel dielectric barrier electrodes in atmospheric pressure helium. Based on three-dimensional images generated from end-view photographs, the number of discharge columns increased, whereas the diameter of each column decreased as the applied voltage was increased. Side-view photographs indicate that columnar discharges exhibited a mode transition ranging from Townsend to glow discharges generated by the same discharge physics as atmospheric pressure glow discharge.

Hao, Yanpeng; Zheng, Bin; Liu, Yaoge [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)] [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)

2014-01-15

181

Emergency and Abnormal Situations Project Emergency and Abnormal Situations  

E-print Network

the landing gear came down... #12;10 Emergency and Abnormal Situations Issues · Checklist and Procedure-board fire and when the aircraft ditches, conducts a forced landing, or crashes is 17 minutes. The Swissair 426768 During approach...the gear failed to come down...after notifying the tower we had a `Gear

182

A MODULAR STEADY STATE GLOW DISCHARGE QUADRUPOLE MASS SPECTROMETER SYSTEM FOR THE AT-LINE ANALYSIS OF PLUTONIUM METAL  

SciTech Connect

Historically, glow discharge mass and optical spectrometric techniques have been used in industry for the characterization of processed metals, such as steels and other alloys. This technique is especially well suited for this type of product analysis because the glow discharge ionization source accommodates solid conducting samples with minimal or no sample preparation. This characteristic along with minimal matrix effect considerations makes the glow discharge source well suited for these types of applications.

R. STEINER; D. WAYNE

1998-12-01

183

Influence of the applied voltage shape on the barrier discharge operation modes in helium  

NASA Astrophysics Data System (ADS)

For the investigation of a barrier discharge (BD) operated in helium, a discharge cell configuration was used which allows an electrical characterization and simultaneous measurements of volume processes as well as the interaction of the BD with a dielectric surface. The emission development in the volume has been recorded spatio-temporally and spectrally resolved by the established cross-correlation spectroscopy (CCS) operating in the PPG mode. The phase resolved measurement (over one discharge period) of surface charges deposited on a BSO crystal was realized by the utilization of the electro-optic Pockels effect in combination with a high-speed camera. Depending on the gap distance, the dielectrics, and the shape of feeding voltage, the BD can operate either in the diffuse Townsend-like or glow-like mode. The emission is localized near the anode and cathode for the Townsend-like mode and glow-like mode, respectively. In small gaps (distance about 1 mm), a sinusoidal feeding voltage leads to the unusual Townsend-like mode in helium. But, a square wave voltage shape induces the glow-like mode, probably due to the fast rise and fall time of the applied voltage slopes. A sawtooth voltage generates both discharge modes over one period. The presented results show clearly the correlation of the emission development with electrical measurements, and deposited surface charge and transported charges.

Bogaczyk, Marc; Sretenovi?, Goran B.; Wagner, Hans-Erich

2013-10-01

184

Neurophysiological model of the normal and abnormal human pupil  

NASA Technical Reports Server (NTRS)

Anatomical, experimental, and computer simulation studies were used to determine the structure of the neurophysiological model of the pupil size control system. The computer simulation of this model demonstrates the role played by each of the elements in the neurological pathways influencing the size of the pupil. Simulations of the effect of drugs and common abnormalities in the system help to illustrate the workings of the pathways and processes involved. The simulation program allows the user to select pupil condition (normal or an abnormality), specific site along the neurological pathway (retina, hypothalamus, etc.) drug class input (barbiturate, narcotic, etc.), stimulus/response mode, display mode, stimulus type and input waveform, stimulus or background intensity and frequency, the input and output conditions, and the response at the neuroanatomical site. The model can be used as a teaching aid or as a tool for testing hypotheses regarding the system.

Krenz, W.; Robin, M.; Barez, S.; Stark, L.

1985-01-01

185

Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials  

NASA Technical Reports Server (NTRS)

Numerous materials used in spaceport operations require stringent evaluation before they can be utilized. It is critical for insulative polymeric materials that any surface charge be dissipated as rapidly as possible to avoid Electrostatic Discharges (ESD) that could present a danger. All materials must pass the Kennedy Space Center (KSC) standard electrostatic test [1]; however several materials that are considered favorable for Space Shuttle and International Space Station use have failed. Moreover, to minimize contamination of Mars spacecraft, spacecraft are assembled under cleanroom conditions and specific cleaning and sterilizing procedures are required for all materials. However, surface characteristics of these materials may allow microbes to survive by protecting them from sterilization and cleaning techniques. In this study, an Atmospheric Pressure Glow Discharge Plasma (APGD) [2] was used to modify the surface of several materials. This allowed the materials surface to be modified in terms of hydrophilicity, roughness, and conductivity without affecting the bulk properties. The objectives of this study were to alter the surface properties of polymers for improved electrostatic dissipation characteristics, and to determine whether the consequent surface modification on spaceport materials enhanced or diminished microbial survival.

Trigwell, S.; Shuerger, A. C.; Buhler, C. R.; Calle, C. J.

2006-01-01

186

Two-dimensional modeling of RF methane glow discharge  

SciTech Connect

A self-consistent two-dimensional three moment radio frequency glow discharge simulation is performed for methane gas using a fluid model. The main objective of the simulation is to provide a better insight on charged species dynamics and their effect on deposition for a polyatomic discharge. The model incorporates continuity equations for electron, radicals and ion number densities.An electron energy equation is also solved in the model to obtain electron temperature. The swarm data as a function of electron energy are provided as input data in the fluid model. Poisson`s equation is solved to obtained the self-consistent electric field in the domain. The governing equations are solved using a finite-difference numerical scheme. The convective-diffusion terms are discretized by the exponential scheme. The model predictions are compared to experimental measurements obtained from a reactor in the laboratories. The effects of variation of RF voltage, DC bias voltage, pressure, and reactor geometry (electrode radius, and spacing, reactor radius, etc.) on plasma properties are discussed. The model predictions will lead to a better understanding on various deposition processes that are carried out in PACVD reactors using hydrocarbon feed gases.

Bera, K.; Farouk, B.; Lee, Y.H. [Drexel Univ., Philadelphia, PA (United States)

1996-12-31

187

Radio frequency glow discharge-induced acidification of fluoropolymers.  

PubMed

Fluoropolymer surfaces are unique in view of the fact that they are quite inert, have low surface energies, and possess high thermal stabilities. Attempts to modify fluoropolymer surfaces have met with difficulties in that it is difficult to control the modification to maintain bulk characteristics of the polymer. In a previously described method, the replacement of a small fraction of surface fluorine by acid groups through radio frequency glow discharge created a surface with unexpected reactivity allowing for attachment of proteins in their active states. The present study demonstrates that 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) reacts with the acid groups on fluoropolymer surfaces in a novel reaction not previously described. This reaction yields an excellent leaving group in which a primary amine on proteins can substitute to form a covalent bond between a protein and these surfaces. In an earlier study, we demonstrated that collagen IV could be deposited on a modified PTFE surface using EDC as a linker. Once collagen IV is attached to the surface, it assembles to form a functional stratum resembling collagen IV in native basement membrane. In this study, we show data suggesting that the fluorine to carbon ratio determines the acidity of the fluoropolymer surfaces and how well collagen IV attaches to and assembles on four different fluoropolymer surfaces. PMID:21887736

Krawczyk, Benjamin M; Baltrusaitis, Jonas; Yoder, Colin M; Vargo, Terrence G; Bowden, Ned B; Kader, Khalid N

2011-12-01

188

Xenon doping of glow discharge polymer by ion implantation  

SciTech Connect

We demonstrate controlled doping of a glow discharge polymer by implantation with 500 keV Xe ions at room temperature. The Xe retention exhibits a threshold behavior, with a threshold dose of {approx}2 x 10{sup 14} cm{sup -2}. Doping is accompanied by irradiation-induced changes in the polymer composition, including gradual H loss and a more complex non-monotonic behavior of the O concentration. The matrix composition saturates at C{sub 0.77}H{sub 0.22}O{sub 0.01} for Xe doses above {approx}5 x 10{sup 14} cm{sup -2} and up to the maximum dose studied (5 x 10{sup 15} cm{sup -2}). The retention mechanism is attributed to the modification of the polymer from a chain-like to clustered ring structure. The dopant profile and the elemental composition of the implanted polymer exhibit good stability upon thermal annealing up to 305 deg. C.

Shin, Swanee J.; Kucheyev, Sergei O.; Orme, Christine A.; Hamza, Alex V. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Youngblood, Kelly P.; Nikroo, Abbas; Moreno, Kari A.; Chen, Bryan [General Atomics, San Diego, California 92186 (United States)

2012-05-01

189

Chromosomal abnormalities associated with omphalocele.  

PubMed

Fetuses with omphalocele have an increased risk for chromosomal abnormalities. The risk varies with maternal age, gestational age at diagnosis, association with umbilical cord cysts, complexity of associated anomalies, and the contents of omphalocele. There is considerable evidence that genetics contributes to the etiology of omphalocele. This article provides an overview of chromosomal abnormalities associated with omphalocele and a comprehensive review of associated full aneuploidy such as trisomy 18, trisomy 13, triploidy, trisomy 21, 45,X, 47,XXY, and 47,XXX, partial aneuploidy such as dup (3q), dup (11p), inv (11), dup (1q), del (1q), dup (4q), dup (5p), dup (6q), del (9p), dup (15q), dup(17q), Pallister-Killian syndrome with mosaic tetrasomy 12p and Miller-Dieker lissencephaly syndrome with deletion of 17p13.3, and uniparental disomy (UPD) such as UPD 11 and UPD 14. Omphalocele is a prominent marker for chromosomal abnormalities. Perinatal identification of omphalocele should alert chromosomal abnormalities and familial unbalanced translocations, and prompt thorough cytogenetic investigations and genetic counseling. PMID:17389182

Chen, Chih-Ping

2007-03-01

190

[A boy with nail abnormalities].  

PubMed

A 12-year-old boy consulted the dermatologist for nail abnormalities. Three weeks earlier, he was treated with doxycycline 100 mg BID for 10 days because of erythema chronicum migrans. Following sun exposure, the patient had developed distal onycholysis surrounded by a hyperpigmented zone. He was diagnosed with doxycycline-induced photo-onycholysis. PMID:23838405

Atiq, Nasirah; van Meurs, Tim

2013-01-01

191

Transcriptional abnormalities in Huntington disease  

Microsoft Academic Search

Huntington disease (HD) is caused by a CAG repeat expansion that is translated into an abnormally long polyglutamine (polyQ) tract in the huntingtin protein. The precise mechanisms leading to neurodegeneration in HD have not been fully elucidated, but alterations in gene transcription could well be involved because the activities of several nuclear proteins are compromised by the polyQ mutation. Recent

Katharine L. Sugars; David C. Rubinsztein

2003-01-01

192

Abnormalities of the optic disc  

Microsoft Academic Search

The optic disc represents the anterior end of the optic nerve, the most forward extension of the central nervous system (CNS). The optic disc gives a rare glimpse into the CNS. Hence, diseases of the CNS are often manifested on fundus examination. Abnormalities of the optic disc may reflect eye disease (such as glaucoma), problems in development (as in various

Alfredo A. Sadun; Michelle Y. Wang

2011-01-01

193

Extraction of oxygen from the Mars atmosphere using glow-discharge and permeation techniques  

NASA Technical Reports Server (NTRS)

Oxygen can be extracted from carbon dioxide via thermal dissociation at elevated temperatures. However, temperatures in excess of 1000 K are needed to effect significant levels of dissociation. The experiments reported here have examined the feasibility of using a glow-discharge in low-pressure carbon dioxide to produce increased atomic oxygen yields at lower temperatures (on the order of 800 K). The experiments have shown that when silver membranes are used simultaneously as anodes for the glow discharge and as permeable membranes for oxygen separation, oxygen yields which are comparable to the permeation rates for pure oxygen, can be produced. Since the silver membrane can be employed as the electrode interface between Mars atmosphere and a stabilized-zirconia electrochemical pump, glow-discharge enhancement can be considered as a complementary technology which can be used with the zirconia-based oxygen extraction systems described previously by others. Not only can glow-discharge be used to increase oxygen yields at lowered temperatures, but it can also be considered as a possible way to avoid filtration and compression of Mars atmosphere, since the glow-discharge can be sustained in Mars ambient pressures.

Wu, Dongchuan; Ash, Robert; Outlaw, Ronald

1993-01-01

194

Thermally stimulated luminescence glow curve structure of ?-irradiated CaB4 O7 :Dy.  

PubMed

Thermally stimulated luminescence glow curves of CaB4 O7 :Dy samples after ?-irradiation showed glow peaks at ~335, 530 and 675 K, with a heating rate of 2 K/s. The main peak at 530 K was analyzed using the Tmax -Tstop method and was found to be composed of at least five overlapping glow peaks. A curve-fitting program was used to perform computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4 O7 :Dy at 520 K were evaluated using peak shape (PS) and isothermal luminescence decay (ILD) methods. In addition, the kinetics was determined to be first order (b =1) by applying the additive dose method. The activation energies and frequency factors obtained using PS and ILD methods are calculated to be 0.72 and 0.72 eV and 8.76 × 10(5) and 1.44 × 10(6) /s, respectively. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25428760

Ak?n, Aycan; Ekdal, Elçin; Tuncer Arslanlar, Yasemin; Ayvac?kl?, Mehmet; Karal?, Turgay; Can, Nurdo?an

2014-11-27

195

Practical sensor for nitrogen in direct current glow discharges  

SciTech Connect

This paper presents a method for precise measurement of atomic and molecular nitrogen in an oxygen-nitrogen dc plasma. This is achieved by monitoring the intensities of the atomic nitrogen spectral line at 821.6 nm and the molecular nitrogen bandhead at 337.1 nm, relative to the atomic oxygen spectral line at 844.7 nm. Oxygen is one of the most frequently used gases for surface chemical treatment, including deposition and etching, therefore the ability to measure and control the process and chemical composition of the process is essential. To validate this oxygen actimometry method for N{sub 2}-xO{sub 2} (where x varies from 0 to 1) dc plasmas, threshold tests have been performed with Ar actinometry. The optical measurements have been performed using two methods. The first approach uses a USB2000 fiber optic spectrometer, calibrated with a Gigahertz-Optik BN-0102-1 reference standard source, to record the desired spectral lines. The second approach uses narrow bandwidth optical filters ({approx}0.7-0.07 nm) with central wavelengths of 821.6, 337.1, and 844.69 nm and photodiodes to detect the emission intensity, also calibrated with the same standard source. Optical data are collected for a range of experimental conditions in a flowing glow discharge of N{sub 2}-xO{sub 2} mixture. The maximum dc voltage is 2.2 kV and maximum chamber pressure is 266 Pa. Data from both optical methods are compared and used to interpret the relative atomic and molecular nitrogen concentrations under various operating conditions.

Popovic, D.; Milosavljevic, V.; Daniels, S. [Faculty of Physics, University of Belgrade, P. O. Box 368, Belgrade (Serbia); Faculty of Physics, University of Belgrade, P. O. Box 368, Belgrade (Serbia) and NCPST and School of Physics, Dublin City University, Dublin 9 (Ireland); NCPST and School of Electronic Engineering, Dublin City University, Dublin 9 (Ireland)

2007-11-15

196

Atlas: Cartilage Abnormalities and Scores  

Microsoft Academic Search

\\u000a The following chapter illustrates cartilage abnormalities and provides semiquantitative scores for these lesions. The focus\\u000a of this chapter is on the most frequently used Recht (modified Noyes and Stabler) score [1, 2] and Whole-Organ-MRI-Score (WORMS)\\u000a [3]. These scores have been used in a number of previous studies and have been found helpful in assessing the grade of cartilage\\u000a lesions, in

Hans Liebl; Thomas M. Link

197

JOURNAL OF ELECTRON MICROSCOPYTECHNIQUE 7x29-33 (1987) A Glow Discharge Unit to Render Electron Microscope Grids and  

E-print Network

, and operation of a simple glow discharge unit that can be used to make surfaces such as carbon-coated electron of a conventional high-voltage power supply and a small plastic desiccator for the vacuum chamber make the unit veryJOURNAL OF ELECTRON MICROSCOPYTECHNIQUE 7x29-33 (1987) A Glow Discharge Unit to Render Electron

1987-01-01

198

Effect of Cl2 additions to an argon glow discharge Nancy L. Bassett and Demetre J. Economoua)  

E-print Network

Effect of Cl2 additions to an argon glow discharge Nancy L. Bassett and Demetre J. Economoua-consistent manner. The model was used to study the effect of attaching gas (Cl,) additions to a noble gas (argon) glow discharge. Specifically a 5% C&/95% Ar discharge was compared to a pristine argon discharge

Economou, Demetre J.

199

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches  

DOEpatents

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

Christophorou, Loucas G. (Oak Ridge, TN); Hunter, Scott R. (Oak Ridge, TN)

1990-01-01

200

386 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 28, NO. 2, APRIL 2000 Enhanced Energy Deposition Efficiency of Glow  

E-print Network

Efficiency of Glow Discharge Electron Beams for Metal Surface Treatment Nélida Mingolo, Yanina Cesa, Oscar E discharges for metal surface treatment are investi- gated for two different cathode geometries. A concave- sired treatment. Index Terms--Glow discharge, electron gun, surface treatment. I. INTRODUCTION

Rocca, Jorge J.

201

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches  

DOEpatents

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

Christophorou, L.G.; Hunter, S.R.

1990-06-26

202

Hybrid Arc\\/Glow Microdischarges at Atmospheric Pressure and Their Use in Portable Systems for Liquid and Gas Sensing  

Microsoft Academic Search

This paper reports on DC pulse-powered microdischarges in air at atmospheric pressure and their potential utility in chemical sensing. For electrode gaps of 50-100 mum, microdischarges take the form of a glow discharge, an arc discharge, or a hybrid of the two. Arc microdischarges have high optical intensity but suffer from high background emission. Glow microdischarges have low background emission,

Bhaskar Mitra; Brandon Levey; Yogesh B. Gianchandani

2008-01-01

203

Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower  

NASA Astrophysics Data System (ADS)

The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

Favalli, A.; Furetta, C.; Zaragoza, E. Cruz; Reyes, A.

204

O2 and CO2 glow-discharge-assisted oxygen transport through Ag  

NASA Technical Reports Server (NTRS)

Experiments were conducted to determine whether dissociative adsorption is a possible limitation of the oxygen permeability through Ag, using the upstream glow-discharge dissociation of O2 and CO2 to provide a gas phase source of atomic oxygen. Results suggest that the dissociative adsorption step limits the supply of oxygen atoms to the upstream side of the membrane. When the upstream O2 was replaced by an equal pressure of CO2 in absence of glow discharge, only a small permeation signal was observed; the application of the glow discharge increasded the oxygen transport flux from 3.25 x 10 to the 12th/sq cm per sec to 1.74 x 10 to the 14th/sq cm per sec. It is suggested that this method of separating O2 from a CO2-rich atmosphere may be considered for providing oxygen for the astronauts in a manned expedition to Mars.

Outlaw, R. A.

1990-01-01

205

Tropospheric Wind Measurements Obtained with the Goddard Lidar Observatory for Winds (GLOW): Validation and Performance  

NASA Technical Reports Server (NTRS)

The Goddard Lidar Observatory for Winds (GLOW) is a mobile Doppler lidar system which uses direct detection Doppler lidar techniques to measure wind profiles from the surface into the lower stratosphere. GLOW is intended to be used as a field deployable system for studying atmospheric dynamics and transport and can also serve as a testbed to evaluate candidate technologies developed for use in future spaceborne systems. In September of 2000 GLOW participated in a three week intercomparison experiment at the GroundWinds facility in North Glen, NH. More than 50 hours of line-of-sight wind profile data were obtained in a wide variety of conditions including both day and night operation. Typical clear air lidar wind profiles extended to altitudes of 20 kin with a 1 km vertical resolution and 1 minute averaging. A description of the mobile system is presented along with the examples of lidar wind profiles obtained with the Goddard system during the New Hampshire experiment.

Gentry, Bruce M.; Chen, Huai-Lin; Einaudi, Franco (Technical Monitor)

2001-01-01

206

Tropospheric Wind Measurements Obtained with the Goddard Lidar Observatory for Winds (GLOW): Validation and Performance  

NASA Technical Reports Server (NTRS)

The Goddard Lidar Observatory for Winds (GLOW) is a mobile Doppler lidar system which uses direct detection Doppler lidar techniques to measure wind profiles from the surface into the lower stratosphere. GLOW is intended to be used as a field deployable system for studying atmospheric dynamics and transport and can also serve as a testbed to evaluate candidate technologies developed for use in future spaceborne systems. In September of 2000 GLOW participated in a three week intercomparison experiment at the GroundWinds facility in North Glen, NE. More than 50 hours of line-of-sight wind profile data was obtained in a wide variety of conditions including both day and night operation. Typical clear air lidar wind profiles extended to altitudes of 20 km with a 1 Ian vertical resolution and I minute averaging. A description of the mobile system is presented along with the examples of lidar wind profiles obtained with the Goddard system during the New Hampshire experiment.

Gentry, Bruce M.; Einaudi, Franco (Technical Monitor)

2001-01-01

207

A study of glow-discharge and permeation techniques for extraterrestrial oxygen beneficiation  

NASA Technical Reports Server (NTRS)

Extraction of oxygen from Martian atmosphere and compression of lunar oxygen can utilize stabilized zirconia electrochemical pumps. Silver membranes can be used as electrodes to increase oxygen yield at relatively low temperatures. This study has investigated oxygen permeation through Ag 0.05Zr membranes with glow-discharge assisted disassociation. Data show that the overall process is controlled by bulk diffusion but the slow dissociative adsorption onto the surface limited the overall transport substantially. With glow-discharge assisted dissociation, an order of magnitude increase in oxygen throughput can be produced at relatively low temperatures (450-550C).

Ash, R. L.; Wu, D.; Outlaw, R. A.

1994-01-01

208

Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium  

NASA Astrophysics Data System (ADS)

In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

2014-03-01

209

Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium  

NASA Astrophysics Data System (ADS)

In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

2014-12-01

210

Binary and ternary gas mixtures for use in glow discharge closing switches  

DOEpatents

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

Hunter, S.R.; Christophorou, L.G.

1988-04-27

211

Detrapping of tungsten nanoparticles in a direct-current argon glow discharge  

NASA Astrophysics Data System (ADS)

Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

Couëdel, L.; Kumar K., Kishor; Arnas, C.

2014-12-01

212

Thermoluminescence response and glow curve structure of Sc?TiO? ß-irradiated.  

PubMed

Discandium titanate (Sc2TiO5) powder was synthesized in order to analyze its thermoluminescence (TL) response. The TL glow curve structure shows two peaks: at 453-433 K and at 590-553 K. The TL beta dose-response has a linear behavior over the dose range 50-500 Gy. The T(stop) preheat method shows five glow peaks that were taken into account to calculate the kinetic parameters using the CGCD procedure. TL results support the possible use of Sc2TiO5 as a new phosphor in high ß-dose dosimetry. PMID:24698777

Muñoz, I C; Brown, F; Durán-Muñoz, H; Cruz-Zaragoza, E; Durán-Torres, B; Alvarez-Montaño, V E

2014-08-01

213

Optical and electrical characterization of C3H6O/Ar glow discharge  

NASA Astrophysics Data System (ADS)

A low pressure glow discharge apparatus was used to produce a glow discharge of C3H6O/Ar mixture at a total pressure of 2.0 Torr. The emission spectra were measured in the wavelength range of 200 to 1100 nm. The principal species observed were Ar I, C6H4O, C6H5, CHO, CH3O, CO2, CO, H2O, and H2. The electron temperature and ion density have been measured using a double Langmuir probe, and the electron temperature and ion density were found in the order of 10 eV and 1010 cm-3.

Villalobos, S.; Castillo, F.; Flores, O.; Reyes, P. G.; Martínez, H.

2015-03-01

214

Oscillation modes of direct current microdischarges with parallel-plate geometry  

SciTech Connect

Two different oscillation modes in microdischarge with parallel-plate geometry have been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier transform spectra of relaxation oscillations reveal chaotic behavior of microdischarges. Volt-ampere (V-A) characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge, and normal glow. However, free-running oscillations appear in subnormal glow only.

Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg [Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, 44781 Bochum (Germany); Skoro, Nikola; Maric, Dragana; Petrovic, Zoran Lj [Institute of Physics, University of Belgrade, POB 68, 11080 Belgrade (Serbia)

2011-10-15

215

Foot abnormalities of wild birds  

USGS Publications Warehouse

The various foot abnormalities that occur in birds, including pox, scaly-leg, bumble-foot, ergotism and freezing are reviewed. In addition, our findings at the Patuxent Wildlife Research Center include pox from dove, mockingbird, cowbird, grackle and several species of sparrows. Scaly-leg has been particularly prevalent on icterids. Bumble foot has been observed in a whistling swan and in a group of captive woodcock. Ergotism is reported from a series of captive Canada geese from North Dakota. Several drug treatments recommended by others are presented.

Herman, C.M.; Locke, L.N.; Clark, G.M.

1962-01-01

216

The Rose-red Glow of Star Formation  

NASA Astrophysics Data System (ADS)

The vivid red cloud in this new image from ESO's Very Large Telescope is a region of glowing hydrogen surrounding the star cluster NGC 371. This stellar nursery lies in our neighbouring galaxy, the Small Magellanic Cloud. The object dominating this image may resemble a pool of spilled blood, but rather than being associated with death, such regions of ionised hydrogen - known as HII regions - are sites of creation with high rates of recent star birth. NGC 371 is an example of this; it is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars. The host galaxy to NGC 371, the Small Magellanic Cloud, is a dwarf galaxy a mere 200 000 light-years away, which makes it one of the closest galaxies to the Milky Way. In addition, the Small Magellanic Cloud contains stars at all stages of their evolution; from the highly luminous young stars found in NGC 371 to supernova remnants of dead stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas, such as leftover hydrogen from their parent nebula, to light up with a colourful glow that extends for hundreds of light-years in every direction. The phenomenon is depicted beautifully in this image, taken using the FORS1 instrument on ESO's Very Large Telescope (VLT). Open clusters are by no means rare; there are numerous fine examples in our own Milky Way. However, NGC 371 is of particular interest due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology [1], and several of these have been confirmed in this cluster. Variable stars play a pivotal role in astronomy: some types are invaluable for determining distances to far-off galaxies and the age of the Universe. The data for this image were selected from the ESO archive by Manu Mejias as part of the Hidden Treasures competition [2]. Three of Manu's images made the top twenty; his picture of NGC 371 was ranked sixth in the competition. Notes [1] Asteroseismology is the study of the internal structure of pulsating stars by looking at the different frequencies at which they oscillate. This is a similar approach to the study of the structure of the Earth by looking at earthquakes and how their oscillations travel through the interior of the planet. [2] ESO's Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO's vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. Participants submitted nearly 100 entries and ten skilled people were awarded some extremely attractive prizes, including an all expenses paid trip for the overall winner to ESO's Very Large Telescope (VLT) on Cerro Paranal, in Chile, the world's most advanced optical telescope. The ten winners submitted a total of 20 images that were ranked as the highest entries in the competition out of the near 100 images. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO op

2011-03-01

217

Disorders caused by chromosome abnormalities  

PubMed Central

Many human genetic disorders result from unbalanced chromosome abnormalities, in which there is a net gain or loss of genetic material. Such imbalances often disrupt large numbers of dosage-sensitive, developmentally important genes and result in specific and complex phenotypes. Alternately, some chromosomal syndromes may be caused by a deletion or duplication of a single gene with pleiotropic effects. Traditionally, chromosome abnormalities were identified by visual inspection of the chromosomes under a microscope. The use of molecular cytogenetic technologies, such as fluorescence in situ hybridization and microarrays, has allowed for the identification of cryptic or submicroscopic imbalances, which are not visible under the light microscope. Microarrays have allowed for the identification of numerous new syndromes through a genotype-first approach in which patients with the same or overlapping genomic alterations are identified and then the phenotypes are described. Because many chromosomal alterations are large and encompass numerous genes, the ascertainment of individuals with overlapping deletions and varying clinical features may allow researchers to narrow the region in which to search for candidate genes. PMID:23776360

Theisen, Aaron; Shaffer, Lisa G

2010-01-01

218

Rare TGFs and common glows: a systematic survey of data from the first flights of ADELE  

NASA Astrophysics Data System (ADS)

The Airborne Detector for Energetic Lightning Emission (ADELE) is a mobile array of gamma and x-ray detectors meant to study radiation associated with thunderstorms. ADELE flew aboard a Gulfstream V jet near the tops of Florida thunderstorms in summer of 2009, performing the first systematic search for Terrestrial Gamma-ray Flashes (TGFs) at aircraft altitudes. We use GEANT3 simulations of electron and gamma-ray propagation in Earth's atmosphere and our instrument to show that ADELE was within the range of detection for TGFs from numerous lightning flashes but only saw one TGF event (see the companion presentation by Lowell et al.). This allows us to place strong upper limits on TGF emission from IC, +CG, and -CG lightning, demonstrating that TGFs are a rare phenomenon in lightning in this region, and cannot be the primary triggering mechanism for most lightning. The ADELE campaign also observed "glows" of high-energy radiation over several clouds. We shall also report the frequency of the occurrence of glows during our Florida 2009 campaign. On one occasion, the glow lasted through two passes of the aircraft over the same cell. This glow may represent the relativistic runaway feedback process continuously limiting the total charging of the cell, showing that this mechanism may compete with discrete lightning discharges as the main charge-limiting process in storms.

Kelley, N.; Lowell, A.; Smith, D. M.; Dwyer, J. R.; Cummer, S. A.; Lu, G.; Blakeslee, R.

2010-12-01

219

Some investigations of the ignition and development of breakdown in cylindrical hollow cathode glow discharges  

Microsoft Academic Search

The breakdown behavior of a hollow cathode glow discharge is investigated in a cylindrical, hollow cathode structure having an internal diameter of 2 cm. The anode is a plane electrode across one end of the cathode cylinder. Pressures of argon between 20 and 107 Pa were used (0.15 to 0.80 torr), and applied voltages between 800 and 2500 V. It

H. Stoeri; T. D. Maerk; M. Pahl; R. N. Varney

1978-01-01

220

Notice to nurserymen of the naming and release for propagation of Ebony Glow crapemyrtle  

Technology Transfer Automated Retrieval System (TEKTRAN)

UNITED STATES DEPARTMENT OF AGRICULTURE Agricultural Research Service Washington, D.C. and MISSISSIPPI STATE UNIVERSITY Starkville, MS NOTICE TO NURSERYMEN OF THE NAMING AND RELEASE FOR PROPAGATION OF ‘EBONY GLOW’ CRAPE MYRTLE The United States Department of Agriculture, Agricultural Research S...

