WorldWideScience

Sample records for auroras glow regulation

  1. Sds22 regulates aurora B activity and microtubule–kinetochore interactions at mitosis

    OpenAIRE

    Posch, Markus; Khoudoli, Guennadi A.; Swift, Sam; King, Emma M.; DeLuca, Jennifer G.; Swedlow, Jason R.

    2010-01-01

    We have studied Sds22, a conserved regulator of protein phosphatase 1 (PP1) activity, and determined its role in modulating the activity of aurora B kinase and kinetochore–microtubule interactions. Sds22 is required for proper progression through mitosis and localization of PP1 to mitotic kinetochores. Depletion of Sds22 increases aurora B T-loop phosphorylation and the rate of recovery from monastrol arrest. Phospho–aurora B accumulates at kinetochores in Sds22-depleted cells juxtaposed to c...

  2. Centromeric Transcription Regulates Aurora-B Localization and Activation

    Directory of Open Access Journals (Sweden)

    Michael D. Blower

    2016-05-01

    Full Text Available Centromeric transcription is widely conserved; however, it is not clear what role centromere transcription plays during mitosis. Here, I find that centromeres are transcribed in Xenopus egg extracts into a long noncoding RNA (lncRNA; cen-RNA that localizes to mitotic centromeres, chromatin, and spindles. cen-RNAs bind to the chromosomal passenger complex (CPC in vitro and in vivo. Blocking transcription or antisense inhibition of cen-RNA leads to a reduction of CPC localization to the inner centromere and misregulation of CPC component Aurora-B activation independently of known centromere recruitment pathways. Additionally, transcription is required for normal bipolar attachment of kinetochores to the mitotic spindle, consistent with a role for cen-RNA in CPC regulation. This work demonstrates that cen-RNAs promote normal kinetochore function through regulation of the localization and activation of the CPC and confirm that lncRNAs are components of the centromere.

  3. Akt Inhibitor A-443654 Interferes with Mitotic Progression by Regulating Aurora A Kinase Expression

    Directory of Open Access Journals (Sweden)

    Xuesong Liu

    2008-08-01

    Full Text Available Both Akt and Aurora A kinase have been shown to be important targets for intervention for cancer therapy. We report here that Compound A (A-443654, a specific Akt inhibitor, interferes with mitotic progression and bipolar spindle formation. Compound A induces G2/M accumulation, defects in centrosome separation, and formation of either monopolar arrays or disorganized spindles. On the basis of gene expression array studies, we identified Aurora A as one of the genes regulated transcriptionally by Akt inhibitors including Compound A. Inhibition of the phosphatidylinositol 3-kinase (PI3K/Akt pathway, either by PI3K inhibitor LY294002 or by Compound A, dramatically inhibits the promoter activity of Aurora A, whereas the mammalian target of rapamycin inhibitor has little effect, suggesting that Akt might be responsible for up-regulating Aurora A for mitotic progression. Further analysis of the Aurora A promoter region indicates that the Ets element but not the Sp1 element is required for Compound A-sensitive transcriptional control of Aurora A. Overexpression of Aurora A in cells treated with Compound A attenuates the mitotic arrest and the defects in bipolar spindle formation induced by Akt inhibition. Our studies suggest that that Akt may promote mitotic progression through the transcriptional regulation of Aurora A.

  4. Function and regulation of Aurora/Ipl1p kinase family in cell division

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    During mitosis, the parent cell distributes its genetic materials equally into two daughter cells through chromosome segregation, a complex movements orchestrated by mitotic kinases and its effector proteins.Faithful chromosome segregation and cytokinesis ensure that each daughter cell receives a full copy of genetic materials of parent cell. Defects in these processes can lead to aneuploidy or polyploidy. Aurora/Ipl1p fanily,a class of conserved serine/threonine kinases, plays key roles in chromosome segregation and cytokinesis.This article highlights the function and regulation of Aurora/Ipl1p family in mitosis and provides potential links between aberrant regulation of Aurora/Ipl1p kinases and pathogenesis of human cancer.

  5. Aurora A kinase regulates proper spindle positioning in C. elegans and in human cells.

    Science.gov (United States)

    Kotak, Sachin; Afshar, Katayon; Busso, Coralie; Gönczy, Pierre

    2016-08-01

    Accurate spindle positioning is essential for error-free cell division. The one-cell Caenorhabditis elegans embryo has proven instrumental for dissecting mechanisms governing spindle positioning. Despite important progress, how the cortical forces that act on astral microtubules to properly position the spindle are modulated is incompletely understood. Here, we report that the PP6 phosphatase PPH-6 and its associated subunit SAPS-1, which positively regulate pulling forces acting on spindle poles, associate with the Aurora A kinase AIR-1 in C. elegans embryos. We show that acute inactivation of AIR-1 during mitosis results in excess pulling forces on astral microtubules. Furthermore, we uncover that AIR-1 acts downstream of PPH-6-SAPS-1 in modulating spindle positioning, and that PPH-6-SAPS-1 negatively regulates AIR-1 localization at the cell cortex. Moreover, we show that Aurora A and the PP6 phosphatase subunit PPP6C are also necessary for spindle positioning in human cells. There, Aurora A is needed for the cortical localization of NuMA and dynein during mitosis. Overall, our work demonstrates that Aurora A kinases and PP6 phosphatases have an ancient function in modulating spindle positioning, thus contributing to faithful cell division. PMID:27335426

  6. Dynamic phosphorylation of Histone Deacetylase 1 by Aurora kinases during mitosis regulates zebrafish embryos development.

    Science.gov (United States)

    Loponte, Sara; Segré, Chiara V; Senese, Silvia; Miccolo, Claudia; Santaguida, Stefano; Deflorian, Gianluca; Citro, Simona; Mattoscio, Domenico; Pisati, Federica; Moser, Mirjam A; Visintin, Rosella; Seiser, Christian; Chiocca, Susanna

    2016-01-01

    Histone deacetylases (HDACs) catalyze the removal of acetyl molecules from histone and non-histone substrates playing important roles in chromatin remodeling and control of gene expression. Class I HDAC1 is a critical regulator of cell cycle progression, cellular proliferation and differentiation during development; it is also regulated by many post-translational modifications (PTMs). Herein we characterize a new mitosis-specific phosphorylation of HDAC1 driven by Aurora kinases A and B. We show that this phosphorylation affects HDAC1 enzymatic activity and it is critical for the maintenance of a proper proliferative and developmental plan in a complex organism. Notably, we find that Aurora-dependent phosphorylation of HDAC1 regulates histone acetylation by modulating the expression of genes directly involved in the developing zebrafish central nervous system. Our data represent a step towards the comprehension of HDAC1 regulation by its PTM code, with important implications in unravelling its roles both in physiology and pathology. PMID:27458029

  7. The budding yeast Ipl1/Aurora protein kinase regulates mitotic spindle disassembly

    OpenAIRE

    Buvelot, Stéphanie; Tatsutani, Sean Y.; Vermaak, Danielle; Biggins, Sue

    2003-01-01

    Ipl1p is the budding yeast member of the Aurora family of protein kinases, critical regulators of genomic stability that are required for chromosome segregation, the spindle checkpoint, and cytokinesis. Using time-lapse microscopy, we found that Ipl1p also has a function in mitotic spindle disassembly that is separable from its previously identified roles. Ipl1–GFP localizes to kinetochores from G1 to metaphase, transfers to the spindle after metaphase, and accumulates at the spindle midzone ...

  8. Aurora B regulates formin mDia3 in achieving metaphase chromosome alignment.

    Science.gov (United States)

    Cheng, Lina; Zhang, Jiayin; Ahmad, Sana; Rozier, Lorene; Yu, Haiqian; Deng, Haiteng; Mao, Yinghui

    2011-03-15

    Proper bipolar attachment of sister kinetochores to the mitotic spindle is critical for accurate chromosome segregation in mitosis. Here we show an essential role of the formin mDia3 in achieving metaphase chromosome alignment. This function is independent of mDia3 actin nucleation activity, but is attributable to EB1-binding by mDia3. Furthermore, the microtubule binding FH2 domain of mDia3 is phosphorylated by Aurora B kinase in vitro, and cells expressing the nonphosphorylatable mDia3 mutant cannot position chromosomes at the metaphase plate. Purified recombinant mDia3 phosphorylated by Aurora B exhibits reduced ability to bind microtubules and stabilize microtubules against cold-induced disassembly in vitro. Cells expressing the phosphomimetic mDia3 mutant do not form stable kinetochore microtubule fibers; despite they are able to congress chromosomes to the metaphase plate. These findings reveal a key role for mDia3 and its regulation by Aurora B phosphorylation in achieving proper stable kinetochore microtubule attachment. PMID:21397845

  9. H3S10 phosphorylation-mediated transcriptional regulation by Aurora kinase A.

    Science.gov (United States)

    Kim, Se-Ryeon; Kim, Kee-Beom; Chae, Yun-Cheol; Park, Jin Woo; Seo, Sang-Beom

    2016-01-01

    Histone H3S10 phosphorylation has been known as a cell cycle-specific marker and has a role in transcriptional activation. Various kinases phosphorylate H3S10 in different species, however, the role of the mitotic serine/threonine protein kinase Aurora A (AURKA) is largely unknown. Here we present evidence that AURKA phosphorylates H3S10 and activates target gene transcription. We show that down-regulation of AURKA level during leukemia cell differentiation results in decreased H3S10 phosphorylation level. We further show that AURKA is recruited to target gene promoters and activates transcription via H3S10 phosphorylation. Furthermore, this recruitment can be disrupted by the AURKA inhibitor Alisertib and results in H3K9-me2 recruitment by G9a. PMID:26607113

  10. Ipl1/Aurora-dependent phosphorylation of Sli15/INCENP regulates CPC–spindle interaction to ensure proper microtubule dynamics

    OpenAIRE

    Nakajima, Yuko; Cormier, Anthony; Tyers, Randall G.; Pigula, Adrianne; Peng, Yutian; Drubin, David G; Barnes, Georjana

    2011-01-01

    Dynamic microtubules facilitate chromosome arrangement before anaphase, whereas during anaphase microtubule stability assists chromosome separation. Changes in microtubule dynamics at the metaphase–anaphase transition are regulated by Cdk1. Cdk1-mediated phosphorylation of Sli15/INCENP promotes preanaphase microtubule dynamics by preventing chromosomal passenger complex (CPC; Sli15/INCENP, Bir1/Survivin, Nbl1/Borealin, Ipl1/Aurora) association with spindles. However, whether Cdk1 has sole con...

  11. Aurora-B and HDAC synergistically regulate survival and proliferation of lymphoma cell via AKT, mTOR and Notch pathways.

    Science.gov (United States)

    Wang, Chong; Chen, Jing; Cao, Weijie; Sun, Ling; Sun, Hui; Liu, Yanfang

    2016-05-15

    Aurora-B is a protein kinase that functions mainly in the attachment of the mitotic spindle to the centromere. Overexpression of Aurora-B causes unequal distribution of genetic information, creating aneuploidy cells, a hallmark of cancer. Histone deacetylases (HDACs) are a class of enzymes that remove acetyl groups from a ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly, thus globally regulating gene transcription. Additionally, these HDACs can also modify non-histone proteins. Inhibition of HDACs is a potent strategy for cancer treatment. Here, we report that inhibition of Aurora-B and HDAC exerts similar tumor suppressive effects in cells. Knockdown of Aurora-B or inhibition of HDAC achieved the same effect on repression of cell proliferation. Furthermore, we found that the tumor suppressive effect of Aurora-B and HDAC inhibition is due to the induction of cell cycle arrest and/or apoptosis. Mechanistically, we demonstrated that Aurora-B and HDAC can cooperatively regulate AKT, mTOR and Notch pathways. PMID:26638998

  12. Sgo1 Regulates Both Condensin and Ipl1/Aurora B to Promote Chromosome Biorientation

    OpenAIRE

    Peplowska, K.; Wallek, A.; Storchova, Z.

    2014-01-01

    Correct chromosome segregation is essential in order to prevent aneuploidy. To segregate sister chromatids equally to daughter cells, the sisters must attach to microtubules emanating from opposite spindle poles. This so-called biorientation manifests itself by increased tension and conformational changes across kinetochores and pericentric chromatin. Tensionless attachments are dissolved by the activity of the conserved mitotic kinase Aurora B/Ipl1, thereby promoting the formation of correct...

  13. Aurora A Kinase Regulates Mammary Epithelial Cell Fate by Determining Mitotic Spindle Orientation in a Notch-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Joseph L. Regan

    2013-07-01

    Full Text Available Cell fate determination in the progeny of mammary epithelial stem/progenitor cells remains poorly understood. Here, we have examined the role of the mitotic kinase Aurora A (AURKA in regulating the balance between basal and luminal mammary lineages. We find that AURKA is highly expressed in basal stem cells and, to a lesser extent, in luminal progenitors. Wild-type AURKA expression promoted luminal cell fate, but expression of an S155R mutant reduced proliferation, promoted basal fate, and inhibited serial transplantation. The mechanism involved regulation of mitotic spindle orientation by AURKA and the positioning of daughter cells after division. Remarkably, this was NOTCH dependent, as NOTCH inhibitor blocked the effect of wild-type AURKA expression on spindle orientation and instead mimicked the effect of the S155R mutant. These findings directly link AURKA, NOTCH signaling, and mitotic spindle orientation and suggest a mechanism for regulating the balance between luminal and basal lineages in the mammary gland.

  14. Elevated Aurora Kinase A Protein Expression in Diabetic Skin Tissue

    Science.gov (United States)

    Cho, Moon Kyun; An, Je Min; Kang, Sang Gue

    2014-01-01

    Background Aurora kinase A (Aurora-A) plays an important role in the regulation of mitosis and cytokinesis. Dysregulated Aurora-A leads to mitotic faults and results in pathological conditions. No studies on Aurora-A expression in human diabetic skin tissue have been reported. In light of this, we explored the expression of Aurora-A in human diabetic skin tissue. Methods Aurora-A protein was evaluated by western blotting in 6 human diabetic skin tissue and 6 normal skin specimens. Results Increased expression of Aurora-A protein was detected in all diabetic skin tissue samples in both western blot analysis and immunohistochemical staining. However, in the case of the normal skin tissue, no bands of Aurora-A protein were detected in either the western blotting analysis or the immunohistochemical staining. Conclusions Thus far, there have been no studies on the expression of Aurora-A in diabetic skin tissue. However, we believe that oxidative DNA damage related to the expression of Aurora-A protein and Aurora-A could be involved inhuman diabetic skin tissue. PMID:24511492

  15. A pathway containing the Ipl1/Aurora protein kinase and the spindle midzone protein Ase1 regulates yeast spindle assembly

    OpenAIRE

    Kotwaliwale, Chitra V.; Frei, Stéphanie Buvelot; Stern, Bodo M.; Biggins, Sue

    2007-01-01

    It is critical to elucidate the pathways that mediate spindle assembly and therefore ensure accurate chromosome segregation during cell division. Our studies of a unique allele of the budding yeast Ipl1/Aurora protein kinase revealed that it is required for centrosome-mediated spindle assembly in the absence of the BimC motor protein Cin8. In addition, we found that the Ase1 spindle midzone-associated protein is required for bipolar spindle assembly. The cin8 ipl1 and cin8 ase1 double mutant ...