221

A model for particulate contaminated glow discharges Michael J. t&Caughey and Mark J. Kushner  

E-print Network

A model for particulate contaminated glow discharges Michael J. t&Caughey and Mark J. Kushner are often contaminated by particulates resulting from gas phase nucleation or sputtering of surfaces-threshold processes such as ionization may be reduced compared to those in pristine plasmas. If the contamination

Kushner, Mark

222

High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry  

SciTech Connect

The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

1996-02-01

223

Glowing Pathfinder Bugs: A Natural Haptic 3D Interface for Interacting Intuitively with Virtual Environments  

Microsoft Academic Search

Glowing Pathfinder Bugs is an interactive art project primarily aimed at children and created by the digital arts group Squidsoup. It uses projection to visualize virtual bugs on a real sandpit. The bugs are aware of their surroundings and respond to its form in their vicinity. By altering the topography of the sand, participants affect the bugs' environment in real

Anthony Rowe; Liam Birtles

2010-01-01

224

Glowing Pathfinder Bugs: a natural haptic 3D interface for interacting intuitively with virtual environments  

Microsoft Academic Search

Glowing Pathfinder Bugs is an interactive art project primarily aimed at children and created by the digital arts group Squidsoup. It uses projection to visualize virtual bugs on a real sandpit. The bugs are aware of their surroundings and respond to its form in their vicinity. By altering the topography of the sand, participants affect the bugs' environment in real

Anthony Rowe; Liam Birtles

2010-01-01

225

Radio-frequency powered glow discharge device and method with high voltage interface  

Microsoft Academic Search

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the

Douglas C. Duckworth; R. Kenneth Marcus; David L. Donohue; Trousdale A. Lewis

1994-01-01

226

Plasma degradation of dyes in water with contact glow discharge electrolysis  

Microsoft Academic Search

Contact glow discharge electrolysis (CGDE) of two dyes, weak acid brilliant red B and weak acid flavine G, was investigated under different concentrations, temperature and mediums. From the variation of their concentration with the reaction time, it was demonstrated that the oxidation would be a first-order reaction. On the base line of UV spectra of solution in the degradation process,

Jinzhang Gao; Xiaoyan Wang; Zhongai Hu; Hualing Deng; Jingguo Hou; Xiaoquan Lu; Jingwan Kang

2003-01-01

227

Plasma Processing with a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)  

NASA Astrophysics Data System (ADS)

The vast majority of all industrial plasma processing is conducted with glow discharges at pressures below 10 torr. This has limited applications to high value workpieces as a result of the large capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharges would play a much larger industrial role if they could be operated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been developed at the University of Tennessee Plasma Sciences Laboratory. The OAUGDP is non-thermal RF plasma with the time-resolved characteristics of a classical low pressure DC normal glow discharge. An interdisciplinary team was formed to conduct exploratory investigations of the physics and applications of the OAUGDP. This team includes collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC) and the Departments of Electrical and Computer Engineering, Microbiology, Food Science and Technology, and Mechanical and Aerospace Engineering and Engineering Science. Exploratory tests were conducted on a variety of potential plasma processing and other applications. These include the use of OAUGDP to sterilize medical and dental equipment and air filters; diesel soot removal; plasma aerodynamic effects; electrohydrodynamic (EDH) flow control of the neutral working gas; increasing the surface energy of materials; increasing the wettability and wickability of fabrics; and plasma deposition and directional etching. A general overview of these topics will be presented.

Reece Roth, J.

2000-10-01

228

Attenuation of single-tone ultrasound by an atmospheric glow discharge plasma barrier  

E-print Network

was a continuous dc discharge formed by a multipin electrode system. Distributions of the gas temperature were also its temperature. At the boundary be- tween hot discharge and cold gas regions the acoustic speedAttenuation of single-tone ultrasound by an atmospheric glow discharge plasma barrier Vadim P

�tügen, Volkan

229

DC Discharge Studies Using PIC-MCC: Unmagnetized Glow Discharge Theory Jeff Hammel & John Verboncoeur  

E-print Network

in Gases. John Wiley and Sons, Inc., New York, 1939. · Yuri P. Raizer. Gas Discharge Physics. SpringerDC Discharge Studies Using PIC-MCC: Unmagnetized Glow Discharge Theory Jeff Hammel & John@langmuir.eecs.berkeley.edu Abstract DC discharges are used in plasma materials processing for sputtering deposition, ion implantation

Wurtele, Jonathan

230

Stabilization of a cold cathode electron beam glow discharge for surface treatment  

E-print Network

Stabilization of a cold cathode electron beam glow discharge for surface treatment N. Mingolo and C source for surface treatment. © 1997 American Institute of Physics. S0021-8979 97 05217-1 Simple cold­6 Of particular interest is the deposition of high power densities for surface treatment of metallic surfaces.6

Rocca, Jorge J.

231

Images of biological samples undergoing sterilization by a glow discharge at atmospheric pressure  

Microsoft Academic Search

Among the various industrial uses of the glow discharge at atmospheric pressure (GDAP), biological applications such as sterilization are under investigation. In this paper, we present images of a liquid medium (Luria-Bertani broth with tetracycline) contaminated by Escherichia coli bacteria (strain PER 322) undergoing plasma treatment. In most cases, it is found that an exposure time of two to 20

Mounir Laroussi; Gary S. Sayler; Battle B. Glascock; Bruce McCurdy; Mary E. Pearce; Nathan G. Bright; Chad M. Malott

1999-01-01

232

The Blue Glow from the Back Row: Live Theater and the Wireless Teen  

ERIC Educational Resources Information Center

Every year the author and his colleagues take their grade 12 English students to see four plays at one of Canada's major theaters. Chatting about the series on the last day of class, his students asked him if he had seen "the blue glow from the back row." Laughing at his bewilderment, they told him that during the performances so many students…

Richardson, John M.

2012-01-01

233

Utilizing a one-atmosphere uniform glow discharge plasma for chemical\\/biological warfare agent decontamination  

Microsoft Academic Search

Summary form only given, as follows. An innovative approach to the decontamination of chemical and\\/or biological warfare agents is described. This recently developed technology involves utilizing a one atmosphere uniform glow discharge plasma (OAUGDP) as the decontaminant\\/sterilant. The plasma provides a very powerful but environmentally safe oxidizing and disinfecting technique without the use of strong chemicals (chlorine bleach) or high

M. R. McLean; J. R. Roth

1998-01-01

234

Characterization of Atmospheric Pressure Glow Discharge in Helium Using Langmuir Probe, Emission Spectroscopy, and Discharge Resistivity  

Microsoft Academic Search

The experimental work reported here is a validation of Langmuir probe measurements against emission spectroscopic and discharge resistivity measurements of atmospheric glow discharge plasma parameters. The probe measurements of plasma density are close to that obtained by spectroscopy and discharge resistivity measurement. However, it is found that the electron temperature measurement by the probe is higher than that obtained by

Anand Kumar Srivastava; Manoj Kumar Garg; K. S. Ganesh Prasad; Vinay Kumar; Malay Bikas Chowdhuri; Ram Prakash

2007-01-01

235

Spectral Evidence for Ionization in Air-Filled Glow Discharge Tubes: Application to Sprites  

NASA Astrophysics Data System (ADS)

The question of ionization in sprites and the evidence for VLF backscatter from sprites has motivated a quantitative spectral analysis of the various (classical) regions of the glow discharge tube under DC excitation and at air densities appropriate for sprites in the mesosphere. A PR-650 colorimeter (Photo Research, Inc.) has enabled calibrated irradiance measurements for localized zones along the axis of the discharge tube--in the dominantly blue negative glow, in the Faraday dark space and in the red/pink positive column. Consistent with historical nomenclature, nitrogen first and second positive emission is dominant in the positive column (associated with neutral N2), and nitrogen first negative emission, with a prominent peak at 4278 A, is dominant in the blue negative glow (associated with ionized N2+). Whereas nitrogen first and second positive emission are also detected in the negative glow, no spectral evidence for ionization (no 4279, no 3914, no Meinel) is found in the red/pink positive column. This negative result is attributed not to an absence of ionization in the positive column, but rather to a sparse population of N2+ relative to neutral nitrogen in this region, and to the prominent emission in the blue part of the spectrum due to nitrogen second positive. A similar interpretation may be appropriate for the time-integrated spectra from the red body of sprites, also lacking direct evidence for ionization.

Armstrong, R. A.; Williams, E. R.; Golka, R. K.; Williams, D. R.

2001-12-01

236

Bored By Non-Glowing Skin? Ultra-Flexible, Waterproof LED Implants Are What You Seek  

E-print Network

Bored By Non-Glowing Skin? Ultra-Flexible, Waterproof LED Implants Are What You Seek By Alasdair Wilkins/io9 Posted 10.19.2010 at 12:15 pm LED Lights Could Be Implanted Under Skin Photo courtesy of iO9 LEDs are, on small scales, the cheapest, most reliable, and most technologically powerful light sources

Rogers, John A.

237

Glow Discharge Characteristics in Relation to Anode Size in Inertial Electrostatic Confinement Fusion  

Microsoft Academic Search

An Inertial Electrostatic Confinement Fusion device is a very simple and safe neutron source that uses a glow discharge for deuterium-deuterium fusion. The discharge characteristics of the device were studied experimentally. The relationship between gas pressure and applied voltage was examined by light changes of the device's anode size. The gas pressure ranges in which the device was able to

Hodaka Osawa; Shigehisa Yoshimura; Takehiro Tabata; Masami Ohnishi

2008-01-01

238

Qualitative gas temperature distribution in positive DC glow corona using spectral image processing in atmospheric air  

NASA Astrophysics Data System (ADS)

An experimental method of determining a qualitative two-dimensional image of the gas temperature in stationary atmospheric nonthermal plasma by spectral image processing was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. The changes in the gas temperature distribution due to the amplitude of applied voltage and the ambient gas pressure were investigated. Spectral images of a positive DC glow corona were taken using a gated ICCD camera with ultranarrow band-pass filters, corresponding to the head and tail of a N2 second positive system band (0–2). The qualitative gas temperature was obtained from the emission intensity ratio between the head and tail of the N2 second positive system band (0–2). From the results, we confirmed that the gas temperature and its distribution of a positive DC glow corona increased with increasing applied voltage. In particular, just before the sparkover voltage, a distinctly high temperature region was formed in the positive DC glow at the tip of the rod electrode. In addition, the gas temperature decreased and its distribution spread diffusely with decreasing ambient gas pressure.

Matsumoto, Takao; Inada, Yoichi; Shimizu, Daisuke; Izawa, Yasuji; Nishijima, Kiyoto

2015-01-01

239

[Studies on the general properties of a novel microwave plasma enhanced glow discharge source].  

PubMed

This paper introduced a novel microwave plasma enhanced glow descharge source, the structure design and operation were decribed, and the mutual effects of the main characters, such as pressure, current, voltage, microwave power and sputtering rates were also investigated in details. PMID:15810307

Li, Y; Du, Z; Duan, Y; Zhang, H; Jin, Q; Liu, H

1998-04-01

240

Glow in the dark cats may lead to important advances in finding a cure for HIV  

NSDL National Science Digital Library

Cats That Glow For AIDS Research Join List of Animals That Shinehttp://www.npr.org/blogs/thetwo-way/2011/09/14/140465088/cats-that-glow-for-aids-research-join-list-of-animals-that-shine'Green-Glowing' Cats May Help to Fight Against HIV/AIDShttp://www.ibtimes.com/articles/213108/20110913/glowing-cats-mayo-clinic-japan-hiv-aids.htmThe Scientist: Fluorescent Cats Aid Researchhttp://the-scientist.com/2011/09/13/fluorescent-cats-aid-research/Glowing Animals: Pictures of Beasts Shining For Sciencehttp://news.nationalgeographic.com/news/2009/05/photogalleries/glowing-animal-picturesInternational Society for Transgenic Technologieshttp://www.transtechsociety.org/The Nobel Prize in Chemistry 2008http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2008/"Glow in the dark" animals have been around for a few years, but scientists at the Mayo Clinic in Minnesota and Yamaguchi University in Japan have come up with a rather curious use for such creatures. This week, researchers at these two institutions announced that they had genetically modified cats to glow in the dark. The cats were created by using a virus to carry a gene, called green fluorescent protein, into the eggs from which these animals eventually grew. It is hoped that this type of genetic modification will allow scholars to learn about vital clues for treating the AIDS virus. The idea is that scientists will now be able to monitor the activity of individual genes or cells in cats, and eventually in a number of different animals. This type of genetic modification expresses fluoresces when illuminated with UV light, which produces a green glow that scientists use to track the activity of individual genes or cells. Commenting on the work he shared with his colleagues, Eric Poeschla of the Mayo Clinic remarked, "One of the best things about this biomedical research is that it is aimed at benefiting both human and feline health." The first link will take visitors to a post from this Wednesday's NPR blog "The Two Way" about this recent discovery. The second link leads to an article from this Tuesday's International Business Times which offers some more details about the world of "green" cats. Moving along, the third link will take visitors to "The Nutshell" column from The Scientist website which also delves into fluorescence, kittens, and genetic modification. The fourth link will whisk users away to an interesting photographic feature on animals that have glowed in the name of science, courtesy of the folks at National Geographic. The fifth link leads to the homepage for the International Society for Transgenic Technologies (ISTT). Here visitors can learn about courses like "Genetics of Laboratory Rodents" and also view professional information about the ISTT and their activities. The last link will take interested parties to the official Nobel Prize page for the individuals who won the prize in 2008. They received the prize for developing the technique used by the researchers working on these cats, and the technique is now widely used throughout the world.

Grinnell, Max

2011-09-16

241

Modelling of tokamak glow discharge cleaning II: comparison with experiment and application to ITER  

NASA Astrophysics Data System (ADS)

The primary function of the ITER glow discharge cleaning (GDC) system will be the preparation of in-vessel component surfaces prior to the machine start-up. It may also contribute to tritium removal in the nuclear phase. In GDC, conditioning efficiency is strongly dependent on the homogeneity of the flux of ions impinging onto wall surfaces. In order to assess the wall particle flux distribution in ITER, a novel 2D multi-fluid model, described in a companion paper, has recently been developed and is benchmarked here against both experimental glow discharge data obtained in a small laboratory chamber with cylindrical geometry and from two large toroidal devices: the JET tokamak and the RFX reverse field pinch. In the laboratory plasma, simulated and measured plasma electron density and temperature are in a good agreement in the negative glow region, while discrepancies exist in the anode glow, where the fluid description of the model is inaccurate due to long mean free paths of electrons. Calculated and measured ion flux distribution profiles in RFX are found in good agreement, whereas in JET comparison it is more difficult, due to the complex geometry of the first wall which leads to local inhomogeneities in the measured flux. Simulations of H2-GDC for ITER with one or two anodes indicate fairly homogeneous plasma parameters and wall ion flux in the negative glow at 0.5?Pa, a commonly used gas pressure for GDC in existing fusion devices. Although the axisymmetric geometry in the model does not allow all seven ITER anodes to be powered simultaneously in the simulations, the results can be extrapolated to the full system and predict ion current densities on wall surfaces close to the simple expectation of total anode current divided by wall surface area (0.21?A?m?2), which is relevant to GDC in JET and other machines.

Kogut, D.; Douai, D.; Hagelaar, G.; Pitts, R. A.

2015-02-01

242

Endotoxin removal by radio frequency gas plasma (glow discharge)  

NASA Astrophysics Data System (ADS)

Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to < 0.5 EU/ml in sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were repeated after employing 3-minute RFGD treatments sequentially for more than 10 cycles to observe removal of deposited matter that correlated with diminished EU titers. The results showed that 5 cycles, for a total exposure time of 15 minutes to low-temperature gas plasma, was sufficient to reduce endotoxin titers to below 0.05 EU/ml, and correlated with concurrent reduction of major endotoxin reference standard absorption bands at 3391 cm-1, 2887 cm-1, 1646 cm -1 1342 cm-1, and 1103 cm-1 to less than 0.05 Absorbance Units. Band depletion varied from 15% to 40% per 3-minute cycle of RFGD exposure, based on peak-to-peak analyses. In some cases, 100% of all applied biomass was removed within 5 sequential 3-minute RFGD cycles. The lipid ester absorption band expected at 1725 cm-1 was not detectable until after the first RFGD cycle, suggesting an unmasking of the actual bacterial endotoxin membrane induced within the gas plasma environment. Future work must determine the applicability of this low-temperature, quick depyrogenation process to medical devices of more complicated geometry than the flat surfaces tested here.

Poon, Angela

2011-12-01

243

Biological assessment of abnormal genitalia.  

PubMed

Biological assessment of abnormal genitalia is based on an ordered sequence of endocrine and genetic investigations that are predicated on knowledge obtained from a suitable history and detailed examination of the external genital anatomy. Investigations are particularly relevant in 46,XY DSD where the diagnostic yield is less successful than in the 46,XX counterpart. Advantage should be taken of spontaneous activity of the pituitary-gonadal axis in early infancy rendering measurements of gonadotrophins and sex steroids by sensitive, validated assays key to assessing testicular function. Allied measurement of serum anti-Müllerian hormone completes a comprehensive testis profile of Leydig and Sertoli cell function. Genetic assessment is dominated by analysis of a plethora of genes that attempts to delineate a cause for gonadal dysgenesis. In essence, this is successful in up to 20% of cases from analysis of SRY and SF1 (NR5A1) genes. In contrast, gene mutation analysis is highly successful in 46,XY DSD due to defects in androgen synthesis or action. The era of next generation sequencing is increasingly being applied to investigate complex medical conditions of unknown cause, including DSD. The challenge for health professionals will lie in integrating vast amounts of genetic information with phenotypes and counselling families appropriately. How tissues respond to hormones is apposite to assessing the range of genital phenotypes that characterise DSD, particularly for syndromes associated with androgen resistance. In vitro methods are available to undertake quantitative and qualitative analysis of hormone action. The in vivo equivalent is some assessment of the degree of under-masculinisation in the male, such as an external masculinisation score, and measurement of the ano-genital distance. This anthropometric marker is effectively a postnatal readout of the effects of prenatal androgens acting during the masculinisation programming window. For investigation of the newborn with abnormal genitalia, a pragmatic approach can be taken to guide the clinician using appropriate algorithms. PMID:23168057

Hughes, I A; Morel, Y; McElreavey, K; Rogol, A

2012-12-01

244

Lommel modes  

NASA Astrophysics Data System (ADS)

We study a non-paraxial family of nondiffracting laser beams whose complex amplitude is proportional to an n-th order Lommel function of two variables. These beams are referred to as Lommel modes. Explicit analytical relations for the angular spectrum of plane waves and orbital angular momentum of the Lommel beams have been derived. The even (n=2p) and odd (n=2p+1) Lommel modes are mutually orthogonal, as are the Lommel modes characterized by different projections of the wave vector on the optical axis. At a definite parameter, the Lommel modes change to conventional Bessel beams. Asymmetry of the Lommel modes depends on a complex parameter ?, with its modulus in the polar notation defining the intensity pattern in the beam?s cross-section and the argument defining the angle of rotation of the intensity pattern about the optical axis. If the parameter ? is real or purely imaginary, the transverse intensity component of the Lommel modes is specularly symmetric about the Cartesian coordinate axes. Besides, with the modulus of the ? parameter increasing from 0 to 1, the orbital angular momentum of the Lommel modes increases from a finite value proportional to the topological charge n to infinity. The orbital angular momentum of the Lommel modes undergoes continuous variations, in contrast to its discrete changes in the Bessel modes.

Kovalev, ?lexey ?.; Kotlyar, Victor V.

2015-03-01

245

Glow Discharge Characteristics of Non-thermal Microplasmas at above Atmospheric Pressures and their Applications in Microscale Plasma Transistors  

E-print Network

and relatively flat voltage current characteristics indicating normal glow discharge behavior in the microplasmas. During device development small diameter metal wires, 25 ?m and 50 ?m, were used to carry out experiments on the microscale device to aid...

Wakim, Dani Ghassan

2013-07-25

246

Emission- and fluorescence-spectroscopic investigation of a glow discharge plasma: absolute number density of radiative and nonradiative atoms in the negative glow.  

PubMed

The excited-state atom densities in the negative glow of a direct-current glow discharge are derived from the spectral-line intensity of radiative atoms and the resonance-fluorescence photon flux of nonradiative atoms. The discharge is operated in a helium-argon gas mixture (molar fraction ratio 91:9; total gas pressure 5 Torr) at a dc current of 0.7-1.2 mA. The observations are made in the region of the maximum luminance in the cathode region, where high-energy electrons accelerated in the cathode fall are injected into the negative glow. The emission intensities of the He I, He II, Ar I, and Ar II spectral lines are measured with a calibrated tungsten ribbon lamp as an absolute spectral-radiance standard. Fluorescence photons scattered by helium and argon atoms in the metastable state and argon atoms in the resonance state are detected by the laser-induced fluorescence (LIF) method with the Rayleigh scattering of nitrogen molecules as an absolute standard of scattering cross section. The laser absorption method is incorporated to confirm the result of the LIF measurement. Excitation energies of the measured spectral lines range from 11.6 (Ar I) to 75.6 eV (He II), where the excitation energy is measured from the ground state of the neutral atom on the assumption that, in the plasma of this study, both the neutral and the ionic lines are excited by electron impact in a single-step process from the ground state of the corresponding neutral atoms. Experimental evidence is shown for the validity of this assumption. PMID:18351942

Takubo, Y; Sato, T; Asaoka, N; Kusaka, K; Akiyama, T; Muroo, K; Yamamoto, M

2008-01-01

247

Emission- and fluorescence-spectroscopic investigation of a glow discharge plasma: Absolute number density of radiative and nonradiative atoms in the negative glow  

NASA Astrophysics Data System (ADS)

The excited-state atom densities in the negative glow of a direct-current glow discharge are derived from the spectral-line intensity of radiative atoms and the resonance-fluorescence photon flux of nonradiative atoms. The discharge is operated in a helium-argon gas mixture (molar fraction ratio 91:9; total gas pressure 5 Torr) at a dc current of 0.7-1.2 mA. The observations are made in the region of the maximum luminance in the cathode region, where high-energy electrons accelerated in the cathode fall are injected into the negative glow. The emission intensities of the He I, He II, Ar I, and Ar II spectral lines are measured with a calibrated tungsten ribbon lamp as an absolute spectral-radiance standard. Fluorescence photons scattered by helium and argon atoms in the metastable state and argon atoms in the resonance state are detected by the laser-induced fluorescence (LIF) method with the Rayleigh scattering of nitrogen molecules as an absolute standard of scattering cross section. The laser absorption method is incorporated to confirm the result of the LIF measurement. Excitation energies of the measured spectral lines range from 11.6 (Ar I) to 75.6 eV (He II), where the excitation energy is measured from the ground state of the neutral atom on the assumption that, in the plasma of this study, both the neutral and the ionic lines are excited by electron impact in a single-step process from the ground state of the corresponding neutral atoms. Experimental evidence is shown for the validity of this assumption.

Takubo, Y.; Sato, T.; Asaoka, N.; Kusaka, K.; Akiyama, T.; Muroo, K.; Yamamoto, M.

2008-01-01

248

Semen abnormalities with SSRI antidepressants.  

PubMed

Despite decades of widespread use, the adverse effect profile of "selective" serotonin reuptake inhibitor (SSRI) antidepressants has still not been fully elucidated. Studies in male animals have shown delayed sexual development and reduced fertility. Three prospective cohort studies conducted in over one hundred patients exposed to an SSRI for periods ranging from 5 weeks to 24 months found altered semen param-eters after as little as 3 months of exposure: reduced sperm concentration, reduced sperm motility, a higher percentage of abnormal spermatozoa, and increased levels of sperm DNA fragmentation. One clinical trial showed growth retardation in children considered depressed who were exposed to SSRls. SSRls may have endocrine disrupting properties. Dapoxetine is a short-acting serotonin reuptake inhibitor that is chemically related to fluoxetine and marketed in the European Union for men complaining of premature ejaculation. But the corresponding European summary of product characteristics does not mention any effects on fertility. In practice, based on the data available as of mid-2014, the effects of SSRI exposure on male fertility are unclear. However, it is a risk that should be taken into account and pointed out to male patients who would like to father a child or who are experiencing fertility problems. PMID:25729824

2015-01-01

249

Biochemical abnormalities in Pearson syndrome.  

PubMed

Pearson marrow-pancreas syndrome is a multisystem mitochondrial disorder characterized by bone marrow failure and pancreatic insufficiency. Children who survive the severe bone marrow dysfunction in childhood develop Kearns-Sayre syndrome later in life. Here we report on four new cases with this condition and define their biochemical abnormalities. Three out of four patients presented with failure to thrive, with most of them having normal development and head size. All patients had evidence of bone marrow involvement that spontaneously improved in three out of four patients. Unique findings in our patients were acute pancreatitis (one out of four), renal Fanconi syndrome (present in all patients, but symptomatic only in one), and an unusual organic aciduria with 3-hydroxyisobutyric aciduria in one patient. Biochemical analysis indicated low levels of plasma citrulline and arginine, despite low-normal ammonia levels. Regression analysis indicated a significant correlation between each intermediate of the urea cycle and the next, except between ornithine and citrulline. This suggested that the reaction catalyzed by ornithine transcarbamylase (that converts ornithine to citrulline) might not be very efficient in patients with Pearson syndrome. In view of low-normal ammonia levels, we hypothesize that ammonia and carbamylphosphate could be diverted from the urea cycle to the synthesis of nucleotides in patients with Pearson syndrome and possibly other mitochondrial disorders. © 2015 Wiley Periodicals, Inc. PMID:25691415

Crippa, Beatrice Letizia; Leon, Eyby; Calhoun, Amy; Lowichik, Amy; Pasquali, Marzia; Longo, Nicola

2015-03-01

250

Pioneer 10 ultraviolet photometer observations of the interplanetary glow at heliocentric distances from 2 to 14 AU  

Microsoft Academic Search

The interplanetary hydrogen Lyman-..cap alpha.. and He 584 A glow observations obtained by the two-channel extreme-ultraviolet photometer on Pioneer 10 at distances of 2--14 AU from the Sun are presented. The data are for the time period from 1972 to 1977. For positions near the Sun, the interplanetary glow is primarily due to single scattering of sunlight by the interstellar

F. M. Wu; K. Suzuki; R. W. Carlson; D. L. Judge

1981-01-01

251

Corrosion resistance properties of glow-discharge nitrided AISI 316L austenitic stainless steel in NaCl solutions  

Microsoft Academic Search

Glow-discharge nitriding treatments can modify the hardness and the corrosion resistance properties of austenitic stainless steels. The modified layer characteristics mainly depend on the treatment temperature. In the present paper the results relative to glow-discharge nitriding treatments carried out on AISI 316L austenitic stainless steel samples at temperatures ranging from 673 to 773K are reported. Treated and untreated samples were

A. Fossati; F. Borgioli; E. Galvanetto; T. Bacci

2006-01-01

252

Surface chemical composition and fibrinogen adsorption-retention of fluoropolymer films deposited from an RF glow discharge  

Microsoft Academic Search

Fluoropolymer films have been deposited in the glow and afterglow regions of radio frequency glow discharges fed with C2F6?H2 mixtures. Structure, growth rate, composition, and wettability of the films have been investigated by means of atomic force\\u000a microscopy, electron spectroscopy for chemical analysis, secondary ion mass spectrometry, and water contact angle measurements.125I labeled baboon fibrinogen in baboon plasma has been

Pietro Favia; Victor H. Perez-Luna; Thomas Boland; David G. Castner; Buddy D. Ratner

1996-01-01

253

Ultrastructurally abnormal mitochondria in the pituitary oncocytoma  

Microsoft Academic Search

Summary A pituitary adenoma in a 67-year-old man was characterized by abundant mitochondria and identified as an oncocytoma, which clinically and histologically appeared as a chromophobe adenoma. In addition to the numerous mitochondria within the neoplastic cells, structurally abnormal mitochondria were also present. Compared with other pituitary oncocytomas reported in the literature, abnormally structured mitochondria appear rare among the mitochondrial

H. H. Goebel; F. Schulz; B. Rama

1980-01-01

254

COURSE SYLLABUS Psychology 350: Abnormal Psychology  

E-print Network

1&2 plus lecture notes Feb 2 Major Mental Disorders Ch 11 Feb 9 Anxiety Disorders Ch 7 Feb 16: Abnormal Psychology by Susan Holen-Hoeksema 4th edition This course covers the history, theories, assessment, and treatments of Abnormal Behavior Final grades are based exclusively on total points. All

Gallo, Linda C.

255

Lipid abnormalities in uremia, dialysis, and transplantation  

Microsoft Academic Search

The institution of renal replacement therapy has sustained the lives of many patients with end-stage renal failure and has made it possible to study in depth the metabolic abnormalities associated with the uremic state. An important consequence of chronic uremia is the development of lipid abnormalities [1, 2], which continue to affect many patients on dialysis [1, 3, 4] and

Man Kam Chan; Zachariah Varghese; John F Moorhead

1981-01-01

256

Retinal Circulatory Abnormalities in Type 1 Diabetes  

Microsoft Academic Search

Purpose. To quantify retinal circulatory abnormalities in patients with type 1 diabetes; to compare blood speed and blood flow in major temporal retinal arteries as well as total retinal arterial cross-section measured in patients to that measured in controls without diabetes; to determine which factors are related to the measured abnormalities within the patient group. Methods. The laser Doppler technique

Gilbert T. Feke; Sheldon M. Buzney; Hironobu Ogasawara; Naoki Fujio; Douglas G. Goger; Norman P. Spack; Kenneth H. GabbayX

257

Challenges in Emergency and Abnormal Checklist Design  

E-print Network

Challenges in Emergency and Abnormal Checklist Design Barbara Burian, Ph.D. San Jose State is funded through the NASA Aviation Safety and Security Program. #12;Emergency and Abnormal Situations Systems Training Human Performance under Stress Checklists and Procedures #12;Challenges in Emergency

258

Multiparametric tissue abnormality characterization using manifold regularization  

NASA Astrophysics Data System (ADS)

Tissue abnormality characterization is a generalized segmentation problem which aims at determining a continuous score that can be assigned to the tissue which characterizes the extent of tissue deterioration, with completely healthy tissue being one end of the spectrum and fully abnormal tissue such as lesions, being on the other end. Our method is based on the assumptions that there is some tissue that is neither fully healthy or nor completely abnormal but lies in between the two in terms of abnormality; and that the voxel-wise score of tissue abnormality lies on a spatially and temporally smooth manifold of abnormality. Unlike in a pure classification problem which associates an independent label with each voxel without considering correlation with neighbors, or an absolute clustering problem which does not consider a priori knowledge of tissue type, we assume that diseased and healthy tissue lie on a manifold that encompasses the healthy tissue and diseased tissue, stretching from one to the other. We propose a semi-supervised method for determining such as abnormality manifold, using multi-parametric features incorporated into a support vector machine framework in combination with manifold regularization. We apply the framework towards the characterization of tissue abnormality to brains of multiple sclerosis patients.