  16. Evolutionary Reconstruction and Population Genetics Analysis of Aurora Kinases

    OpenAIRE

    Balu Kamaraj; Ambuj Kumar; Rituraj Purohit

    2013-01-01

    BACKGROUND: Aurora kinases belong to the highly conserved kinase family and play a vital role in cell cycle regulation. The structure and function of these kinases are inter-related and sometimes they also act as substitutes in case of knockdown of other aurora kinases. METHOD: In this work we carried out the evolutionary reconstruction and population genetic studies of aurora kinase proteins. Substitution saturation test, CAI (Codon adaptation index), gene expression and RSCU (Relative synon...

  17. Evolutionary reconstruction and population genetics analysis of aurora kinases.

    Directory of Open Access Journals (Sweden)

    Balu Kamaraj

    Full Text Available BACKGROUND: Aurora kinases belong to the highly conserved kinase family and play a vital role in cell cycle regulation. The structure and function of these kinases are inter-related and sometimes they also act as substitutes in case of knockdown of other aurora kinases. METHOD: In this work we carried out the evolutionary reconstruction and population genetic studies of aurora kinase proteins. Substitution saturation test, CAI (Codon adaptation index, gene expression and RSCU (Relative synonymous codon usage values were computed for all the three aurora kinases. Linear regression method was used to check the dependency of gene expression on their CAI values. RESULTS: The results suggested that aurora-B and aurora-C has shown convergence in their evolutionary pathway. Moreover, the aurora-A I57V mutation showed high penetrance in human population and exist at very high frequency (84.4% when compared to the native residue (15.6%. The mutation showed notable range of functional gain and seemed to be promising for the evolution of aurora-A function. Mutant allele might also become a challenging prospect for understanding the pattern of evolution followed by cell cycle kinases. CONCLUSION: The overall result suggested that the aurora-A is currently under the evolutionary transition and to determine the functional significance of the mutation further investigation are required.

  18. Aurora final report

    Energy Technology Data Exchange (ETDEWEB)

    Robert, Dross; Amedeo, Conti

    2013-12-06

    Final Technical report detailing the work done by Nuvera and its partners to fulfill the goals of the program "Transport Studies Enabling Efficiency Optimization of Cost-Competitive Fuel Cell Stacks" (a.k.a. AURORA)

  19. The dynamic aurora

    International Nuclear Information System (INIS)

    Auroral physicists today know that auroras are lights emitted when atoms and molecules in the ionosphere are struck by electrons blowing in from the sun. The apparent motion of the auroral curtain is caused not by atmospheric turbulence but by changes in the electromagnetic conditions that propel the electrons, just as motion on a television screen is an illusion created by changes in the magnetic field that directs electrons from a cathode tube onto the screen. In the case of the aurora, what serves as the cathode tube? Where is its power supply? Why does that power seem to fluctuate from time to time, causing the aurora to ebb and flow across the polar sky? More than 20 years ago it was determined that auroral emissions occur because the ionosphere is bombarded by electron beams generated by a complex interaction between the solar wind and the earth's magnetic envelope. The geomagnetic nature of the aurora can be seen clearly from outer space. Centered on each of the geomagnetic poles is a great luminous oval that is a permanent feature of the planet. The one around the North Pole is the aurora borealis. Its counterpart in the south is the aurora australis. The authors and his colleagues have now found a numerical relation between the solar wind and the generation of the power that drives the aurora, as well as other disturbances of the geomagnetic field. They are also gaining a better idea of how the sun's activity affects the solar wind. This progress raises the interesting possibility of developing a computer method to predict the intensity of auroral activity. Because auroras can interfere significantly with radio and satellite communications, as well as with power lines and some defense systems, the ability to predict auroral intensity has become increasingly important as human activity expands into polar regions and into space

  20. Structure of black aurora associated with pulsating aurora

    Science.gov (United States)

    Fritz, Bruce A.; Lessard, Marc L.; Blandin, Matthew J.; Fernandes, Philip A.

    2015-11-01

    Morphological behavior of black aurora as it relates to pulsating aurora is investigated by examining a collection of ground-based observations from January 2007 in support of the Rocket Observations of Pulsating Aurora rocket campaign. Images were sampled from video recorded by a Xybion intensified camera (30 fps) at Poker Flat Research Range, AK. The primary observations of black aurora recorded during the substorm recovery phase were between separate patches of pulsating aurora as well as pulsating aurora separated from diffuse aurora. In these observations the black aurora forms an apparent firm boundary between the auroral forms in a new behavior that is in contrast with previously reported observations. Also presented for the first time are black curls in conjunction with pulsating aurora. Curl structures that indicate shear plasma flows in the ionosphere may be used as a proxy for converging/diverging electric fields in and above the ionosphere. This new subset of black auroral behavior may provide visual evidence of black aurora as an ionospheric feedback mechanism as related to pulsating aurora.

  1. Aurora-A regulates MTOCs (centrosome) biogenesis but it does not trigger G2/M transition in mouse oocytes matured in vivo

    Czech Academy of Sciences Publication Activity Database

    Šolc, Petr; Panenková, Gabriela; Baran, Vladimír; Šašková, Adéla; Schultz, R. M.; Motlík, Jan

    Waterville : -, 2009. s. 1-1. [Cell Growth & Proliferation. 05.07.2009-10.07.2009, Waterville] R&D Projects: GA MŠk ME08030 Institutional research plan: CEZ:AV0Z50450515 Keywords : Aurora-A Subject RIV: EB - Genetics ; Molecular Biology

  2. Preclinical validation of Aurora kinases-targeting drugs in osteosarcoma

    OpenAIRE

    Tavanti, E; Sero, V; Vella, S; M. Fanelli; Michelacci, F; Landuzzi, L; Magagnoli, G; Versteeg, R; Picci, P; Hattinger, C M; M. Serra

    2013-01-01

    Background: Aurora kinases are key regulators of cell cycle and represent new promising therapeutic targets in several human tumours. Methods: Biological relevance of Aurora kinase-A and -B was assessed on osteosarcoma clinical samples and by silencing these genes with specific siRNA in three human osteosarcoma cell lines. In vitro efficacy of two Aurora kinases-targeting drugs (VX-680 and ZM447439) was evaluated on a panel of four drug-sensitive and six drug-resistant human osteosarcoma cell...

  3. Evolutionary relationships of Aurora kinases: Implications for model organism studies and the development of anti-cancer drugs

    Directory of Open Access Journals (Sweden)

    Patrick Denis R

    2004-10-01

    Full Text Available Abstract Background As key regulators of mitotic chromosome segregation, the Aurora family of serine/threonine kinases play an important role in cell division. Abnormalities in Aurora kinases have been strongly linked with cancer, which has lead to the recent development of new classes of anti-cancer drugs that specifically target the ATP-binding domain of these kinases. From an evolutionary perspective, the species distribution of the Aurora kinase family is complex. Mammals uniquely have three Aurora kinases, Aurora-A, Aurora-B, and Aurora-C, while for other metazoans, including the frog, fruitfly and nematode, only Aurora-A and Aurora-B kinases are known. The fungi have a single Aurora-like homolog. Based on the tacit assumption of orthology to human counterparts, model organism studies have been central to the functional characterization of Aurora kinases. However, the ortholog and paralog relationships of these kinases across various species have not been rigorously examined. Here, we present comprehensive evolutionary analyses of the Aurora kinase family. Results Phylogenetic trees suggest that all three vertebrate Auroras evolved from a single urochordate ancestor. Specifically, Aurora-A is an orthologous lineage in cold-blooded vertebrates and mammals, while structurally similar Aurora-B and Aurora-C evolved more recently in mammals from a duplication of an ancestral Aurora-B/C gene found in cold-blooded vertebrates. All so-called Aurora-A and Aurora-B kinases of non-chordates are ancestral to the clade of chordate Auroras and, therefore, are not strictly orthologous to vertebrate counterparts. Comparisons of human Aurora-B and Aurora-C sequences to the resolved 3D structure of human Aurora-A lends further support to the evolutionary scenario that vertebrate Aurora-B and Aurora-C are closely related paralogs. Of the 26 residues lining the ATP-binding active site, only three were variant and all were specific to Aurora-A. Conclusions In

  4. Aurora laser optical system

    International Nuclear Information System (INIS)

    The Los Alamos National Laboratory KrF Aurora laser optical system is described. Conceptual, first-order, and detailed designs are presented for the major 248-nm ultraviolet optical, subsystems. In Aurora, a 5-ns front-end pulse is replicated and time encoded into a 96-beam, 480-ns pulse train, angle encoded, amplified, and then time and angle decoded so that all the 5-ns pulses arrive at the target plane simultaneously. The encoder and the centered optical system that directs the pulse train through the amplifiers have been installed, on major alignment system has been built and tested, and most decoder optical components have been designed and ordered. The plan is to have the entire optical system installed and initial integration completed by October 1987

  5. Aurora-A regulates MTOCs (centrosome) biogenesis but it does not trigger G2/M transition in mouse oocytes matured in vivo

    Czech Academy of Sciences Publication Activity Database

    Šolc, Petr; Baran, V.; Panenková, Gabriela; Šašková, Adéla; Böhmová, Tereza; Mayer, Alexandra; Schultz, R. M.; Motlík, Jan

    San Juan Island : Friday Harbor Laboratories, 2010. s. 12-12. [Mechanism of Egg Maturation and Fertilization: From Sea to Land: An international symposium at Friday Harbor Laboratories. 10.09.-12.09.2010, San Juan Island] R&D Projects: GA MŠk ME08030 Institutional research plan: CEZ:AV0Z50450515 Keywords : Aurora-A * mouse oocytes * biogenesis Subject RIV: EB - Genetics ; Molecular Biology

  6. Aurora-A regulates MTOCs (centrosome) biogenesis it does not trigger G2/M transition in mouse oocytes matured in vivo

    Czech Academy of Sciences Publication Activity Database

    Šolc, Petr; Baran, Vladimír; Panenková, Gabriela; Šašková, Adéla; Böhmová, Tereza; Mayer, Alexandra; Schultz, R. M.; Motlík, Jan

    Liběchov : Institute of Animal Physiology and Genetics AS CR, v.v ,, 2010. s. 22-22. [Czech‐Japan Joint Symposium for Animal Reproduction. 20.09.-21.09.2010, Liblice] R&D Projects: GA MŠk ME08030 Institutional research plan: CEZ:AV0Z50450515 Keywords : Aurora-A * mouse oocytes * MTOCs Subject RIV: EB - Genetics ; Molecular Biology

  7. Baxter Aurora dialysis system.

    Science.gov (United States)

    Kelly, Thomas D

    2004-01-01

    With the recent focus on the benefits of more frequent dialysis, the Baxter Aurora dialysis system provides maximum flexibility for therapy prescription, including short daily treatments, long nocturnal treatments, hemodialysis, hemofiltration, and online hemodiafiltration, all in a compact, reliable, easy to use system. A self-prompting touch screen user interface mounted on a movable arm provides for comfortable operation, whether sitting and standing. An automatic treatment setup mode facilitates easy treatment setup. Complex menus are eliminated by the use of a hardware key that automatically selects only the prescribed options during power up, eliminating all menus associated with nonprescribed functions and modalities. This prevents the user from becoming confused or accidentally altering the dialysis treatment. Prior to dialysis the instrument goes through an automatic self-test that confirms the operation of internal systems. The screen will dim when there is no action that the patient needs to attend to on the instrument. After dialysis, press the disinfect button and the instrument disinfects itself and shuts off. For patient safety, the "disinfect" menus are not available during dialysis. The instrument can also be programmed to automatically start and rinse at a set time. For remote treatment monitoring, the instrument connects to the Internet. The Aurora records information about the machine's technical status, providing a record of instrument history for easy servicing. The Aurora is a flexible platform that provides the desired renal therapy with ease of use and proper support for the hemodialysis patient when combined with Baxter's 24-hour infrastructure and support. PMID:15043620

  8. Aurora laser optical system

    International Nuclear Information System (INIS)

    Aurora is the Los Alamos short-pulse high-power krypton fluoride laser system. It is primarily an end-to-end technology demonstration prototype for large-scale UV laser systems of interest for short-wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and aerial amplification by electron-beam-driven KrF laser amplifiers to deliver to ICF targets a stack of pulses with a duration of 5 ns containing several kilojoules at a wavelength of 248 nm. A program of high-energy density plasma physics investigations is now planned, and a sophisticated target chamber was constructed. The authors describe the design of the optical system for Aurora and report its status. This optical system was designed and is being constructed in two phases. The first phase carries only through the amplifier train and does not include a target chamber or any demultiplexing. Installation should be complete, and some performance results should be available. The second phase provides demultiplexing and carries the laser light to target. The complete design is reported

  9. Estrogen-Induced Aurora Kinase-A (AURKA) Gene Expression is Activated by GATA-3 in Estrogen Receptor-Positive Breast Cancer Cells

    OpenAIRE

    Jiang, Shoulei; Katayama, Hiroshi; Jin WANG; Li, Sara Antonia; Hong, Yan; Radvanyi, Laszlo; Li, Jonathan J.; Sen, Subrata

    2010-01-01

    Aurora-A is a proto-oncogenic mitotic kinase that is frequently overexpressed in human epithelial malignancies including in breast and ovarian cancers. The mechanism of transcriptional upregulation of Aurora-A in human breast cancer is not yet elucidated. We report herein that Aurora-A transcription is positively regulated by GATA-3 in response to estrogen in estrogen receptor α (ERα)-positive cells. Transient expression of aurora-A promoter deletion mutants in luciferase constructs identifie...

  10. Aurorae in Australian Aboriginal Traditions

    CERN Document Server

    Hamacher, Duane W

    2013-01-01

    Transient celestial phenomena feature prominently in the astronomical knowledge and traditions of Aboriginal Australians. In this paper, I collect accounts of the Aurora Australis from the literature regarding Aboriginal culture. Using previous studies of meteors, eclipses, and comets in Aboriginal traditions, I anticipate that the physical properties of aurora, such as their generally red colour as seen from southern Australia, will be associated with fire, death, blood, and evil spirits. The survey reveals this to be the case and also explores historical auroral events in Aboriginal cultures, aurorae in rock art, and briefly compares Aboriginal auroral traditions with other global indigenous groups, including the Maori of New Zealand.

  11. Aurorae in Australian Aboriginal Traditions

    Science.gov (United States)

    Hamacher, Duane W.

    2013-07-01

    Transient celestial phenomena feature prominently in the astronomical knowledge and traditions of Aboriginal Australians. In this paper, I collect accounts of the Aurora Australis from the literature regarding Aboriginal culture. Using previous studies of meteors, eclipses, and comets in Aboriginal traditions, I anticipate that the physical properties of aurora, such as their generally red colour as seen from southern Australia, will be associated with fire, death, blood, and evil spirits. The survey reveals this to be the case and also explores historical auroral events in Aboriginal cultures, aurorae in rock art, and briefly compares Aboriginal auroral traditions with other global indigenous groups, including the Maori of New Zealand.