Batmanghelich, Kayhan; Wu, Xiaoying; Zacharaki, Evangelia; Markowitz, Clyde E.; Davatzikos, Christos; Verma, Ragini

2008-03-01

259

Immune Abnormalities in Patients with Autism.  

ERIC Educational Resources Information Center

A study of 31 autistic patients (3-28 years old) has revealed several immune-system abnormalities, including decreased numbers of T lymphocytes and an altered ratio of helper-to-suppressor T cells. Immune-system abnormalities may be directly related to underlying biologic processes of autism or an indirect reflection of the actual pathologic…

Warren, Reed P.; And Others

1986-01-01

260

Is gastric emptying abnormal in duodenal ulcer?  

Microsoft Academic Search

To investigate the possibility that an abnormality of gastric emptying exists in duodenal ulcer and to determine if such an abnormality persists after ulcer healing, scintigraphic gastric emptying measurements were undertaken in 16 duodenal ulcer patients before, during, and after therapy with cimetidine; in 12 patients with pernicious anemia, and in 12 control subjects. No difference was detected in the

Stephen Holt; Robert C. Heading; Thomas V. Taylor; John A. Forrest; Peter Tothill

1986-01-01

261

Renal abnormalities and their developmental origin  

Microsoft Academic Search

Congenital abnormalities of the kidney and urinary tract (CAKUT) occur in 1 out of 500 newborns, and constitute approximately 20–30% of all anomalies identified in the prenatal period. CAKUT has a major role in renal failure, and there is increasing evidence that certain abnormalities predispose to the development of hypertension and cardiovascular disease in adult life. Moreover, defects in nephron

Andreas Schedl

2007-01-01

262

Abnormal Electrical Brain Responses to Pitch in  

E-print Network

Abnormal Electrical Brain Responses to Pitch in Congenital Amusia Isabelle Peretz, PhD,1 Elvira- sults suggest that this disorder is critically dependent on fine-grained pitch discrimination. Here, we2-P3 response elicited by pitch changes. This abnormal brain response begins as early as 200

263

Severely Symptomatic Craniovertebral Junction Abnormalities in Children  

Microsoft Academic Search

Objectives: The treatment of symptomatic cranio-vertebral junction (CVJ) instability in children affected by CVJ abnormalities is a challenge. A series of severely symptomatic children has been reviewed to understand the controversial long-term effectiveness of the aggressive management of CVJ abnormalities, in terms of clinical improvement, spinal stability and growth. Methods: Three Down syndrome patients, 1 with mucopolysaccharidosis and 1 with

Carlo Giussani; Franck-Emmanuel Roux; Paolo Guerra; David Pirillo; Marco Grimaldi; Giuseppe Citerio; Erik P. Sganzerla

2009-01-01

264

Spectral emission from glow peaks in x-irradiated Al2O3  

NASA Astrophysics Data System (ADS)

Spectral emission associated with the 214, 246, and 286 K glow peaks of Al2O3 reveals that in addition to the previously reported 330- and 410-nm emission, R-line (694.3 nm) emission also accompanies the glow. Of particular interest is the model which explains the appearance of each type of emission. Our data are qualitatively consistent with a model where trapped holes are thermally released and recombine with F centers and Cr2+ ions to yield 330-nm and R-line emission at 214 K, respectively. Furthermore, F centers are thermally destroyed near 260-290 K thereby producing excited F+ centers which emit 410-nm radiation. In addtiion, the electron released by the F center is captured by a Cr4+ ion converting it to Cr3+ in an excited state which ultimately produces R-line emission.

Cooke, D. Wayne

1984-05-01

265

CCCO: Generation by dc glow discharge in carbon suboxide, and microwave spectrum  

NASA Astrophysics Data System (ADS)

Generation of the CCCO molecule was observed through its microwave spectrum in a dc glow discharge of carbon suboxide. Thirteen rotational transitions J = 7-6 to 19-18 were measured in the frequency region 67-183 GHz with the use of a source-modulation microwave spectrometer. A least-squares analysis of 19 observed spectral lines, including the six previously reported by Brown et al., yielded the following revised molecular constants for CCCO: Bo = 4810.88624(65) MHz and Do = 0.00077707(130) MHz, with 3? in parentheses. The concentrations of CCO as well as CCCO produced in the glow discharge are estimated to be about 11 ppm.

Tang, Tong B.; Inokuchi, Hiroo; Saito, Shuji; Yamada, Chikashi; Hirota, Eizi

1985-04-01

266

Plasma Treatment of Polyethylene Powder Particles in Hollow Cathode Glow Discharge  

SciTech Connect

Polyethylen (PE) is widely used in the production of foils, insulators, packaging materials, plastic bottles etc. Untreated PE is hydrophobic due to its unpolar surface. Therefore, it is hard to print or glue PE and the surface has to be modified before converting.In the present experiments a hollow cathode glow discharge is used as plasma source which is mounted in a spiral conveyor in order to ensure a combines transport of PE powder particles. With this set-up a homogeneous surface treatment of the powder is possible while passing the glow discharge. The plasma treatment causes a remarkable enhancement of the hydrophilicity of the PE powder which can be verified by contact angle measurements and X-ray photoelectron spectroscopy.

Wolter, Matthias; Quitzau, Meike; Bornholdt, Sven; Kersten, Holger [IEAP, University Kiel, Kiel (Germany)

2008-09-07

267

Boundary Layer Flow Control with a One Atmosphere Uniform Glow Discharge Surface Plasma  

NASA Technical Reports Server (NTRS)

Low speed wind tunnel data have been acquired for planar panels covered by a uniform, glow-discharge surface plasma in atmospheric pressure air known as the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). Streamwise and spanwise arrays of flush, plasma-generating surface electrodes have been studied in laminar, transitional, and fully turbulent boundary layer flow. Plasma between symmetric streamwise electrode strips caused large increases in panel drag, whereas asymmetric spanwise electrode configurations produced a significant thrust. Smoke wire flow visualization and mean velocity diagnostics show the primary cause of the phenomena to be a combination of mass transport and vortical structures induced by strong paraelectric ElectroHydroDynamic (EHD) body forces on the flow.

Roth, J. Reece; Sherman, Daniel M.; Wilkinson, Stephen P.

1998-01-01

268

SkyGlowNet: Multi-Disciplinary Independent Student Research in Environmental Light at Night Monitoring  

NASA Astrophysics Data System (ADS)

SkyGlowNet uses Internet-enabled sky brightness meters (iSBM) to monitor sky brightness over school sites. The data are used professionally and in STEM outreach to study natural and artificial sources of sky brightness, light pollution, energy efficiency, and environmental and health impacts of artificial night lighting. The iSBM units are owned by participating institutions and managed by faculty or students via proprietary Internet links. Student data are embargoed for two semesters to allow students to analyze data and publish results, then they are moved to a common area where students from different institutions can collaborate. The iSBM units can be set to operate automatically each night. Their data include time, sky brightness, weather conditions, and other related parameters. The data stream can be viewed and processed online or downloaded for study. SkyGlowNet is a unique, multi-disciplinary, real science program aiding research for science and non-science students.

Craine, B. L.; Craine, E. R.; Culver, R. B.; DeBenedetti, J. C.; Flurchick, K. M.

2014-07-01

269

Attenuation of single-tone ultrasound by an atmospheric glow discharge plasma barrier  

SciTech Connect

Propagation of 143 kHz ultrasound through an atmospheric pressure glow discharge in air was studied experimentally. The plasma was a continuous dc discharge formed by a multipin electrode system. Distributions of the gas temperature were also obtained in and around the plasma using laser-induced Rayleigh scattering technique. Results show significant attenuation of the ultrasound by the glow discharge plasma barrier (up to -24 dB). The results indicate that sound attenuation does not depend on the thickness of the plasma and attenuation is caused primarily by reflection of the sound waves from the plasma due to the sharp gas temperatures gradients that form at the plasma boundary. These gradients can be as high as 80 K/mm.

Stepaniuk, Vadim P. [Lenterra Inc., 7 Tenney Road, West Orange, New Jersey 07052 (United States); Ioppolo, Tindaro; Oetuegen, M. Volkan [Southern Methodist University, 3101 Dyer Street, Dallas, Texas 75205 (United States); Sheverev, Valery A. [Lenterra Inc., 7 Tenney Road, West Orange, New Jersey 07052 (United States); Polytechnic Institute of NYU, 6 Metrotech Center, Brooklyn, New York 11201 (United States)

2010-09-15

270

Microstructure and biocompatibility of titanium oxides produced on nitrided surface layer under glow discharge conditions.  

PubMed

The disadvantages of titanium implants are their low wear resistance and the release of titanium elements into surrounding tissue. These can be eliminated by modifying the surface by surface engineering methods, among them nitriding under glow discharge conditions which allow to produce diffusive surface layers. Their combining with an oxide layer might be valuable for biological events occurring at the bone implant interface. The aim of this study was to enhance the titanium biomaterial performance via combining nitriding and oxidizing treatments in one process under glow discharge conditions. The oxynitrided surface layers were produced at 680 degrees C. The obtained layer was TiO + TiN + Ti2N + alphaTi(N) type and about 4-microm thick and was of diffusive character. This layer significantly increased wear resistance and slightly corrosion resistance compared to that of the reference titanium alloy. The produced titanium oxide was about 400-nm thick and built from fine crystallites. This oxide exhibits bioactivity in SBF (simulated body fluid). Osteoblasts of Saos-2 line incubated on this surface exhibited good adhesion and proliferation and ALP release comparable with cells cultured on the reference titanium alloy and TiN + Ti2N + alphaTi(N) surface layers. A quantitative analysis of blood platelets adhering to this layer revealed their highest amount in comparison to that on both the nitrided surface layer and titanium alloy. The presented study provided a simple and reproducible method of combining oxidizing and nitriding under glow discharge in one process. Experimental data in vitro suggests that titanium alloy oxynitriding under low temperatures at glow discharge conditions improves titanium alloy properties and biocompatibility and tissue healing. Therefore, the layer of TiO + TiN +Ti2N + alphaTi(N) type could be valuable for long-term bone implants. PMID:22400281

Czarnowska, E; Morgiel, J; Ossowski, M; Major, R; Sowinska, A; Wierzchon, T

2011-10-01

271

Heat transfer between tungsten surface and glow discharge plasmas in argon and CO 2  

Microsoft Academic Search

A hot-filament method is used to study the heat transfer between tungsten surface and hollow-cathode glow discharge plasmas\\u000a in argon and CO2. The dependence of the electric power supplied to a tungsten wire on the discharge current is determined for argon and carbon\\u000a dioxide in the temperature range between 1000 and 1700 K. A difference in heat transfer at the

F. D. Polikarpov; A. F. Polikarpov; S. F. Borisov; S. P. Nikulin; P. V. Tretnikov

2009-01-01

272

The millimeter and submillimeter spectrum of CF 2 and its production in a dc glow discharge  

NASA Astrophysics Data System (ADS)

Extensive measurements of the free radical CF 2 were made with microwave techniques in the millimeter and submillimeter spectral region. For this work, CF 2 was observed in a glow discharge of fluorocarbons. Cell conditioning is shown to dramatically alter the concentration of CF 2. The rotational transition frequencies were analyzed in the context of Watson's reduced centrifugal distortion Hamiltonian. The results of this analysis include both precise rotation and distortion parameters and an accurate spectral map.

Charo, Arthur; De Lucia, Frank C.

1982-08-01

273

Dielectric Electrode Surface Effects on Atmospheric Pressure Glow Discharges in Helium  

Microsoft Academic Search

Comparative experimental and theoretical studies are carried with 0.5-mm gaps using metallic and dielectric electrodes to examine the influence of dielectric surfaces upon the behavior of atmospheric pressure glow discharges in helium at frequencies of up to 22 kHz. The charge transfers associated with the discrete discharge current pulses exhibit a direct proportionality to the difference between the breakdown Vb

R. Bartnikas; I. Radu; M. R. Wertheimer

2007-01-01

274

Surface cleaning of metals in air with a one atmosphere uniform glow discharge plasma  

Microsoft Academic Search

Summary form only given, as follows. We report the use of active species generated in a one atmosphere uniform glow discharge plasma reactor with a parallel-plate configuration to clean the surface of as-received metal samples from the machine shop floor. The unmagnetized air plasma in this reactor had the following characteristic operating and plasma parameters: RF frequency, 1-4 kHz; RMS

J. Reece Roth; Yongmin Ku

1995-01-01

275

Accumulation and evolution of the spatial distribution of radicals in vitreous propanol in a glow discharge  

SciTech Connect

Analysis of the dipole broadening of an EPR line is used to explain the change in the spatial distribution of radicals formed in the plasma of a high-frequency glow discharge on the surface of vitreous propanol, which contains an electron acceptor. The contributions of various mechanisms for radical formation are evaluated. A model is proposed to describe both the accumulation and the evolution of the stabilization region of radicals in the plasmolysis process. 13 refs., 4 figs.

Kurshev, V.V.; Raitsimring, A.M.

1992-09-01

276

Plasma-polymerized tetrafluoroethylene coatings on silica particles by atmospheric-pressure glow discharge  

Microsoft Academic Search

This paper presents a method of novel plasma treatment for fine particles by the atmospheric-pressure glow (APG) discharge, in which particles were circulated and repeatedly plasma-treated at atmospheric pressure. Using this method, plasma-polymerized tetrafluoroethylene (TFE) film formations on the porous granulated silica particles of 152 ?m mean diameter were investigated. The XPS C(1s) spectrum of the treated surfaces deconvoluted into

Yasushi Sawada; Masuhiro Kogama

1997-01-01

277

Anode Glow Discharge Plasma Treatment Enhances Calcium Phosphate Adsorption onto Titanium Plates  

Microsoft Academic Search

Glow discharge plasma (GDP) supplied to a cathode (GDP-) has been applied for cleaning, surface activating, and sterilizing biomaterials, because the kinetic energy in the case of the GDP-is larger than that supplied to the anode (GDP+). However, no comparison between GDP+ and GDP-has been reported. In this study, a titanium surface pre-treated with GDP+ and GDP-was characterized by x-ray

Y. Shibata; T. Miyazaki

2002-01-01

278

Validity of the similarity law for the glow discharges in non-plane-parallel gaps  

NASA Astrophysics Data System (ADS)

The glow discharges in the gaps geometrically similar to that used in glow discharge cleaning of the International Thermonuclear Experimental Reactor (ITER) were numerically simulated based on a two-dimensional fluid model in which the linear dimensions of gap A are two times that of gap B and the pressure of gap A is half that of gap B. Under an applied voltage of 1000 V, the physical parameters at the corresponding point pz in these two gaps were compared. It was found that the electric potential U(pz), the reduced field E(pz)/p and the electron temperature Te(pz) are equal in values for these two gaps, but the electron density ne(pz) and ion density ni(pz) for gap B are four times that of gap A. All these parameter ratios are the same as that defined by similarity law, which confirmed that the similarity law is valid for the glow discharges in non-plane-parallel gaps.

Fu, Yangyang; Luo, Haiyun; Zou, Xiaobing; Wang, Xinxin

2014-12-01

279

The Use of a Glow Discharge Source in Teaching Introductory Physics  

NASA Astrophysics Data System (ADS)

Plasma physics provides a unique opportunity to teach introductory level high school physics as a unified approach to analyzing real phenomena instead of presenting it as a collection of disjointed topics. Departing from the conventional single-concept laboratory exercises, the simple tabletop experiments with low temperature plasma are rich enough to allow for a synthesis of concepts and methods taught in an introductory level physics course. Several glow discharge sources have been constructed for use as demonstration devices and as a base for advanced experiments. The constructed glow discharge sources in conjunction with commercially available sources, such as fluorescent light bulbs and plasma globes, have been used throughout the curriculum for a variety of topics. These include elastic and inelastic collisions; the properties of electric field and the motion of particles in electric and magnetic fields; electrical circuits; the principles of spectral analysis; the basic principles of conservation of energy; the interactions of electromagnetic waves with plasma. The advanced experiments have included the study of breakdown in low-pressure gases, the spectroscopic analysis of the discharge, and the use of microwave interferometry to determine the plasma density. New topics using plasmas are currently under design. The glow discharge sources have also been used for teaching basic plasma physics concepts to high school physics teachers.

Gershman, Sophia

2001-10-01

280

Atmospheric pressure glow discharge deposition of thermo-sensitive poly (N-isopropylacrylamide)  

NASA Astrophysics Data System (ADS)

In this paper, a self-made atmospheric pressure dielectric barrier discharge reactor on intermediate frequency is brought forward and developed, which is equipped with power supply of 1-20 KHz, and the working gas is argon. The experimental results show that is a very stable and uniform atmospheric pressure glow discharge (APGD). Through a series of experiments, the waveforms of single pulse and multi-pulse glow discharge were both obtained. The voltage amplitude, discharge gap and dielectric material are studied, and the conditions of multi-pulse glow discharge are discussed as well. The novel methods of depositing poly (N-isopropylacrylamide) (PNIPAAm) coatings on the surface of glass slides and PS petri dish are provided by atmospheric pressure plasma polymerization. PNIPAAm can be obtained by plasma polymerization of N-isopropylacrylamide using the self-made equipment of atmospheric pressure plasma vapor treatment. The samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle. SEM analysis has revealed that the PNIPAAm coatings were formed on the surface of the smooth glass slides. Further evaluation by using XPS, it has shown the presence of PNIPAAm. The wettability can be significantly modified by changing of the temperatures at above and below of the lower critical solution temperature (LCST) from the data of the contact angle test. These results have advantage for further application on the thermo-sensitive textile materials.

Shao, M.; Tang, X. L.; Wen, D.; Chen, Y.; Qiu, G.

2013-12-01

281

The role of electronic mechanisms in surface erosion and glow phenomena  

NASA Technical Reports Server (NTRS)

Experimental studies of desorption induced by electronic transitions (DIET) are described. Such studies are producing an increasingly complete picture of the dynamical pathways through which incident electronic energy is absorbed and rechanneled to produce macroscopic erosion and glow. These mechanistic studies can determine rate constants for erosion and glow processes in model materials and provide valuable guidance in materials selection and development. Extensive experiments with electron, photon, and heavy particle irradiation of alkali halides and other simple model materials have produced evidence showing that: (1) surface erosion, consisting primarily in the ejection or desorption of ground-state neutral atoms, occurs with large efficiencies for all irradiated species; (2) surface glow, resulting from the radiative decay of desorbed atoms, likewise occurs for all irradiating species; (3) the typical mechanism for ground-state neutral desorption is exciton formation, followed by relaxation to a permanent, mobile electronic defect which is the precursor to bond-breaking in the surface or near-surface bulk of the material; and (4) the mechanisms for excited atom formation may include curve crossing in atomic collisions, interactions with surface defect or impurity states, or defect diffusion.

Haglund, Richard F., Jr.

1987-01-01

282

Fluid simulations of glow discharges: Effect of metastable atoms in argon  

NASA Astrophysics Data System (ADS)

A one-dimensional fluid simulation of a 13.56 MHz argon glow discharge including metastable species was performed as an example of a coupled glow-discharge/neutral-transport-reaction system. Due to the slow response time of metastables (˜10 ms) direct time integration of the coupled system requires ˜105 rf cycles to converge. This translates to prohibitively long computation time. An ``acceleration'' scheme was employed using the Newton-Raphson method to speed up convergence, thereby reducing the computation time by orders of magnitude. For a pressure of 1 Torr, metastables were found to play a major role in the discharge despite the fact that their mole fraction was less than 10-5. In particular, metastable (two-step) ionization was the main mechanism for electron production to sustain the discharge. Bulk electric field and electron energy were lower, and a smaller fraction of power was dissipated in the bulk plasma when compared to the case without metastables. These results suggest that neutral transport and reaction must be considered in a self-consistent manner in glow discharge simulations, even in noble gas discharges.

Lymberopoulos, Dimitris P.; Economou, Demetre J.

1993-04-01

283

Optical and electrical characteristics of air dielectric barrier discharges in mode transition at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Atmospheric pressure dielectric barrier discharges (DBDs) have a wide range of industrial applications, generally exhibiting either filamentary or diffuse (i.e. glow) discharges. The focus of this investigation is on the formation mechanisms of the discharge current pulse width, on the order of tens of microseconds, accompanied by a light source formation, which is called a light source (LS) mode in air DBDs at atmospheric pressure. From a macroscopic point of view, the characteristics of the discharge current in the LS mode are similar with those of the glow mode. The optical and electrical characteristics of air DBDs at atmospheric pressure are investigated in the transition from the filamentary mode to the LS mode by measuring the optical emission spectroscopy and electrical signals. It is shown that in the manual increasing voltage stage, the vibrational temperature almost never changes and the gas temperature, electron temperature, dielectric capacitance, gas voltage (Vg) and discharge power (P) increase with an increase in the applied voltage. In the automatic decreasing voltage stage, all of these parameters, except Vg and P, increase with a decrease in the voltage. But, when the voltage decreases to a minimum value corresponding to the LS mode, P reaches a maximum value. In this paper, the variations of these parameters are analyzed and discussed in detail. The formation of the LS mode originates from the secondary electrons. The formation mechanisms of the secondary electrons are also discussed.

Wang, Weiwei; Liu, Feng; Wang, Xue; Han, Haiyan; Huang, Yanbin; Liang, Rongqing

2015-04-01

284

Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air  

NASA Astrophysics Data System (ADS)

The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering: Volume I, Principles. Institute of Physics Publishing, Bristol and Philadelphia 1995, ISBN 0-7503-0318-2. [2] Roth, J. R. Industrial Plasma Engineering: Volume II Applications to Nonthermal Plasma Processing Institute of Physics Publishing, Bristol and Philadelphia. 2001, ISBN 0-7503-0545-2.

Reece Roth, J.

2004-11-01

285

Numerically abnormal chromosome constitutions in humans  

SciTech Connect

Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

NONE

1993-12-31

286

Endogenous and exogenous hydrogen influence on amorphous silicon thin films analysis by pulsed radiofrequency glow discharge optical emission spectrometry.  

PubMed

During the last decade the photovoltaic industry has been growing rapidly. One major strategy to reduce the production costs is the use of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The potential of pulsed radiofrequency glow discharge coupled to optical emission spectrometry (rf-PGD-OES) for the analysis of such type of materials has been investigated in this work. It is known that when hydrogen is present in the argon discharge, even in small quantities, significant changes can occur in the emission intensities and sputtering rates measured. Therefore, a critical comparison has been carried out by rf-PGD-OES, in terms of emission intensities, penetration rates and depth resolution for two modes of hydrogen introduction in the discharge, manually external hydrogen in gaseous form (0.2% H(2)-Ar) or internal hydrogen, sputtered as a sample constituent. First, a comparative optimisation study (at 600 Pa and 50 W) was performed on conducting materials and on a silicon wafer varying the pulse parameters: pulse frequency (500 Hz-20 kHz) and duty cycle (12.5-50%). Finally, 600 Pa, 50 W, 10 kHz and 25% duty cycle were selected as the optimum conditions to analyse three types of hydrogenated samples: an intrinsic, a B-doped and a P-doped layer based on a-Si:H. Enhanced emission intensities have been measured for most elements in the presence of hydrogen (especially for silicon) despite the observed reduced sputtering rate. The influence of externally added hydrogen and that of hydrogen sputtered as sample constituent from the analysed samples has been evaluated. PMID:22244132

Sánchez, Pascal; Alberts, Deborah; Fernández, Beatriz; Menéndez, Armando; Pereiro, Rosario; Sanz-Medel, Alfredo

2012-02-10

287

Abnormal Selective Attention Normalizes P3 Amplitudes in PDD  

Microsoft Academic Search

This paper studied whether abnormal P3 amplitudes in PDD are a corollary of abnormalities in ERP components related to selective attention in visual and auditory tasks. Furthermore, this study sought to clarify possible age differences in such abnormalities. Children with PDD showed smaller P3 amplitudes than controls, but no abnormalities in selective attention. Adolescents with PDD showed abnormal selective attention,

Marco Rudolf Hoeksma; Chantal Kemner; J. Leon Kenemans; Herman van Engeland

2006-01-01

288

Four families with immunodeficiency and chromosome abnormalities.  

PubMed Central

Six children, with severe deficiency of some or all of the immunoglobulins and minor somatic abnormalities, had chromosomal abnormalities: (1) 45,XY,t(13q/18q), (2) 46,XY,21ps +, (3) two brothers 46,XY (inv. 7) (4) 45,X,t(11p/10p)/46X,iXq,t(11p/10p) and, (5) in addendum, 45,XX,-18;46,XX, r18. The chromosome abnormalities were detected in B- as well as T-lymphocytes (as evidenced by using both PHA- and PWM-stimulated cultures) in all probands, but one was mosaic in PHA culture, although all his PWM-stimulated cells were abnormal. Chromosomal variants were also detected in relatives of three and immunodeficiency in relatives of two. Images Fig. 1 Fig. 3 PMID:314782

Candy, D C; Hayward, A R; Hughes, D T; Layward, L; Soothill, J F

1979-01-01

289

Abnormal Position and Presentation of the Fetus  

MedlinePLUS

... Sections Symptoms Multimedia Table Index In This Topic Women's Health Issues Complications of Labor and Delivery Abnormal Position ... Older People's Health Issues Skin Disorders Special Subjects Women's Health Issues Chapters in Women's Health Issues Biology of ...

290

ICSN Data - Abnormal Result Technologies and Procedures  

Cancer.gov

Skip to Main Content Search International Cancer Screening Network Sponsored by the National Cancer Institute Home | About ICSN | Collaborative Projects | Meetings | Cancer Sites | Publications | Contact Us Breast Cancer (Archived Tables): Home Abnormal

291

Limiting Abnormal Mold Growth in Buildings  

E-print Network

. Unfortunately, we are learning from studies of contemporary buildings that abnormal amounts of certain molds inside our buildings can adversely affect the health of humans and animals. The same conditions that support mold growth also support fungal decay...

Graham, C. W.

2002-01-01

292

Pinna abnormalities and low-set ears  

MedlinePLUS

... because they do not affect hearing. However, sometimes cosmetic surgery is recommended. Skin tags may be tied off, ... 5 years old. More severe abnormalities may require surgery for cosmetic reasons as well as for function. Surgery to ...

293

scMRI Reveals Large-Scale Brain Network Abnormalities in Autism  

PubMed Central

Autism is a complex neurological condition characterized by childhood onset of dysfunction in multiple cognitive domains including socio-emotional function, speech and language, and processing of internally versus externally directed stimuli. Although gross brain anatomic differences in autism are well established, recent studies investigating regional differences in brain structure and function have yielded divergent and seemingly contradictory results. How regional abnormalities relate to the autistic phenotype remains unclear. We hypothesized that autism exhibits distinct perturbations in network-level brain architecture, and that cognitive dysfunction may be reflected by abnormal network structure. Network-level anatomic abnormalities in autism have not been previously described. We used structural covariance MRI to investigate network-level differences in gray matter structure within two large-scale networks strongly implicated in autism, the salience network and the default mode network, in autistic subjects and age-, gender-, and IQ-matched controls. We report specific perturbations in brain network architecture in the salience and default-mode networks consistent with clinical manifestations of autism. Extent and distribution of the salience network, involved in social-emotional regulation of environmental stimuli, is restricted in autism. In contrast, posterior elements of the default mode network have increased spatial distribution, suggesting a ‘posteriorization’ of this network. These findings are consistent with a network-based model of autism, and suggest a unifying interpretation of previous work. Moreover, we provide evidence of specific abnormalities in brain network architecture underlying autism that are quantifiable using standard clinical MRI. PMID:23185305

Zielinski, Brandon A.; Anderson, Jeffrey S.; Froehlich, Alyson L.; Prigge, Molly B. D.; Nielsen, Jared A.; Cooperrider, Jason R.; Cariello, Annahir N.; Fletcher, P. Thomas; Alexander, Andrew L.; Lange, Nicholas; Bigler, Erin D.; Lainhart, Janet E.

2012-01-01

294

Analysis of non-clonal chromosome abnormalities observed in hematologic malignancies among Southwest Oncology Group patients  

SciTech Connect

From 1987-1994, the Southwest Oncology Group Cytogenetics Committee reviewed 1571 studies in 590 adult patient cases with ALL, AML, CML or CLL. These were analyzed for the presence of clinically important non-clonal abnormalities (NCA). Abnormalities were defined as non-clonal if one metaphase had a structural abnormality or an extra chromosome. Chromosome loss was not analyzed due to the possibility of random loss. In 72 cases (12%) comprising 136 studies, at least one NCA was observed. In 21 of these cases (29%), NCAs consisted of obvious clonal evolution or instability, and thus were not included in the analysis. At least one structural NCA was observed in which the abnormality differed from the mainline in 36 (50%) patients. Seventeen of the 36 cases had a normal mode. Nineteen of the 36 patients had an abnormal or normal/abnormal mode. At least one numerical NCA was found in 15 cases (21%). Fifteen cases (21%) contained at least one marker chromosome. Several cases involved NCA in more than one of the above divisions. NCAs could be classified into several categories: (1){open_quotes}the clone to come{close_quotes}, (2) evolving clones which then disappeared, (3) NCAs with putative clinical importance that never became clonal, (4) NCAs during remission identical to the preceding clonal abnormality, (5) NCAs which indicated clonal evolution or instability. Examples include one metaphase with t(9;22) or del(20q) or inv(16) or +8 which either preceded or followed clonal findings of the same aberration. Such findings should be communicated to the clinician.

McConnell, T.S. [Univ. of New Mexico, Albuquerque, NM (United States); Dobin, S.M. [Oregon Health Sciences Univ., Portland, OR (United States)

1994-09-01

295

42 CFR 37.54 - Notification of abnormal radiographic findings.  

Code of Federal Regulations, 2013 CFR

...abnormality of cardiac shape or size, tuberculosis, lung cancer, or any other significant abnormal findings other...abnormality of cardiac shape or size, tuberculosis, cancer, complicated pneumoconiosis, and any other...

2013-10-01

296

42 CFR 37.54 - Notification of abnormal radiographic findings.  

Code of Federal Regulations, 2014 CFR

...abnormality of cardiac shape or size, tuberculosis, lung cancer, or any other significant abnormal findings other...abnormality of cardiac shape or size, tuberculosis, cancer, complicated pneumoconiosis, and any other...

2014-10-01

297

The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano.  

PubMed

Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms' anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms. PMID:25679913

Mordhorst, Thorsten; Awal, Sushil; Jordan, Sebastian; Petters, Charlotte; Sartoris, Linda; Dringen, Ralf; Bickmeyer, Ulf

2015-01-01

298

The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano  

PubMed Central

Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms’ anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms. PMID:25679913

Mordhorst, Thorsten; Awal, Sushil; Jordan, Sebastian; Petters, Charlotte; Sartoris, Linda; Dringen, Ralf; Bickmeyer, Ulf

2015-01-01

299

An improved ion guide for external ion injection in glow discharge-Fourier transform ion cyclotron resonance (GD-FTICR) mass spectrometry  

Microsoft Academic Search

To improve the existing ion transport optics of our glow discharge-Fourier transform ion cyclotron resonance (GD-FTICR) mass spectrometer, we have simulated several ion trajectories between the glow discharge source region and the ICR analyzer cell. These calculations suggested that a number of simple improvements, including the use of an ion flight tube and an electrically isolated conductance limit, would increase

Christopher M. Barshick; John R. Eyler

1992-01-01

300

Efficient Sustainment of a DC Atmospheric Pressure Glow Discharge by use of an Auxiliary Gas Flow in Pin-Plate Electrodes  

E-print Network

1 Efficient Sustainment of a DC Atmospheric Pressure Glow Discharge by use of an Auxiliary Gas Flow, when a gas is forced to flow between the electrodes to prevent a transition from a glow discharge state results are reported on the effects of the main and auxiliary gas flow driven through the discharge region

Paris-Sud XI, Université de

301

Current and light waveforms associated with the dark- to glow-discharge transition in medium- and low-pressure point-to-plane gaps  

Microsoft Academic Search

In nitrogen, for pressures below 200 Torr, the anodic glow is characterized by current oscillations, superimposed on a dc component. These oscillations may be attributed to fluctuations of the space charge, structured as a double sign sheath (double layer). The transition from a dark to a glow discharge can occur either directly from the oscillating state or, in the 20-200

A. E. Ercilbengoa; J. F. Loiseau; N. Spyrou

2000-01-01

302

Nonlocal control of electron temperature in short direct current glow discharge plasma  

SciTech Connect

To demonstrate controlling the electron temperature in nonlocal plasma, experiments have been performed on a short (without positive column) dc glow discharge with a cold cathode by applying different voltages to the conducting discharge wall. The experiments have been performed for low-pressure noble gas discharges. The applied voltage can modify trapping the energetic electrons emitted from the cathode sheath and arising from the atomic and molecular processes in the plasma within the device volume. This phenomenon results in the energetic electrons heating the slow plasma electrons, which consequently modifies the electron temperature. Furthermore, a numerical model of the discharge has demonstrated the electron temperature modification for the above case.

Demidov, V. I. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A.; Stepanova, O. M. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Kurlyandskaya, I. P. [International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

2014-09-15

303

Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium  

SciTech Connect

Due to low gas temperatures and high densities of active species, atmospheric-pressure glow discharges (APGDs) would have potential applications in the fields of plasma-based sterilization, gene mutation, etc. In this letter, the genetic effects of helium radio-frequency APGD plasmas with the plasmid DNA and oligonucleotide as the treated biomaterials are presented. The experimental results show that it is the chemically active species, instead of heat, ultraviolet radiation, intense electric field, and/or charged particles, that break the double chains of the plasmid DNA. The genetic effects depend on the plasma operating parameters, e.g., power input, helium flow rate, processing distance, time, etc.

Li Guo; Li Heping; Wang Sen; Sun Wenting; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Wang Liyan; Zhao Hongxin; Xing Xinhui [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2008-06-02

304

Stabilized aqueous dispersion of multi-walled carbon nanotubes obtained by RF glow-discharge treatment  

Microsoft Academic Search

This article reports a method for surface modification of multi-walled carbon nanotubes (MWNTs) using a low-pressure capacitively\\u000a coupled RF glow-discharge. Ar\\/C2H6 and Ar\\/C2H6\\/O2 gaseous mixtures were used to produce non-polar (np-) and polar (p-) coatings, respectively, onto MWNTs. After 5 min of plasma\\u000a treatment at 20 W and 20 torr, strongly hydrophobic and non-electrically conductive np-MWNTs were produced. The p-MWNTs were\\u000a strongly hydrophilic

Leron Vandsburger; Edward J. Swanson; Jason Tavares; Jean-Luc Meunier; Sylvain Coulombe

2009-01-01

305

Analysis of green fluorescent protein bioluminescence in vivo and in vitro using a glow discharge  

NASA Astrophysics Data System (ADS)

The discovery of fluorescent proteins has been a revolution in cell biology and related sciences because of their many applications, mainly emphasizing their use as cellular markers. The green fluorescent protein (GFP) is one of the most used as it requires no cofactors to generate fluorescence and retains this property into any organism when it is expressed by recombinant DNA techniques, which is a great advantage. In this work, we analyze the emission spectra of recombinant green fluorescent protein in vivo and in vitro exposed to a glow discharge plasma of nitrogen in order to relate electron temperature to fluorescence intensity.

Hernández, L.; Mandujano, L. A.; Cuevas, J.; Reyes, P. G.; Osorio-González, D.

2015-03-01

306

Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium  

NASA Astrophysics Data System (ADS)

Due to low gas temperatures and high densities of active species, atmospheric-pressure glow discharges (APGDs) would have potential applications in the fields of plasma-based sterilization, gene mutation, etc. In this letter, the genetic effects of helium radio-frequency APGD plasmas with the plasmid DNA and oligonucleotide as the treated biomaterials are presented. The experimental results show that it is the chemically active species, instead of heat, ultraviolet radiation, intense electric field, and/or charged particles, that break the double chains of the plasmid DNA. The genetic effects depend on the plasma operating parameters, e.g., power input, helium flow rate, processing distance, time, etc.

Li, Guo; Li, He-Ping; Wang, Li-Yan; Wang, Sen; Zhao, Hong-Xin; Sun, Wen-Ting; Xing, Xin-Hui; Bao, Cheng-Yu

2008-06-01

307

Generation of O2 From CO2 by Glow Discharge And Permeation  

NASA Technical Reports Server (NTRS)

Technique for generating supply of highly pure O2 from CO2 developed. First, atomic oxygen at useful partial pressure generated by glow-discharge dissociation of CO2. Atomic oxygen formed in vicinity of hot silver membrane and permeates through membrane to downstream region, where thermally recombined into O2 and pumped away to storage tank. Pure oxygen stored suitable for human consumption and other uses. Originally developed to convert Martian atmosphere of CO2 to O2 for astronaut consumption. Other potential applications include purification of atmospheres in Space Shuttle and Space Station Freedom. Byproduct CO must be handled by other techniques.

Outlaw, R. A.

1993-01-01

308

Influence of discharge conditions on energetic hydrogen atoms in a glow discharge  

NASA Astrophysics Data System (ADS)

Influence of discharge conditions on fast hydrogen atoms in glow discharge is investigated using Balmer alpha emission spectroscopy. Investigation was performed in two orthogonal directions of observation in pure hydrogen. The shapes of the profiles are examined together with the space intensity distribution of the excessively broadened Balmer alpha line. It was found that line profile, space intensity distribution, and energy distribution of exited atoms strongly depend on voltage, pressure, and the reduced electric field. This confirms that fast H atoms are generated in charge exchange processes and neutralization of ions at cathode surface and not in a non-field process.

Cvetanovi?, N.; Obradovi?, B. M.; Kuraica, M. M.

2011-10-01

309

Electron trapping in radio-frequency atmospheric-pressure glow discharges  

SciTech Connect

In this letter, the authors present experimental evidence of electron trapping in radio-frequency (rf) atmospheric-pressure glow discharges. By linking electron density to nanosecond plasma images and optical emission spectroscopy, they show that electron trapping occurs under most discharge conditions. The level of electron trapping increases with increasing discharge current or/and increasing excitation frequency, and manifests itself in the change of the differential conductivity at the point of the gas breakdown. Finally, they demonstrate that electron trapping is largely related to whether the half rf period is shorter than the electron transition time across the electrode gap.

Liu, D. W.; Shi, J. J.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2007-01-22

310

Influence of annular magnet on discharge characteristics in enhanced glow discharge plasma immersion ion implantation  

SciTech Connect

A permanent annular magnet positioned at the grounded anode alters the discharge characteristics in enhanced glow discharge plasma immersion ion implantation (EGD-PIII). The nonuniform magnetic field increases the electron path length and confines electron motion due to the magnetic mirror effect and electron-neutral collisions thus occur more frequently. The plasma potential and ion density measured by a Langmuir probe corroborate that ionization is improved near the grounded anode. This hybrid magnetic field EGD-PIII method is suitable for implantation of gases with low ionization rates.

Li Liuhe; Wang Zhuo [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Department 702, School of Mechanical and Automation Engineering, Beijing University of Aeronautics and Astronautics, Beijing (China); Lu Qiuyuan; Fu, Ricky K. Y.; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Pang Enjing; Dun Dandan; He Fushun; Li Fen [Department 702, School of Mechanical and Automation Engineering, Beijing University of Aeronautics and Astronautics, Beijing (China)

2011-01-10

311

Optical Actionometry Of Cathode Material Sputtered Into Plasma Phase Of Glow Discharges  

NASA Astrophysics Data System (ADS)

Cathode sputtering by glow discharge plasma is the effective solid etching. The emission of optical lines by plasma is a complex process depending on gas used. The peculiar processes such fast ion-sputte-red atom interaction and Penning excitation have been found to contribute much to the emission of optical lines of sputtered species. The optical actionometry of sputtered atoms is not suggested to be a useful method because of a lack of proper cross sections of the above peculiar processes. At present the computer simulation of both etching and characteristics of sputtered atoms in the plasma phase seems to be the preferential method..

Wro?ski, Zdzis?aw

2006-01-01

312

Dysmorphometrics: the modelling of morphological abnormalities  

PubMed Central

Background The study of typical morphological variations using quantitative, morphometric descriptors has always interested biologists in general. However, unusual examples of form, such as abnormalities are often encountered in biomedical sciences. Despite the long history of morphometrics, the means to identify and quantify such unusual form differences remains limited. Methods A theoretical concept, called dysmorphometrics, is introduced augmenting current geometric morphometrics with a focus on identifying and modelling form abnormalities. Dysmorphometrics applies the paradigm of detecting form differences as outliers compared to an appropriate norm. To achieve this, the likelihood formulation of landmark superimpositions is extended with outlier processes explicitly introducing a latent variable coding for abnormalities. A tractable solution to this augmented superimposition problem is obtained using Expectation-Maximization. The topography of detected abnormalities is encoded in a dysmorphogram. Results We demonstrate the use of dysmorphometrics to measure abrupt changes in time, asymmetry and discordancy in a set of human faces presenting with facial abnormalities. Conclusion The results clearly illustrate the unique power to reveal unusual form differences given only normative data with clear applications in both biomedical practice & research. PMID:22309623

2012-01-01

313

Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence  

NASA Astrophysics Data System (ADS)

We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet --> singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature.

Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

2015-03-01

314

Abnormal hepatocellular mitochondria in methylmalonic acidemia.  

PubMed

Methylmalonic acidemia (MMA) is one of the most frequently encountered forms of branched-chain organic acidemias. Biochemical abnormalities seen in some MMA patients, such as lactic acidemia and increased tricarboxylic acid cycle intermediate excretion, suggest mitochondrial dysfunction. In order to investigate the possibility of mitochondrial involvement in MMA, we examined liver tissue for evidence of mitochondrial ultrastructural abnormalities. Five explanted livers obtained from MMA mut(0) patients undergoing liver transplantation were biopsied. All patients had previous episodes of metabolic acidosis, lactic acidemia, ketonuria, and hyperammonemia. All biopsies revealed a striking mitochondriopathy by electron microscopy. Mitochondria were markedly variable in size, shape, and conformation of cristae. The inner matrix appeared to be greatly expanded and the cristae were diminutive and disconnected. No crystalloid inclusions were noted. This series clearly documents extensive mitochondrial ultrastructure abnormalities in liver samples from MMA patients undergoing transplantation, providing pathological evidence for mitochondrial dysfunction in the pathophysiology of MMA mut(0). Considering the trend to abnormally large mitochondria, the metabolic effects of MMA may restrict mitochondrial fission or promote fusion. The correlation between mitochondrial dysfunction and morphological abnormalities in MMA may provide insights for better understanding and monitoring of optimized or novel therapeutic strategies. PMID:24933007

Wilnai, Yael; Enns, Gregory M; Niemi, Anna-Kaisa; Higgins, John; Vogel, Hannes

2014-10-01

315

Abnormal magnetic field effects on electrogenerated chemiluminescence.  

PubMed

We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet ? singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes in solution at room temperature. PMID:25772580

Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

2015-01-01

316

Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence  

PubMed Central

We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet ? singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature. PMID:25772580

Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

2015-01-01

317

[Dental abnormalities after treatment for childhood cancer].  

PubMed

Childhood cancer therapy often increases the risk of dental complications, such as tooth and roots agenesis, microdontia, abnormal development of tooth enamel, increased risk of cavity and other abnormalities. In a comparison with other late adverse effects of chemotherapy, radiotherapy and hematopoietic stem cell transplantion, a relative small number of clinical stud-ies observing patients for more than two years after completion of anticancer treatment was published. In this article, we review the incidence of dental abnormalities caused by commonly used anticancer treatment modalities as well as discuss their risk factors. Early identification of high-risk patients, early detection and management of dental abnormalities and better education of patients or their guardians, may have an impact on quality of life of cancer survivors.Key words: chemotherapy - radiotherapy - late effects - tooth abnormalities - childhood cancer The authors declare they have no potential conflicts of interest concerning drugs, products, or?services used in the study. The Editorial Board declares that the manuscript met the ICMJE "uniform requirements" for biomedical papers.Submitted: 3. 3. 2014Accepted: 4. 12. 2014. PMID:25692751

Mladosievi?ová, B; Jurkovi?, R; Izakovi?ová Hollá, L

2015-01-01

318

p53 abnormalities and potential therapeutic targeting in multiple myeloma.  

PubMed

p53 abnormalities are regarded as an independent prognostic marker in multiple myeloma. Patients harbouring this genetic anomaly are commonly resistant to standard therapy. Thus, various p53 reactivating agents have been developed in order to restore its tumour suppressive abilities. Small molecular compounds, especially, have gained popularity in its efficacy against myeloma cells. For instance, promising preclinical results have steered both nutlin-3 and PRIMA-1 into phase I/II clinical trials. This review summarizes different modes of p53 inactivation in myeloma and highlights the current p53-based therapies that are being utilized in the clinic. Finally, we discuss the potential and promise that the novel small molecules possess for clinical application in improving the treatment outcome of myeloma. PMID:25028664

Teoh, P J; Chng, W J

2014-01-01

319

Investigation of the growth kinetics of glow-discharge hydrogenated amorphous silicon using a radical separation technique  

Microsoft Academic Search

The deposition kinetics of hydrogenated amorphous silicon (a-Si:H) from a SiH4 glow-discharge plasma have been investigated by examining the diffusion of SiH3 monoradicals in the discharge-free space within a triode reactor. This experiment suggests that the SiH3 radicals are responsible for about 37% of the total deposition rate of a-Si:H in a conventional SiH4 glow-discharge process. The contribution of other

Akihisa Matsuda; Kazunobu Tanaka

1986-01-01

320

LONG-TERM MONITORING OF MODE SWITCHING FOR PSR B0329+54  

SciTech Connect

The mode-switching phenomenon of PSR B0329+54 is investigated based on the long-term monitoring from 2003 September to 2009 April made with the Urumqi 25 m radio telescope at 1540 MHz. At that frequency, the change of relative intensity between the leading and trailing components is the predominant feature of mode switching. The intensity ratios between the leading and trailing components are measured for the individual profiles averaged over a few minutes. It is found that the ratios follow normal distributions, where the abnormal mode has a greater typical width than the normal mode, indicating that the abnormal mode is less stable than the normal mode. Our data show that 84.9% of the time for PSR B0329+54 was in the normal mode and 15.1% was in the abnormal mode. From the two passages of eight-day quasi-continuous observations in 2004, supplemented by the daily data observed with the 15 m telescope at 610 MHz at Jodrell Bank Observatory, the intrinsic distributions of mode timescales are constrained with the Bayesian inference method. It is found that the gamma distribution with the shape parameter slightly smaller than 1 is favored over the normal, log-normal, and Pareto distributions. The optimal scale parameters of the gamma distribution are 31.5 minutes for the abnormal mode and 154 minutes for the normal mode. The shape parameters have very similar values, i.e., 0.75{sup +0.22}{sub -0.17} for the normal mode and 0.84{sup +0.28}{sub -0.22} for the abnormal mode, indicating that the physical mechanisms in both modes may be the same. No long-term modulation of the relative intensity ratios was found for either mode, suggesting that the mode switching was stable. The intrinsic timescale distributions, constrained for this pulsar for the first time, provide valuable information to understand the physics of mode switching.

Chen, J. L.; Wang, N.; Liu, Z. Y.; Yuan, J. P. [Xinjiang Astronomical Observatory, 150, Science-1 Street, Urumqi, Xinjiang, 830011 (China); Wang, H. G. [Center for Astrophysics, Guangzhou University, Guangzhou 510006 (China); Lyne, A. [University of Manchester, Jodrell Bank (United Kingdom); Jessner, A.; Kramer, M., E-mail: hgwang@gzhu.edu.cn [Max-Planck Institute for Radio Astronomy, Bonn 53121 (Germany)

2011-11-01

321

[Abnormal hemoglobins and thalassemias in Mexico].  

PubMed

The distribution of abnormal hemoglobins in Mexico is derived from surveys and from the study of patients with hemolytic anemia. In aboriginal populations, more than 3,000 individuals have been studied: structural abnormal hemoglobins are virtually absent in Mexican Indians and the sporadic finding of hemoglobin S among them is due to admixture with Africans brought as slaves during the Spanish domination; two new variants of hemoglobin (Mexico and Chiapas) were found in aborigines. The surveys in hybrid groups in selected areas of the country show that in some West and East Coast communities there are different frequencies of Hb S heterozygous, and that a high prevalence of Hb S trait has been found in some communities similar to that in some African areas. In a group of 200 subjects of a town located along the Gulf of Mexico Coast, 6% of Hb S and 15% of thalassemia beta heterozygous is observed. In hospital surveys in two cities (Guadalajara and Puebla) several abnormalities of hemoglobin have been identified (C, SC, Riyadh, Baltimore, Tarrant, Fannin-Lubbock and Mexico). In the study of isolated cases, mainly of patients with hemolytic anemia, hemoglobins I-Philadelphia, G-San Jose and D-Los Angeles are seen. The thalassemias are the more frequent hemoglobin abnormalities in selected populations of our country. In a community of Italian ancestry a frequency of 1.3% of beta thalassemia trait is found. In our laboratory, 76% of the abnormalities are cases of beta thalassemia trait. Patients with Hb H disease, beta thalassemia (homozygous and heterozygous) and combinations of these abnormalities with hemoglobins S, Hb S + hereditary persistence of fetal hemoglobin (HPFH) and Hb E as well as families with delta-beta thalassemia, HPFH and Hb Lepore-Washington-Boston have been also detected. PMID:9658939

Ruiz-Reyes, G

1998-01-01

322

Development of ac corona discharge modes at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

El-Koramy, Reda Ahmed; Yehia, Ashraf; Omer, Mohamed

2011-02-01

323

Normal and abnormal human vestibular ocular function  

NASA Technical Reports Server (NTRS)

The major motivation of this research is to understand the role the vestibular system plays in sensorimotor interactions which result in spatial disorientation and motion sickness. A second goal was to explore the range of abnormality as it is reflected in quantitative measures of vestibular reflex responses. The results of a study of vestibular reflex measurements in normal subjects and preliminary results in abnormal subjects are presented in this report. Statistical methods were used to define the range of normal responses, and determine age related changes in function.

Peterka, R. J.; Black, F. O.

1986-01-01

324

Electrocardiographic abnormalities associated with raised intracranial pressure.  

PubMed Central

Serial electrocardiographic (E.C.G.) recordings were taken in seven patients suffering from intracranial conditions, for which their intracranial pressure was directly and continuously monitored with a Konigsberg extradural transducer. The E.C.G. changes observed in patients with raised intracranial pressure were prominent U waves, ST-T segment changes, notched T waves, and shortening and prolongation of Q-T intervals. Two patients with normal intracranial pressure showed no E.C.G. abnormalities but also establish a relationship between E.C.G. abnormalities and changing intracranial pressure. Images FIG. 1 FIG. 2 FIG. 3 PMID:1111762

Jachuck, S J; Ramani, P S; Clark, F; Kalbag, R M

1975-01-01

325

Hemorheological abnormalities in human arterial hypertension  

NASA Astrophysics Data System (ADS)

Blood rheology is impaired in hypertensive patients. The alteration involves blood and plasma viscosity, and the erythrocyte behaviour is often abnormal. The hemorheological pattern appears to be related to some pathophysiological mechanisms of hypertension and to organ damage, in particular left ventricular hypertrophy and myocardial ischemia. Abnormalities have been observed in erythrocyte membrane fluidity, explored by fluorescence spectroscopy and electron spin resonance. This may be relevant for red cell flow in microvessels and oxygen delivery to tissues. Although blood viscosity is not a direct target of antihypertensive therapy, the rheological properties of blood play a role in the pathophysiology of arterial hypertension and its vascular complications.

Lo Presti, Rosalia; Hopps, Eugenia; Caimi, Gregorio

2014-05-01

326

Temporal abnormalities in children with developmental dyscalculia.  

PubMed

Recent imaging studies have associated Developmental dyscalculia (DD) to structural and functional alterations corresponding Parietal and the Prefrontal cortex (PFC). Since these areas were shown also to be involved in timing abilities, we hypothesized that time processing is abnormal in DD. We compared time processing abilities between 10 children with pure DD (8 years old) and 11 age-matched healthy children. Results show that the DD group underestimated duration of a sub-second scale when asked to perform a time comparison task. The timing abnormality observed in our DD participants is consistent with evidence of a shared fronto-parietal neural network for representing time and quantity. PMID:23066940

Vicario, Carmelo Mario; Rappo, Gaetano; Pepi, Annamaria; Pavan, Andrea; Martino, Davide

2012-01-01

327

[Research progress on hereditary fibrinogen abnormalities].  

PubMed

As the most abundant component of coagulation system, fibrinogen not only takes part in clotting, but also works as one of acute phase proteins, which participates in many physiological and pathophysiological processes. Studies of fibrinogen abnormalities contribute to understand the molecular basis of disorders of fibrinogen protein function and metabolism, caused mainly by gene mutation, commonly associated with bleeding, thrombophilia, or both. Diseases affecting fibrinogen could be classified to the acquired or inherited disease. In this review, the research progress on the molecular basis, possible action mechanism of the hereditary fibrinogen abnormalities and its clinical research are summarized. PMID:25130854

Ou, Ning-Jiang; Tang, Min-Zhong

2014-08-01

328

Influence of the transverse dimension on the structure and properties of dc glow discharges  

SciTech Connect

Two-dimensional (2D) simulations of a dc glow discharge with a cold cathode in argon have been performed for various radii of the discharge tube. It is shown that the loss of the charged particles to the walls can significantly affect plasma parameters as well as properties of the cathode sheath. The longitude dimensions of the negative glow and Faraday dark space depend on the transverse loss of the charge particles and are not consistently predicted with a 1D model. The common assumption that the cathode sheath can be analyzed independently of the plasma also may not be valid. The transverse inhomogeneity of the plasma leads to a change in the current density distribution over the cathode surface. The thickness of the cathode sheath can vary with radial distance from the discharge axis, even for the case of negligible radial loss of the charge particles. The 2D model results provide an analysis of the conditions of applicability of the 1D model.

Bogdanov, E. A. [St. Petersburg State University, St. Petersburg 198904 (Russian Federation); Adams, S. F. [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Demidov, V. I. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A. [Department of Optics, St. Petersburg State University, St. Petersburg 198904 (Russian Federation); Williamson, J. M. [UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, Ohio 45432 (United States)

2010-10-15

329

ON FIFTY YEARS OF THE NEUTRON DISCOVERY: Glow discharge in a gas flow  

NASA Astrophysics Data System (ADS)

The status of research on glow discharges in a gas flow, used in pumping fast-flow lasers, is reviewed. Systematic study of this discharge began about 10 years ago. This discharge form, according to a number of properties (current flow mechanism, nature of the development of instabilities, etc.), differs considerably from the well-studied glow discharge in tubes. One of the distinguishing features of such a discharge is the negligibly small role of ionization in a large part of the positive column, so that narrow regions near the electrodes contribute most of the positive ions and electrons. Negative ions, which compensate the charge of the positive column, are generated in its volume. The discharge turns out to be weakly inhomogeneous in the direction from the cathode to the anode and the ion currents can form an appreciable part of the total current. These facts have not yet been sufficiently widely discussed in reviews and monographs. In this review, results of experimental investigations of the mechanism of current flow, energy balance, plasmochemical processes, and discharge instabilities are presented, the mathematical models used in their analysis are analyzed, and the possibilities for increasing the stability and efficiency of the discharge in fast-flow lasers are examined.

Velikhov, E. P.; Golubev, V. S.; Pashkin, S. V.

1982-05-01

330

Plasma chemical model for decomposition of SF6 in a negative glow corona discharge  

NASA Astrophysics Data System (ADS)

A zonal plasma chemical model is proposed to account for the observed oxidation and decomposition of sulfur hexafluoride (SF6) by a negative, point-to-plane glow-type corona discharge in pressurized SF6/O2/H2O gas mixtures. The model yields dependencies of stable neutral oxidation by-products such as SOF2, SO2F2, SOF4, S2F10, and SO2 on time, discharge current, and O2 and H2O concentrations which are consistent with measured results. Electron-impact-induced dissociation of SF6 in the glow region of the discharge is the decomposition rate-controlling process. The relative roles played by different reactions involving neutral free radicals and ions in different zones of the discharge are examined, and in some cases, reaction rate coefficients have been adjusted within reasonable limits to give best fits to observed production rates of various by-products. Problems of uniqueness that arise because of gaps in our knowledge about important processes that should be included in the model are also discussed.

van Brunt, R. J.; Herron, J. T.

1994-01-01

331

Growth of tungsten nanoparticles in direct-current argon glow discharges  

SciTech Connect

The growth of nanoparticles from the sputtering of a tungsten cathode in DC argon glow discharges is reported. The study was performed at fixed argon pressure and constant discharge current. The growth by successive agglomerations is evidenced. First, tungsten nanocrystallites agglomerate into primary particles, the most probable size of which being {approx}30 nm. Primary particles of this size are observed for all plasma durations and always remain the most numerous in the discharge. Primary particles quickly agglomerate to form particles with size up to {approx}150 nm. For short plasma duration, log-normal functions describe accurately the dust particle size distributions. On the contrary, for long discharge durations, a second hump appears in the distributions toward large particle sizes. In the meantime, the discharge voltage, electron density, and emission line intensities strongly evolve. Their evolutions can be divided in four separate phases and exhibit unusual distinctive features compared to earlier observations in discharges in which particles were growing. The evolution of the different parameters is explained by a competition between the surface state of the tungsten cathode and the influence of the growing nanoparticles. The differences with sputtering glow discharges and chemically active plasmas suggest that the nanoparticle growth and its influence on discharge parameters is system and material dependent.

Kishor Kumar, K.; Coueedel, L.; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moleculaires, CNRS-Aix-Marseille Universite, 13397 Marseille (France)

2013-04-15

332

A Study on Helium Glow Discharge Cleaning in the HL-1M Tokamak  

NASA Astrophysics Data System (ADS)

Based on the principle of ion-bombarded reemission and sputtering desorption, the Glow Discharge Cleaning with helium (GDC(He)) is an effective method for controlling the recycle of H on the chamber wall, Carbon (C), Oxygen (O) impurity and improving the wall conditioning in HL-1M tokamak. It is characterized by simplicity without magnet and safety, compared with Taylor Discharge Cleaning (TDC), Alternating current glow discharge Cleaning (AC), Electron Cyclotron Resonance-Discharge Cleaning (ECR-DC). Compared with bake-out degassing, the wall has a higher degassing rate during GDC(He) and a lower impurity concentration in vacuum chambers after GDC(He). Cleaning patterns have been developed dominantly for de-oxidization, decarbonization and de-hydrogenization. The cleaning parameters for H recycle on the wall are also presented. This paper mainly describes the GDC system along with its parameters, breakdown voltage, volt-ampere characteristic, the range of operation safe and suitable cleaning patterns in the HL-1M tokamak, finally concluding with some suggestions on HL-2A GDC.

Wang, Zhi-wen; Yan, Dong-hai; Wang, En-yao

2002-12-01

333

NEW RESEARCH Abnormal Amygdalar Activation and  

E-print Network

of the most disabling symptoms associated with attention-deficit/hyperactivity disorder (ADHD). We aimedNEW RESEARCH Abnormal Amygdalar Activation and Connectivity in Adolescents With Attention- Deficit/Hyperactivity Words: ADHD, amygdala, effective connectivity, fear, stimulant medication A lthough attention-deficit/hyperactivity

334

Abnormal interhemispheric connectivity in male psychopathic offenders  

PubMed Central

Background Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. Methods We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. Results We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. Limitations The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. Conclusion To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders. PMID:23937798

Hoppenbrouwers, Sylco S.; De Jesus, Danilo R.; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J.; Schutter, Dennis J.L.G.

2014-01-01

335

Emergency Abnormal Conditions Animals on Campus  

E-print Network

, but they are best left alone for your and their protection. In general, a healthy "wild" animal will make every1 Emergency Abnormal Conditions Animals on Campus a. Domestic Animals on Campus. For reasons of safety, health and sanitation, domestic animals (pets) are not allowed inside Institute buildings

Davis, Lloyd M.

336

Abnormal visual phenomena in posterior cortical atrophy  

Microsoft Academic Search

Individuals with posterior cortical atrophy (PCA) report a host of unusual and poorly explained visual disturbances. This preliminary report describes a single patient (CRO), and documents and investigates abnormally prolonged colour afterimages (concurrent and prolonged perception of colours complimentary to the colour of an observed stimulus), perceived motion of static stimuli, and better reading of small than large letters. We

Sebastian J. Crutch; Manja Lehmann; Nikos Gorgoraptis; Diego Kaski; Natalie Ryan; Masud Husain; Elizabeth K. Warrington

2011-01-01

337

Abnormalities of cingulate gyrus neuroanatomy in schizophrenia  

Microsoft Academic Search

Objective and methodsAbnormalities of the neuroanatomy of the gray matter of the cingulate gyrus, especially its anterior segment, have been suggested to be an important characteristic of schizophrenia. In this study, T1-weighted magnetic resonance scans were collected in 53 individuals with schizophrenia and 68 comparison subjects matched for age, gender, race and parental socioeconomic status. We applied Labeled Cortical Mantle

Lei Wang; Malini Hosakere; Joshua C. L. Trein; Alex Miller; J. Tilak Ratnanather; Deanna M. Barch; Paul A. Thompson; Anqi Qiu; Mokhtar H. Gado; Michael I. Miller; John G. Csernansky

2007-01-01

338

ADEPT - Abnormal Doppler Enteral Prescription Trial  

Microsoft Academic Search

BACKGROUND: Pregnancies complicated by abnormal umbilical artery Doppler blood flow patterns often result in the baby being born both preterm and growth-restricted. These babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure, and there is no clinical consensus about how best to feed them. Policies of both early milk feeding and late

Alison Leaf; Jon Dorling; Steve Kempley; Kenny McCormick; Paul Mannix; Peter Brocklehurst

2009-01-01

339

PSY 350 Abnormal Psychology Spring 2008  

E-print Network

disorders, dissociative and somatoform disorders, mood disorders, substance abuse and dependence, eating of major behavior disorders. A sampling of the specific topics will include: stress and health, #12;anxiety disorders, gender and sexuality, psychotic disorders, personality disorders, abnormal behavior in childhood

Gallo, Linda C.