  12. The Aurora B kinase in chromosome biorientation and spindle checkpoint signalling

    Directory of Open Access Journals (Sweden)

    Veronica eKrenn

    2015-10-01

    Full Text Available Aurora B, a member of the Aurora family of serine/threonine protein kinases, is a key player in chromosome segregation. As part of a macromolecular complex known as the chromosome passenger complex, Aurora B concentrates early during mitosis in the proximity of centromeres and kinetochores, the sites of attachment of chromosomes to spindle microtubules. There, it contributes to a number of processes that impart fidelity to cell division, including kinetochore stabilization, kinetochore-microtubule attachment, and the regulation of a surveillance mechanism named the spindle assembly checkpoint. In the regulation of these processes, Aurora B is the fulcrum of a remarkably complex network of interactions that feed back on its localization and activation state. In this review we discuss the multiple roles of Aurora B during mitosis, focusing in particular on its role at centromeres and kinetochores. Many details of the network of interactions at these locations remain poorly understood, and we focus here on several crucial outstanding questions.

  13. The dawn of Aurora kinase research: from fly genetics to the clinic.

    Directory of Open Access Journals (Sweden)

    Mar eCarmena

    2015-11-01

    Full Text Available Aurora kinases comprise a family of highly conserved serine-threonine protein kinases that play a pivotal role in the regulation of cell cycle. Aurora kinases are not only involved in the control of multiple processes during cell division but also coordinate chromosomal and cytoskeletal events, contributing to the regulation of checkpoints and ensuring the smooth progression of the cell cycle.Because of their fundamental contribution to cell cycle regulation, Aurora kinases were originally identified in independent genetic screens designed to find genes involved in the regulation of cell division. The first aurora mutant was part of a collection of mutants isolated in C. Nusslein-Volhard’s laboratory. This collection was screened in D. M. Glover’s laboratory in search for mutations disrupting the centrosome cycle in embryos derived from homozygous mutant mothers. The mutants identified were given names related to the polar regions, and included not only aurora but also the equally famous polo. Ipl1, the only Aurora in yeast, was identified in a genetic screen looking for mutations that caused chromosome segregation defects. The discovery of a second Aurora-like kinase in mammals opened a new chapter in the research of Aurora kinases. The rat kinase AIM was found to be highly homologous to the fly and yeast proteins, but localised at the midzone and midbody and was proposed to have a role in cytokinesis. Homologs of the equatorial Aurora (Aurora B were identified in metazoans ranging from flies to humans. Xenopus Aurora B was found to be in a complex with the chromosomal passenger INCENP, and both proteins were shown to be essential in flies for chromosome structure, segregation, central spindle formation and cytokinesis. Fifteen years on, Aurora kinase research is an active field of research. After the successful introduction of the first anti-mitotic agents in cancer therapy, both Auroras have become the focus of attention as targets for

  14. Aurora status and plans

    International Nuclear Information System (INIS)

    Aurora is a short wavelength (248 nm) 10 to kJ KrF laser systems in the ICF program at Los Alamos National Laboratory. It is both an experiment in driver technology and a means for studying target performance using KrF laser light. Both features will be used to help evaluate the uv excimer laser as a viable fusion driver. The system has been designed to employ several electron-beam pumped amplifiers in series, with a final aperture of one meter square, to amplify 96 angularly mulitplexed 5 ns beamlets to the 10 kJ level. In Phase I, 48 of these beamlets are brought to target by demultiplexing and focusing with f26 optics. The beamlet ensemble, contained within an f1.9 bundle, is focused as a single beam;however, pointing is done individually. Spot size in the target plane is variable from 0.1-4 mm, with maximum averaged intensity of /similar to/ 4 x 1015 Wcm2. The illumination geometry is designed specifically for several classes of important target physics experiments. These include: energy flow, symmetry and preheat studies related to indirectly driven targets;x-ray conversion and plasma coupling characterization on disc targets, and hydrodynamic instability studies in planar geometry. System integration is proceeding toward initial target experiments in /similar to/ late 1988. Ninety-six beam amplification through the penultimate amplifier has been obtained at the sub-kJ level. Installation of beam train optics is proceeding, and the target system vacuum envelope is in place. 18 refs., 12 figs., 2 tabs

  15. Triton torus and Neptune aurora

    Science.gov (United States)

    Cheng, Andrew F.

    1990-01-01

    Triton is shown to be the dominant source of plasma for L equal to or greater than 7 in the magnetosphere of Neptune. Triton maintains a neutral hydrogen torus of average density comparable to a greater than that of the Titan torus at Saturn. The Triton torus may be detectable in H Lyman-alpha emissions. However, the energy source from plasma outward transport and mass loading in the Triton torus is insufficient to explain the Neptune aurora. It is proposed that Neptune's aurora is driven mainly by a solar wind interaction.

  16. Inhibition of Survivin and Aurora B Kinase Sensitizes Mesothelioma Cells by Enhancing Mitotic Arrests

    International Nuclear Information System (INIS)

    Purpose: Survivin, a member of the inhibitor of apoptosis gene family, has also been shown to regulate mitosis. It binds Aurora B kinase and the inner centromere protein to form the chromosome passenger complex. Both Aurora B and survivin are overexpressed in many tumors. In this study, we examined whether irradiation affected survivin and Aurora B expression in mesothelioma cells, and how inhibition of these molecules affected radiosensitivity. Methods and Materials: ZM447439 and survivin antisense oligonucleotides were used to inhibit survivin and Aurora B kinase respectively. Western blot was performed to determine the expression of survivin, Aurora B, phosphorylated-histone H3 (Ser 10), and caspase cleavage. Multinucleated cells were counted using flow cytometry, and cell survival after treatment was determined using clonogenic assay. Results: At 3-Gy irradiation an increase was observed in levels of survivin and Aurora B as well as the kinase activity of Aurora B, with an increase in G2/M phase. The radiation-induced upregulation of these molecules was effectively attenuated by antisense oligonucleotides against survivin and a small-molecule inhibitor of Aurora B, ZM447439. Dual inhibition of survivin and Aurora B synergistically radiosensitized mesothelioma cells with a dose enhancement ratio of 2.55. This treatment resulted in increased formation of multinucleated cells after irradiation but did not increase levels of cleaved caspase 3. Conclusion: Inhibition of survivin and Aurora B induces mitotic cell arrest in mesothelioma cells after irradiation. These two proteins may be potential therapeutic targets for the enhancement of radiotherapy in malignant pleural mesothelioma

  17. Image analysis of dayside aurora

    International Nuclear Information System (INIS)

    Ground based observations from Svalbard of the midday aurora by all sky cameras and meridian scanning photometers showed the sporadic occurrence of discrete auroral forms within or near the stable cusp or cleft aurora. Some of these forms appeared near the equatorward boundary of the stable cusp/cleft aurora and moved westward and northward. The duration of the whole event was typically less than 10 minutes. Series of such events were observed when the cusp/cleft was located at low latitudes. Satellite measurements of magnetic field and ion drift components above auroral strucures gave detailed information of auroral electrodynamics in the cusp/cleft ionosphere. Satellite observations of the dayside oval at ∼ 09 MLT showed that auroral emissions can be separated in different latitudinal zones with corresponding structures in the particle precipitation. The ground based optical instruments at Svalbard measured the stationary cleft aurora produced by soft electrons and transient discrete arcs produced by precipitating keV electrons. 89 refs

  18. Arsenic-induced Aurora-A activation contributes to chromosome instability and tumorigenesis

    Science.gov (United States)

    Wu, Chin-Han; Tseng, Ya-Shih; Yang, Chao-Chun; Kao, Yu-Ting; Sheu, Hamm-Ming; Liu, Hsiao-Sheng

    2013-11-01

    Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been determined. Arsenic shows genotoxic effect on human beings who uptake water contaminated by arsenic. Chromosome aberration is frequently detected in arsenic exposure-related diseases and is associated with increased oxidative stress and decreased DNA repairing activity, but the underlying mechanism remains elusive. Aurora-A is a mitotic kinase, over-expression of Aurora-A leads to centrosome amplification, chromosomal instability and cell transformation. We revealed that Aurora-A is over-expressed in the skin and bladder cancer patients from blackfoot-disease endemic areas. Our cell line studies reveal that arsenic exposure between 0.5 μM and 1 μM for 2-7 days are able to induce Aurora-A expression and activation based on promoter activity, RNA and protein analysis. Aurora-A overexpression further increases the frequency of unsymmetrical chromosome segregation through centrosome amplification followed by cell population accumulated at S phase in immortalized keratinocyte (HaCaT) and uroepithelial cells (E7). Furthermore, Aurora-A over-expression was sustained for 1-4 weeks by chronic treatment of immortalized bladder and skin cells with NaAsO2. Aurora-A promoter methylation and gene amplification was not detected in the long-term arsenic treated E7 cells. Furthermore, the expression level of E2F1 transcription factor (E2F1) is increased in the presence of arsenic, and arsenic-related Aurora-A over-expression is transcriptionally regulated by E2F1. We further demonstrated that overexpression of Aurora-A and mutant Ha-ras or Aurora-A and mutant p53 may act additively to trigger arsenic-related bladder and skin cancer

  19. Ionospheric Response to Flickering Aurora

    Science.gov (United States)

    Gustavsson, B.; Grydeland, T.; Blixt, M.; Baddeley, L.; Lunde, J.

    2007-12-01

    Flickering aurora is characterized by optical emissions varying in intensity with frequencies typically between 5 and 20 Hz. Here we use high-speed narrow field-of-view imaging in white light to determine the intensity variation in the field aligned direction, which is also the direction of the beam of the EISCAT Svalbard Radar (ESR). Incoherent scatter radar data is noise-like, and must be integrated over multiple pulses to reduce the variance to useful levels, even for high signal to noise ratios. Usually, this means integrating over several seconds to some tens of seconds of observation, which is not very useful with respect to flickering aurora. In the experiment presented here, we have taken data at the voltage level, before any integration. By integrating pulses with the same relative phase with respect to the optical intensity we can determine the variation in radar back-scatter on time-scales of 0.02 s.

  20. Periodisme i literatura: Aurora Bertrana

    Directory of Open Access Journals (Sweden)

    Neus Real

    2014-06-01

    Full Text Available This article relates the activity in the press of the writer Aurora Bertrana with her literature, and it makes evident the interdependence of journalism and literary creation in the first stage of the author’s production. It also analyzes the key role of this interaction in the construction of her image as well as in the consolidation of her intellectual prestige.

  1. Hydrogeology baseline study Aurora Mine

    International Nuclear Information System (INIS)

    A baseline hydrogeologic study was conducted in the area of Syncrude's proposed Aurora Mine in order to develop a conceptual regional hydrogeologic model for the area that could be used to understand groundwater flow conditions. Geologic information was obtained from over 2,000 coreholes and from data obtained between 1980 and 1996 regarding water level for the basal aquifer. A 3-D numerical groundwater flow model was developed to provide quantitative estimates of the potential environmental impacts of the proposed mining operations on the groundwater flow system. The information was presented in the context of a regional study area which encompassed much of the Athabasca Oil Sands Region, and a local study area which was defined by the lowlands of the Muskeg River Basin. Characteristics of the topography, hydrology, climate, geology, and hydrogeology of the region are described. The conclusion is that groundwater flow in the aquifer occurs mostly in a westerly direction beneath the Aurora Mine towards its inferred discharge location along the Athabasca River. Baseflow in the Muskeg River is mostly related to discharge from shallow surficial aquifers. Water in the river under baseflow conditions was fresh, of calcium-carbonate type, with very little indication of mineralization associated with deeper groundwater in the Aurora Mine area. 44 refs., 5 tabs., 31 figs

  2. Mechanistic investigations of shuttle glow

    Science.gov (United States)

    Caledonia, G. E.; Holtzclaw, K. W.; Krech, R. H.; Sonnenfroh, D. M.; Leone, A.; Blumberg, W. A. M.

    1993-01-01

    A series of laboratory measurements have been performed in order to provide a mechanistic interpretation for the visible shuttle glow. These studies involved interactions of an 8 km/s oxygen atom beam with both contaminant dosed surfaces and gaseous targets. We conclude that visible shuttle glow arises from surface mediated O + NO recombination via a Langmuir-Hinshelwood mechanism and that the gas-phase exchange reaction O + N2 - NO + N provides a viable source of precursor NO above surfaces oriented in the ram direction.

  3. Stable operation of high current glow discharges

    International Nuclear Information System (INIS)

    Glow discharges are very suited for cleaning and other surface treatment of plasma vessels. In this report, an extended version of a colloquium talk, given at Juelich, October 1977, the phenomenon of glow discharges and the operation of an apparatus for glow discharging nitriding are discussed

  4. Aurora B inhibitor barasertib prevents meiotic maturation and subsequent embryo development in pig oocytes.

    Science.gov (United States)

    Ju, Shiqiang; Peng, Xu; Yang, Xiaoliu; Sozar, Sparksi; Muneri, Caroline W; Xu, Yaping; Chen, Changchao; Cui, Panpan; Xu, Weichao; Rui, Rong

    2016-07-15

    Barasertib, a highly selective Aurora B inhibitor, has been widely used in a variety of cells to investigate the role of Aurora B kinase, which has been implicated in various functions in the mitotic process. However, effects of barasertib on the meiotic maturation process are not fully understood, particularly in porcine oocyte meiotic maturation. In the present study, the effects of barasertib on the meiotic maturation and developmental competence of pig oocytes were investigated, and the possible roles of Aurora B were also evaluated in porcine oocytes undergoing meiosis. Initially, we examined the expression and subcellular localization of Aurora B using Western blot analysis and immunofluorescent staining. Aurora B was found to express and exhibit specific dynamic intracellular localization during porcine oocyte meiotic maturation. Aurora B was observed around the chromosomes after germinal vesicle breakdown. Then it was transferred to the spindle region after metaphase I stage, and was particularly concentrated at the central spindles at telophase I stage. barasertib treatment resulted in the failure of polar body extrusion in pig oocytes, with a larger percentage of barasertib-treated oocytes remaining at the pro-metaphase I stage. Additional results reported that barasertib treatment had no effect on chromosome condensation but resulted in a significantly higher percentage of the treated oocytes with aberrant spindles and misaligned chromosomes during the first meiotic division. In addition, inhibition of Aurora B with lower concentrations of barasertib during pig oocyte meiotic maturation decreased the subsequent embryo developmental competence. Thus, these results illustrate that barasertib has significant effects on porcine oocyte meiotic maturation and subsequent development through Aurora B inhibition, and this regulation is related to its effects on spindle formation and chromosome alignment during the first meiotic division in porcine oocytes. PMID

  5. Antineoplastic effects of an Aurora B kinase inhibitor in breast cancer

    Directory of Open Access Journals (Sweden)

    Velazquez-Torres Guermarie

    2010-02-01

    Full Text Available Abstract Background Aurora B kinase is an important mitotic kinase involved in chromosome segregation and cytokinesis. It is overexpressed in many cancers and thus may be an important molecular target for chemotherapy. AZD1152 is the prodrug for AZD1152-HQPA, which is a selective inhibitor of Aurora B kinase activity. Preclinical antineoplastic activity of AZD1152 against acute myelogenous leukemia, multiple myeloma and colorectal cancer has been reported. However, this compound has not been evaluated in breast cancer, the second leading cause of cancer deaths among women. Results The antineoplastic activity of AZD1152-HQPA in six human breast cancer cell lines, three of which overexpress HER2, is demonstrated. AZD1152-HQPA specifically inhibited Aurora B kinase activity in breast cancer cells, thereby causing mitotic catastrophe, polyploidy and apoptosis, which in turn led to apoptotic death. AZD1152 administration efficiently suppressed the tumor growth in a breast cancer cell xenograft model. In addition, AZD1152 also inhibited pulmonary metastatic nodule formation in a metastatic breast cancer model. Notably, it was also found that the protein level of Aurora B kinase declined after inhibition of Aurora B kinase activity by AZD1152-HQPA in a time- and dose-dependent manner. Investigation of the underlying mechanism suggested that AZD1152-HQPA accelerated protein turnover of Aurora B via enhancing its ubiquitination. Conclusions It was shown that AZD1152 is an effective antineoplastic agent for breast cancer, and our results define a novel mechanism for posttranscriptional regulation of Aurora B after AZD1152 treatment and provide insight into dosing regimen design for this kinase inhibitor in metastatic breast cancer treatment.

  6. Aurora kinase inhibitors: a new class of drugs targeting the regulatory mitotic system.

    Science.gov (United States)

    Pérez Fidalgo, José Alejandro; Roda, Desamparados; Roselló, Susana; Rodríguez-Braun, Edith; Cervantes, Andrés

    2009-12-01

    The present review gives a perspective on the Aurora kinase family members, their function in normal cells, their role in cancer progression as well as their potential as target for anticancer treatment. Mitosis has been an important target for anticancer therapy development, leading to some specific drugs mainly addressing Tubulines, as a key structure of the mitotic spindle. Vinca alkaloids, taxanes or epotilones are good examples of conventionally developed antimitotic agents. However, novel classes of antineoplastic drugs are being studied, targeting the regulatory system that controls functional aspects of mitosis, such as Aurora or Polo-like kinases or Kinespondin inhibitors. The specific role of the different Aurora kinase proteins as regulator enzymes of the mitotic process in normal cells is discussed. Some of the mechanisms that link Aurora overexpression with cancer are also considered. Thereafter, the clinical and preclinical development of the different Aurora kinase inhibitors is presented. This is nowadays a very active area of therapeutic research and at least, sixteen new compounds are being studied as potential antineoplastic drugs. Most of them are in a very early phase of clinical development. However, we summarized the most recently published findings related with these drugs: main characteristics, way of administration, dose limiting toxicities and recommended doses for further studies. Another important aspect in Aurora kinase inhibition is the study and validation of potential biomarkers to optimize the clinical development. Several studies included pharmacodynamic assessments in normal blood cells, skin or/and tumor biopsies. Several proposals included a higher mitotic index, a decreased number of mitosis with bipolar spindles or normal alignment of chromosomes and inhibition of histone H3 phosphorylation. Future strategies and challenges for trials with Aurora kinase inhibitors are also discussed. PMID:20045785

  7. Targeting the interaction of Aurora kinases and SIRT1 mediated by Wnt signaling pathway in colorectal cancer: A critical review.

    Science.gov (United States)

    Subramaniyan, Boopathi; Jagadeesan, Kaviya; Ramakrishnan, Sabitha; Mathan, Ganeshan

    2016-08-01

    The Aurora kinases belong to the family of serine/threonine kinase, a central regulator of mitosis and their expression increased during G2/M phase. It is classified into Aurora A, B and C, each has distinct roles in cellular processes, which includes regulation of spindle assembly, function of centrosomes, cytoskeleton and cytokinesis. During cancer growth, their rapid increase makes most attractive marker for cancer treatment at present. However Aurora A kinase is known to be a marker for cancer therapy, the most important serine/threonine kinase of Aurora B kinase involvement in cancer is still inadequate. Subsequently, the recent findings revealed that the class III histone deacetylase of SIRT1 is a key regulator to activate Aurora kinases from S phase damaged DNA through Wnt signaling pathway. Even if both Aurora A kinase and SIRT1 serve as a marker for cancer therapy, the present review reveals it is interaction in Wnt signaling pathway that solely for colorectal cancer. PMID:27470380

  8. Numerical analysis of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

  9. Glow Sticks: Spectra and Color Mixing

    Science.gov (United States)

    Birriel, Jennifer; Birriel, Ignacio

    2014-01-01

    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…

  10. Environmental TLD Glow Curve Analysis

    International Nuclear Information System (INIS)

    Environmental radioactive monitoring in Serbia is performed according the Law of Radiation Protection against Ionizing Radiation. Comparing to GM counter network, environmental TLDs are used for control more points. Some other measuring methods are also used (gamma, alpha-beta samples analyzing; continuously ambient dose equivalent screening etc.). Environmental TLD badge has four crystals: 2 CaSO4 and 2 LiF. As relative measurement method TLD requires careful calibration of reader and dosimeter itself. Different causes could damage TLD crystal placed at site. Each glow curve has to be checked for regularity and irregular one has to be eliminated. The main (the fifth) eak ofLiF crystals has to be at read-out temperature. Also, the shape of second glow curve depends on irradiation modality. Using HARSHAW CGCD Programme it is possible to estimate time of one-shot exposure as well as to differ continuously exposing crystal from one irradiated in few portions. The method applied in the LPD (Laboratory for personal dosimetry of IORH Dr Dragomir Karajovic, Belgrade), is represented in the paper.(author)

  11. Evaluation of the Aurora Application Shade Measurement Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    2015-12-01

    Aurora is an integrated, Web-based application that helps solar installers perform sales, engineering design, and financial analysis. One of Aurora's key features is its high-resolution remote shading analysis.

  12. Recent developments in pulsating aurora studies

    International Nuclear Information System (INIS)

    The field of pulsating aurora studies is reviewed. The paper begins with a short description of the characteristics of pulsating auroras and the theoretical ideas which, in view of existing experimental results, seem most important. A selection of new theoretical results and experimental results from both ground based instruments and instruments on rockets and satellites is then presented. There is now convincing evidence that the luminosity modulation is caused by a modulated flux of electron. The electron flux modulation seems to arise from a modulated resonant interaction between electrons and whistler mode waves in the equatorial plane, but the reason for the modulation is not known. Measurements concerning the drift and location of patches and the creation of Pi1 micropulsations are also deiscussed. Finally some suggestions for future research work are outlined. Optical measurements, especially with low light level TV, have proven to be of great importance in experimental studies of pulsating auroras. (author)

  13. Discovery of diffuse aurora on Mars.

    Science.gov (United States)

    Schneider, N M; Deighan, J I; Jain, S K; Stiepen, A; Stewart, A I F; Larson, D; Mitchell, D L; Mazelle, C; Lee, C O; Lillis, R J; Evans, J S; Brain, D; Stevens, M H; McClintock, W E; Chaffin, M S; Crismani, M; Holsclaw, G M; Lefevre, F; Lo, D Y; Clarke, J T; Montmessin, F; Jakosky, B M

    2015-11-01

    Planetary auroras reveal the complex interplay between an atmosphere and the surrounding plasma environment. We report the discovery of low-altitude, diffuse auroras spanning much of Mars' northern hemisphere, coincident with a solar energetic particle outburst. The Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, detected auroral emission in virtually all nightside observations for ~5 days, spanning nearly all geographic longitudes. Emission extended down to ~60 kilometer (km) altitude (1 microbar), deeper than confirmed at any other planet. Solar energetic particles were observed up to 200 kilo--electron volts; these particles are capable of penetrating down to the 60 km altitude. Given minimal magnetic fields over most of the planet, Mars is likely to exhibit auroras more globally than Earth. PMID:26542577

  14. The retrieval of abnormal TL glow curves using modified glow curve analysis method

    International Nuclear Information System (INIS)

    The shape of TL glow curve is a useful indicator for assurance of correct reading of the personal dosimeter. Since the reading procedure of TLD is irreversible, however, an analytic remedy should be considered to procure reliable dosimetric information for the readings with irregular glow curve shape. In this study, kinetic trapping parameter of CaSO4 : Dy Teflon personal dosimeter (Teledyne PB-6A) were analyzed by Halperin and Braner's model for general-order kinetics. From these kinetic trapping parameters, we also developed a simple procedure to retrieve the dosimetric information from abnormally distorted glow curves. The computerized glow curve deconvolution (CGCD) fitting of the reference glow curve with kinetic parameters from this study yields relative errors of about 5% from the expected integral. It was also found that the glow curve remedial procedure developed could retrieve the distorted TL glow curves within error ranges of 15%. With the glow curve retrieval techniques, doses incurred by gamma radiation can now be successfully re-constructed for the CaSO4 : Dy Teflon dosimeter resulting abnormal glow curves. (author)

  15. San Huang Decoction downregulates Aurora kinase A to inhibit breast cancer cell growth and enhance chemosenstivity to anti-tumor drugs.

    Science.gov (United States)

    Xu, Yanlei; Chen, Xu; Chen, Xiyan; Bian, Weihe; Yao, Chang; Zhang, Xiaoqing; Zhu, Xiaoshu; Chen, Jiajing; Ye, Xiaozhou

    2016-08-01

    Our study aimed to explore whether San Huang Decoction (SHD) inhibited the development of breast cancer by regulating Aurora A. Human breast cancer cell lines MCF-7 and MDA-MB-231 were cultured and SHD extract was prepared. Cell growth assay and apoptosis analysis were respectively performed to detect the effects of SHD on breast cancer cells. In addition, the effects of SHD on the expression of Aurora A and p53 were determined by RT-PCR and western blot. Besides, we used Aurora A siRNA to knock down Aurora A. We then co-administrated SHD and tamoxifen or epirubicin to detect the effect of SHD on chemosensitivity to tamoxifen or epirubicin. SHD treatment significantly inhibited cell growth in a dose-dependent manner. Moreover, SHD treatment resulted in a marked decrease in Aurora A expression and obvious increase in p53 expression. In addition, knockdown of Aurora A induced cell growth inhibition, which was similar to the effect of SHD treatment. Besides, SHD exerted an additive effect on cell growth inhibition and apoptosis induction when breast cancer cells were co-administration of SHD with tamoxifen or epirubicin. Our study indicates that SHD treatment may inhibit cell growth and enhance chemosenstivity to other anti-tumor drugs in breast cancer via down-regulation of Aurora A. PMID:27461831

  16. Glow discharge cleaning of vacuum switch tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, T.; Toya, H. (Mitsubishi Electric Corp., Amagasaki, Hyogo (Japan). Central Research Lab.)

    1991-10-01

    This paper reports that glow discharge cleaning has ben advancing as a means of degassing vacuum chambers constructed for a large accelerator or for nuclear fusion research. To clean the whole surface of parts inside a vacuum switch tube (VST), a new technique is tried which generates glow discharge between the inner electrodes and copper grid surrounding it. Photographic observation reveals that the glow discharge spreads out and cleans the whole surface inside the VST. A breakdown test between the inner electrodes shows the effect of the cleaning with this technique. Higher breakdown voltage between the inner electrodes is attained by performing this glow discharge cleaning in argon rather than hydrogen gas. The difference of the cleaning effect seems to be attributed to that of the energy transfer from ion species to the absorbed molecules and microprotrusions on the surfaces.

  17. Irregular glow curves in TL dosimetry

    International Nuclear Information System (INIS)

    The Personal Dosimetry Service Seibersdorf analyses monthly a large number of thermo luminescent dosemeters. In rare cases the luminescent glow curves of the routine analyse do not have the expected form. The typical spurious effects in glow curves are well known and it is possible to find many examples in the related literature. A curve can have an abnormal shape due to UV radiation, electric discharge, external contaminants on or absorbed in the crystal, the light sensitivity of the PTFE components, etc. In this work many of these effects were verified and another (like the effect of mechanic shock, static electricity, humidity,..) were examined. Particularly the influence on the shape of the glow curves was studied. It is necessary to know, if these experimental effects could also take place during the routine evaluation. An algorithm, which permits to identify irregular glow curves through comparison with a standard curve, was developed and applied in routine evaluations. This investigation has shown that in rare cases, in which the dosimeter was not used correctly (opened package, stored with high temperatures, washing machine, etc.), irregular glow curves can appear and a correct dose evaluation is not possible. Current analyse of the glow curves is therefore necessary in order to find such effects and to enforce the necessary corrections. (orig.)

  18. BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

    OpenAIRE

    Moustafa-Kamal, M; Gamache, I; Lu, Y.; Li, S; Teodoro, J G

    2013-01-01

    Bcl-2-interacting mediator of cell death (Bim) is a pro-apoptotic B-cell lymphoma 2 family member implicated in numerous apoptotic stimuli. In particular, Bim is required for cell death mediated by antimitotic agents, however, mitotic regulation of Bim remains poorly understood. Here, we show that the major splice variant of Bim, BimEL, is regulated during mitosis by the Aurora A kinase and protein phosphatase 2A (PP2A). We observed that BimEL is phosphorylated by Aurora A early in mitosis an...

  19. The thermoluminescence glow-curve analysis using GlowFit - the new powerful tool for deconvolution

    International Nuclear Information System (INIS)

    A new computer program, GlowFit, for deconvoluting first-order kinetics thermoluminescence (TL) glow-curves has been developed. A non-linear function describing a single glow-peak is fitted to experimental points using the least squares Levenberg-Marquardt method. The main advantage of GlowFit is in its ability to resolve complex TL glow-curves consisting of strongly overlapping peaks, such as those observed in heavily doped LiF:Mg,Ti (MTT) detectors. This resolution is achieved mainly by setting constraints or by fixing selected parameters. The initial values of the fitted parameters are placed in the so-called pattern files. GlowFit is a Microsoft Windows-operated user-friendly program. Its graphic interface enables easy intuitive manipulation of glow-peaks, at the initial stage (parameter initialization) and at the final stage (manual adjustment) of fitting peak parameters to the glow-curves. The program is freely downloadable from the web site www.ifj.edu.pl/NPP/deconvolution.htm (author)

  20. High expression of nuclear survivin and Aurora B predicts poor overall survival in patients with head and neck squamous cell cancer

    Energy Technology Data Exchange (ETDEWEB)

    Erpolat, O.P.; Akmansu, M. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Radiation Oncology; Gocun, P.U.; Karakus, E.; Akyol, G. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Pathology

    2012-03-15

    Survivin is one of the apoptosis inhibitor proteins. Together with Aurora B, it also plays a role in regulating several aspects of mitosis. High expression of these markers is correlated with malignant behavior of various cancers and resistance to therapy. Our aim was to evaluate the prognostic role of these markers in head and neck cancers. We evaluated the expression of Aurora B and survivin in tissue specimens of 58 patients with head and neck squamous cell carcinoma using immunohistochemistry. Patients who showed high expression of cytoplasmic and nuclear survivin and Aurora B had significantly shorter overall survival (p = 0.036, p < 0.000, p = 0.032, respectively). In multivariate analysis, high expression of nuclear survivin was the only independent negative prognostic factor (p = 0.024). Moreover, it was found that high co-expression of nuclear survivin and Aurora B had a negative effect on survival in univariate (p < 0.000) and multivariate (p < 0.000) analyses. The negative prognostic values of high expression of Aurora B and high co-expression of nuclear survivin and Aurora B on survival were shown. These findings suggest that co-expression of nuclear survivin and Aurora B can be useful diagnostic markers and therapeutic targets for head and neck squamous cell carcinoma. However, further studies with a larger number of patients in a more homogeneous disease group are needed to confirm the conclusion.