340

Motor Control Abnormalities in Parkinson's Disease  

E-print Network

Motor Control Abnormalities in Parkinson's Disease Pietro Mazzoni, Britne Shabbott, and Juan Camilo York 10032 Correspondence: pm125@columbia.edu The primary manifestations of Parkinson's disease control processes. In the case of Parkinson's disease, movement slowness, for example, would be explained

341

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities  

E-print Network

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities in Children With Cerebral Palsy Influence of Cerebral Palsy Subtype, Age, and Previous Surgery Tishya A. L. Wren, PhD,* Susan Rethlefsen, PT. These findings provide important information for counsel- ing ambulatory children with cerebral palsy

Valero-Cuevas, Francisco

342

Craniofacial abnormalities among patients with Edwards Syndrome  

PubMed Central

OBJECTIVE To determine the frequency and types of craniofacial abnormalities observed in patients with trisomy 18 or Edwards syndrome (ES). METHODS This descriptive and retrospective study of a case series included all patients diagnosed with ES in a Clinical Genetics Service of a reference hospital in Southern Brazil from 1975 to 2008. The results of the karyotypic analysis, along with clinical data, were collected from medical records. RESULTS: The sample consisted of 50 patients, of which 66% were female. The median age at first evaluation was 14 days. Regarding the karyotypes, full trisomy of chromosome 18 was the main alteration (90%). Mosaicism was observed in 10%. The main craniofacial abnormalities were: microretrognathia (76%), abnormalities of the ear helix/dysplastic ears (70%), prominent occiput (52%), posteriorly rotated (46%) and low set ears (44%), and short palpebral fissures/blepharophimosis (46%). Other uncommon - but relevant - abnormalities included: microtia (18%), orofacial clefts (12%), preauricular tags (10%), facial palsy (4%), encephalocele (4%), absence of external auditory canal (2%) and asymmetric face (2%). One patient had an initial suspicion of oculo-auriculo-vertebral spectrum (OAVS) or Goldenhar syndrome. CONCLUSIONS: Despite the literature description of a characteristic clinical presentation for ES, craniofacial alterations may be variable among these patients. The OAVS findings in this sample are noteworthy. The association of ES with OAVS has been reported once in the literature. PMID:24142310

Rosa, Rafael Fabiano M.; Rosa, Rosana Cardoso M.; Lorenzen, Marina Boff; Zen, Paulo Ricardo G.; Graziadio, Carla; Paskulin, Giorgio Adriano

2013-01-01

343

Neuropsychological Abnormalities in Schizophrenia and Major Mood  

E-print Network

Neuropsychological Abnormalities in Schizophrenia and Major Mood Disorders: Similarities in schizophrenia. This work has led to an increased emphasis on identifying and evaluating treatments that enhance cognition in schizophrenia, with the hope that this would translate into a better quality of life

344

Renal Abnormalities in Psoriatic Patients: A Review  

Microsoft Academic Search

Numerous systemic diseases affect both skin and kidneys: autoimmune diseases (e.g. lupus, vasculitis), hematologic abnormalities, genetic disorders and others have been described (table 1). Although psoriasis is considered an immunomediated disease, it is assumed to affect the skin and joints exclusively. Psoriasis [1] is a common chronic inflammatory disorder of the skin, which affects more than 2% of people with

J. Heuvels; A. Maximus; J. L. Bosmans; J. Lambert; M. E. De Broe

1999-01-01

345

Abnormal vasculature in intestinal neuronal dysplasia  

Microsoft Academic Search

Intestinal neuronal dysplasia (IND) is an intestinal motility disorder, which clinically resembles Hirschsprung's disease (HD). Adventitial fibromuscular dysplasia (AFMD) consists of proliferation of smooth muscle cells and collagen fibers in the adventitia of blood vessels. The purpose of this study was to investigate vascular abnormalities in large bowel biopsies from patients with isolated HD, IND associated with HD and isolated

Udo Rolle; Anna Piaseczna Piotrowska; Prem Puri

2003-01-01

346

Psychology Faculty Perceptions of Abnormal Psychology Textbooks  

ERIC Educational Resources Information Center

The problem. The purpose of the current study was to investigate the perceptions and opinions of psychology professors regarding the accuracy and inclusiveness of abnormal psychology textbooks. It sought answers from psychology professors to the following questions: (1) What are the expectations of the psychology faculty at a private university of…

Rapport, Zachary

2011-01-01

347

On (ab)normality: Einstein's fusiform gyrus.  

PubMed

Recently, Hines (2014) wrote an evocative paper challenging findings from both histological and morphological studies of Einstein's brain. In this discussion paper, I extend Hines' theoretical point and further discuss how best to determine 'abnormal' morphology. To do so, I assess the sulcal patterning of Einstein's fusiform gyrus (FG) for the first time. The sulcal patterning of the FG was unconsidered in prior studies because the morphological features of the mid-fusiform sulcus have only been clarified recently. On the one hand, the sulcal patterning of Einstein's FG is abnormal relative to averages of 'normal' brains generated from two independent datasets (N=39 and N=15, respectively). On the other hand, within the 108 hemispheres used to make these average brains, it is not impossible to find FG sulcal patterns that resemble those of Einstein. Thus, concluding whether a morphological pattern is normal or abnormal heavily depends on the chosen analysis method (e.g. group average vs. individual). Such findings question the functional meaning of morphological 'abnormalities' when determined by comparing an individual to an average brain or average frequency characteristics. These observations are not only important for analyzing a rare brain such as that of Einstein, but also for comparing macroanatomical features between typical and atypical populations. PMID:25562419

Weiner, Kevin S

2015-03-01

348

Renal abnormalities in sickle cell disease  

Microsoft Academic Search

Renal abnormalities in sickle cell disease. Sickle cell nephropathy is indicated by sickled erythrocytes, with the consequent effects of decreased medullary blood flow, ischemia, microinfarct and papillary necrosis. Impaired urinary concentrating ability, renal acidification, hematuria, and potassium secretion are also found. There may be a causal relationship between an increase in nitric oxide synthesis and experimental sickle cell nephropathy, and

Phuong-Thu T Pham; Phuong-Chi T Pham; Alan H Wilkinson; Susie Q Lew

2000-01-01

349

Abnormal Cervical Cancer Screening Test Results  

MedlinePLUS

... LEEP) —A thin wire loop that carries an electric current is used to remove abnormal areas of the ... the cervix using a thin wire loop and electric energy. Pap Test: A test in ... document sets forth current information and opinions related to women’s health. The ...

350

Gastric emptying abnormal in duodenal ulcer  

SciTech Connect

To investigate the possibility that an abnormality of gastric emptying exists in duodenal ulcer and to determine if such an abnormality persists after ulcer healing, scintigraphic gastric emptying measurements were undertaken in 16 duodenal ulcer patients before, during, and after therapy with cimetidine; in 12 patients with pernicious anemia, and in 12 control subjects. No difference was detected in the rate or pattern of gastric emptying in duodenal ulcer patients before and after ulcer healing with cimetidine compared with controls, but emptying of the solid component of the test meal was more rapid during treatment with the drug. Comparison of emptying patterns obtained in duodenal ulcer subjects during and after cimetidine treatment with those obtained in pernicious anemia patients and controls revealed a similar relationship that was characterized by a tendency for reduction in the normal differentiation between the emptying of solid and liquid from the stomach. The similarity in emptying patterns in these groups of subjects suggests that gastric emptying of solids may be influenced by changes in the volume of gastric secretion. The failure to detect an abnormality of gastric emptying in duodenal ulcer subjects before and after ulcer healing calls into question the widespread belief that abnormally rapid gastric emptying is a feature with pathogenetic significance in duodenal ulcer disease.

Holt, S.; Heading, R.C.; Taylor, T.V.; Forrest, J.A.; Tothill, P.

1986-07-01

351

Abnormally high formation pressures, Potwar Plateau, Pakistan  

USGS Publications Warehouse

Abnormally high formation pressures in the Potwar Plateau of north-central Pakistan are major obstacles to oil and gas exploration. Severe drilling problems associated with high pressures have, in some cases, prevented adequate evaluation of reservoirs and significantly increased drilling costs. Previous investigations of abnormal pressure in the Potwar Plateau have only identified abnormal pressures in Neogene rocks. We have identified two distinct pressure regimes in this Himalayan foreland fold and thrust belt basin: one in Neogene rocks and another in pre-Neogene rocks. Pore pressures in Neogene rocks are as high as lithostatic and are interpreted to be due to tectonic compression and compaction disequilibrium associated with high rates of sedimentation. Pore pressure gradients in pre-Neogene rocks are generally less than those in Neogene rocks, commonly ranging from 0.5 to 0.7 psi/ft (11.3 to 15.8 kPa/m) and are most likely due to a combination of tectonic compression and hydrocarbon generation. The top of abnormally high pressure is highly variable and doesn't appear to be related to any specific lithologic seal. Consequently, attempts to predict the depth to the top of overpressure prior to drilling are precluded.

Law, B.E.; Shah, S.H.A.; Malik, M.A.

1998-01-01

352

Emergency Abnormal Conditions 1. Bomb Threat  

E-print Network

1 Emergency Abnormal Conditions 1. Bomb Threat a. Bomb threats usually occur by telephone. b. Try OR PACKAGE OR MOVE IT IN ANY WAY! #12;UNIVERSITY OF TENNESSEE SPACE INSTITUTE BOMB THREAT CALL FORM: ___________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ QUESTIONS TO ASK THE CALLER CONCERNING THE BOMB Who are you

Davis, Lloyd M.

353

Simulation of the shielding of dust particles in low pressure glow Seung J. Choi and Mark J. Kushner  

E-print Network

of the ions. Collisions of orbiting ions effectively increase the ion flux collected by the particle, thereby sections represented by the geometrical obscuration of the charged dust particles and their shield- ingSimulation of the shielding of dust particles in low pressure glow discharges Seung J. Choi

Kushner, Mark

354

Multiple steady states in a radio frequency chlorine glow discharge Eray S. Aydil and Demetre J. Economoua)  

E-print Network

Multiple steady states in a radio frequency chlorine glow discharge Eray S. Aydil and Demetre J June 1990; accepted for publication 10 September 1990) Multiple steady states have been observed for dc discharges. Dettmer' (see also references therein) observed two steady states in the positive

Economou, Demetre J.

355

In eastern North America, the glow of a sugar maple-covered hillside in full autumn color is an unforgettable  

E-print Network

In eastern North America, the glow of a sugar maple- covered hillside in full autumn color is an unforgettable sight. Sugar maple (Acer saccharum) (Figure 1) is one of several major tree species of its range (southern Ontario and Quebec, New England and New York) sugar maple is often the domi- nant

Weathers, Kathleen C.

356

Account of nonlocal ionization by fast electrons in the fluid models of a direct current glow discharge  

SciTech Connect

We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the 'simple' and 'extended' fluid frameworks. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.

Rafatov, I. [Physics Department, Middle East Technical University, Ankara (Turkey); Bogdanov, E. A.; Kudryavtsev, A. A. [Saint Petersburg State University, St. Petersburg (Russian Federation)

2012-09-15

357

The physics and phenomenology of One Atmosphere Uniform Glow Discharge Plasma (OAUGDP™) reactors for surface treatment applications  

Microsoft Academic Search

In this paper, we present data on the physics and phenomenology of plasma reactors based on the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP™) that are useful in optimizing the conditions for plasma formation, uniformity and surface treatment applications. It is shown that the real (as opposed to reactive) power delivered to a reactor is divided between dielectric heating of

J. Reece Roth; Jozef Rahel; Xin Dai; Daniel M. Sherman

2005-01-01

358

Voltage-current characteristics of a high-power pulsed sputtering (HPPS) glow discharge and plasma density estimation  

NASA Astrophysics Data System (ADS)

A droplet-free metallic plasma source is promising for enhanced adhesion of films with a smooth coating surface. This paper concerns the study of a highly ionized metallic plasma source using a pulsed Penning discharge designed with a magnetic field oriented parallel to an electric field. Such a plasma is called a high-power pulsed sputtering (HPPS) glow discharge plasma. This technology is related to so-called high-power impulse magnetron sputtering (HIPIMS), though the interaction of the magnetic and electric field in the HPPS glow plasma is different from the HIPIMS plasma. The titanium metallic species are sputtered by energetic argon ion bombardment, causing their ionization in as short as a few microsecond. The typical electrical characteristics are as follows: a peak current of 45 A (0.9 A/cm 2), a peak power of 18 kW (0.8 kW/cm 2), and an average power of 1 kW. The target voltage is approximately 400 V at 30 ?s for glow currents of 30-120 A. A negative pulse voltage is applied to the substrate holder electrode to extract ions from the magnetically confined HPPS glow plasma. Using the recovery characteristics of the voltage applied to the substrate, the ion density at the substrate surface is estimated to be on the order of 10 16-17 m -3 for a singly charged titanium plasma.

Yukimura, Ken; Mieda, Ryosuke; Azuma, Kingo; Tamagaki, Hiroshi; Okimoto, Tadao

2009-05-01

359

Anomalous Broadening of Balmer H{sub {alpha}} Line in Aluminum and Copper Hollow Cathode Glow Discharges  

SciTech Connect

The presented results are concerned with the shape of Balmer alpha line emitted from a low pressure DC glow discharge with aluminum (Al) and copper (Cu) hollow cathode (HC) in pure H{sub 2} and Ar-H{sub 2} gas mixture. The analysis indicates that the line profile represents a convolution of Gaussian profiles resulting from different collision excitation processes.

Sisovic, N. M.; Majstorovic, G. Lj.; Konjevic, N. [Faculty of Physics, 11001 Belgrade, P.O. Box 368 (Serbia)

2008-10-22

360

Prevention of Plasticizer Leaching From the Inner Surface of Narrow Polyvinyl Chloride Tube by DC Glow Discharge Plasma  

Microsoft Academic Search

The prevention of plasticizer leaching from the inner surface of a narrow polyvinyl chloride (PVC) tube by dc glow discharge plasma generated inside the tube was investigated. The inner surface of PVC tubes with a 4-mm inner diameter was treated by Ar plasma. The amount of plasticizer leached from the inner surface of the PVC tubes was measured by using

Xiao Qiong Wen; Xue Hua Liu; Gui Shi Liu

2010-01-01

361

The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes  

NASA Astrophysics Data System (ADS)

Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform ? mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

Sun, Wen-Ting; Liang, Tian-Ran; Wang, Hua-Bo; Li, He-Ping; Bao, Cheng-Yu

2007-05-01

362

Glowing Flowers  

NSDL National Science Digital Library

Student teams learn about engineering design of green fluorescent proteins (GFPs) and their use in medical research, including stem cell research. They simulate the use of GFPs by adding fluorescent dye to water and letting a flower or plant to transport the dye throughout its structure. Students apply their knowledge of GFPs to engineering applications in the medical, environmental and space exploration fields. Due to the fluorescing nature of the dye, plant life of any color, light or dark, can be used — unlike dyes that can only be seen in visible light.

Integrated Teaching and Learning Program,

363

Glow Up  

NSDL National Science Digital Library

In this activity, learners explore chemiluminescence and fluorescence. Learners examine 3 different solutions in regular light, in the dark with added bleach solution, and under a black light. This resource includes information about chemiluminescence and fluorescence including how these properties pertain to molecular and cell biology.

Julie Yu

2008-01-01

364

Characteristics and time evolution of a hollow cathode produced glow discharge plasma in air  

NASA Astrophysics Data System (ADS)

Current radar systems use mechanical directors and phased array technology for beam steering. Use of a sheet plasma as a microwave reflector promises several advantages over these methods. Operation is inherently broad-band, since all frequencies below the plasma frequency are reflected. The orientation and shape of the reflector may be changed directly through electronic control without resort to moving parts or expensive RF switches. The relatively fast plasma formation and extinction times ([/approx]10/ /mus) allow for rapid redirection of the microwave beam. An experimental system, dubbed the Agile Mirror, has been constructed using a cylindrical LexanTM vacuum chamber suspended within a water cooled Helmholtz coil pair capable of producing a uniform 500 Gauss field. Using this system we have created plasmas capable of reflecting 10 GHz microwaves with characteristics comparable to that of a plane metallic reflector. Most previous glow discharge work has concentrated either on the DC characteristics, or on the very early evolution (<1-2 ?s), of the discharge. To create a practical agile mirror direction, we must be able to produce a stable, flat, homogeneous plasma sheet with predictable characteristics timescales from 5 ?s to 1 ms-a regime where little pertinent quantitative data exists. This work concentrates on diagnosing the time resolved behavior of the agile mirror plasma during the mid-time, from t = 5-300 ?s, in a regime which accentuates observed changes in the discharge circuit characteristics. Measurements on an air discharge produced using VD/approx2.2 kV, p ? 208 mTorr, and B ? 250 G reveal an ne=1011/ cm-3,/ Te=1[-]3 eV plasma with distinct negative glow, Faraday dark space, and positive column regions. Analysis of time resolved potential, temperature, and spectroscopic data reveal that this discharge transitions-on time scales of [/approx]100/ /mus-into a pure negative glow discharge. The characteristics and evolution of the discharge are highly reproducible. A computer model of the discharge reveals that heating of the background gas is responsible for the transition. Implications for operation of the agile mirror discharge as a plasma mirror are discussed.

Gregor, Joseph Atilla

365

Activity of horseradish peroxide adsorbed on radio frequency glow discharge-treated polymers.  

PubMed

Horseradish peroxidase (HRP) has been used as a model enzyme in this study of its physical adsorption and residual enzyme activity on radio frequency glow discharge (RFGD)-treated polymers. The specific enzymatic activity of HRP adsorbed on different surfaces was assumed to be an indication of the extent of its conformational alterations on the surfaces. The surfaces studied were poly (ethylene terephthalate) (PET), polytetrafluoroethylene (PTFE), and tetrachloroethylene and tetrafluoroethylene glow discharge-treated PET, abbreviated as TCE/PET and TFE/PET. All surfaces were characterized by electron spectroscopy for chemical analysis (ESCA) and liquid contact angles in air. HRP adsorbs more strongly onto the two discharge-treated surfaces than onto the untreated polymers, as evidenced by the lower amount of HRP eluted by sodium dodecyl sulfate (SDS) from the treated polymers. For example, seventy percent of the HRP adsorbed on TCE/PET or TFE/PET remains on the surface after overnight elution with a 1% solution of SDS. In contrast, untreated PET and PTFE each retains only c. 20% of the absorbed enzyme. The enzymatic activity of HRP adsorbed on the different surfaces was studied using hydrogen peroxide (H2O2) as the substrate. HRP adsorbed on the higher energy surfaces, PET and TCE/PET, retains significantly more activity than the HRP adsorbed on the lower energy surfaces, PTFE and TFE/PET which appear to destroy rapidly almost all of the activity of HRP after it adsorbs. HRP adsorbed on TCE/PET is relatively more stable over time than HRP adsorbed on PET or free HRP in solution. (For example, only 45% of the specific enzymatic activity of HRP adsorbed on TCE/PET was lost after 3 h of storage in phosphate buffer at 37 degrees C, while 70% of that adsorbed on PET was lost.) In summary, when HRP is adsorbed on TCE/PET, it is very tightly bound, and yet it maintains a significant fraction of its initial specific activity and also retains this activity for 3 h in phosphate buffer at 37 degrees C. Thus, tenacious physical adsorption of proteins such as enzymes on TCE glow discharge-treated surfaces may have potential as a new method of immobilization of such molecules, for uses in biosensors, diagnostics, bioseparations, cell culture and bioreactors. PMID:8297829

Chen, J P; Kiaei, D; Hoffman, A S

1993-01-01

366

OXIDATIVE STRESS AS A POSSIBLE MODE OF ACTION FOR ARSENIC CARCINOGENESIS  

EPA Science Inventory

Abstract Many modes of action for arsenic carcinogenesis have been proposed, but few theories have a substantial mass of supporting data. Three stronger theories of arsenic carcinogenesis are production of chromosomal abnormalities, promotion of carcinogenesis and oxidati...

367

Selective mutism and abnormal electroencephalography (EEG) tracings.  

PubMed

Epileptic discharges are not considered a part of the clinical picture of selective mutism, and electroencephalography is generally not recommended in its work-up. This report describes 6 children with selective mutism who were found to have a history of epilepsy and abnormal interictal or subclinical electroencephalography recordings. Two of them had benign epilepsy of childhood with centro-temporal spikes. The mutism was not related in time to the presence of active seizures. While seizures could be controlled in all children by medications, the mutism resolved only in 1. Although the discharges could be coincidental, they might represent a co-morbidity of selective mutism or even play a role in its pathogenesis. Selective mutism should be listed among the psychiatric disorders that may be associated with electroencephalographic abnormalities. It can probably be regarded as a symptom of a more complicated organic brain disorder. PMID:21596703

Politi, Keren; Kivity, Sara; Goldberg-Stern, Hadassa; Halevi, Ayelet; Shuper, Avinoam

2011-11-01

368

Chromosomal abnormalities in a psychiatric population  

SciTech Connect

Over a 3.5 year period of time, 345 patients hospitalized for psychiatric problems were evaluated cytogenetically. The patient population included 76% males and 94% children with a mean age of 12 years. The criteria for testing was an undiagnosed etiology for mental retardation and/or autism. Cytogenetic studies identified 11, or 3%, with abnormal karyotypes, including 4 fragile X positive individuals (2 males, 2 females), and 8 with chromosomal aneuploidy, rearrangements, or deletions. While individuals with chromosomal abnormalities do not demonstrate specific behavioral, psychiatric, or developmental problems relative to other psychiatric patients, our results demonstrate the need for an increased awareness to order chromosomal analysis and fragile X testing in those individuals who have combinations of behavioral/psychiatric, learning, communication, or cognitive disturbance. 5 refs., 1 fig., 2 tabs.

Lewis, K.E.; Lubetsky, M.J.; Wenger, S.L.; Steele, M.W. [Univ. of Pittsburgh Medical Center, PA (United States)

1995-02-27

369

Effect of metastable neon atoms in a positive column of glow discharge with dust particles  

NASA Astrophysics Data System (ADS)

The diffusion/drift model of the positive column of glow discharge in neon was used for the analysis of the role of neon metastable atoms in the interaction between neon plasma and dust particles. The radial profiles of electrons and metastable atoms were simulated in the typical range of neon pressure and discharge current where dust particles may form dense dust structures changing the plasma properties. The results showed the nonlocal effect of dust particles on the plasma composition. Within the dust structure, the metastable atom concentration was shown to be higher than in the discharge without dust particles at the same discharge parameters; the ratio of concentrations of metastable atoms and electrons may increase with increasing dust particle concentration in a certain range of discharge parameters. The partial contribution of metastable atoms to the ionization was found to be higher than their losses on the surface of dust particles and increased when the gas pressure was increased.

Shumova, V. V.; Polyakov, D. N.; Vasilyak, L. M.

2014-12-01

370

Observation of dust torus with poloidal rotation in direct current glow discharge plasma  

NASA Astrophysics Data System (ADS)

Observation of dust cloud rotation in parallel-plate DC glow discharge plasma is reported here. The experiments are carried out at high pressures (˜130 Pa) with a metallic ring placed on the lower electrode (cathode). The dust cloud rotates poloidally in the vertical plane near the cathode surface. This structure is continuous toroidally. Absence of magnetic field rules out the possibility of E × B induced ion flow as the cause of dust rotation. The dust rotational structures exist even with water cooled cathode. Therefore, temperature gradient driven mechanisms, such as thermophoretic force, thermal creep flow, and free convection cannot be causing the observed dust rotation. Langmuir probe measurement reveals the existence of a sharp density gradient near the location of the rotating dust cloud. The gradient in the density, giving rise to a gradient in the ion drag force, has been identified as the principal cause behind the rotation of dust particles.

Kaur, Manjit; Bose, Sayak; Chattopadhyay, P. K.; Sharma, Devendra; Ghosh, J.; Saxena, Y. C.

2015-03-01

371

Measurements and models of transient and stationary regimes of glow discharge in argon  

NASA Astrophysics Data System (ADS)

The experimental and theoretical analyses of different regimes of argon DC glow discharge are reported. The experiments were carried out on the argon gas tube with a plane- parallel electrode system made from OFHC (oxygen-free high thermal conductivity) copper. Modelling of the static breakdown voltages was performed by simple fluid model. The applicability of fluid models for modelling of I - U (current-voltage) characteristics at different values of pd (pressure times inter-electrode distance) is tested. The formative time delays are determined from experiment and compared to modeled values obtained by [1D] and [2D] fluid models. The memory curve bar td (?) (the dependence of the mean value of breakdown time delay on the relaxation time) is presented and the main processes responsible for the memory effect were determined by applying the analytical and numerical models.

Stankov, M. N.

2014-12-01

372

Synthesis of Poly (Butyl Methacrylate/Butyl Acrylate) Highly Absorptive Resin Using Glow Discharge Electrolysis  

NASA Astrophysics Data System (ADS)

A highly absorptive resin poly (butyl methacrylate (BMA)-co-butyl acrylate (BA)) was prepared by emulsion polymerization, which was initiated by glow discharge electrolysis plasma (GDEP). The effects of discharge voltage, discharge time, monomer ratio and the amounts of cross-linking agent were examined and discussed in detail. The chemical structure of the obtained resin was characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The optimal conditions were obtained as: discharge voltage was 600 V, discharge time was 8 min, the ratios of BMA:BA being 2:1 for chloroform and 3:1 for xylene, with 2% N, N'-methylenebis. Under optimal conditions, the oil absorbency was 70 g/g for chloroform and 46 g/g for xylene. Moreover, the absorptive dynamical behavior of the resulting resin was also investigated.

Li, Yan; Yao, Mengqi; Liao, Ruirui; Yang, Wu; Gao, Jinzhang; Ren, Jie

2014-08-01

373

Analysis of glow discharges for understanding the process of film formation  

NASA Technical Reports Server (NTRS)

The physical and chemical processes which occur during the formation of different types of films in a variety of glow discharge plasmas are discussed. Emphasis is placed on plasma diagnostic experiments using spectroscopic methods, probe analysis, mass spectrometric sampling and magnetic resonance techniques which are well suited to investigate the neutral and ionized gas phase species as well as some aspects of plasma surface interactions. The results on metallic, semi-conducting and insulating films are reviewed in conjunction with proposed models and the problem encountered under film deposition conditions. It is concluded that the understanding of film deposition process requires additional experimental information on plasma surface interactions of free radicals and the synergetic effects where photon, electron and ion bombardment change the reactivity of the incident radical with the surface.

Venugopalan, M.; Avni, R.

1984-01-01

374

Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon  

SciTech Connect

Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering.

Luo, J. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Department of 702, Beihang University, Beijing 100191 (China); Li, L. H., E-mail: liliuhe@buaa.edu.cn, E-mail: paul.chu@cityu.edu.hk; Liu, H. T.; Xu, Y.; Zuo, X. J.; Zhu, P. Z.; Ma, Y. F. [Department of 702, Beihang University, Beijing 100191 (China); Yu, K. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Fu, Ricky K. Y.; Chu, Paul K., E-mail: liliuhe@buaa.edu.cn, E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2014-06-15

375

Shock-wave propagation in the plasma of a transverse glow discharge in argon  

SciTech Connect

Shock waves traveling perpendicularly to a glow discharge in an Ar plasma and Ar with no plasma were observed experimentally to examine the dissipation of shock wave energy. A piezoelectric gage attached to a quartz rod furnished the pressure pulse data by which the shock velocities could be monitored at two points in the ambient medium. The shock wave propagated almost three times as fast in the plasma. No connection was found between the speed-up of a shock and decreases in the shock wave amplitude. A correlation was found between the radial change in the shock velocity and the radial electron temperature profile. It is concluded that ion acoustic waves forming ahead of the shock induce an acceleration of the neutral particles and thereby an increase in the velocity of the shock wave. 7 references.

Basargin, I.V.; Mishin, G.I.

1985-02-01

376

PROGRESS IN 2 mm GLOW DISCHARGE POLYMER MANDREL DEVELOPMENT FOR NIF  

SciTech Connect

OAK-B135 All planned National Ignition Facility (NIF) capsule targets except machined beryllium require a glow discharge polymer (GDP) mandrel upon which the albator is applied. This mandrel, {approx} 2 mm in diameter, must at least meet if not exceed the symmetry and surface finish requirements of the final capsule. Such mandrels are currently produced by the three-step depolymerizable mandrel technique. The quality of the final mandrel depends upon precise optimization and execution of each of the three steps. They had shown previously that fabrication of a mandrel which met the symmetry and surface finish requirements was feasible using this technique. In this paper they will discuss recent progress towards converting this process into a high yield, production scale process.

NIKROO,A; BOUSQUET,J; COOK,R; McQUILLAN,B.W; PAGUIO,R; TAKAGI,M

2003-06-01

377

A study of the glow discharge characteristics of contact electrodes at atmospheric pressure in air  

SciTech Connect

Electric field distributions and discharge properties of rod-rod contact electrodes were studied under the condition of DBD for the steady generation of atmospheric pressure glow discharge plasma (APGD) in air. We found that under the effect of the initial electrons generated in a nanometer-scale gap, the rod-rod cross-contact electrodes yielded APGD plasma in air. Regarding the rod-rod cross-contact electrodes, increasing the working voltage expanded the strong electric field area of the gas gap so that both discharge area and discharge power increased, and the increase in the number of contact points kept the initial discharge voltage unchanged and caused an increase in the plasma discharge area and discharge power. A mesh-like structure of cross-contact electrodes was designed and used to generate more APGD plasma, suggesting high applicability.

Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Sun, Guangliang, E-mail: 11121659@bjtu.edu.cn; Li, Chuanhui; Zhang, Rongrong [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)] [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

2014-04-15

378

Investigation and quantification of nonlinearity using surrogate data in a glow discharge plasma  

NASA Astrophysics Data System (ADS)

Detection of nonlinearity has been carried out in periodic and aperiodic floating potential fluctuations of DC glow discharge plasma by generating surrogate data using iterative amplitude adjusted Fourier transform method. We introduce "delay vector variance" analysis (DVV) for the first time, which allows reliable detection of nonlinearity and provides some easy to interpret diagram conveying information about the nature of the experimental floating potential fluctuations (FPF). The method of false nearest neighbourhood is deployed on the FPF's to find a good embedding so as to be acquainted with the precise knowledge of m, which is desirable for carrying out DVV analysis. The emergence of nonlinearity with increase in discharge voltage has been ensured by taking into consideration the total energy present in different band of frequencies excited due to nonlinear processes. Rejection of null hypothesis has been verified by performing the rank test method that confirms the presence of nonlinearity quantitatively.