  1. Horse-collar aurora: A frequent pattern of the aurora in quiet times

    International Nuclear Information System (INIS)

    Reported here are DE 1 auroral imager observations of an auroral configuration which is given the name ''horse-collar aurora.'' The horse-collar pattern comprises the total area of auroral emissions from a single hemisphere and derives its name from the shape of the emitting area. The pattern is found in images recorded during quiet geomagnetic conditions and is possibly related to the theta aurora, another quiet time configuration of the auroras. This initial report of the DE 1 observations illustrates the horse-collar aurora with a 2-hour images sequence that displays its basic features and shows an example of its evolution into a theta-like auroral pattern. The interplanetary magnetic field was northward during this image sequence and there is some evidence for IMF B/sub y/ influence of the temporal development of the horse-collar pattern. A preliminary statistical analysis found the horse-collar pattern appearing in one-third or more of image sequences recorded during quiet conditions; it did not appear during disturbed conditions. Further study is required to establish more fully the characteristics of the horse-collar aurora and to determine its implications concerning solar wind-magnetosphere coupling when the IMF B/sub z/ is northward. copyright American Geophysical Union 1989

  2. Aurora A's functions during mitotic exit: the Guess Who game

    Directory of Open Access Journals (Sweden)

    David eReboutier

    2015-12-01

    Full Text Available Until recently, the knowledge of Aurora A kinase functions during mitosis was limited to pre-metaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. However, an involvement of Aurora A in post-metaphase events was also suspected, but not clearly demonstrated due to the technical difficulty to perform the appropriate experiments. Recent developments of both an analog specific version of Aurora A, and of small molecule inhibitors have led to the first demonstration that Aurora A is required for the early steps of cytokinesis. As in pre-metaphase, Aurora A plays diverse functions during anaphase, essentially participating in astral microtubules dynamics and central spindle assembly and functioning. The present review describes the experimental systems used to decipher new functions of Aurora A during late mitosis and situate these functions into the context of cytokinesis mechanisms.

  3. Aurora A's Functions During Mitotic Exit: The Guess Who Game.

    Science.gov (United States)

    Reboutier, David; Benaud, Christelle; Prigent, Claude

    2015-01-01

    Until recently, the knowledge of Aurora A kinase functions during mitosis was limited to pre-metaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. However, an involvement of Aurora A in post-metaphase events was also suspected, but not clearly demonstrated due to the technical difficulty to perform the appropriate experiments. Recent developments of both an analog-specific version of Aurora A and small molecule inhibitors have led to the first demonstration that Aurora A is required for the early steps of cytokinesis. As in pre-metaphase, Aurora A plays diverse functions during anaphase, essentially participating in astral microtubules dynamics and central spindle assembly and functioning. The present review describes the experimental systems used to decipher new functions of Aurora A during late mitosis and situate these functions into the context of cytokinesis mechanisms. PMID:26734572

  4. Jung's quest for the Aurora consurgens.

    Science.gov (United States)

    Haaning, Aksel

    2014-02-01

    The paper focuses on the year 1929 when Jung published 'A European commentary' to Richard Wilhelm's German translation of the Taoist text The Secret of the Golden Flower. This shows that Jung had already started on the track of European alchemy by following up Conrad Waldkirch's preface in Artis Auriferae (1593); and it raises the question of whether this could be the possible missing link to Jung's subsequent research in Alchemy and Hermetic Philosophy in the years to come. It is argued that here was the beginning of Jung's quest for the Aurora consurgens, the publication of which concludes the Mysterium Conuinctionis more than twenty years later. It is further maintained that this choice of the Aurora is a profound expression of Jung's ambition to revitalize the past from within the individual, and helps explain Jung's deep concern with the welfare and future of modern society. PMID:24467350

  5. Aurora Mine project - historical resources baseline study

    International Nuclear Information System (INIS)

    This volume contains the results of a base line archaeological study of the Aurora Mine Project local study area. It was compiled in support of Syncrude Canada's application to the Alberta Energy and Utilities Board (AEUB) and Alberta Environmental Protection to construct and operate it new Aurora Mine, located northeast of Fort McMurray, Alberta. The objective of this study was to compile, consolidate, review and analyze the reports for the area compiled over the past 22 years in and adjacent to the local study area (LSA), particularly those of now existing and Syncrude projects, and previously proposed Alsands and OSLO projects. The report is a summary of the human history in the area including pre-contact native archaeological sites, past archaeological studies, the Hinterland site pattern, post-contact native traditional sites, oil sands exploration/development related sites and paleontological sites in the subject area, and areas adjacent to it. 150 refs., 5 tabs., 43 figs

  6. Aurora kinase inhibitors: Progress towards the clinic

    Czech Academy of Sciences Publication Activity Database

    Kollareddy, M.; Zheleva, D.; Dzubak, P.; Brahmkshatriya, Pathik; Lepšík, Martin; Hajduch, M.

    2012-01-01

    Roč. 30, č. 6 (2012), s. 2411-2432. ISSN 0167-6997 Grant ostatní: GA ČR(CZ) GA301/08/1649; GA ČR(CZ) GD303/09/H048 Institutional research plan: CEZ:AV0Z40550506 Keywords : Aurora kinases * cancer * inhibitors Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2012

  7. Viking observations above a postnoon aurora

    International Nuclear Information System (INIS)

    This is the first paper that combines observations of the electric and magnetic fields, particles, wave emissions and UV images taken at intermediate altitude (two Earth radii) above the acceleration region of a 14 MLT aurora. The observations were made by the Swedish Viking satellite. The aurora appeared in the region of large-scale reversal of the perpendicular electric field. Strong fluctuations in the electric and magnetic field indicated that the aurora consisted of many arcs of varying latitudinal extent. Spin-averaged data show that an upward current sheet was connected with the observed UV aurora, with an ionospheric current density of 4 μA/m2 in the center of the sheet and 7 μA/m2 near the equatorward edge. The field-aligned potential drop Vparallel was determined from the mean energy of the upward ion beams and the width of the electron loss cone. Vparallel increased from several hundred volts near the equatorward edge of the current sheet to at least 3 kV in the center. Auroral kilometric radiation (AKR) and the widened electron loss cone indicated that the top of the acceleration region wwith Vparallel ≥ 3 kV was located near one Earth radius. The critical field-aligned potential drop, Vparallelc, which is strong enough to accelerate the bulk of the electrons into the loss cone, was derived from the characteristic electron energy T and the ratio of the magnetic field in the ionosphere to taht at the top of the acceleration region, Bi/Bv. The source plasma parameters were typical for magnetosheath plasma with a characteristic electron energy of about 200 eV

  8. NITROGEN POTENTIAL DURING ION NITRIDING PROCESS IN GLOW-DISCHARGE PLASMA

    OpenAIRE

    Kozlov, A. A.

    2015-01-01

    The paper considers problems on regulation of phase composition of a nitrided layer during gas and ion nitriding process in a glow-discharge. It has been established that  available models for control of nitrided layer structure with the help of nitriding index (nitrogen potential) can not be applied for nitriding process in the glow-discharge. Principal difference of the ion nitriding from the gas one is in the fact that chemically active nitrogen is formed in the discharge zone (cathode lay...

  9. Polar Embedding for Aurora Image Retrieval.

    Science.gov (United States)

    Yang, Xi; Gao, Xinbo; Tian, Qi

    2015-11-01

    Exploring the multimedia techniques to assist scientists for their research is an interesting and meaningful topic. In this paper, we focus on the large-scale aurora image retrieval by leveraging the bag-of-visual words (BoVW) framework. To refine the unsuitable representation and improve the retrieval performance, the BoVW model is modified by embedding the polar information. The superiority of the proposed polar embedding method lies in two aspects. On the one hand, the polar meshing scheme is conducted to determine the interest points, which is more suitable for images captured by circular fisheye lens. Especially for the aurora image, the extracted polar scale-invariant feature transform (polar-SIFT) feature can also reflect the geomagnetic longitude and latitude, and thus facilitates the further data analysis. On the other hand, a binary polar deep local binary pattern (polar-DLBP) descriptor is proposed to enhance the discriminative power of visual words. Together with the 64-bit polar-SIFT code obtained via Hamming embedding, the multifeature index is performed to reduce the impact of false positive matches. Extensive experiments are conducted on the large-scale aurora image data set. The experimental result indicates that the proposed method improves the retrieval accuracy significantly with acceptable efficiency and memory cost. In addition, the effectiveness of the polar-SIFT scheme and polar-DLBP integration are separately demonstrated. PMID:26068312

  10. Source of high-voltage power supply for ozone generators at glow discharge

    International Nuclear Information System (INIS)

    High-voltage power supply source on quasi-resonance inverter base which works at direct current regime is described. This source forms 20 kV voltage with 0 - 10 mA current regulation. It protects the source from current break-downs and feeds ozone generators at glow discharge

  11. Dayside aurorae and their relation to other geophysical phenomena

    International Nuclear Information System (INIS)

    Principal morphological peculiarities of auroral luminosity are investigated on the basis of the data from multi-year aurorae observations in day hours at Spitzbergen and Franz Jozef Land. It is shown that in this region the typical forms of aurorae are moving poleward rayed arcs appearing at the equatorward boundary of the auroral oval and disappearing at its pole boundary. Discrete forms of aurorae are located inside a much broader red luminosity band in its equatorward part. Auroral pulsations with a period of 10 50 s are observed in the prenoon sector in a region of much harder precipitations found more equatorward with respect to the daytime red luminosity band. The influence of a Bz IMF component upon daytime aurorae is exercised both directly through an equatorward (poleward) shift of daytime aurorae upon decreasing (increasing) Bz and via an increase in planetary geomagnetic activity related to the appearance of substorms during which the whole region of the daytime luminosity is shifted to much lower latitudes. A decrease of intensity of daytime aurorae with duration of 5-10 min before the beginning of an expansive phase of a substorm on the night side is detected. The peculiarities of the daytime aurorae dynamics during substorms are also investigated. A scheme of the daytime auroral luminosity distribution is presented. Analytical expressions of the dependence of the daytime aurorae position on IMF are provided. Certain physical mechanisms that can explain the peculiarities of daytime aurorae dynamics are also discussed. (Author)

  12. Glow-discharge nitriding of gears

    International Nuclear Information System (INIS)

    The method of glow-discharge nitriding of gear parts made of 30Kh2NMFA steel is introduced. The diffusion saturation is carried out in the atmosphere of dissociated ammonia at the temperature of 520-540 deg C and 200-800 Pa pressure for 16-40 h depending on the required thickness of the nitrided layer (0.2-0.5 mm). The structure of the nitrided metal is a layer of nitride compounds of the Fe4N type and diffusion zone enriched with nitrides. Glow-discharge nitrided parts with 600-650 HV strength retain certain wear resistance and fatigue strength as compared with gas nitriding

  13. Retrieval of dosimetric information from distorted glow curves using computerised glow curve deconvolution

    International Nuclear Information System (INIS)

    Computerised glow curve deconvolution (CGCD) can be used to retrieve dosimetric information from glow curves distorted by various irregularities. These may include reader malfunction, abnormal background arising from various sources and other system malfunctions. this paper illustrates how the dosimetric information can be retrieved from these irregular glow curves. The accuracy of the retrieved information depends, of course, on the extent of the damage to the glow curve. In LiF:Mg,Ti(TLD-100) for example, peaks 4 + 5 (the dosimetric peaks) are observed over the temperature range of 400 K - 500 K, i.e. 100 degrees Kelvin. Even for distortions over 20 K, i.e. 20% of the temperature range, the dosimetric information can be retrieved to an accuracy of approximately 1%. (author)

  14. Computerized deconvolution of thermoluminescence glow curve

    CERN Document Server

    Ning Jing; Guo Yong; Wang Jun

    2002-01-01

    Computerized glow curve deconvolution (CGCD) is one of the most important progress in application of thermoluminescence dosimetry (TLD). It has greatly improved the precision and efficiency of measurement and widened the scope of TLD application. The basic issues about CGCD such as kinetic model, algorithm and figure of merit are described

  15. Plasma Beam Interaction with Negative glow discharge

    International Nuclear Information System (INIS)

    A miniature coaxial gun has been used to study the effect of the energy spectrum of the ejected plasma on the interaction with negative glow region in a normal glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 K A as a single pulse with pulse duration of 60 MUs. Investigations are carried out with argon gas at pressure 0.4 Torr. The sheath thickness of the ejected plasma from the coaxial discharge was 6 cm with different densities and energies. The spectrum of electron energy varies between 6 eV and 1 eV, while the electron density varies between 5 x 1012 cm -3 and 4x1013 cm -3. The peak velocity of the ejected plasma was 0. 8 x 105 cm sec-1 in the neutral argon atoms. Argon negative glow region used as base plasma has an electron temperature of 2.2 eV and electron density of 6.2 x107 cm-3. It had been found that the velocity of the ejected plasma decreased when it moves in the negative glow region and its mean electron temperature decreased. The results are compared with the theory of beam interaction with cold plasma

  16. Solar activity around AD 775 from aurorae and radiocarbon

    CERN Document Server

    Neuhaeuser, Ralph

    2015-01-01

    A large variation in 14 C around AD 775 has been considered to be caused by one or more solar super-flares within one year. We critically review all known aurora reports from Europe as well as the Near, Middle, and Far East from AD 731 to 825 and find 39 likely true aurorae plus four more potential aurorae and 24 other reports about halos, meteors, thunderstorms etc., which were previously misinterpreted as aurorae or misdated; we assign probabilities for all events according to five aurora criteria. We find very likely true aurorae in AD 743, 745, 762, 765, 772, 773, 793, 796, 807, and 817. There were two aurorae in the early 770s observed near Amida (now Diyarbakir in Turkey near the Turkish-Syrian border), which were not only red, but also green-yellow - being at a relatively low geo-magnetic latidude, they indicate a relatively strong solar storm. However, it cannot be argued that those aurorae (geo-magnetical latitude 43 to 50 deg, considering five different reconstructions of the geo-magnetic pole) coul...

  17. Jung's quest for the "Aurora consurgens"

    DEFF Research Database (Denmark)

    Haaning, Aksel

    2014-01-01

    Auriferae (1593); and it raises the question of whether this could be the possible missing link to Jung's subsequent research in Alchemy and Hermetic Philosophy in the years to come. It is argued that here was the beginning of Jung's quest for the Aurora consurgens, the publication of which concludes the......The paper focuses on the year 1929 when Jung published ‘A European commentary’ to Richard Wilhelm's German translation of the Taoist text The Secret of the Golden Flower. This shows that Jung had already started on the track of European alchemy by following up Conrad Waldkirch's preface in Artis...

  18. Bioactive compounds of Eriocaulon sieboldianum blocking proliferation and inducing apoptosis of HepG2 cells might be involved in Aurora kinase inhibition.