Saha, Debajyoti; Shaw, Pankaj Kumar; Ghosh, Sabuj; Janaki, M. S.; Sekar Iyengar, A. N.

2015-02-01

379

The Role of Fe(II) in the Contact Glow Discharge Electrolysis  

NASA Astrophysics Data System (ADS)

In this paper, we use methyl violet as a model organic substrate in wastewater to study the effect of Fe(II) ion on the contact glow discharge electrolysis (CGDE). The decoloration rate and the COD (Chemical Oxygen Demand) value have been examined. It is found that the presence of Fe(II) ion can accelerate obviously the degradation of methyl violet, because it reacts with H2O2 in the CGDE process to yield hydroxyl radical, just acting as a Fenton-like reagent. Moreover, the optimal conditions for decoloring methyl violet were obtained, by means of an orthogonal experiment, to be [Fe2+] =1× 10-3 mol/L, applied voltage of 700 V of and pH = 9.0.

Gao, Jinzhang; Guo, Xiao; Ma, Dongping; Yang, Wu

2007-08-01

380

Dynamic contraction of the positive column of a self-sustained glow discharge in air flow  

SciTech Connect

We study the dynamic contraction of a self-sustained glow discharge in air in a rectangular duct with convective cooling. A two dimensional numerical model of the plasma contraction was developed in a cylindrical frame. The process is described by a set of time-dependent continuity equations for the electrons, positive and negative ions; gas and vibrational temperature; and equations which account for the convective heat and plasma losses by the transverse flux. Transition from the uniform to contracted state was analyzed. It was shown that such transition experiences a hysteresis, and that the critical current of the transition increases when the gas density drops. Possible coexistence of the contracted and uniform state of the plasma in the discharge, where the current flows along the density gradient of the background gas, is discussed.

Shneider, M. N. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)] [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Mokrov, M. S. [Institute for Problems in Mechanics, RAS, Moscow (Russian Federation)] [Institute for Problems in Mechanics, RAS, Moscow (Russian Federation); Milikh, G. M. [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)] [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)

2014-03-15

381

Xe isotopic fractionation in a cathodeless glow discharge. [for carbonaceous meteoritic composition studies  

NASA Technical Reports Server (NTRS)

Results are reported on the isotopic composition of Xe processed in cathodeless glow discharges in rarefied air at pressures of 20-40 microns Hg, in the presence of activated charcoal and in empty pyrex containers. Residual gas phase Xe and trapped Xe were found to be fractionated, with the trapped Xe fractionated up to 1 percent per amu. A model is presented for the fractionating process in which Xe ions are simultaneously implanted and sputtered from substrate material, with a mass dependence favoring retention of the heavy isotopes in the substrate. Results of the investigation show that plasma synthesis of carbonaceous material is unnecessary for producing Xe fractionations, and that the fractionations observed in previous synthesis experiments are probably due to implantation of ions into the synthesized material.

Bernatowicz, T. J.; Fahey, A. J.

1986-01-01

382

Sonic Hedgehog Genetic Abnormalities and Tissue Donations  

NSDL National Science Digital Library

In this case study about a baby born with the genetic condition holoprosencephaly, students explore the “Sonic hedgehog” gene, signal transduction, and the ethics of body and tissue donation. The assignment involves students writing an informed consent document that explains the science behind this congenital abnormality. Designed for an upper-level undergraduate biology course, the case could also be used in a cell biology, developmental biology, neurobiology, or other related upper-level course.

Lauren E. Yaich

2001-01-01

383

Esophageal motility abnormalities in gastroesophageal reflux disease  

PubMed Central

Esophageal motility abnormalities are among the main factors implicated in the pathogenesis of gastroesophageal reflux disease. The recent introduction in clinical and research practice of novel esophageal testing has markedly improved our understanding of the mechanisms contributing to the development of gastroesophageal reflux disease, allowing a better management of patients with this disorder. In this context, the present article intends to provide an overview of the current literature about esophageal motility dysfunctions in patients with gastroesophageal reflux disease. Esophageal manometry, by recording intraluminal pressure, represents the gold standard to diagnose esophageal motility abnormalities. In particular, using novel techniques, such as high resolution manometry with or without concurrent intraluminal impedance monitoring, transient lower esophageal sphincter (LES) relaxations, hypotensive LES, ineffective esophageal peristalsis and bolus transit abnormalities have been better defined and strongly implicated in gastroesophageal reflux disease development. Overall, recent findings suggest that esophageal motility abnormalities are increasingly prevalent with increasing severity of reflux disease, from non-erosive reflux disease to erosive reflux disease and Barrett’s esophagus. Characterizing esophageal dysmotility among different subgroups of patients with reflux disease may represent a fundamental approach to properly diagnose these patients and, thus, to set up the best therapeutic management. Currently, surgery represents the only reliable way to restore the esophagogastric junction integrity and to reduce transient LES relaxations that are considered to be the predominant mechanism by which gastric contents can enter the esophagus. On that ground, more in depth future studies assessing the pathogenetic role of dysmotility in patients with reflux disease are warranted. PMID:24868489

Martinucci, Irene; de Bortoli, Nicola; Giacchino, Maria; Bodini, Giorgia; Marabotto, Elisa; Marchi, Santino; Savarino, Vincenzo; Savarino, Edoardo

2014-01-01

384

Vestibular and Saccadic Abnormalities in Gaucher's Disease.  

PubMed

Gaucher's disease (GD) is a hereditary lysosomal storage disease characterized by abnormal deposition of glucocerebroside due to the enzyme glucocerebrosidase deficiency, resulting in multi-organ pathology. GD type III has a progressive neurological involvement. We studied the vestibular and saccadic abnormalities in GD type III to determine if these parameters may be useful for assessing neurological involvement. We evaluated the vestibular and saccadic responses of two siblings with genetically identified GD type III on enzyme replacement therapy. Vestibular functions were assessed with the head impulse test (HIT), vestibular evoked myogenic potentials (VEMPs), and electrical vestibular stimulation (EVS). Saccadic functions were investigated with volitional horizontal and vertical saccades to ±20°. Three-dimensional head and eye movements were recorded with dual-search coils and VEMP with surface electrodes. HIT showed impaired individual semicircular canal function with halved angular vestibulo-ocular reflex (VOR) gains and absent horizontal refixation saccade. Ocular and cervical VEMPs to air-conducted clicks were absent in the older sibling, and only cervical VEMP was present in the younger sibling indicating otolithic dysfunction. EVS showed prolonged onset latency and attenuated tonic and phasic responses suggesting impaired neural conduction and vestibular function. Horizontal saccadic velocity was miniscule (<30°/s) and multiple back-to-back saccades with saccade-vergence interaction were utilized to minimize eye position error in the older sibling. Vertical saccades were slightly abnormal, but vergence and smooth pursuit were normal in both siblings. Our findings suggest that GD affected the vestibular nuclei in addition to the paramedian pontine reticular formation. These vestibular and saccadic abnormalities may be useful biomarkers to monitor neurological deterioration. PMID:24142279

Chen, Luke; Halmagyi, G Michael; Todd, Michael J; Aw, Swee T

2014-01-01

385

Central pain in multiple sclerosis - sensory abnormalities.  

PubMed

Many patients with multiple sclerosis (MS) develop central neuropathic pain (CP). In the present study somatosensory abnormalities have been analysed in detail in 62 patients with MS and CP (42 women, 20 men; mean age 52 years) and in a control group of 10 women and 6 men (mean age 47 years) with MS and sensory symptoms, but without pain. Assessment included clinical testing and quantitative methods (QST) for the measurement of perception thresholds for touch, vibration, and temperatures. All CP patients except two (97%) had abnormal thresholds for innoxious and/or noxious temperatures, compared to 81% in the control group (p<0.05). There was a tendency towards the opposite regarding sensibility to touch, which was decreased in 66% vs. 87% (n.s.), vibration (55% vs. 81%; n.s.) and to joint movement (32% vs. 62%; p<0.04). Comparisons between painful and non-painful regions showed both the absolute threshold values and the index values to be significantly more abnormal, in the CP regions, for warmth (p<0.001), cold (p<0.05), difference limen (innoxious warmth and cold, p<0.01), cold pain (p<0.01) and heat pain/cold pain combined (p<0.001). Also the comparisons between regions with central pain and regions with sensory symptoms in the controls showed significantly more abnormal thresholds in the CP patients for warmth (p<0.05), cold (p<0.01), difference limen (innoxious warmth and cold, p<0.01) and heat pain/cold pain combined (p<0.001). The results support the general hypothesis that only patients who have lesions affecting the spinothalamo-cortical pathways run the risk of developing central pain. PMID:19359204

Osterberg, A; Boivie, J

2010-01-01

386

Surgical management of complete ureteric duplication abnormalities  

Microsoft Academic Search

In 2 decades (1974–1993), the senior author (S.A.) managed 148 patients with various abnormalities associated with complete\\u000a ureteric duplication. Included were 72 patients with primary vesicoureteric reflux, 50 with ureteroceles, and 26 with upper-pole\\u000a ectopic ureters. The majority of the patients were female, and the common clinical presentations included urinary tract infection\\u000a (UTI), UTI with septicemia, and urinary incontinence. Ten

S. Sen; S. Ahmed; M. Borghol

1997-01-01

387

Glucocorticoids, cytokines and brain abnormalities in depression  

Microsoft Academic Search

Major depression (MD) is a common psychiatric disorder with a complex and multifactor aetiology. Potential mechanisms associated with the pathogenesis of this disorder include monoamine deficits, hypothalamic-pituitary-adrenal (HPA) axis dysfunctions, inflammatory and\\/or neurodegenerative alterations. An increased secretion and reactivity of cortisol together with an altered feedback inhibition are the most widely observed HPA abnormalities in MD patients. Glucocorticoids, such as

Patricia A. Zunszain; Christoph Anacker; Annamaria Cattaneo; Livia A. Carvalho; Carmine M. Pariante

2011-01-01

388

The Classification of Abnormal Behavior: An Overview  

Microsoft Academic Search

Tremendous progress in classifying abnormal behavior has been made in the past 25 years. With the advent of DSM-III and its\\u000a multiaxial system, along with the purging of psychodynamic theory from classification in favor of operational definitions,\\u000a we now have a much improved classification scheme. Nonetheless, there is still room for improvement within that system, including\\u000a a more open-minded evaluation

Henry E. Adams; Kristen A. Luscher; Jeffrey A. Bernat

389

Abnormal functional connectivity density in Parkinson's disease.  

PubMed

The pathology of Parkinson's disease (PD) is not confined to the nigrostriatal pathway, but also involves widespread cerebral cortical areas. Using seed-based resting state functional connectivity, many previous studies have demonstrated that PD patients have abnormal functional integration. However, this technique strongly relies on a priori selection of the seed regions and may miss important unpredictable findings. Using an ultrafast voxel-wise functional connectivity density approach, this study performed a whole brain functional connectivity analysis to investigate the abnormal resting-state functional activities in PD patients. Compared with healthy controls, PD patients exhibited decreased short-range functional connectivity densities in regions that were mainly located in the ventral visual pathway and decreased long-range functional connectivity densities in the right middle and superior frontal gyrus, which have been speculated to be associated with visual hallucinations and cognitive dysfunction, respectively. PD patients also exhibited increased short- and long-range functional connectivity densities in the bilateral precuneus and posterior cingulate cortex, which may represent a compensatory process for maintaining normal brain function. The observed functional connectivity density alterations might be related to the disturbed structural connectivity of PD patients, leading to abnormal functional integration. Our results suggest that functional connectivity density mapping may provide a useful means to assess PD-related neurodegeneration and to study the pathophysiology of PD. PMID:25496782

Zhang, Jiuquan; Bi, Wenwei; Zhang, Yuling; Zhu, Maohu; Zhang, Yanling; Feng, Hua; Wang, Jian; Zhang, Yuanchao; Jiang, Tianzi

2015-03-01

390

Abnormal Asymmetry of Brain Connectivity in Schizophrenia  

PubMed Central

Recently, a growing body of data has revealed that beyond a dysfunction of connectivity among different brain areas in schizophrenia patients (SCZ), there is also an abnormal asymmetry of functional connectivity compared with healthy subjects. The loss of the cerebral torque and the abnormalities of gyrification, with an increased or more complex cortical folding in the right hemisphere may provide an anatomical basis for such aberrant connectivity in SCZ. Furthermore, diffusion tensor imaging studies have shown a significant reduction of leftward asymmetry in some key white-matter tracts in SCZ. In this paper, we review the studies that investigated both structural brain asymmetry and asymmetry of functional connectivity in healthy subjects and SCZ. From an analysis of the existing literature on this topic, we can hypothesize an overall generally attenuated asymmetry of functional connectivity in SCZ compared to healthy controls. Such attenuated asymmetry increases with the duration of the disease and correlates with psychotic symptoms. Finally, we hypothesize that structural deficits across the corpus callosum may contribute to the abnormal asymmetry of intra-hemispheric connectivity in schizophrenia. PMID:25566030

Ribolsi, Michele; Daskalakis, Zafiris J.; Siracusano, Alberto; Koch, Giacomo

2014-01-01

391

Chromosomal Abnormality in Men with Impaired Spermatogenesis  

PubMed Central

Background: Chromosomal abnormalities and Y chromosome microdeletions are regarded as two most frequent genetic causes associated with failure of spermatogenesis in the Caucasian population. Materials and Methods: To investigate the distribution of genetic defects in the Romanian population with azoospermia or severe oligozoospermia, karyotype analysis by G-banding was carried out in 850 idiopathic infertile men and in 49 fertile men with one or more children. Screening for microdeletions in the azoospermia factor (AZF) region of Y chromosome was performed by multiplex polymerase chain reaction (PCR) on a group of 67 patients with no detectable chromosomal abnormality. The results of the two groups were compared by a two-tailed Fisher’s exact test. Results: In our study chromosomal abnormalities were observed in 12.70% and 8.16% of infertile and fertile individuals respectively. Conclusion: Our data suggests that infertile men with severe azoospermia have higher incidences of genetic defects than fertile men and also patients from any other group. Infertile men with normal sperm present a higher rate of polymorphic variants. It is important to know whether there is a genetic cause of male infertility before patients are subjected to intracytoplasmic sperm injection (ICSI) or testicular sperm extraction (TESE)/ICSI treatment. PMID:24696767

Mierla, Dana; Jardan, Dumitru; Stoian, Veronica

2014-01-01

392

Spectroscopic study of hydrogen rotational, vibrational and translational temperatures in a hollow cathode glow discharge  

NASA Astrophysics Data System (ADS)

Hydrogen hollow cathode glow discharges (HCGD) have been extensively used for study of fundamental discharge processes as well as for wide variety of applications. For instance, recently, this type of discharge was utilized for producing hydrogen by reforming natural gas (da Silva et al. 2006). The translational or gas kinetic temperature in gas discharges is a parameter of utmost importance in the field of plasma chemistry while vibrationally excited neutral hydrogen molecules play significant role in the chemistry of weakly ionized hydrogen plasmas. This is why the modeling of cold, reactive hydrogen plasma includes rotational and vibrational energy of the hydrogen molecule. This is the reason why we study HC discharge parameters like rotational, translational and vibrational temperature. Several diagnostic techniques are developed to determine gas kinetic temperature T_g like coherent anti-stokes Raman scattering (CARS), laser-induced fluorescence (LIF) and optical emission spectroscopy (OES). Here we selected OES. This diagnostic technique provides information about atom, molecule and ion density in excited and ground state, as well as rotational, vibrational, and gas temperature including the excitation temperature of certain group of excited levels. The technique is applied for measurements of the rotational T_rot, vibrational T_vib and determines translational temperatures in a hollow cathode glow discharge in hydrogen. The rotational temperature of excited electron energy levels is determined from the Boltzmann plot of intensities of rotational moleculelar hydrogen lines belonging to Fulcher-alpha diagonal bands. Following procedure described elsewhere (Astashkevich et al. 2006) the temperature of ground state rovibronic levels is evaluated. The constrains of rotational temperature are discussed in detail. The vibrational temperature is also determined, but from the relative intensities of the H_2 Fulcher-alpha diagonal bands. The dependence of these temperatures and their radial distribution within HC upon HC wall temperature was determined and discussed (Majstorovic et al. 2007).

Majstorovic, G. Lj.

2008-07-01

393

Retarding field energy analyzer for the characterization of negative glow sheet plasmas in a magnetic field  

SciTech Connect

A retarding field energy analyzer has been developed for diagnosing 300 {mu}s duration, 60 cm{times}60 cm negative glow, sheet plasmas immersed in a 150{endash}250 G axial magnetic field. The electron density in these 4.5 kV, 13 A, 120 mTorr discharges in air and other gases, is high enough to reflect {ital X}-band microwaves. The presence of the magnetic field makes the suppression of secondary electrons from the Faraday collector surface more difficult. The approach taken here is to bias the entire collection circuit and the amplifiers 90 V positive with respect to the data acquisition room. The differentially pumped analyzer is designed to accept electrons with a large range of perpendicular velocities, and it measures the parallel velocity distribution function of the discharge electrons entering a 0.64-mm-diam hole in the anode plate. It gives valuable information about the energy spectrum of the energetic beam electrons emitted from the cathode, and the effect of energy loss and scattering processes on this propagating beam component. Additionally, since the analyzer sampling hole is offset from the anode-cathode axis, the current density profile can be measured for different bias voltages on the retarding grid, by rotating the linear cathode about the vertical anode-cathode axis. These profiles give the sheet thickness for the beam and plasma components of the negative glow discharge. It also gives useful information about the scattering induced beam spreading and its effects on the plasma sheet thickness and electron density. {copyright} {ital 1996 American Institute of Physics.}

Mathew, J.; Meger, R.A.; Fernsler, R.F. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375-5346 (United States)] [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375-5346 (United States); Gregor, J.A. [Institute for Plasma Physics, University of Maryland, College Park, Maryland 20742 (United States)] [Institute for Plasma Physics, University of Maryland, College Park, Maryland 20742 (United States)

1996-08-01

394

Decomposition of toluene in a steady-state atmospheric-pressure glow discharge  

SciTech Connect

Results are presented from experimental studies of decomposition of toluene (C{sub 6}H{sub 5}CH{sub 3}) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C{sub 6}H{sub 5}CH{sub 3} removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N{sub 2}: O{sub 2}: H{sub 2}O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C{sub 6}H{sub 5}CH{sub 3} decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C{sub 6}H{sub 5}CH{sub 3} is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)] [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2013-02-15

395

Down's Syndrome and Leukemia: Mechanism of Additional Chromosomal Abnormalities  

ERIC Educational Resources Information Center

Chromosomal abnormalities, some appearing in a stepwise clonal evoluation, were found in five Down's syndrome patients (35 weeks to 12 years old), four with acute leukemia and one with abnormal regulation of leukopoiesis. (Author/SBH)

And Others; Goh, Kong-oo

1978-01-01

396

NEW FRONTIER IN UNDERSTANDING THE MECHANISMS OF DEVELOPMENTAL ABNORMALITIES  

EPA Science Inventory

Recent advancements in molecular developmental biology afford an opportunity to apply newly developed tools for understanding the mechanisms of both normal and abnormal development. lthough a number of agents have been identified as causing developmental abnormalities, knowledge ...

397

Performance and Economics of Catalytic Glow Plugs and Shields in Direct Injection Natural Gas Engines for the Next Generation Natural Gas Vehicle Program: Final Report  

Microsoft Academic Search

Subcontractor report details work done by TIAX and Westport to test and perform cost analysis for catalytic glow plugs and shields for direct-injection natural gas engines for the Next Generation Natural Gas Vehicle Program.

J. P. Mello; D. Bezaire; S. Sriramulu; R. Weber

2003-01-01

398

VOLUME 6S, NUMBER 18 PHYSICAL REVIE% LETTERS 4 MAY 1992 Evidence of Homoclinic Chaos in the Plasma of a Glow Discharge  

E-print Network

of a Glow Discharge Thomas Braun, ' Jorge A. Lisboa, ' ' and Jason A. C. Gallas ' ' ' Instituto de Fisica da Jii lich, W-5170 Jii lich, Germany (Received 16 December l99l) Homoclinic chaos is sho~n to occur

Gallas, Jason

399

Computed tomography and pulmonary function abnormalities in sickle cell disease  

E-print Network

ABSTRACT: The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A

unknown authors

400

Incidental abnormalities detected during scintigraphy for gastrointestinal bleeding  

SciTech Connect

The authors describe a number of abnormalities that were incidentally found in a series of 132 scintigraphic studies performed for acute gastrointestinal hemorrhage. These incidental abnormalities involved the vascular system, reticuloendothelial system, and soft tissues. Correlative radiographs and computed tomographic scans are presented for some cases. The authors explore the potential impact of these abnormalities on subsequent patient evaluation and care, including radiologic workup.

Zuckier, L.S.; Patel, Y.D. (Albert Einstein College of Medicine, Bronx, NY (USA))

1990-05-01

401

Structural Pituitary Abnormalities Associated With CHARGE Syndrome  

PubMed Central

Introduction: CHARGE syndrome is a multisystem disorder that, in addition to Kallmann syndrome/isolated hypogonadotrophic hypogonadism, has been associated with anterior pituitary hypoplasia (APH). However, structural abnormalities such as an ectopic posterior pituitary (EPP) have not yet been described in such patients. Objective: The aims of the study were: 1) to describe the association between CHARGE syndrome and a structurally abnormal pituitary gland; and 2) to investigate whether CHD7 variants, which are identified in 65% of CHARGE patients, are common in septo-optic dysplasia /hypopituitarism. Methods: We describe 2 patients with features of CHARGE and EPP. CHD7 was sequenced in these and other patients with septo-optic dysplasia/hypopituitarism. Results: EPP, APH, and GH, TSH, and probable LH/FSH deficiency were present in 1 patient, and EPP and APH with GH, TSH, LH/FSH, and ACTH deficiency were present in another patient, both of whom had features of CHARGE syndrome. Both had variations in CHD7 that were novel and undetected in control cohorts or in the international database of CHARGE patients, but were also present in their unaffected mothers. No CHD7 variants were detected in the patients with septo-optic dysplasia/hypopituitarism without additional CHARGE features. Conclusion: We report a novel association between CHARGE syndrome and structural abnormalities of the pituitary gland in 2 patients with variations in CHD7 that are of unknown significance. However, CHD7 mutations are an uncommon cause of septo-optic dysplasia or hypopituitarism. Our data suggest the need for evaluation of pituitary function/anatomy in patients with CHARGE syndrome. PMID:23526466

Gregory, Louise C.; Gevers, Evelien F.; Baker, Joanne; Kasia, Tessa; Chong, Kling; Josifova, Dragana J.; Caimari, Maria; Bilan, Frederic; McCabe, Mark J.

2013-01-01

402

Eye Movement Abnormalities in Joubert Syndrome  

PubMed Central

Purpose Joubert syndrome is a genetic disorder characterized by hypoplasia of the midline cerebellum and deficiency of crossed connections between neural structures in the brain stem that control eye movements. The goal of the study was to quantify the eye movement abnormalities that occur in Joubert syndrome. Methods Eye movements were recorded in response to stationary stimuli and stimuli designed to elicit smooth pursuit, saccades, optokinetic nystagmus (OKN), vestibulo-ocular reflex (VOR), and vergence using video-oculography or Skalar search coils in 8 patients with Joubert syndrome. All patients underwent high-resolution magnetic resonance imaging (MRI). Results All patients had the highly characteristic molar tooth sign on brain MRI. Six patients had conjugate pendular (n = 4) or see-saw nystagmus (n = 2); gaze holding was stable in four patients. Smooth-pursuit gains were 0.28 to 1.19, 0.11 to 0.68, and 0.33 to 0.73 at peak stimulus velocities of 10, 20, and 30 deg/s in six patients; smooth pursuit could not be elicited in four patients. Saccade gains in five patients ranged from 0.35 to 0.91 and velocities ranged from 60.9 to 259.5 deg/s. Targeted saccades could not be elicited in five patients. Horizontal OKN gain was uniformly reduced across gratings drifted at velocities of 15, 30, and 45 deg/s. VOR gain was 0.8 or higher and phase appropriate in three of seven subjects; VOR gain was 0.3 or less and phase was indeterminate in four subjects. Conclusions The abnormalities in gaze-holding and eye movements are consistent with the distributed abnormalities of midline cerebellum and brain stem regions associated with Joubert syndrome. PMID:19443711

Weiss, Avery H.; Doherty, Dan; Parisi, Melissa; Shaw, Dennis; Glass, Ian; Phillips, James O.

2011-01-01

403

Chromosome abnormalities in primary ovarian cancer  

SciTech Connect

Chromosome abnormalities that are specific and recurrent may occur in regions of the genome that are involved in the conversion of normal cells to those with tumorigenic potential. Ovarian cancer is the primary cause of death among patients with gynecological malignancies. We have performed cytogenetic analysis of 16 ovarian tumors from women age 28-82. Three tumors of low malignant potential and three granulosa cell tumors had normal karyotypes. To look for the presence of trisomy 12, which has been suggested to be a common aberration in this group of tumors, interphase fluorescence in situ hybridization was performed on direct preparations from three of these tumors using a probe for alpha satellite sequences of chromosome 12. In the 3 preparations, 92-98 percent of the cells contained two copies of chromosome 12, indicating that trisomy 12 is not a universal finding in low grade ovarian tumors. Endometrioid carcinoma of the ovary is histologically indistinguishable from endometial carcinoma of the uterus. We studied 10 endometrioid tumors to determine the degree of genetic similarity between these two carcinomas. Six out of ten endometrioid tumors showed a near-triploid modal number, and one presented with a tetraploid modal number. Eight of the ten contained structural chromosome abnormalities, of which the most frequent were 1p- (5 tumors), 19q+ (3 tumors), 6q- or ins(6) (4 tumors), 3q- or 3q+ (4 tumors). These cytogenetic results resemble those reported for papillary ovarian tumors and differ from those of endometrial carcinoma of the uterus. We conclude that despite the histologic similarities between the endometrioid and endometrial carcinomas, the genetic abnormalities in the genesis of these tumors differ significantly.

Yonescu, R.; Currie, J.; Griffin, C.A. [John Hopkins Univ., Baltimore, MD (United States)

1994-09-01

404

Thenar hypoplasia with associated radiologic abnormalities.  

PubMed

We report on five patients who presented with unilateral or bilateral hypoplasia of the thenar eminence. X rays of the affected limbs showed varying degrees of malformation and underdevelopment of the thumb phalanges and first metacarpal bone, and of the carpal bones at the base of the thumb, indicating a developmental abnormality. Our electrodiagnostic findings were compatible with this interpretation. We suggest that this condition is part of the clinical spectrum of radial club hand (radial dysplasia) and that when seen in adults, its recognition is important in the differential diagnosis of carpal tunnel syndrome. PMID:514310

Cavanagh, N P; Yates, D A; Sutcliffe, J

1979-01-01

405

Sexsomnia: abnormal sexual behavior during sleep.  

PubMed

This review attempts to assemble the characteristics of a distinct variant of sleepwalking called sexsomnia/sleepsex from the seemingly scarce literature into a coherent theoretical framework. Common features of sexsomnia include sexual arousal with autonomic activation (e.g. nocturnal erection, vaginal lubrication, nocturnal emission, dream orgasms). Somnambulistic sexual behavior and its clinical implications, the role of precipitating factors, diagnostic, treatment, and medico-legal issues are also reviewed. The characteristics of several individuals described in literature including their family/personal history of parasomnia as well as the abnormal behaviors occurring during sleep are reported. PMID:17706786

Andersen, Monica L; Poyares, Dalva; Alves, Rosana S C; Skomro, Robert; Tufik, Sergio

2007-12-01

406

Nail abnormalities associated with systemic pathologies.  

PubMed

Nail abnormalities can arise in conjunction with or as a result of systematic pathologies. These pathologies include single-organ diseases, multisystemic diseases, and drug-induced insults. Clinical signs associated with these conditions include dyschromias, vascular alterations, periungual tissue changes, textural dystrophies, contour alterations, and growth-rate alterations. The associated systemic pathologies may affect any part of the nail apparatus, including the nail matrix, the nail plate, the nail bed, the underlying vasculature, and the periungual tissues. The anatomical location and extent of damage determine the clinically manifested anomaly. PMID:24079592

Zaiac, Martin N; Walker, Ashley

2013-01-01

407

Abnormal mental phenomena in the prophets.  

PubMed

Abnormal mental phenomena of varying emotional depth are found frequently among the earlier, nonliterary, and literary prophets. Three levels are discerned: inspiration, i.e., a state of excitement with well-preserved reality controls; ecestasy, as a state in which reality control has been lost temporarily; and eidetic imagery characterized by dreams and visions. It is argued that the prophets were psychotics, or mystics, or poets, or endowed with psychic gifts. I have attempted to consider some of these phenomena from the psychiatric viewpoint, keeping in mind that such interpretations many centuries later must remain speculative. PMID:24408495

Nussbaum, K

1974-07-01

408

Reversible intestinal mucosal abnormality in acrodermatitis enteropathica.  

PubMed Central

In 3 cases of acrodermatitis enteropathica duodenal biopsy performed at the outset of treatment showed a similar abnormality of the intestinal mucosa. Further biopsies taken during treatment showed progressive improvement of the intestinal mucosa with subsequent complete restoration of the normal cellular and villous pattern. The initial treatment was with expressed human breast milk and oral di-iodohydroxyquinoline. The latter was continued alone and later replaced by zinc sulphate. Changes in the intestinal epithelial cells and inflammatory cell infiltration of the lamina propria still detectable on di-iodohydroxyquinoline therapy reverted to normal with oral zinc. Images Fig. 1 Fig. 2 PMID:952555

Kelly, R; Davidson, G P; Townley, R R; Campbell, P E

1976-01-01

409

Acoustic wave propagation in uniform glow discharge plasma at an arbitrary angle between the electric field and wave vectors  

SciTech Connect

This paper extends the recently reported one-dimensional model for sound propagation in glow discharge plasma to arbitrary mutual orientation of the plasma electric field and acoustic wave vectors. The results demonstrate that an acoustic wave in plasma may amplify, attenuate, or remain unchanged depending on the angle between these vectors and on the power input into the discharge. Quantitative evaluations indicate that for glow discharge plasma of a self-sustained discharge in air at the electric current densities of the order of 100 mA cm{sup -2}, a gain of as much as 1 m{sup -1} at 0 deg. angle between the vectors changes to similar strength attenuation for the 90 deg. angle.

Soukhomlinov, Vladimir; Gerasimov, Nikolay [Research Institute for Physics, Saint-Petersburg State University, 1 Ulianovskaya Street, S. Petergof, Saint Petersburg 198904 (Russian Federation); Sheverev, Valery A. [Polytechnic University, Six Metrotech Center, Brooklyn, New York 11201 (United States)

2008-08-15

410

An improved ion guide for external ion injection in glow discharge—fourier transform ion cyclotron resonance mass spectrometry  

Microsoft Academic Search

To improve the existing ion transport optics of our glow discharge (GD)-Fourier transformion cyclotron resonance (FT-ICR)\\u000a mass spectrometer, we simulated several ion trajectories between the GD source region and the ICR analyzer cell. These calculations\\u000a suggested that a number of simple improvements, including the use of an ion flight tube and an electrically isolated conductance\\u000a limit, would increase the efficiency

Christopher M. Barshick; John R. Eyler

1993-01-01

411

Inhibition of bacterial adhesion on PVC endotracheal tubes by RF-oxygen glow discharge, sodium hydroxide and silver nitrate treatments  

Microsoft Academic Search

Medical-grade poly(vinyl chloride) (PVC) was chemically modified to study how the incorporation of monovalent silver influences Pseudomonas aeruginosa adhesion and colonization. The modification investigated consisted of a radio frequency-oxygen (RF-O2) glow discharge pre-functionalization, followed by a two-step wet-treatment in sodium hydroxide and silver nitrate solutions. X-ray photoelectron spectroscopy (XPS) analysis and contact angle measurements were used to investigate the chemical

D. J. Balazs; K. Triandafillu; P. Wood; Y. Chevolot; C. van Delden; H. Harms; C. Hollenstein; H. J. Mathieu

2004-01-01

412

On the increase in the limiting current of an atmospheric-pressure glow discharge in an argon flow  

NASA Astrophysics Data System (ADS)

The initiation of an atmospheric-pressure glow discharge (APGD) is studied in the multitip cathode-planar anode electrode system through which an argon flow passes. It is shown that sectioning of the cathode and ballast resistances present at corona tips make it possible to substantially expand the current region of the discharge and considerably raise the limiting current of the APGD. The shape of the coronafree electrode is found to influence the limiting discharge current.

Baldanov, B. B.; Ranzhurov, Ts. V.

2014-04-01

413

Control of Abnormal Synchronization in Neurological Disorders  

PubMed Central

In the nervous system, synchronization processes play an important role, e.g., in the context of information processing and motor control. However, pathological, excessive synchronization may strongly impair brain function and is a hallmark of several neurological disorders. This focused review addresses the question of how an abnormal neuronal synchronization can specifically be counteracted by invasive and non-invasive brain stimulation as, for instance, by deep brain stimulation for the treatment of Parkinson’s disease, or by acoustic stimulation for the treatment of tinnitus. On the example of coordinated reset (CR) neuromodulation, we illustrate how insights into the dynamics of complex systems contribute to successful model-based approaches, which use methods from synergetics, non-linear dynamics, and statistical physics, for the development of novel therapies for normalization of brain function and synaptic connectivity. Based on the intrinsic multistability of the neuronal populations induced by spike timing-dependent plasticity (STDP), CR neuromodulation utilizes the mutual interdependence between synaptic connectivity and dynamics of the neuronal networks in order to restore more physiological patterns of connectivity via desynchronization of neuronal activity. The very goal is to shift the neuronal population by stimulation from an abnormally coupled and synchronized state to a desynchronized regime with normalized synaptic connectivity, which significantly outlasts the stimulation cessation, so that long-lasting therapeutic effects can be achieved. PMID:25566174

Popovych, Oleksandr V.; Tass, Peter A.

2014-01-01

414

Abnormal Striatal Dopamine Transmission in Schizophrenia  

PubMed Central

Despite numerous revisions and reformulations, dopamine (DA) hypothesis of schizophrenia remains a pivotal neurochemical hypothesis of this illness. The aim of this review is to expose and discuss findings from positron emission tomography (PET) or single-photon-emission computed tomography (SPECT) studies investigating DA function in the striatum of medicated, drug-naïve or drug-free patients with schizophrenia and in individuals at risk compared with healthy volunteers. DA function was studied at several levels: i) at a presynaptic level where neuroimaging studies investigating DOPA uptake capacity clearly show an increase of DA synthesis in patients with schizophrenia; ii) at a synaptic level where neuroimaging studies investigating dopamine transporter availability (DAT) does not bring any evidence of dysfunction; iii) and finally, neuroimaging studies investigating DA receptor density show a mild increase of D2 receptor density in basic condition and, an hyperreactivity of DA system in dynamic condition. These results are discussed regarding laterality, sub-regions of striatum and implications for the at-risk population. Striatal DA abnormalities are now clearly demonstrated in patients with schizophrenia and at risk population and could constitute an endophenotype of schizophrenia. Subtle sub-clinical striatal DA abnormalities in at risk population could be a biomarker of transition from a vulnerability state to the expression of frank psychosis. PMID:23157632

Brunelin, Jerome; Fecteau, Shirley; Suaud-Chagny, Marie-Françoise

2013-01-01

415

Ectodermal abnormalities in patients with Kabuki syndrome.  

PubMed

Kabuki syndrome (KS) is extensively described in the literature and characterized by a typical facial gestalt in combination with postnatal short stature, hypotonia, joint laxity, developmental delay, persistent fetal fingertip pads, and an ever-growing group of congenital abnormalities. In this study, we focus on some ectodermal manifestations that we have observed. We studied seven patients who fulfilled the clinical criteria for KS and undertook a detailed clinical, dental, cytogenetic, and immunoglobulin assessments. In addition, microscopic hair examinations were performed on all patients and compared with matched control patients. All patients had receding of the anterior hair line, but five had evident sparse frontal scalp hair. They all showed peculiar similar microscopic hair abnormalities in the form of twisting of the hair shafts, irregularity of the diameter of the hair, and trichorrhexis nodosa. In addition, hypoplastic nails, café-au-lait patches, and missing upper lateral incisors were observed in 57.1%, 28.6%, and 14.3% of the patients, respectively. Variable orodental anomalies were seen in all the patients with an everted lower lip found in four patients (57.1%). This report provides further evidence that some cases of KS have ectodermal involvement. PMID:21692838

Abdel-Salam, Ghada M H; Afifi, Hanan H; Eid, Maha M; El-Badry, Tarek H; Kholoussi, Naglaa

2011-01-01

416

Protruding labia minora: abnormal or just uncool?  

PubMed

There is a wide variety in the appearance of normal female external genitalia. Nevertheless a specific prototype is promoted by the media, leading to a false sense that all other appearances are abnormal. As adolescents become sexually aware at an earlier age, most of them are worried about the appearance of their genitalia, especially when labia minora protrude beyond labia majora. This is a prospective audit of adolescents presenting for assessment of their perceived abnormal genitalia. Sixteen girls aged 10.2 to 17.8 years presented between June 2009 and December 2010 to a specialist adolescent gynecology service. Their mean labial width was 36?mm (range: 20-55?mm). In six girls, the reason for attending the service was inequality of the size of labia ranging between 6?mm and 35?mm (mean of 20?mm). Among the remaining 10 girls, the concern had arisen through comparison with a prepubescent sibling (one case), change of genitalia during puberty (four cases), looking at internet pictures (four cases), and looking at an anatomy book (one case). Risks of Female Genital Cosmetic Surgery (FGCS) have not been adequately documented, especially with regards to sexual function and long-term patient satisfaction. External genitalia are likely to change during puberty and therefore, any genital operation in the absence of clear pathology should be deferred until adulthood. Even then, women should have clear expectations of what will be achieved with the operation in terms of appearance and function. PMID:21696338

Michala, Lina; Koliantzaki, Sofia; Antsaklis, Aris

2011-09-01

417

Native fluorescence characterization of human liver abnormalities  

NASA Astrophysics Data System (ADS)

Fluorescence spectroscopy of intrinsic biomolecules has been extensively used in biology and medicine for the past several decades. In the present study, we report the native fluorescence characteristics of blood plasma from normal human subjects and patients with different liver abnormalities such as hepatitis, leptospirosis, jaundice, cirrhosis and liver cell failure. Native fluorescence spectra of blood plasma -- acetone extract were measured at 405 nm excitation. The average spectrum of normal blood plasma has a prominent emission peak around 464 nm whereas in the case of liver diseased subjects, the primary peak is red shifted with respect to normal. In addition, liver diseased cases show distinct secondary emission peak around 615 nm, which may be attributed to the presence of endogenous porphyrins. The red shift of the prominent emission peak with respect to normal is found to be maximum for hepatitis and minimum for cirrhosis whereas the secondary emission peak around 615 nm was found to be more prominent in the case of cirrhosis than the rest. The ratio parameter I465/I615 is found to be statistically significant (p less than 0.001) in discriminating liver abnormalities from normal.

Ganesan, Singaravelu; Madhuri, S.; Aruna, Prakasa R.; Suchitra, S.; Srinivasan, T. G.

1999-05-01

418

Hepatic perfusion abnormalities during CT angiography: Detection and interpretation  

SciTech Connect

Twenty-seven perfusion abnormalities were detected in 17 of 50 patients who underwent computed tomographic angiography (CTA) of the liver. All but one of the perfusion abnormalities occurred in patients with primary or metastatic liver tumors. Perfusion abnormalities were lobar in nine cases, segmental in 11, and subsegmental in seven; 14 were hypoperfusion and 13 were hyperperfusion abnormalities. The causes for the abnormalities included nonperfusion of a replaced hepatic artery (n = 11), cirrhosis and nodular regeneration (n = 3), altered hepatic hemodynamics (e.g., siphoning, laminar flow) caused by tumor (n = 7), contrast media washout from a nonperfused vessel (n = 1), compression of adjacent hepatic parenchyma (n = 1), and unknown (n = 4). Differentiation of perfusion abnormalities from tumor usually can be made by comparing the morphology of the known tumor with the suspected perfusion abnormality, changes of each on delayed CTA scans, and review of initial angiograms and other imaging studies.

Freeny, P.C.; Marks, W.M.

1986-06-01

419

Abnormal Elastic and Vibrational Behaviors of Magnetite at High Pressures  

PubMed Central

Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive. We have studied a highly stoichiometric magnetite using inelastic X-ray scattering, X-ray diffraction and emission, and Raman spectroscopies in diamond anvil cells up to ~20?GPa, while complementary electrical conductivity measurements were conducted in a cubic anvil cell up to 8.5?GPa. We have observed an elastic softening in the diagonal elastic constants (C11 and C44) and a hardening in the off-diagonal constant (C12) at ~8?GPa where significant elastic anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] direction. An additional vibrational Raman band between the A1g and T2g modes was also detected at the transition pressure. These abnormal elastic and vibrational behaviors of magnetite are attributed to the occurrence of the octahedrally-coordinated Fe2+-Fe3+-Fe2+ ions charge-ordering along the [110] direction in the inverse spinel structure. We propose a new phase diagram of magnetite in which the temperature for the metal-insulator and distorted structural transitions decreases with increasing pressure while the charge-ordering transition occurs at ~8?GPa and room temperature. PMID:25186916

Lin, Jung-Fu; Wu, Junjie; Zhu, Jie; Mao, Zhu; Said, Ayman H.; Leu, Bogdan M.; Cheng, Jinguang; Uwatoko, Yoshiya; Jin, Changqing; Zhou, Jianshi

2014-01-01

420

Abnormal elastic and vibrational behaviors of magnetite at high pressures.  

PubMed

Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive. We have studied a highly stoichiometric magnetite using inelastic X-ray scattering, X-ray diffraction and emission, and Raman spectroscopies in diamond anvil cells up to ~20 GPa, while complementary electrical conductivity measurements were conducted in a cubic anvil cell up to 8.5 GPa. We have observed an elastic softening in the diagonal elastic constants (C11 and C44) and a hardening in the off-diagonal constant (C12) at ~8 GPa where significant elastic anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] direction. An additional vibrational Raman band between the A1g and T2g modes was also detected at the transition pressure. These abnormal elastic and vibrational behaviors of magnetite are attributed to the occurrence of the octahedrally-coordinated Fe(2+)-Fe(3+)-Fe(2+) ions charge-ordering along the [110] direction in the inverse spinel structure. We propose a new phase diagram of magnetite in which the temperature for the metal-insulator and distorted structural transitions decreases with increasing pressure while the charge-ordering transition occurs at ~8 GPa and room temperature. PMID:25186916

Lin, Jung-Fu; Wu, Junjie; Zhu, Jie; Mao, Zhu; Said, Ayman H; Leu, Bogdan M; Cheng, Jinguang; Uwatoko, Yoshiya; Jin, Changqing; Zhou, Jianshi

2014-01-01

421

Abnormal Elastic and Vibrational Behaviors of Magnetite at High Pressures  

NASA Astrophysics Data System (ADS)

Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive. We have studied a highly stoichiometric magnetite using inelastic X-ray scattering, X-ray diffraction and emission, and Raman spectroscopies in diamond anvil cells up to ~20 GPa, while complementary electrical conductivity measurements were conducted in a cubic anvil cell up to 8.5 GPa. We have observed an elastic softening in the diagonal elastic constants (C11 and C44) and a hardening in the off-diagonal constant (C12) at ~8 GPa where significant elastic anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] direction. An additional vibrational Raman band between the A1g and T2g modes was also detected at the transition pressure. These abnormal elastic and vibrational behaviors of magnetite are attributed to the occurrence of the octahedrally-coordinated Fe2+-Fe3+-Fe2+ ions charge-ordering along the [110] direction in the inverse spinel structure. We propose a new phase diagram of magnetite in which the temperature for the metal-insulator and distorted structural transitions decreases with increasing pressure while the charge-ordering transition occurs at ~8 GPa and room temperature.

Lin, Jung-Fu; Wu, Junjie; Zhu, Jie; Mao, Zhu; Said, Ayman H.; Leu, Bogdan M.; Cheng, Jinguang; Uwatoko, Yoshiya; Jin, Changqing; Zhou, Jianshi

2014-09-01

422

Experimental and numerical study of an atmospheric pressure glow discharge in helium  

NASA Astrophysics Data System (ADS)

. Atmospheric pressure glow discharges in helium have been reported to produce radially uniform plasmas and to show one single current pulse per half cycle of the AC high voltage [1]. However, in other studies the appearance of multiple periodic peaks per half cycle has been reported as well. Different interpretations have been given for this effect ranging from the oscillation of the cathode sheath [2] to multiple successive breakdowns [3]. We have performed studies with different dielectrics to investigate their effect on the discharge behavior: two circular 4 cm diameter electrodes have been covered with (1) 1.7 mm thick glass plates (er = 4.6) and with (2) 0.635 mm thick alumina plates (er = 9). At a gap of 5 mm, multiple current peaks were observed with both configurations. Time resolved measurements of the emission intensity using a gated intensified CCD camera were performed, both in axial and radial direction. These indicate that the first current pulse is produced by a radially propagating ionization front, while later peaks are related to breakdowns at the electrode edges. With 0.635 mm thick alumina plates we could observe the appearance of a strong cathode fall in front of the momentary cathode, together with a Faraday dark space and a positive column that extended for a length of 2-3 mm. A two-dimensional fluid model has been realized to study the glow discharge behavior. The numerical result is qualitatively in good agreement with the observed structure of the discharge. The model reproduces the radial propagation of the ionization wave. This work is supported by the Department of Energy under grant DE-FG02-00ER54583. [1] Massines F., Rabehi A., Decomps P., Gadri R.B., Segur P., and Mayoux C., J.Appl.Phys. 83, 2950- 2957 (1998). [2] Akishev Y.S., Dem'yanov A., Karal'nik V.B., Trushkin N.I., and Pan'kin M.V., Proc. Of XXIV ICPIG, Poland, July 11-16, 137-138, (1999). [3] Mangolini L., Orlov K., Kortshagen U., Heberlein J., and Kogelschatz U., Appl.Phys.Lett.80, 1723 (2002).

Mangolini, Lorenzo; Zhang, Peng; Anderson, Curtis; Kortshagen, Uwe; Heberlein, Joachim

2002-10-01

423

Spatial distribution of the neutral carboneous compounds glow in the sunward Halley comet coma  

NASA Astrophysics Data System (ADS)

This work presents a study of the C 2, C 3, CH, and CN glow in the Halley's coma in sunward direction. For that purpose, 1035 spectra in the near UV and visible region registered by the Three-Channel Spectrometer (TKS) on board Vega-2 station on 9 March 1986 are used. An improved method of the dust continuum extraction in the visible region is applied. The "dust regions" in the Halley's comet spectra are re-examined. The spectral index u and a normalization coefficient of the continuum are computed for each spectrum by the least squares method on the basis of a linear regression. The index u is obtained to lay in the interval 3-3.4. For all spectra, the average u and d u values are: uav = 3.2126, d uav = 0.1197. Thus, the dust continuum evaluation is reliable, which conduces to a correct separation of the gas emissions. The radial profiles, presenting the carboneous compounds column intensities as a function of the distance p of the line of sight to the nucleus, termed projected distance or p-parameter, are examined. The obtained profiles correspond very well to the Haser's distribution when the optical thickness in the inner coma environment is taken into account. The deviation from Haser's model for CN and C 3 in the p < 1000 km region, obtained in previous investigations, is not seen now. Possibly, this deviation had been the result of a dust continuum in this zone, not perfectly subtracted. Some estimates of the production rates Q and scale lengths L and their dependences on the distance to the nucleus R are made. We obtain Q=1028mol/s for 0.83 AU on 9 March 1986, which presupposes some changes of the used parameters. For the CH radical, best results are obtained when the dependencies LCH ˜ R2 and Q ˜ R-8 are used. A slight discrepancy between the measurements and the theoretical curve is obtained in the case of C 3 and CH at p > 4000 km. The peculiarities of the C 2, C 3, CH, and CN glow, observed until now, are confirmed. Thanks to the TKS scanning, composed intensity distributions for each carboneous compound are constructed, covering a larger space region. The obtained distributions are alike and similar to the dust one and relatively stable in the measurement period. The intensities decrease with the increase of the distance to the nucleus. The two jets and the jet-free zone as well as the jet structure are examined.

Guineva, V.; Werner, R.; Stoeva, P.; Kostadinov, I.

2006-01-01

424

Abnormal Parathyroid Cell Proliferation Precedes Biochemical Abnormalities in a Mouse Model of Primary Hyperparathyroidism  

Microsoft Academic Search

The properties of neoplastic proliferation and hor- monal dysregulation are tightly linked in primary hyperparathyroidism (HPT). However, whether ab- normal parathyroid proliferation is the cause or result of a shift in calcium-sensitive parathyroid hormonal regulation has been controversial. We addressed this issue by analyzing the temporal se- quence of these fundamental abnormalities in a mouse model of primary HPT. These

Sanjay M. Mallya; James J. Gallagher; Yvette K. Wild; Olga Kifor; Jessica Costa-Guda; Kirsten Saucier; Edward M. Brown; Andrew Arnold

2005-01-01

425

Computed tomography of the abnormal thymus  

SciTech Connect

Computed tomography (CT) should be the imaging method of choice following plain chest radiographs when a suspected thymic abnormality requires further evaluation. Based upon a six-year experience, including the evaluation of 25 patients with thymic pathology, CT was found useful in suggesting or excluding a diagnosis of thymoma and in distinguishing thymic hyperplasis from thymoma in patients with myasthenia gravis. The thickness of the thymic lobes determined by CT was found to be a more accurate indicator of infiltrative disease (thymic hyperplasia and lymphoma) than the width. CT was helpful in differentiating benign thymic cysts from solid tumors, and in defining the extent of a thymic neoplasms. On occasion, CT may suggest the specific histologic nature of a thymic lesion.

Baron, R.L.; Lee, J.K.T.; Sagel, S.S.; Levitt, R.G.

1982-01-01

426

How Growth Abnormalities Delay "Puberty" in Drosophila  

NSDL National Science Digital Library

In various organisms, including flies, amphibians, and mammals, major developmental transitions such as metamorphosis and puberty are triggered by specific hormones. The requirement for a hormone to proceed to the next stage allows the organism to reestablish the temporal coordination of development between multiple organs that might develop at slightly different rates. Additionally, organisms appear to have evolved mechanisms for delaying these transitions in situations where growth in an organ is abnormal or delayed. New evidence in the fruit fly Drosophila melanogaster indicates that DILP8, a protein of the insulin and relaxin family, delays the onset of metamorphosis under several conditions that alter growth in imaginal discs. Similar mechanisms might operate in disease states in humans where alterations in growth or tissue inflammation can delay puberty.

Iswar K. Hariharan (University of California Berkeley; Department of Molecular and Cell Biology REV)

2012-06-19

427

CT and ultrasonography of acute renal abnormalities.  

PubMed

Computed tomography and ultrasonography are important in the evaluation of patients with acute renal abnormalities, either as adjuncts or, less commonly, as alternatives to excretory urography. Ultrasonography has become the imaging procedure of choice in evaluation of acute renal failure. Detection of obstructive uropathy by ultrasonography is very accurate, although the potential pitfalls of minimal dilatation obstructive uropathy, false absence of caliectasis in dehydrated patients, and peripelvic cysts simulating hydronephrosis should be considered. Both CT and ultrasonography have improved our ability to define specific causes of intrinsic or extrinsic renal or ureteral obstructing lesions, including tumor, inflammatory masses, and calculi. Renal infections and infarctions also have characteristic appearances on CT and ultrasonography, though ultrasonography is somewhat limited by its inability to reliably demonstrate gas-containing or small abscesses, and its inability to provide functional information about the concentrating capacity of regional areas of the kidney. PMID:6356219

Jeffrey, R B; Federle, M P

1983-09-01

428

Abnormalities of the tubular genital organs.  

PubMed

Abnormalities of the tubular reproductive tract are responsible for decreased fertility in the cow. Typically, these are related to congenital defects such as segmental aplasia or to acquired conditions resulting from infections or trauma caused during breeding or parturition. Infection of the tubular tract may result in vaginitis, cervicitis, metritis, endometritis, pyometra, or salpingitis. Trauma to the tract may result in urovagina, pneumovagina, or prolapse of the vagina or uterus. Retained placenta may result in metritis. Potentially, all of these conditions, unless properly treated, may result in reduced fertility or, in the extreme, sterility. Judicial and properly timed use of antibiotics and ecbolic agents should return the tract to proper function with little or no reduction in fertility. Some conditions, such as prolapse, retained placenta, and pneumovagina, may call for manual or surgical intervention for successful resolution. PMID:8348374

Youngquist, R S; Braun, W F

1993-07-01

429

"Idiopathic" mental retardation and new chromosomal abnormalities  

PubMed Central

Mental retardation is a heterogeneous condition, affecting 1-3% of general population. In the last few years, several emerging clinical entities have been described, due to the advent of newest genetic techniques, such as array Comparative Genomic Hybridization. The detection of cryptic microdeletion/microduplication abnormalities has allowed genotype-phenotype correlations, delineating recognizable syndromic conditions that are herein reviewed. With the aim to provide to Paediatricians a combined clinical and genetic approach to the child with cognitive impairment, a practical diagnostic algorithm is also illustrated. The use of microarray platforms has further reduced the percentage of "idiopathic" forms of mental retardation, previously accounted for about half of total cases. We discussed the putative pathways at the basis of remaining "pure idiopathic" forms of mental retardation, highlighting possible environmental and epigenetic mechanisms as causes of altered cognition. PMID:20152051

2010-01-01

430

Chemical corrosion by chlorides on ancient-like bronzes and treatment by hydrogen glow discharge plasma  

NASA Astrophysics Data System (ADS)

Three representative ancient-like bronzes are employed for the chemical synthesis of Cu2(OH)3Cl rich patinas in order to study the influence of the alloying elements in the evolution of the chloride attack and to further conduct stabilization treatment via Hydrogen Glow Discharge Plasma (HGDP) at low temperature and pressure. The corrosion behavior of specimens having Sn and Pb as main alloying elements is governed by a decuprification mechanism and by the formation of Sn-Pb-O enriched barrier layers. In the case of the Zn containing alloy, dezincification is more pronounced at the corrosion initial stages, and copper species predominate the corrosion products evolution. A three-hour HGDP treatment leads to Cu+ production and metallic Cu, Sn, Zn, and Pb redeposition, as a result of metal cation reduction. This process is accompanied by partial removal of Cl species, O diminution, and change in coloration. The further increase of the Cl/O atomic ratio measured on the post-treated surfaces leads to the formation of nantokite and thus to the conclusion that the stabilization of objects with extensive Cl attack is not feasible by HGDP without preliminary chemical treatment.

Papadopoulou, O.; Novakovic, J.; Vassiliou, P.; Filippaki, E.; Bassiakos, Y.

2013-12-01

431

Rapid oxidation and immobilization of arsenic by contact glow discharge plasma in acidic solution.  

PubMed

Arsenic is a priority pollutant in aquatic ecosystem and therefore the remediation of arsenic-bearing wastewater is an important environmental issue. This study unprecedentedly reported simultaneous oxidation of As(III) and immobilization of arsenic can be achieved using contact glow discharge process (CGDP). CGDP with thinner anodic wire and higher energy input were beneficial for higher As(V) production efficiency. Adding Fe(II) in CGDP system significantly enhanced the oxidation rate of As(III) due to the generations of additional OH and Fe(IV) species, accompanied with which arsenic can be simultaneously immobilized in one process. Arsenic immobilization can be favorably obtained at solution pH in the range of 4.0-6.0 and Fe(II) concentration from 250 to 1000?M. The presence of organics (i.e., oxalic acid, ethanol and phenol) retarded the arsenic immobilization by scavenging OH or complexing Fe(III) in aqueous solution. On the basis of these results, a mechanism was proposed that the formed ionic As(V) rapidly coprecipitated with Fe(III) ions or was adsorbed on the ferric oxyhydroxides with the formation of amorphous ferric arsenate-bearing ferric oxyhydroxides. This CGDP-Fenton system was of great interest for engineered systems concerned with the remediation of arsenic containing wastewater. PMID:25600320

Jiang, Bo; Hu, Ping; Zheng, Xing; Zheng, Jingtang; Tan, Minghui; Wu, Mingbo; Xue, Qinzhong

2015-04-01

432

Detailed comparison between probe density measurements of glow discharge in argon and in helium  

NASA Astrophysics Data System (ADS)

In this article we shall look a bit more closely at some of the fundamental plasma parameters obtained by a cylindrical Langmuir probe within low-pressure electrical gas discharge plasma. The presented measurements were made in argon and in helium glow discharge plasmas. We are mainly concerned with the densities of the charged particles (electrons and ions) within the plasma and the effect of the discharge conditions upon them. The electron density is calculated from the electron current at the space potential and from the integration over the EEDF. The ion density is calculated by using the OML collisionless theory. The parameterization of Laframboise's numerical results is also used for the ion density calculation. In the range of our experimental conditions the results of plasma density, for both gases, tend to show that the ion densities measured with the OML and Laframboise theories exceeds the measured electron densities. The results also show that the plasma electron and ion densities increased with both discharge power and gas pressure.

Elghazaly, M. H.; Abdel Baky, A. M.; Mansour, M. M.; Gabr, M.; Elsayed, N. M.

2006-01-01

433

THz imaging using Glow Discharge Detector (GDD) focal plane arrays and large aperture quasi optic mirrors  

NASA Astrophysics Data System (ADS)

The properties of terahertz (THz) radiation are well known. They penetrate well most nonconducting media; there are no known biological hazards, and atmospheric attenuation and scattering is lower than for visual and IR radiation. Recently we have found that common miniature commercial neon glow discharge detector (GDD) lamps costing typically about 30 cents each exhibit high sensitivity to THz radiation, with microsecond order rise times, thus making them excellent candidates for such focal plane arrays. Based on this technology we designed, built and tested 4X4 and 8X8 GDD focal plane arrays. A line vector of 32 GDD pixels is being designed in order to increase the number of pixels in such arrays and thus the image resolution. Unique large aperture quasi optic mirrors were design and tested experimentally in this work. A new technology of light weight large aperture mirrors is proposed in this work. In this case a metal coating on plastic substrate is demonstrated. According to first experiments this technology proves to reliable with minimal deformation in LAB conditions. THz Images at 100 GHz were taken using this new inexpensive technology with good quality and resolution.

Kopeika, N. S.; Abramovich, A.; Joseph, H.; Rozban, D.; Akram, A.; Levanon, A.; Yadid-Pecht, O.; Belenky, A.; Lineykin, S.

2010-10-01

434

Surface characterization of radio-frequency glow discharged and autoclaved titanium surfaces.  

PubMed

To characterize titanium surfaces treated with radio-frequency glow discharge (RFGD) after media exposure, surface chemical analyses were performed using x-ray photoelectron spectroscopy. Auger electron spectroscopy, and Fourier transform infrared-reflection absorption spectroscopy (FTIR-RAS). The RFGD treatments resulted in a cleaner surface as compared to as-sputtered or as-autoclaved titanium specimens. The oxide thickness of RFGD-treated titanium specimens was not statistically different from the as-autoclaved and as-sputter cleaned titanium specimens. Exposure to a phosphate-buffered saline solution revealed a greater deposition of calcium and phosphorous on the RFGD-treated surfaces. Auger electron spectroscopy depth profiles showed that calcium and phosphorous ions diffused into the titanium oxide layer. The calcium and phosphorous deposits were identified as amorphous calcium phosphate compounds using FTIR-RAS. These results suggest that RFGD treatments of titanium enhance calcium and/or phosphate affinity because of an increase in elemental interactions at the surface, thereby resulting in the formation of amorphous calcium phosphate compounds. PMID:8803338

Kawahara, D; Ong, J L; Raikar, G N; Lucas, L C; Lemons, J E; Nakamura, M

1996-01-01

435

High frequency glow discharges at atmospheric pressure with micro-structured electrode arrays  

NASA Astrophysics Data System (ADS)

Micro-structured electrode (MSE) arrays allow the generation of large-area uniform glow discharges over a wide pressure range up to atmospheric pressure. The electrode widths, thicknesses and distances in the micrometre range are realized by means of modern micro-machining and galvanic techniques. The electrode distance, the gap width d, is small enough to generate sufficiently high electric field strengths to ignite gas discharges by applying only moderate radio frequency (RF, 13.56 MHz) voltages (80-390 V in Ne, He, Ar, N2 and air). The non-thermal plasma system is characterized by a special probe measuring the electric parameters. We tested MSE arrays with d = 70, 25 and 15 µm. The MSE driven plasmas show a different behaviour from conventional RF discharge plasmas. Due to the very small electrode gap width we can describe the behaviour of the charged particles in the RF field of our system with the dc Townsend breakdown theory, depending on the pressure range and gas. With decreasing pressure, the gas discharges, especially in Ne and He, are increasingly dominated by field electron emission. With the MSE arrays as plasma sources several applications were developed and successfully tested, e.g. decomposition of waste gases and sterilization of food packaging materials at atmospheric pressure.

Baars-Hibbe, L.; Sichler, P.; Schrader, C.; Lucas, N.; Gericke, K.-H.; Büttgenbach, S.