    Science.gov (United States)

    Fan, Yanhua; Lu, Hongyuan; Ma, Hongda; Feng, Fan; Hu, Xiaolong; Zhang, Qiao; Wang, Jian; Xu, Yongnan; Zhao, Qingchun

    2015-12-01

    Eriocaulon sieboldianum (Sieb. & Zucc. ex Steud.) is an edible and medicinal plant used in traditional Chinese medicine. Often in combination with other herbs, it is processed into healthcare beverages for expelling wind-heat, protecting eyes, and reducing blood lipids. Besides, its water decoction together with other herbs has been utilized to treat cancer in China. However, the active ingredients and the precise cellular mechanisms of E. sieboldianum remain to be elucidated. The Aurora kinase family plays critical roles in the regulation of cell division and has attracted great attention to the identification of small-molecule Aurora kinase inhibitors for potential treatment of cancer. A molecular docking study was employed for docking of the most bioactive compounds. Hispidulin (HPDL) and quercetin-3-O-(6''-O-galloyl)-β-D-galactopyranoside (QGGP) were singled out as potent inhibitors of Aurora kinase. Their inhibitory activity towards Aurora kinase was further confirmed by the obvious decrease in autophosphorylation of Aurora-A (Thr288) and Aurora-B (Thr232). Moreover, the induction of cell cycle arrest in HepG2 cells and the suppressed phosphorylation of histone H3 were also consistent with the inhibition of Aurora kinase. The data indicate that the E. sieboldianum extract and its two active compounds, HPDL and QGGP, could effectively induce apoptosis via p53, MAPKs and the mitochondrial apoptotic pathways. These findings could improve the understanding and enhance the development of drugs based on E. sieboldianum and raise its application value in anticancer therapy or prevention. In addition, our results indicated that Aurora kinase might be a novel target of HPDL and QGGP. PMID:26369427

  19. Aurora kinases are expressed in medullary thyroid carcinoma (MTC) and their inhibition suppresses in vitro growth and tumorigenicity of the MTC derived cell line TT

    International Nuclear Information System (INIS)

    The Aurora kinase family members, Aurora-A, -B and -C, are involved in the regulation of mitosis, and alterations in their expression are associated with cell malignant transformation. To date no information on the expression of these proteins in medullary thyroid carcinoma (MTC) are available. We here investigated the expression of the Aurora kinases in human MTC tissues and their potential use as therapeutic targets. The expression of the Aurora kinases in 26 MTC tissues at different TNM stages was analyzed at the mRNA level by quantitative RT-PCR. We then evaluated the effects of the Aurora kinase inhibitor MK-0457 on the MTC derived TT cell line proliferation, apoptosis, soft agar colony formation, cell cycle and ploidy. The results showed the absence of correlation between tumor tissue levels of any Aurora kinase and tumor stage indicating the lack of prognostic value for these proteins. Treatment with MK-0457 inhibited TT cell proliferation in a time- and dose-dependent manner with IC50 = 49.8 ± 6.6 nM, as well as Aurora kinases phosphorylation of substrates relevant to the mitotic progression. Time-lapse experiments demonstrated that MK-0457-treated cells entered mitosis but were unable to complete it. Cytofluorimetric analysis confirmed that MK-0457 induced accumulation of cells with ≥ 4N DNA content without inducing apoptosis. Finally, MK-0457 prevented the capability of the TT cells to form colonies in soft agar. We demonstrate that Aurora kinases inhibition hampered growth and tumorigenicity of TT cells, suggesting its potential therapeutic value for MTC treatment

  20. Aurora kinases are expressed in medullary thyroid carcinoma (MTC and their inhibition suppresses in vitro growth and tumorigenicity of the MTC derived cell line TT

    Directory of Open Access Journals (Sweden)

    Morrone Stefania

    2011-09-01

    Full Text Available Abstract Background The Aurora kinase family members, Aurora-A, -B and -C, are involved in the regulation of mitosis, and alterations in their expression are associated with cell malignant transformation. To date no information on the expression of these proteins in medullary thyroid carcinoma (MTC are available. We here investigated the expression of the Aurora kinases in human MTC tissues and their potential use as therapeutic targets. Methods The expression of the Aurora kinases in 26 MTC tissues at different TNM stages was analyzed at the mRNA level by quantitative RT-PCR. We then evaluated the effects of the Aurora kinase inhibitor MK-0457 on the MTC derived TT cell line proliferation, apoptosis, soft agar colony formation, cell cycle and ploidy. Results The results showed the absence of correlation between tumor tissue levels of any Aurora kinase and tumor stage indicating the lack of prognostic value for these proteins. Treatment with MK-0457 inhibited TT cell proliferation in a time- and dose-dependent manner with IC50 = 49.8 ± 6.6 nM, as well as Aurora kinases phosphorylation of substrates relevant to the mitotic progression. Time-lapse experiments demonstrated that MK-0457-treated cells entered mitosis but were unable to complete it. Cytofluorimetric analysis confirmed that MK-0457 induced accumulation of cells with ≥ 4N DNA content without inducing apoptosis. Finally, MK-0457 prevented the capability of the TT cells to form colonies in soft agar. Conclusions We demonstrate that Aurora kinases inhibition hampered growth and tumorigenicity of TT cells, suggesting its potential therapeutic value for MTC treatment.

  1. Artificial Aurora Generated by HAARP (Invited)

    Science.gov (United States)

    Streltsov, A. V.; Kendall, E. A.

    2013-12-01

    We present results from the ionospheric heating experiment conducted on March 12, 2013 at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. During the experiment HAARP transmitted X-mode 4.57 MHz waves modulated with the frequency 0.9 mHz and pointed in the direction of the magnetic zenith. The beam was focused to ~20 km spot at the altitude 100 km. The heating produces two effects: First, it generates magnetic field-aligned currents producing D and H components of the magnetic field with frequency 0.9 mHz detected by fluxgate magnetometer in Gakona. Second, the heating produced bright luminous structures in the heated region detected with the SRI telescope in 427.8 nm, 557.7 nm, 630.0 nm wavelengths. We emphasize, that for the best of our knowledge, this is the first experiment where the heating of the ionosphere with X-mode produces luminous structures in the ionosphere. We classify this luminosity as an 'artificial aurora', because it correlate with the intensity of the magnetic field-aligned currents, and such correlation is constantly seen in the natural aurora.

  2. High-speed stereoscopy of aurora

    Science.gov (United States)

    Kataoka, R.; Fukuda, Y.; Uchida, H. A.; Yamada, H.; Miyoshi, Y.; Ebihara, Y.; Dahlgren, H.; Hampton, D.

    2016-01-01

    We performed 100 fps stereoscopic imaging of aurora for the first time. Two identical sCMOS cameras equipped with narrow field-of-view lenses (15° by 15°) were directed at magnetic zenith with the north-south base distance of 8.1 km. Here we show the best example that a rapidly pulsating diffuse patch and a streaming discrete arc were observed at the same time with different parallaxes, and the emission altitudes were estimated as 85-95 km and > 100 km, respectively. The estimated emission altitudes are consistent with those estimated in previous studies, and it is suggested that high-speed stereoscopy is useful to directly measure the emission altitudes of various types of rapidly varying aurora. It is also found that variation of emission altitude is gradual (e.g., 10 km increase over 5 s) for pulsating patches and is fast (e.g., 10 km increase within 0.5 s) for streaming arcs.

  3. Jovian-like aurorae on Saturn.

    Science.gov (United States)

    Stallard, Tom; Miller, Steve; Melin, Henrik; Lystrup, Makenzie; Cowley, Stan W H; Bunce, Emma J; Achilleos, Nicholas; Dougherty, Michele

    2008-06-19

    Planetary aurorae are formed by energetic charged particles streaming along the planet's magnetic field lines into the upper atmosphere from the surrounding space environment. Earth's main auroral oval is formed through interactions with the solar wind, whereas that at Jupiter is formed through interactions with plasma from the moon Io inside its magnetic field (although other processes form aurorae at both planets). At Saturn, only the main auroral oval has previously been observed and there remains much debate over its origin. Here we report the discovery of a secondary oval at Saturn that is approximately 25 per cent as bright as the main oval, and we show this to be caused by interaction with the middle magnetosphere around the planet. This is a weak equivalent of Jupiter's main oval, its relative dimness being due to the lack of as large a source of ions as Jupiter's volcanic moon Io. This result suggests that differences seen in the auroral emissions from Saturn and Jupiter are due to scaling differences in the conditions at each of these two planets, whereas the underlying formation processes are the same. PMID:18563160

  4. Evolution of Striation in Pulsed Glow Discharges

    Science.gov (United States)

    Liu, Yuanye; He, Feng; Zhao, Xiaofei; Ouyang, Jiting

    2016-01-01

    In this work, striations in pulsed glow discharges are studied by experiments and Particle-In-Cell/Monte Carlo Collision (PIC/MCC) simulation. The spatio-temporal evolution of the potential and the electron energy during the discharge are analyzed. The processes of striation formation in pulsed glow discharges and dielectric barrier discharges (DBD) are compared. The results show that the mechanisms of striation in pulsed DC discharge and DBD are similar to each other. The evolution of electron energy distribution function before and after the striation formation indicates that the striation results from the potential well of the space charge. During a pulsed breakdown, the striations are formed one by one towards the anode in a weak field channel. This indicates that the formation of striations in a pulsed discharge depends on the flow of modulated electrons. supported by National Natural Science Foundation of China (Nos. 10875010 and 11175017)

  5. Saturn's aurora observed by the Cassini camera at visible wavelengths

    CERN Document Server

    Dyudina, Ulyana A; Ewald, Shawn P; Wellington, Danika

    2015-01-01

    The first observations of Saturn's visible-wavelength aurora were made by the Cassini camera. The aurora was observed between 2006 and 2013 in the northern and southern hemispheres. The color of the aurora changes from pink at a few hundred km above the horizon to purple at 1000-1500 km above the horizon. The spectrum observed in 9 filters spanning wavelengths from 250 nm to 1000 nm has a prominent H-alpha line and roughly agrees with laboratory simulated auroras. Auroras in both hemispheres vary dramatically with longitude. Auroras form bright arcs between 70 and 80 degree latitude north and between 65 and 80 degree latitude south, which sometimes spiral around the pole, and sometimes form double arcs. A large 10,000-km-scale longitudinal brightness structure persists for more than 100 hours. This structure rotates approximately together with Saturn. On top of the large steady structure, the auroras brighten suddenly on the timescales of a few minutes. These brightenings repeat with a period of about 1 hour....

  6. TPX2 Protein of Arabidopsis Activates Aurora Kinase 1, But Not Aurora Kinase 3 In Vitro

    Czech Academy of Sciences Publication Activity Database

    Tomaštíková, Eva; Demidov, D.; Jeřábková, Hana; Binarová, Pavla; Houben, A.; Doležel, Jaroslav; Petrovská, Beáta

    2015-01-01

    Roč. 33, č. 6 (2015), s. 1988-1995. ISSN 0735-9640 R&D Projects: GA ČR(CZ) GA14-28443S; GA MŠk(CZ) LO1204; GA ČR GAP501/12/2333 Institutional support: RVO:61389030 ; RVO:61388971 Keywords : Aurora kinase * Targeting protein for Xklp2 * In vitro kinase assay Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.656, year: 2014

  7. Perceived three-dimensional shape toggles perceived glow.

    Science.gov (United States)

    Kim, Minjung; Wilcox, Laurie M; Murray, Richard F

    2016-05-01

    Most surfaces reflect light from external sources, but others emit light: they glow. Glowing surfaces are often a sign of an important feature of the environment, such as a heat source or a bioluminescent life form, but we know little about how the human visual system identifies them. Previous work has shown that luminance and luminance gradients are important in glow perception [1,2]. While a link between glow and shape has been suggested in the literature [3], there has been no systematic investigation of this relationship. Here we show that perceived three-dimensional shape plays a decisive role in glow perception; vivid percepts of glow can be toggled on and off, simply by changing cues to three-dimensional shape while holding other image features constant. PMID:27166688

  8. Were Greek temples oriented towards aurorae?

    Science.gov (United States)

    Liritzis, Ioannis; Vassiliou, Helen

    2006-02-01

    Two ancient Greek temples of Apollo at Bassae (Phigaleia, western Peloponnese, Greece), and Thermon at Aetolia, (Aetoloacarnania, western central Greece), have a north-south orientation of their main entrances. This is a rather rare alignment of temples in general and specifically of Apollo in classical Greece, where most of them have broadly an east-west orientation. Based on historical and mythological accounts, as well as astronomical orientation measurements, the northern direction orientation of these constructions may relate to the rare, albeit impressive, occurrence of aurorae borealis, the northern lights. These strong lights are attributed to god Apollo by the epithet ``hyperborean'', meaning to the northern lands. Attribution is supported by archaeomagnetic directional data accompanied by auroral occurrence during those times.

  9. Global magnetic anomaly and aurora of Neptune

    Science.gov (United States)

    Cheng, Andrew F.

    1990-01-01

    The large offset and tilt of Neptune's dipole magnetic field combine to create a global magnetic anomaly, analogous to but much more important than earth's South Atlantic Anomaly. Energetic particle precipitation loss within the Neptune anomaly creates 'atmospheric drift shadows' within which particle fluxes are greatly reduced. The energetic particle dropout observed by Voyager near closest approach occurred near the predicted times when Voyager passed within the atmospheric drift shadow. Extremely soft, structured bursts of ions and electrons within the drift shadow may result from plasma wave-induced pitch angle scattering of trapped particles confined near the magnetic equator. The dropout does not necessarily imply that Voyager passed through an earth-like discrete auroral zone, as earlier reported. The ion and electron fluxes observed within the dropout period correspond to particles that must precipitate to Neptune's atmosphere within the anomaly region. This anomaly precipitation can account for a major portion of the ultraviolet emissions previously identified as Neptune aurora.

  10. SPICAM observations and modeling of Mars aurorae

    Science.gov (United States)

    Soret, Lauriane; Gérard, Jean-Claude; Libert, Ludivine; Shematovich, Valery I.; Bisikalo, Dmitry V.; Stiepen, Arnaud; Bertaux, Jean-Loup

    2016-01-01

    Martian aurorae have been detected with the SPICAM instrument on board Mars Express both in the nadir and the limb viewing modes. In this study, we focus on three limb observations to determine both the altitudes and the intensities of the auroral emissions. The CO (a3Π-X1Σ) Cameron bands between 190 and 270 nm, the CO (A1Π-X1Σ+) Fourth Positive system (CO 4P) between 135 and 170 nm, the CO2+ (B2Σu+-X2Πg) doublet at 289 nm, the OI at 297.2 nm and the 130.4 nm OI triplet emissions have been identified in the spectra and in the time variations of the signals. The intensities of these auroral emissions have been quantified and the altitude of the strongest emission of the CO Cameron bands has been estimated to be 137 ± 27 km. The locations of these auroral events have also been determined and correspond to the statistical boundary of open-closed magnetic field lines, in cusp-like structures. The observed altitudes of the auroral emissions are reproduced by a Monte-Carlo model of electron transport in the Martian thermosphere for mono-energetic electrons between 40 and 200 eV. No correlation between electron fluxes measured in the upper thermosphere and nadir auroral intensity has been found. Here, we simulate auroral emissions observed both at the limb and at the nadir using electron energy spectra simultaneously measured with the ASPERA-3/ELS instrument. The simulated altitudes are in very good agreement with the observations. We find that predicted vertically integrated intensities for the various auroral emissions are overestimated, probably as a consequence of the inclination and curvature of the magnetic field line threading the aurora. However, the relative brightness of the CO and CO2+ emissions is in good agreement with the observations.

  11. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  12. A new Director for the BAA Aurora Section

    Science.gov (United States)

    Gavine, D.

    2011-02-01

    from 2011 January 1, Dr Dave Gavine handed over the Aurora Section Directorship to Ken Kennedy, who has been Assistant Director for the last five years, with special responsibility for Noctilucent Clouds, currently the Section's most important work.

  13. Research Ship Aurora Australis Underway Meteorological Data, Quality Controlled

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Research Ship Aurora Australis Underway Meteorological Data (delayed ~10 days for quality control) are from the Shipboard Automated Meteorological and Oceanographic...

  14. Night trend in average brightness of aurora discrete forms

    International Nuclear Information System (INIS)

    Using the method of imposed epochs according to the data of visual observations for many years of aurorae at the Tixi and Norilsk stations, a systematic decrease in the average brightness of aurora discrete forms in diurnal course with the increase in time elapsed after the sunset at the altitude of 200 km above the station is detected. It is assumed that the tendency is caused by the change in electric conductivity of ionospheric link of auroral current systems

  15. Preservation of minimally processed 'aurora-1' peaches using additives

    OpenAIRE

    Ramilo Nogueira Martins; Ben-Hur Mattiuz; Leandra Oliveira Santos; Cristiane Maria Ascari Morgado; Claudia Fabrino Machado Mattiuz

    2011-01-01

    'Aurora-1' peaches establishes an interesting alternative as a minimally processed product, due to its characteristics like flavor, color, smell, and also because of its handling resistance. However, it has a short shelf life after a fresh-cut due to enzymatic browning and stone cavity collapse. The main purpose of this research was to test the additive with antioxidant effect to prevent browning in minimally processed 'Aurora-1' peaches. The minimal processing consists of washing, sanitizing...

  16. IK-guided PP2A suppresses Aurora B activity in the interphase of tumor cells.

    Science.gov (United States)

    Lee, Sunyi; Jeong, Ae Lee; Park, Jeong Su; Han, Sora; Jang, Chang-Young; Kim, Keun Il; Kim, Yonghwan; Park, Jong Hoon; Lim, Jong-Seok; Lee, Myung Sok; Yang, Young

    2016-09-01

    Aurora B activation is triggered at the mitotic entry and required for proper microtubule-kinetochore attachment at mitotic phase. Therefore, Aurora B should be in inactive form in interphase to prevent aberrant cell cycle progression. However, it is unclear how the inactivation of Aurora B is sustained during interphase. In this study, we find that IK depletion-induced mitotic arrest leads to G2 arrest by Aurora B inhibition, indicating that IK depletion enhances Aurora B activation before mitotic entry. IK binds to Aurora B, and colocalizes on the nuclear foci during interphase. Our data further show that IK inhibits Aurora B activation through recruiting PP2A into IK and Aurora B complex. It is thus believed that IK, as a scaffold protein, guides PP2A into Aurora B to suppress its activity in interphase until mitotic entry. PMID:26906715

  17. An air spark glow phase model

    International Nuclear Information System (INIS)

    A )-dimensional kinetic model is developed for the glow phase of a spark gap in air. The model includes heavy-heavy collisions leading to thermal ionization, and electron collision processes. Rates for the latter are calculated by a Boltzmann analysis and from empirical measurements. These include attachment and ionization, excitation/ionization and dissociation/ionization; detachment was found to be necessary to match experimental closing times. With only those processes, the model predicts closing times well over a wide range above and below the DC breakdown voltage

  18. Solar activity around AD 775 from aurorae and radiocarbon

    Science.gov (United States)

    Neuhäuser, R.; Neuhäuser, D. L.

    2015-04-01

    A large variation in 14C around AD 775 has been considered to be caused by one or more solar super-flares within one year. We critically review all known aurora reports from Europe as well as the Near, Middle, and Far East from AD 731 to 825 and find 39 likely true aurorae plus four more potential aurorae and 24 other reports about halos, meteors, thunderstorms etc., which were previously misinterpreted as aurorae or misdated; we assign probabilities for all events according to five aurora criteria. We find very likely true aurorae in AD 743, 745, 762, 765, 772, 773, 793, 796, 807, and 817. There were two aurorae in the early 770s observed near Amida (now Diyarbak\\i r in Turkey near the Turkish-Syrian border), which were not only red, but also green-yellow - being at a relatively low geomagnetic latitude, they indicate a relatively strong solar storm. However, it cannot be argued that those aurorae (geomagnetic latitude 43 to 50°, considering five different reconstructions of the geomagnetic pole) could be connected to one or more solar super-flares causing the 14C increase around AD 775: There are several reports about low- to mid-latitude aurorae at 32 to 44° geomagnetic latitude in China and Iraq; some of them were likely observed (quasi-)simultaneously in two of three areas (Europe, Byzantium/Arabia, East Asia), one lasted several nights, and some indicate a particularly strong geomagnetic storm (red colour and dynamics), namely in AD 745, 762, 793, 807, and 817 - always without 14C peaks. We use 39 likely true aurorae as well as historic reports about sunspots together with the radiocarbon content from tree rings to reconstruct the solar activity: From AD {˜ 733} to {˜ 823}, we see at least nine Schwabe cycles; instead of one of those cycles, there could be two short, weak cycles - reflecting the rapid increase to a high 14C level since AD 775, which lies at the end of a strong cycle. In order to show the end of the dearth of naked-eye sunspots, we

  19. Stimulated Electromagnetic Emission Indicator of Glow Plasma Discharges from Ionospheric HF Wave Transmissions with HAARP

    Science.gov (United States)

    Bernhardt, P. A.; Scales, W.; Briczinski, S. J.; Fu, H.; Mahmoudian, A.; Samimi, A.

    2012-12-01

    High power radio waves resonantly interact with to accelerate electrons for production of artificial aurora and plasma clouds. These plasma clouds are formed when the HF frequency is tuned near a harmonic of the electron cyclotron frequency. At a narrow band resonance, large electrostatic fields are produced below the F-layer and the neutral atmosphere breaks down with a glow plasma discharge. The conditions for this resonance are given by matching the pump wave frequency and wave-number with the sum of daughter frequencies and wave-numbers for several plasma modes. The most likely plasma mode that accelerates the electrons is the electron Bernstein wave in conjunction with an ion acoustic wave. Both upper hybrid and whistler mode waves are also possible sources of electron acceleration. To determine the plasma process for electron acceleration, stimulated electromagnetic emissions are measured using ground receivers in a north-south chain from the HAARP site. Recent observations have shown that broad band spectral lines downshifted from the HF pump frequency are observed when artificial plasma clouds are formed. For HF transmissions are the 2nd, 3rd, and 4th gyro harmonic, the downshifted indicators are found 500 Hz, 20 kHz, and 140 kHz, respectively, from the pump frequency. This Indicator Mode (IM) anticipates that a plasma layer will be formed before it is recorded with an ionosonde or optical imager.

  20. Nitrogen Removal from Molten Steel under Argon DC Glow Plasma

    Institute of Scientific and Technical Information of China (English)

    SUN Ming-shan; DING Wei-zhong; LU Xiong-gang

    2005-01-01

    Under argon DC glow plasma, the nitrogen removal from molten steel was studied. The experimental result showed that nitrogen mass percent could be reduced to 0.000 8%. The change of polarity had no impact on nitrogen removal when the nitrogen mass percent was low. The mechanism of denitrogenation of molten steel under argon DC glow plasma was discussed.

  1. Sporadic aurorae observed in East Asia

    Directory of Open Access Journals (Sweden)

    D. M. Willis

    2007-03-01

    aurorae observed in the United States during the interval AD 1880–1940. The localised nature and spatial structure of some sporadic aurorae observed in East Asia is indicated by the use of descriptive terms such as "lightning", "rainbow", "streak" and "grid".

  2. Acting green elicits a literal warm glow

    Science.gov (United States)

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

    2015-01-01

    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.

  3. Way of stability increase of the glow discharge

    Science.gov (United States)

    Asadullin, T. Ya; Galeyev, I. G.; Timerkayev, B. A.

    2016-01-01

    Instabilities of a glow discharge significantly limit the opportunities for use of nonequilibrium plasma of a glow discharge [1]. The ionization overheat instability is the main type of glow discharge instabilities. It causes the loss of a non-equilibrium and put the glow discharge to a contracted state. The way of stabilization of glow discharge in transverse gas flow by the use of adaptive control system is considered in the work. The system controls voltage (resistance) of cathodic sections of the discharge chamber. Such fast advancing influence prevents the cathode spot shrinking and subsequent transition to contracted state. The controlling algorithm can be realized both following type and dynamic non-equilibrium type.

  4. Ipl1/Aurora B kinase coordinates synaptonemal complex disassembly with cell cycle progression and crossover formation in budding yeast meiosis

    OpenAIRE

    Jordan, Philip; Copsey, Alice; Newnham, Louise; Kolar, E; Lichten, M; Hoffmann, Eva

    2009-01-01

    Several protein kinases collaborate to orchestrate and integrate cellular and chromosomal events at the G2/M transition in both mitotic and meiotic cells. During the G2/M transition in meiosis, this includes the completion of crossover recombination, spindle formation, and synaptonemal complex (SC) breakdown. We identified Ipl1/Aurora B kinase as the main regulator of SC disassembly. Mutants lacking Ipl1 or its kinase activity assemble SCs with normal timing, but fail to dissociate the centra...

  5. Dancing Lights: Creating the Aurora Story

    Science.gov (United States)

    Wood, E. L.; Cobabe-Ammann, E. A.

    2009-12-01

    Science tells a story about our world, our existence, our history, and the larger environment our planet occupies. Bearing this in mind, we created a series of lessons for 3rd-5th grades using a cross-disciplinary approach to teaching about the aurora by incorporating stories, photos, movies, and geography into the science in order to paint a broad picture and answer the question, “why do we care?” The fundamental backbone of the program is literacy. Students write and illustrate fiction and non-fiction work, poetry, and brochures that solidify both language arts skills and science content. In a time when elementary teachers relegate science to less than one hour per week, we have developed a novel science program that can be easily integrated with other topics during the typical school day to increase the amount of science taught in a school year. We are inspiring students to take an interest in the natural world with this program, a stepping-stone for larger things.

  6. Aurora A drives early signalling and vesicle dynamics during T-cell activation

    Science.gov (United States)

    Blas-Rus, Noelia; Bustos-Morán, Eugenio; Pérez de Castro, Ignacio; de Cárcer, Guillermo; Borroto, Aldo; Camafeita, Emilio; Jorge, Inmaculada; Vázquez, Jesús; Alarcón, Balbino; Malumbres, Marcos; Martín-Cófreces, Noa B.; Sánchez-Madrid, Francisco

    2016-01-01

    Aurora A is a serine/threonine kinase that contributes to the progression of mitosis by inducing microtubule nucleation. Here we have identified an unexpected role for Aurora A kinase in antigen-driven T-cell activation. We find that Aurora A is phosphorylated at the immunological synapse (IS) during TCR-driven cell contact. Inhibition of Aurora A with pharmacological agents or genetic deletion in human or mouse T cells severely disrupts the dynamics of microtubules and CD3ζ-bearing vesicles at the IS. The absence of Aurora A activity also impairs the activation of early signalling molecules downstream of the TCR and the expression of IL-2, CD25 and CD69. Aurora A inhibition causes delocalized clustering of Lck at the IS and decreases phosphorylation levels of tyrosine kinase Lck, thus indicating Aurora A is required for maintaining Lck active. These findings implicate Aurora A in the propagation of the TCR activation signal. PMID:27091106

  7. 16-Hydroxycleroda-3,13-dien-15,16-olide deregulates PI3K and Aurora B activities that involve in cancer cell apoptosis

    International Nuclear Information System (INIS)

    Highlights: → Natural product PL3 induced cancer cell apoptosis and cell cycle arrest. → PL3 targeted and de-regulated PI3K pathway activities. → De-activated PI3K pathway caused Aurora B degradation and spindle dysfunction. → PL3 could reverse the drug-resistance of Bcr-ABL T315I-positive cells to Imatinib. -- Abstract: The PI3K-AKT pathway and Aurora kinase play essential roles in such cellular processes as cell survival, angiogenesis, and differentiation, and are usually expressed at maximum levels during cancer cell proliferation. The present study investigated the effect of the natural compound, 16-hydroxycleroda-3,13-dien-15,16-olide (PL3), on regulating the PI3K-AKT pathway and Aurora B, which led to cancer cell apoptosis. PL3 acts as a PI3K inhibitor by influencing cell survival, signaling transduction, and cell cycle progression. It was observed that PL3 targeted and induced dephosphorylation of the PI3K pathway, degradation of Aurora B and mitotic-related gene expressions, and sequentially shut down the cell cycle. This eventually resulted in cell death. As Aurora B was downregulated, spindle dysfunction and destruction of the G2/M phase checkpoint resulted in DNA-damaged cells undergoing apoptosis. Moreover, PL3 also resensitized T315I-mutated Bcr-ABL+ BA/F3 cells to improve the cytotoxicity of Imatinib in Imatinib-resistant cell line. Taken together, PL3 can perturb the PI3K-AKT pathway and Aurora B resulting in gene silencing and cell cycle disturbance. It was demonstrated that PL3 acted like a novel small-molecule PI3K modulator, thereby potentially contributing to cancer chemotherapy and combination medication.

  8. Making Sense of the Aurora: A Research Project

    Directory of Open Access Journals (Sweden)

    Robert Marc Friedman

    2012-05-01

    Full Text Available The article provides an introduction to a on-going research project based at University of Tromsø that seeks to analyze the history of efforts to make sense of the aurora borealis from the early 1700s through to the Cold War. Following brilliant displays of the northern lights in the early eighteenth century, natural philosophers strove to explain this phenomenon that evoked widespread fear and superstition. It was not until well into the twentieth century that consensual explanation emerged for this, one of the great enigmas in the history of science. From the start, the quest to explain the aurora borealis became enmeshed with patriotic science and nationalist sentiments. The history of efforts to understand the nature and cause of the aurora poses a number of thematic problems. Being a fleeting and at times rapidly changing phenomenon, only occasionally seen south of far-northern latitudes, the aurora needed to be constituted as an object able to be brought into the domain of rational science. Observational accounts of the aurora came most often from by personsliving or travelling in the far north or in the Arctic, but these persons were generally not trained scientists: Whose witnessing counted and how was authority negotiated among professional scientists and amateurs?

  9. Aurora Borealis, A Painting by Frederic Edwin Church

    Science.gov (United States)

    Love, J. J.

    2015-12-01

    This year marks the sesquicentennial anniversary of the end of the American Civil War. In 1865, the same year as the War's end, the great American landscape artist, Frederic Edwin Church, unveiled Aurora Borealis, a painting that depicts a fantastic, far-northern place, an auroral arch stretched across a quiet night-time sky, above dark mountains and a frozen sea. Church was born in Connecticut, lived in New York, and traveled to Labrador; he would have often seen the northern lights. Church might have also been influenced by the spectacular displays of aurora that were caused by some unusually intense magnetic storms in 1859. Aurora Borealis can certainly be interpreted in terms of 19th-century romanticism, scientific philosophy, and Arctic missions of exploration, all subjects of interest to Church. As with so many of his paintings, Church's meticulous attention to detail in Aurora Borealis reveals his deep admiration of nature. But his depiction of auroral light is a curious and possibly intentional departure from natural verisimilitude. Some art historians have suggested that Church painted Aurora Borealis as a subdued tribute to the end of the Civil War, with the drapery of auroral light forming an abstract representation of the American flag. If so, then colors of the flag have been unfurled across a cold and barren landscape, not in extravagant celebration, but in somber recognition of the reality of post-war desolation and an uncertain future.