2005-02-01

436

Application of Glow Discharge Plasma to Alter Surface Properties of Materials  

NASA Technical Reports Server (NTRS)

Some polymer materials that are considered important for spaceport operations are rendered noncompliant when subjected to the Kennedy Space Center (KSC) Standard electrostatic testing. These materials operate in stringent environmental conditions, such as high humidity. Treating materials that fail electrostatic testing and altering their surface properties so that they become compliant would result in considerable cost savings. Significant improvement in electrostatic dissipation of Saf-T-Vu PVC after treatment with air Atmospheric Plasma Glow Discharge (APGD) was observed and the material now passed the KSC electrostatic test. The O:C ratio on the surface, as monitored by X-ray Photoelectron Spectroscopy, increased from 0.165 tO 0.275 indicating enhanced oxidation, and surface contact angle measurements decreased from 107.5 to 72.6 showing increased hydrophilicity that accounted for the increased conductivity. Monitoring of the aging showed that the materials hydrophobic recovery resulted in it failing the electrostatic test 30 hours after treatment. This was probably due to the out-diffusion of the added Zn, Ba, and Cd salt stabilizers detected on the surface and/or diffusion of low molecular weight oligomers. On going work includes improving the long term hydrophilicity by optimizing the APGD process with different gas mixtures. Treatment of other spaceport materials is also presented.

Trigwell, Steve; Buhler, Charles R.; Calle, Carlos I.

2005-01-01

437

Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges  

SciTech Connect

In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times.

Huo, W. G. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Jian, S. J.; Yao, J.; Ding, Z. F., E-mail: zfding@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

2014-05-15

438

Atmospheric Pressure Glow Discharge for Point-of-Use Water Treatment  

NASA Astrophysics Data System (ADS)

Treatment of biological and chemical contaminants is an area of growing global interest where atmospheric pressure plasmas can make a significant contribution. Addressing key challenges of volume processing and operational cost, a large volume 162 MHz coaxial air-plasma source has been developed.footnotetextByrns (2012) J. Phys. D: Appl. Phys. 45 (2012) 195204 Because of VHF ballasting effects, the electric discharge is maintained at a steady glow, allowing formation of critical non-equilibrium chemistry. High densities, ne = 10^11-10^12, have been recorded. The atmospheric nature of the device permits straightforward and efficient treatment of water samples. [H^+] concentrations in 150 milliliter tap water samples have been shown to increase by 10^5 after five minutes of discharge exposure. Recent literature has demonstrated that increasing acidity is strongly correlated with a solution's ability to deactivate microbial contaminants.footnotetextTraylor (2011) J. Phys. D: Appl. Phys. 44 (2011) 472001 The work presented here will explore the impact of treatment gas, system configuration, and power density on water disinfection and PFC abatement. An array of plasma diagnostics, including OES and electrical measurements, are combined with post-process water analysis, including GC-MS and QT analysis of coliform and E.coli bacteria. Development of volume processing atmospheric plasma disinfection methods offers promise for point-of-use treatments in developing areas of the world, potentially supplementing or replacing supply and weather-dependent disinfection methods.

Lindsay, Alexander; Byrns, Brandon; Shannon, Steven; Knappe, Detlef

2012-10-01

439

Spatial distribution and accumulation of radicals arising in organic solids under the action of glow discharge  

NASA Astrophysics Data System (ADS)

The method, based on analyzing the dipolar broadening of EPR spectra was applied for investigation of the spatial distribution of radicals generated by high-frequency glow discharge in organic molecular crystals (powders of malonic and dimethylmalonic acids) and glassy isopropanol contained electron scavenger. It was shown that in the first case the radical distribution does not depend on time of discharge. The radicals are generated in layer of size ˜.05-0.1 ?m at a concentration of ˜2 10 20 cm -3. For the second case the distribution function was changed in the course of plasma treatment and the depth of radical generation was varied from 0.25 to 1.5 ?m during the discharge action. Contribution of the various mechanisms of radical formation were evaluated and it was shown that ionic mechanism predominated. A kinetic model is proposed to describe both the radical accumulation and evolution of spatial distribution function in plasmolysis. The use of the model, method and obtained data for general and practical applications is discussed.

Raitsimring, A. M.; Kurshev, V. V.

1994-12-01

440

Sterilization of Materials with a One Atmosphere Uniform Glow Discharge Plasma.*  

NASA Astrophysics Data System (ADS)

The relatively recent development of the One Atmosphere Uniform Glow Discharge Plasma sterilization technique at the UTK Plasma Science Laboratory has produced initial results which indicate that the technique may have commercial potential. We have shown that active species in a OAUGDP can be applied to the sterilization of fabrics, films, solid materials, and microbiological culture media. With a OAUGDP, we can eliminate the vacuum system which enforces batch processing and requires a continuous input of electrical power. With a OAUGDP, the exposure time is as little as 15 seconds. Sterilization of microorganisms with a kill ratio of 10E6 or higher, can be achieved with minimal unwanted byproducts and at less expense, compared to such conventional sterilization methods as autoclaving, ethylene oxide, or low pressure plasma treatment. This paper discusses the sterilization mechanisms of this new technique, and compares its advantages and disadvantages with other widely used techniques. ^1 Department of Microbiology, UTK ^2 UTK Textiles and Nonwovens Development Center (TANDEC) Research supported in part by the UTK Textiles and Nonwovens Development Center and UTK Center for Materials Processing.

Ku, Yongmin; Brickman, C.; Tosh, K.; Kelly-Wintenberg, K.; Montie, T. C.; Tsai, P.; Wadsworth, L.; Roth, J. Reece

1996-11-01

441

Influencing an Aerodynamic Boundary Layer using a Surface Layer of One Atmosphere Uniform Glow Discharge Plasma.*  

NASA Astrophysics Data System (ADS)

The results of low-speed wind tunnel testing at the NASA Langley Research Center of a flat panel substantially covered by a thin layer of one atmosphere uniform glow discharge plasma (OAUGDP)^1 will be reported. The orientation of the electrode strips and the resulting lineation of the OAUGDP with respect to the airflow was found to have a significant effect on the amount of measured drag. When the plasma panel is oriented so that the electrode strips are parallel to the airflow, the measured drag increases. Utilizing standard circuit board technology, a multi-strip OAUGDP layer was created on a rectangular surface (30 × 34 cm). One side of the panel was a series of connected strip electrodes and the other side a single sheet electrode. The panel was operated at a RMS voltage of 1.0-4.0 kV, RF frequency of 1.0-4.0 kHz, in a parallel and perpendicular airflow. ^1 Roth, J.R. (1995): Industrial Plasma Engineering: Vol. I - Principles. Institute of Physics Press, Bristol, UK ISBN 0-7503-0318-2. Supported in part by the NASA Langley Research Center, NCC1-223.

Sherman, D. M.; Roth, J. R.; Wilkinson, S. P.

1996-11-01

442

Formation Of Chromium Nitride Layers Produced By MOPACVD Processes Under Glow Discharge Conditions  

NASA Astrophysics Data System (ADS)

Because of the ecological aspect the electrochemical process of obtaining chromium coatings should be replaced by other technologies. The production of chromium coating involves as the main component of the bath chromium trioxide CrO3 which is very carcinogenic. Moreover the current efficiency of this process is very low what makes it very uneconomical in order to obtain coatings several ?m thick. That is why the new method of obtaining the chromium and chromium nitride coating are searched. The new hybrid technology combining plasma nitriding and PACVD method with the use of metalorganic compounds could have the big practical aspect. This method can be applied for the details with complicated shapes. The paper presents the microstructure and useful properties like corrosion and wear resistance of chromium nitride layers produced by hybrid process which consists of first depositing of chromium coating by PAMOCVD method form liquid precursor 2-ethylheksanoate chromium (III) and then annealing so obtained coating in nitrogen and hydrogen atmosphere using the glow discharge conditions.

Sobiecki, Jerzy Robert; Wierzcho?, Tadeusz

2011-01-01

443

Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis.  

PubMed

Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon (TOC) in water correspondingly decreased, while the sulfonate group of 4-PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH. PMID:24191593

Yang, Haiming; An, Baigang; Wang, Shaoyan; Li, Lixiang; Jin, Wenjie; Li, Lihua

2013-06-01

444

The use of matrix-specific calibrations for oxygen in analytical glow discharge spectrometry.  

PubMed

The performance of glow discharge optical emission spectroscopy and mass spectrometry for oxygen determination is investigated using a set of new conductive samples containing oxygen in the percent range in three different matrices (Al, Mg, and Cu) prepared by a sintering process. The sputtering rate corrected calibrations obtained at standard conditions for the 4 mm anode (700 V, 20 mA) in GD-OES are matrix independent for Mg and Al but not for Cu. The importance of a "blue shifted" line of oxygen at 130.22 nm (first reported by Köster) for quantitative analyses by GD-OES is confirmed. Matrix-specific calibrations for oxygen in GD-MS are presented. Two source concepts-fast flow (ELEMENT GD) and low gas flow (VG9000)-are evaluated obtaining higher sensitivity with the static flow source. Additional experiments using Ar-He mixtures or ?s pulsed GD are carried out in ELEMENT GD aiming to improve the oxygen sensitivity. PMID:25335819

Gonzalez-Gago, Cristina; Smid, Petr; Hofmann, Thomas; Venzago, Cornel; Hoffmann, Volker; Gruner, Wolfgang

2014-11-01

445

Inhibition of monocyte adhesion and fibrinogen adsorption on glow discharge plasma deposited tetraethylene glycol dimethyl ether.  

PubMed

Monocytes and macrophages play important roles in host responses to implanted biomedical devices. Monocyte and macrophage interactions with biomaterial surfaces are thought to be mediated by adsorbed adhesive proteins such as fibrinogen and fibronectin. Non-fouling surfaces that minimize protein adsorption may therefore minimize monocyte adhesion, activation, and the foreign body response. Radio-frequency glow discharge plasma deposition (RF-GDPD) of tetraethylene glycol dimethyl ether (tetraglyme) was used to produce polyethylene oxide (PEO)-like coatings on a fluorinated ethylene-propylene (FEP) surface. Electron spectroscopy for chemical analysis (ESCA) and static time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterize the surface chemistry of tetraglyme coating. Fibrinogen adsorption to the tetraglyme surface was measured with 125I-labeled fibrinogen and ToF-SIMS. Adsorption of fibrinogen to plasma deposited tetraglyme was less than 10 ng cm(-2), a 20-fold decrease compared to untreated FEP or tissue culture polystyrene (TCPS). Monocyte adhesion to plasma deposited tetraglyme was significantly lower than adhesion to FEP or TCPS. In addition, when the surfaces were preadsorbed with fibrinogen, fibronectin, or blood plasma, monocyte adhesion to plasma deposited tetraglyme after 2 h or 1 day was much lower than adhesion to FEP. RF-GDPD tetraglyme coating provides a promising approach to make non-fouling biomaterials that can inhibit non-specific material-host interactions and reduce the foreign body response. PMID:11787523

Shen, M; Pan, Y V; Wagner, M S; Hauch, K D; Castner, D G; Ratner, B D; Horbett, T A

2001-01-01

446

Liquid-phase reactions induced by atmospheric pressure glow discharge with liquid electrode  

NASA Astrophysics Data System (ADS)

We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. We used an H-shaped glass reactor to observe the effects of electron irradiation and positive-ion irradiation on the liquid-phase reaction separately and simultaneously. Aqueous solutions of NaCl, AgNO3, HAuCl4, and FeCl2 are used as the electrolyte. Solutions of AgNO3 and HAuCl4 are used for the generation of Ag and Au nanoparticles, respectively. Solution of FeCl2 is used for the generation of ferromagnetic particles. Experimental results showed that electron irradiation of the liquid surface generates OH? in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. We also showed that the control of reductive and oxidative environment in the liquid is possible not only by the gas composition for the plasma generation but also by the liquid composition.

Tochikubo, Fumiyoshi; Shirai, Naoki; Uchida, Satoshi

2014-12-01

447

Impurity reduction in a plasma by using the deuterium and helium glow discharge method  

NASA Astrophysics Data System (ADS)

To reduce the levels of impurities such as water, oxygen and nitrogen in a plasma chamber, we evaporated and deposited carborane (C2B10H12) powders on a silicon substrate by using a glow discharge method, and investigated the effects of boronization as functions of the carborane temperature and the rates of the flowing gases between deuterium and helium. The reduced amount of impurities after boronization was estimated by measuring the partial pressures of the corresponding gases in the chamber and the concentrations of nitrogen and oxygen in a deposited carborane film. The ratio of deuterium to hydrogen in the deposited film was analyzed by using secondary ion mass spectrometry (SIMS). When carborane powders were evaporated under a deuterium atmosphere, the residual gas analyzer showed a significant decrease in the partial pressure of water while less change was noted from the partial pressures of nitrogen and oxygen. The most efficient removal rate for water was obtained when carborane powder was flown under deuterium atmosphere at 150 °C. The SIMS data showed higher concentrations of nitrogen and oxygen in the carborane films deposited on Si substrates under a deuterium atmosphere, demonstrating that boronization under a deuterium atmosphere is an effective method to remove impurities.

Lee, Sangyong; Kim, Jaeyong

2015-02-01

448

The Use of a Glow Discharge Source in Teaching Introductory Physics  

NASA Astrophysics Data System (ADS)

Plasma physics provides a unique opportunity to teach introductory level high school physics as a unified approach to analyzing real phenomena, instead of presenting it as a collection of disjointed topics. Departing from the conventional single-concept laboratory exercises, simple tabletop experiments with low temperature plasma are rich enough to allow for a synthesis of concepts and methods taught in introductory level physics. A dc glow discharge source was constructed for use as a demonstration device as well as a base for advanced high school-level experiments. The source, in conjunction with commercially available sources such as fluorescent light bulbs and plasma globes, was used throughout the curriculum for a variety of topics. These include the elastic and inelastic collisions of various species in the plasma; the properties of electric field and the motion of particles in electric and magnetic fields; the knowledge of electrical circuits; the principles of spectral analysis; the basic principles of conservation of energy; the interactions involving electromagnetic waves. The advanced experiments conducted by high school juniors and seniors included the study of breakdown in low-pressure gases, the spectroscopic analysis of the discharge, and the use of microwave interferometry to determine the plasma density. New topics using plasmas are currently under design.

Post-Zwicker, Andrew; Gershman, Sophia

2001-04-01

449

Nonlocal electron kinetics and spectral line emission in the positive column of an argon glow discharge  

NASA Astrophysics Data System (ADS)

Modern non-local electron kinetics theory predicts several interesting effects connected with spectral line emission from the positive column in the range of low and medium pressures and currents. Some theoretical works describe non-monotonic behavior of the radial profiles of line emission at intermediate pressures and currents between the validity ranges of the non-local and local approximation of the electron kinetics. Despite a great number of publications, there have been no systematic measurements attempting to confirm these theoretical predictions through experiments. In this work the radial profiles of the line emission from the positive column of an argon glow discharge have been measured with high spatial resolution and new effects caused by the narrowing and broadening of the spatial emission profiles with dependence on discharge conditions have been discovered. The effect of intensity maximum shift predicted by theory using a self-consistent model was not found in the experiment. The properties of the spectral line radiation are influenced by the peculiarities of the formation of the high-energy tail of the electron energy distribution function. An interpretation of the observed effects based on the non-local character of the electron kinetics in radially inhomogeneous fields is given. The obtained experimental data are compared with the results of calculations.

Golubovskii, Yu; Kalanov, D.; Gorchakov, S.; Uhrlandt, D.

2015-04-01

450

Cell adhesion study of the titanium alloys exposed to glow discharge  

NASA Astrophysics Data System (ADS)

Titanium for biomedical application stems mainly from its advantageous bulk mechanical properties in combination with a high degree of biocompatibility that is largely attributable to their surface properties. This work is focused on the investigation of surface properties of treated titanium and cell adhesion to titanium treated in glow-discharge plasma. Pure titanium samples (grade 4) were exposed to low-energy ion irradiation in a specially constructed plasma generator, where materials were irradiated by ions of residual gases in vacuum. The ion energy was 1-10 keV. The irradiation dose was maintained at 10 17 ions cm -2. The irradiation time varied from 5 to 60 min. Rutherford backscattering spectrometry (RBS) was used for surface studies. RBS showed the presence of iron on the titanium surface that occurred from the cathode of plasma generator. In vitro biocompatibility test have been carried out with model cell lines (L929 mouse fibroblasts) to demonstrate that low-energy ion irradiation can favorably influence the surface of titanium for biomedical application. Scanning electron microscopy (SEM) was the main tool to demonstrate the cell attachment properties.

Abidzina, V.; Deliloglu-Gürhan, I.; Özdal-Kurt, F.; Sen, B. H.; Tereshko, I.; Elkin, I.; Budak, S.; Muntele, C.; Ila, D.

2007-08-01

451

Isotope dilution mass spectrometry for quantitative elemental analysis of powdered samples by radiofrequency pulsed glow discharge time of flight mass spectrometry.  

PubMed

In recent years particular effort is being devoted to the development of pulsed glow discharges (PGDs) for mass spectrometry because this powering operation mode could offer important ionization analytical advantages. However, the capabilities of radiofrequency (RF) PGD coupled to a time of flight mass spectrometry (ToFMS) for accurate isotope ratio measurements have not been demonstrated yet. This work is focused on investigating different time positions along the pulse profile for the accurate measurement of isotope ratios. As a result, a method has been developed for the direct and simultaneous multielement determination of trace elements in powdered geological samples by RF-PGD-ToFMS in combination with isotope dilution mass spectrometry (IDMS) as an absolute measurement method directly traceable to the International System of Units. Optimized operating conditions were 70 W of applied radiofrequency power, 250 Pa of pressure, 2 ms of pulse width and 4 ms of pulse period, being argon the plasma gas used. To homogeneously distribute the added isotopically-enriched standards, lithium borate fusion of powdered solid samples was used as sample preparation approach. In this way, Cu, Zn, Ba and Pb were successfully determined by RF-PGD-ToF(IDMS) in two NIST Standard Reference Materials (SRM 2586 and SRM 2780) representing two different matrices of geological interest (soil and rock samples). Cu, Zn, Ba and Pb concentrations determined by RF-PGD-ToF(IDMS) were well in agreement with the certified values at 95% confidence interval and precisions below 12% relative standard deviation were observed for three independent analyses. Elemental concentrations investigated were in the range of 81-5770 mg/kg, demonstrating the potential of RF-PGD-ToF(IDMS) for a sensitive, accurate and robust analysis of powdered samples. PMID:24054645

Alvarez-Toral, Aitor; Fernandez, Beatriz; Malherbe, Julien; Claverie, Fanny; Molloy, John L; Pereiro, Rosario; Sanz-Medel, Alfredo

2013-10-15

452

Eye-Head Coordination Abnormalities in Schizophrenia  

PubMed Central

Background Eye-movement abnormalities in schizophrenia are a well-established phenomenon that has been observed in many studies. In such studies, visual targets are usually presented in the center of the visual field, and the subject's head remains fixed. However, in every-day life, targets may also appear in the periphery. This study is among the first to investigate eye and head movements in schizophrenia by presenting targets in the periphery of the visual field. Methodology/Principal Findings Two different visual recognition tasks, color recognition and Landolt orientation tasks, were presented at the periphery (at a visual angle of 55° from the center of the field of view). Each subject viewed 96 trials, and all eye and head movements were simultaneously recorded using video-based oculography and magnetic motion tracking of the head. Data from 14 patients with schizophrenia and 14 controls were considered. The patients had similar saccadic latencies in both tasks, whereas controls had shorter saccadic latencies in the Landolt task. Patients performed more head movements, and had increased eye-head offsets during combined eye-head shifts than controls. Conclusions/Significance Patients with schizophrenia may not be able to adapt to the two different tasks to the same extent as controls, as seen by the former's task-specific saccadic latency pattern. This can be interpreted as a specific oculomotoric attentional dysfunction and may support the hypothesis that schizophrenia patients have difficulties determining the relevance of stimuli. Patients may also show an uneconomic over-performance of head-movements, which is possibly caused by alterations in frontal executive function that impair the inhibition of head shifts. In addition, a model was created explaining 93% of the variance of the response times as a function of eye and head amplitude, which was only observed in the controls, indicating abnormal eye-head coordination in patients with schizophrenia. PMID:24040351

Schwab, Simon; Würmle, Othmar; Razavi, Nadja; Müri, René M.; Altorfer, Andreas

2013-01-01

453

Timeliness of follow-up after abnormal screening mammography  

Microsoft Academic Search

Summary Little information has been published concerning the timeliness of follow-up after abnormal mammography. This article presents data on follow-up after abnormal mammography, including differences in follow-up by age, race, mammographic interpretation, and type of tracking system. From unpublished data, the rate of timely follow-up 8 to 12 weeks after index abnormal mammography ranges from 69% to 99%. Women aged

Karla Kerlikowske

1996-01-01

454

List mode multichannel analyzer  

DOEpatents

A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

Archer, Daniel E. (Livermore, CA); Luke, S. John (Pleasanton, CA); Mauger, G. Joseph (Livermore, CA); Riot, Vincent J. (Berkeley, CA); Knapp, David A. (Livermore, CA)

2007-08-07

455

Kink modes in pedestal  

SciTech Connect

Kink modes are investigated in pedestal for shaped tokamaks. An analytic combining criterion is presented. It lies on the middle of the sufficient criterion of Lortz and necessary criterion of Mercier giving a more restricted necessary criterion. Growth rates and mode structure are calculated. For large poloidal mode number, the modes are highly localized in both poloidal and radial directions. The modes increase rapidly when they approach to the resonant surface. They are typical of edge localized modes (ELMs). It is assumed that the modes vanish inside the next resonant surface, then, there seems to be a second stable region. Several mitigation methods for controlling ELMs are proposed.

Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China) [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Dong, J. Q.; Wang, Z. H.; Xu, M. [Southwestern Institute of Physics, Chengdu 610041 (China)] [Southwestern Institute of Physics, Chengdu 610041 (China); Xu, X. L.; Mou, M. L.; Sun, T. T.; Huang, J.; Chen, S. Y.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)] [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

2014-03-15

456

Microstructural Abnormalities in Children with Post-traumatic Stress Disorder: A Diffusion Tensor Imaging Study at 3.0T.  

PubMed

Posttraumatic stress disorder (PTSD) is a severe anxiety disorder characterized by re-experiencing, avoidance and hyperarousal. Brain microstructure abnormalities in PTSD, especially in children, are not yet well characterized. The aim of this study was to use MR diffusion tensor imaging (DTI) to identify brain microstructure alterations in children with PTSD compared to non-PTSD controls who experienced the same time-limited trauma. We studied 27 children with PTSD and 24 age- and gender-matched traumatized controls without PTSD, who all experienced the 2008 Sichuan major earthquake. DTI data were acquired and analyzed in terms of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Children with PTSD showed an abnormal pattern, not only of FA, but also of the diffusivity measures MD, AD and RD. Most of the abnormal brain regions belonged to two important networks: the default-mode network, including precuneus and angular gyrus, and the salience network, including insula, putamen and thalamus. This DTI study identifies microstructural abnormalities of children with PTSD after a major earthquake, our results are consistent with the suggestion that pediatric PTSD is accompanied by a connectivity disequilibrium between the salience and default-mode networks, a finding of potential pathophysiological significance. PMID:25757374

Lei, Du; Li, Lingjiang; Li, Lei; Suo, Xueling; Huang, Xiaoqi; Lui, Su; Li, Jing; Bi, Feng; Kemp, Graham J; Gong, Qiyong

2015-01-01

457

Microstructural Abnormalities in Children with Post-traumatic Stress Disorder: A Diffusion Tensor Imaging Study at 3.0T  

PubMed Central

Posttraumatic stress disorder (PTSD) is a severe anxiety disorder characterized by re-experiencing, avoidance and hyperarousal. Brain microstructure abnormalities in PTSD, especially in children, are not yet well characterized. The aim of this study was to use MR diffusion tensor imaging (DTI) to identify brain microstructure alterations in children with PTSD compared to non-PTSD controls who experienced the same time-limited trauma. We studied 27 children with PTSD and 24 age- and gender-matched traumatized controls without PTSD, who all experienced the 2008 Sichuan major earthquake. DTI data were acquired and analyzed in terms of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Children with PTSD showed an abnormal pattern, not only of FA, but also of the diffusivity measures MD, AD and RD. Most of the abnormal brain regions belonged to two important networks: the default-mode network, including precuneus and angular gyrus, and the salience network, including insula, putamen and thalamus. This DTI study identifies microstructural abnormalities of children with PTSD after a major earthquake, our results are consistent with the suggestion that pediatric PTSD is accompanied by a connectivity disequilibrium between the salience and default-mode networks, a finding of potential pathophysiological significance. PMID:25757374

Lei, Du; Li, Lingjiang; Li, Lei; Suo, Xueling; Huang, Xiaoqi; Lui, Su; Li, Jing; Bi, Feng; Kemp, Graham J.; Gong, Qiyong

2015-01-01

458

Right ventricular abnormalities in ventricular tachycardia of right ventricular origin: relation to electrophysiological abnormalities.  

PubMed Central

Patients with right ventricular tachycardia may have adverse electrophysiological abnormalities linked to disturbed right ventricular structure. Seventeen patients who presented with right ventricular tachycardia without coronary artery disease or gross abnormalities of left ventricular function were studied. Patients had the ventricular tachycardia characterised at electrophysiological study and most underwent radionuclide and contrast angiography. At echocardiography specific attention was paid to the right ventricular chamber size. Two groups were identified at echocardiographic study. In group 1, nine patients had normal left ventricular dimensions and relatively normal features at electrophysiological study. Mean right ventricular ejection fraction was 0.45 by krypton-81 measurement. Group 2 comprised eight patients who had dilatation of right ventricular inflow tract, outflow tract, and right ventricular body. This group had more severe features at presentation and at electrophysiological study. In this group all available echocardiographic measurements of right ventricular chamber size were greater than those of group 1 and outside the normal range. Four of the eight patients in group 2 showed regional right ventricular dyskinesia at echocardiography. Mean right ventricular ejection fraction (0.23) in group 2 was significantly lower than in group 1. One patient in group 2 subsequently died. In patients with right ventricular tachycardia, those with less favourable prognostic features at electrophysiological study may have distinct abnormalities of right ventricular structure that can be identified at echocardiographic study. Echocardiography may be of value in the recognition of potentially malignant clinical and electrophysiological features in this group. Images Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:3730207

Foale, R A; Nihoyannopoulos, P; Ribeiro, P; McKenna, W J; Oakley, C M; Krikler, D M; Rowland, E

1986-01-01

459

Right ventricular abnormalities in ventricular tachycardia of right ventricular origin: relation to electrophysiological abnormalities.  

PubMed

Patients with right ventricular tachycardia may have adverse electrophysiological abnormalities linked to disturbed right ventricular structure. Seventeen patients who presented with right ventricular tachycardia without coronary artery disease or gross abnormalities of left ventricular function were studied. Patients had the ventricular tachycardia characterised at electrophysiological study and most underwent radionuclide and contrast angiography. At echocardiography specific attention was paid to the right ventricular chamber size. Two groups were identified at echocardiographic study. In group 1, nine patients had normal left ventricular dimensions and relatively normal features at electrophysiological study. Mean right ventricular ejection fraction was 0.45 by krypton-81 measurement. Group 2 comprised eight patients who had dilatation of right ventricular inflow tract, outflow tract, and right ventricular body. This group had more severe features at presentation and at electrophysiological study. In this group all available echocardiographic measurements of right ventricular chamber size were greater than those of group 1 and outside the normal range. Four of the eight patients in group 2 showed regional right ventricular dyskinesia at echocardiography. Mean right ventricular ejection fraction (0.23) in group 2 was significantly lower than in group 1. One patient in group 2 subsequently died. In patients with right ventricular tachycardia, those with less favourable prognostic features at electrophysiological study may have distinct abnormalities of right ventricular structure that can be identified at echocardiographic study. Echocardiography may be of value in the recognition of potentially malignant clinical and electrophysiological features in this group. PMID:3730207

Foale, R A; Nihoyannopoulos, P; Ribeiro, P; McKenna, W J; Oakley, C M; Krikler, D M; Rowland, E

1986-07-01

460

Enhanced tissue integration of implantable electrodes for sensing, and stimulation, via radio frequency glow discharge  

NASA Astrophysics Data System (ADS)

Biopotential electrodes are conductive materials that convert electronic currents to or from ionic currents for sensing, and stimulating specific tissue sites for medical applications. Implanted electrodes become "walled off" by the foreign body tissue reactions producing poorly attached scar capsules dominated by surrounding dense collagenous lamellae and source fibroblasts which are electrically resistive. The conductive interstitial fluid that is typical between an electrode and the resistive capsule allows spurious current paths. The insulating layer increases the distance between the electrode and the target sites and poor attachment often results in electrode migration within the host tissue. This investigation tested the hypothesis that surface-energy modulation of electrodes, via Radio Frequency Glow Discharge Treatment (RFGDT), can improve the performance of tissue-implantable electrodes by reducing the foreign body tissue reaction and enhancing interfacial bonding between the tissue and electrode material. Previously published findings were reproduced in a pilot study of explanted reference grade medical-grade methyl silicone (PDMS) and commercially pure titanium (cpTi) materials and their tissue capsules from 30-day subcutaneous exposures in Balb/C mice. The low-critical surface tension PDMS produced thick, dense, poorly attached scar capsules while the higher-surface-energy commercially pure titanium (cpTi) produced more cellular and strongly attached tissue layers difficult to delaminate from the biomaterial. For the main body of work, cpTi, capacitor-grade Tantalum (Ta), and synthetic heart valve-quality Pyrolytic Carbon (PyC) were evaluated, representative of potential high-surface-energy implant electrode materials. Their surface characteristics were determined as-manufactured and after Radio Frequency Glow Discharge Treatment (RFGDT) by Critical Surface Tension (CST) measurement, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), and Electron Spectroscopy for Chemical Analysis (ESCA). Representative tissue/electrode interfaces were created through subcutaneous implantation and harvest from Balb/C mice after 7, 28 and 56 days. The recovered, formalin preserved conductive implant/tissue specimens were examined by Electrical Impedance Spectroscopy (EIS) over the range from 0.1 Hz to 100,000 Hz, in Bode plot and Nyquist plot formats. After EIS the implants were extracted from the tissue for surface examination by SEM and the separated tissue capsules were evaluated by histological examination in hematoxylin and eosin (H&E)-stained light microscopic thin sections. The differential findings were that the RFGDT PyC and Ta implants had significantly increased interface resistance and capacitance over their sterilized-only controls, correlating with more flattened cellular layers retained on the RFGDT specimens. The cpTi specimens, earlier identified as promoting hard tissue-to-surface integration in dental implants, showed only marginal improvements in soft tissue attachment following RFGDT. These experimental findings were confirmed through equivalent circuit modeling by the conversion from a standard Randles model with constant phase elements, which described the pre-implant materials, to a modified Randles model with additional resistance and capacitance to describe the implants with well-integrated surface coatings. Future work with RFGDT-modified electrode materials must include actual signal acquisition/stimulation trials in implant host tissues, to assess possible improvements in electrical energy-transfer efficiency and battery lifetime extensions.

O'Connor, Laurie M.