  10. Three spacecraft observe Jupiter's glowing polar regions

    Science.gov (United States)

    1996-09-01

    The aurorae on Jupiter are like the Aurorae Borealis and Australis on the Earth, although visible only by ultraviolet light. They flicker in a similar way in response to variations in the solar wind of charged particles blowing from the Sun. While Galileo monitored the changing environment of particles and magnetism in Jupiter's vicinity, IUE recorded surprisingly large and rapid variations in the overall strength of the auroral activity. IUE's main 45-centimetre telescope did not supply images,but broke up the ultraviolet rays into spectra, like invisible rainbows, from which astrophysicists could deduce chemical compositions, motions and temperatures in the cosmic objects under examination. In the case of Jupiter's aurorae, the strongest emission came from activated hydrogen atoms at a wavelength of 1216 angstroms. The Hubble Space Telescope's contributions to the International Jupiter Watch included images showing variations in the form of the aurorae, and "close-up" spectra of parts of the auroral ovals. Astronomers will compare the flickering aurorae on Jupiter with concurrent monitoring of the Sun and the solar wind by the ESA-NASA SOHO spacecraft and several satellites of the Interagency Solar-Terrestrial Programme. It is notable that changes in auroral intensity by a factor of two or three occurred during the 1996 observational period, even though the Sun was in an exceptionally quiet phase, with very few sunspots. In principle, a watch on Jupiter's aurorae could become a valuable means of checking the long-range effects of solar activity, which also has important consequences for the Earth. The situation at Jupiter is quite different from the Earth's, with the moons strongly influencing the planet's space environment. But with Hubble busy with other work, any such Jupiter-monitoring programme will have to await a new ultraviolet space observatory. IUE observed Jupiter intensively in 1979-80 in conjunction with the visits of NASA's Voyager spacecraft, and

  11. Reconstruction of thermally quenched glow curves in quartz

    International Nuclear Information System (INIS)

    The experimentally measured thermoluminescence (TL) glow curves of quartz samples are influenced by the presence of the thermal quenching effect, which involves a variation of the luminescence efficiency as a function of temperature. The real shape of the thermally unquenched TL glow curves is completely unknown. In the present work an attempt is made to reconstruct these unquenched glow curves from the quenched experimental data, and for two different types of quartz samples. The reconstruction is based on the values of the thermal quenching parameter W (activation energy) and C (a dimensionless constant), which are known from recent experimental work on these two samples. A computerized glow-curve deconvolution (CGCD) analysis was performed twice for both the reconstructed and the experimental TL glow curves. Special attention was paid to check for consistency between the results of these two independent CGCD analyses. The investigation showed that the reconstruction attempt was successful, and it is concluded that the analysis of reconstructed TL glow curves can provide improved values of the kinetic parameters E, s for the glow peaks of quartz. This also leads to a better evaluation of the half-lives of electron trapping levels used for dosimetry and luminescence dating.

  12. A mathematical model of Aurora B activity in prophase and metaphase.

    Science.gov (United States)

    Doherty, Kevin; Meere, Martin; Piiroinen, Petri T

    2016-07-01

    Aurora B kinase is a protein that controls several processes in mitosis when it is found associated with INCENP, Survivin and Borealin in a complex known as the Chromosomal Passenger Complex. Aurora B in complex with INCENP is phosphorylated on three sites, resulting in the full activation of Aurora B. In prophase and metaphase, Aurora B is activated at centromeres, the region of chromatin linking sister chromatids, due to an autophosphorylation mechanism, and it has been hypothesised that Aurora B is activated throughout the cytoplasm due to its concentration at centromeres. In this article, we first develop a time-dependent model of Aurora B activation that does not incorporate spatial variation. This model is used to demonstrate the various qualitative behaviours that the activation of Aurora B is capable of displaying for different model parameters. Next, we develop a spatio-temporal model of Aurora B activation that includes diffusion of soluble Aurora B and binding of Aurora B to immobile centromeric binding sites. This model describes the activation of Aurora B throughout the cytoplasm due to its concentration-dependent activation at centromeres. The models demonstrate the effects that a soluble phosphatase concentration, multisite phosphorylation and diffusion have on the activation of Aurora B. PMID:27155569

  13. Glow discharge amorphous silicon tin alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mahan, A H; Sanchez, A; Williamson, D L; von Roedern, B; Madan, A

    1984-06-01

    We present basic density of states, photoresponse, and transport measurements made on low bandgap a-SiSn:H alloys produced by RF glow discharge deposition of SiH/sub 4/, H/sub 2/ and Sn(CH/sub 3/)/sub 4/. Although we demonstrate major changes in the local bonding structure and the density of states, the normalized photoresponse still remains poor. We provide evidence that two types of defect levels are produced with Sn alloying, and that the resultant density of states increase explains not only the n- to p-type conductivity transition reported earlier, but also the photoresponse behavior. We also report that a-SiSn:H can be doped with P. From our device analysis we suggest that in order to improve the alloy performance significantly, the density of states should be decreased to levels comparable to or lower than those presently obtained in a-Si:H.

  14. Paschen law for argon glow discharge

    International Nuclear Information System (INIS)

    Electric discharge between two electrically charged surfaces occurs at a well-defined, gas-dependent combination of atmospheric pressure and the distance between those surfaces, as described by Paschen's law. The understanding of when the discharge will occur in an Ar discharge is essential basic knowledge. A glow discharge apparatus was used in this experiment of Ar discharge at a pressure range between 2.0 Torr and 12 Torr, a power of 20 W and 40 l/min flow rate of gases. The optical emission spectroscopy was carried out in the wavelength range of 200 to 1100 nm. Here, we present experimentally measured plasma Paschen curves for Ar gas and compare our results of breakdown voltages with the literature. The minimum voltage measured for a discharge in Ar atmosphere was 215 ± 2.2 at 0.7 Torr-cm, which agree with previous measurements.

  15. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.

    Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  16. Ionospheric response to particle precipitation within aurora

    International Nuclear Information System (INIS)

    The aurora is just the visible signature of a large number of processes occurring in a planetary ionosphere as a response to energetic charged particles falling in from the near-empty space far above the planetary atmosphere. This thesis, based on measurements using the EISCAT incoherent scatter radar system in northern Scandinavia, discusses ionospheric response processes and especially a mechanism leading to atmospheric gas escape from a planet. One of the most spectacular events in the high latitude atmosphere on earth are the 'auroral arcs' - dynamic rayed sheets of light. An investigation of the conditions of the ionosphere surrounding auroral arcs shows that strong field-aligned bulk ion outflows appear in the topside ionosphere which account for a large fraction of the escape of atmospheric oxygen from earth. Four different additional ionospheric responses are closely related to this ion outflow; 1. enhanced electron temperatures of several thousand Kelvin above an altitude of about 250 km, 2. enhanced ionization around an altitude of 200 km corresponding to electron precipitation with energies of a few hundred eV, 3. the occurrence of naturally enhanced ion acoustic fluctuations seen in the radar spectrum, most likely produced by an ion-ion two-stream instability, and 4. upward directed field-aligned currents partly carried by the outflowing ions. From these observations, it is suggested that the energy dissipation into the background plasma through Joule heating, the production of a few hundred eV energetic run-away electrons, and strong ion outflows are partly produced by the simultaneous presence of ion acoustic turbulence and field-aligned currents above auroral arcs. (20 refs.) (au)

  17. Multiplicity detector using a glow-discharge memory

    International Nuclear Information System (INIS)

    It has been proposed to eliminate the x-y cor relation ambiguities introduced by multiple tracks in a wire chamber by using the chamber itself as a memory. Hits in the chamber itself ignite glow discharges storing the x-y location of the hits in a correlated fashion. Glow ignition may be achieved by employing a multi-step avalanche chamber above a memory gap. Correlation is maintained during readout by successively pulsing each hit wire in one coordinate and sensing transmissions through glows in the other coordinate. Prototypes constructed by the authors are discussed along with the associated high voltage and readout systems

  18. Glow Discharge Characteristics in Transverse Supersonic Air Flow

    International Nuclear Information System (INIS)

    A low pressure glow discharge in a transverse supersonic gas flow of air at pressures of the order 1 torr has been experimentally studied for the case where the flow only partially fills the inter electrode gap. It is shown that the space region with supersonic gas flow has a higher concentration of gas particles and, therefore, works as a charged particle generator. The near electrode regions of glow discharge are concentrated specifically in this region. This structure of glow discharge is promising for plasma deposition of coatings under ultralow pressures

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

    Science.gov (United States)

    Swenson, G.

    1999-10-01

    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.

  20. Multifunctional Glow Discharge Analyzer for Spacecraft Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge emission for the...

  1. Thermoluminescence glow curve analysis of natural onyx from Turkey

    International Nuclear Information System (INIS)

    In this study, the thermoluminesce (TL) properties of natural onyx were determined after β-irradiation (90Sr/90Y) 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 β-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. - Highlights: • Thermoluminesce (TL) properties of natural onyx were determined after β-irradiation at room temperature. • Computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters. • The peak intensities and total area of glow peaks are decreasing with increasing heating rate

  2. An efficient algorithm for computerized deconvolution of thermoluminescent glow curves

    International Nuclear Information System (INIS)

    The models employed so far for deconvolving thermoluminescent glow curves are either derived by neglecting the interaction among traps and resorting to the quasi-equilibrium approximation, or are simply phenomenological. Several published articles have shown that the approximations are difficult to justify. Further it has never been shown that they are rigorously applicable to any known system. As to the phenomenological model it is no physically meaningful. An algorithm is reported which allows analyses of glow curves without the aforementioned approximations.

  3. Mixed Feelings: Theories and Evidence of Warm Glow and Altruism

    OpenAIRE

    Konow, James

    2006-01-01

    This paper presents theoretical and empirical analyses of experiments that test competing theories of altruism, including pure altruism (a preference for the well-being of others), warm glow (a good feeling from giving) and impure altruism (a combination of pure altruism and warm glow). These theories produce different predictions regarding crowding out, i.e., the reduction in private donations due to public spending. Variations on dictator experiments involving both students and charities ex...

  4. The grand aurorae borealis seen in Colombia in 1859

    Science.gov (United States)

    Moreno Cárdenas, Freddy; Cristancho Sánchez, Sergio; Vargas Domínguez, Santiago

    2016-01-01

    On Thursday, September 1, 1859, the British astronomer Richard Carrington, for the first time ever, observes a spectacular gleam of visible light on the surface of the solar disk, the photosphere. The Carrington Event, as it is nowadays known by scientists, occurred because of the high solar activity that had visible consequences on Earth, in particular reports of outstanding aurorae activity that amazed thousands of people in the western hemisphere during the dawn of September 2. The geomagnetic storm, generated by the solar-terrestrial event, had such a magnitude that the auroral oval expanded towards the equator, allowing low latitudes, like Panama's 9°N, to catch a sight of the aurorae. An expedition was carried out to review several historical reports and books from the northern cities of Colombia allowed the identification of a narrative from Montería, Colombia (8° 45‧N), that describes phenomena resembling those of an aurorae borealis, such as fire-like lights, blazing and dazzling glares, and the appearance of an immense S-like shape in the sky. The very low latitude of the geomagnetic north pole in 1859, the lowest value in over half a millennia, is proposed to have allowed the observations of auroral events at locations closer to the equator, and supports the historical description found in Colombia. The finding of such chronicle represents one of the most complete descriptions of low-latitude sightings of aurorae caused by the Carrington Event.

  5. New auroras on the roles of the Chromosomal Passenger Complex in cytokinesis: implications for cancer therapies

    Directory of Open Access Journals (Sweden)

    Pier Paolo eD'Avino

    2015-10-01

    Full Text Available The Chromosomal Passenger Complex (CPC, composed of a kinase component, Aurora B, the scaffolding subunit Inner Centromeric Protein (INCENP, Borealin, and Survivin, is a key regulator of cell division. It controls multiple events, from chromosome condensation in prophase to the final separation or abscission of the two daughter cells. The essential functions of the CPC during metaphase, however, have always hindered an accurate study of its role during cytokinesis. The recent development of small molecule inhibitors against Aurora B and the use of elegant technologies such as chemical genetics have offered new approaches to study the functions of the CPC at the end of cell division. Here we review the recent findings about the roles of the CPC in controlling the assembly of the cleavage furrow, central spindle and midbody. We will also discuss the crucial function of this complex in controlling abscission timing in order to prevent abscission when lagging chromatin is present at the cleavage site, thereby avoiding the formation of genetically abnormal daughter cells. Finally, we offer our perspective on how to exploit the potential therapeutic applications of inhibiting CPC activity during cytokinesis in cancer cells.

  6. Aurora kinases as druggable targets in pediatric leukemia: heterogeneity in target modulation activities and cytotoxicity by diverse novel therapeutic agents.

    Directory of Open Access Journals (Sweden)

    Aarthi Jayanthan

    Full Text Available Leukemia is the most common pediatric malignancy, constituting more than 30% of all childhood cancers. Although cure rates have improved greatly, approximately one in five children relapse and poor survival rates post relapse remain a challenge. Given this, more effective and innovative therapeutic strategies are needed in order to improve prognosis. Aurora kinases, a family of serine/threonine kinases essential for the regulation of several mitotic processes, have been identified as potential targets for cancer therapeutics. Elevated expression of Aurora kinases has been demonstrated in several malignancies and is associated with aberrant mitotic activity, aneuploidy and alterations in chromosomal structure and genome instability. Based on this rationale, a number of small molecule inhibitors have been formulated and advanced to human studies in the recent past. A comparative analysis of these agents in cytotoxicity and target modulation analyses against a panel of leukemia cells provides novel insights into the unique mechanisms and codependent activity pathways involved in targeting Aurora kinases, constituting a distinctive preclinical experimental framework to identify appropriate agents and combinations in future clinical studies.

  7. Advances in the Remote Glow Discharge Experiment

    Science.gov (United States)

    Dominguez, Arturo; Zwicker, A.; Rusaits, L.; McNulty, M.; Sosa, Carl

    2014-10-01

    The Remote Glow Discharge Experiment (RGDX) is a DC discharge plasma with variable pressure, end-plate voltage and externally applied axial magnetic field. While the experiment is located at PPPL, a webcam displays the live video online. The parameters (voltage, magnetic field and pressure) can be controlled remotely in real-time by opening a URL which shows the streaming video, as well as a set of Labview controls. The RGDX is designed as an outreach tool that uses the attractive nature of a plasma in order to reach a wide audience and extend the presence of plasma physics and fusion around the world. In March 2014, the RGDX was made publically available and, as of early July, it has had approximately 3500 unique visits from 107 countries and almost all 50 US states. We present recent upgrades, including the ability to remotely control the distance between the electrodes. These changes give users the capability of measuring Paschen's Law remotely and provides a comprehensive introduction to plasma physics to those that do not have access to the necessary equipment.

  8. v-Src causes delocalization of Mklp1, Aurora B, and INCENP from the spindle midzone during cytokinesis failure

    Energy Technology Data Exchange (ETDEWEB)

    Soeda, Shuhei [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414 (Japan); Honda, Takuya; Aoki, Azumi; Tamura, Naoki; Abe, Kohei; Fukumoto, Yasunori [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Yamaguchi, Naoto, E-mail: nyama@faculty.chiba-u.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan)

    2013-06-10

    Src-family tyrosine kinases are aberrantly activated in cancers, and this activation is associated with malignant tumor progression. v-Src, encoded by the v-src transforming gene of the Rous sarcoma virus, is a mutant variant of the cellular proto-oncogene c-Src. Although investigations with temperature sensitive mutants of v-Src have shown that v-Src induces many oncogenic processes, the effects on cell division are unknown. Here, we show that v-Src inhibits cellular proliferation of HCT116, HeLa S3 and NIH3T3 cells. Flow cytometry analysis indicated that inducible expression of v-Src results in an accumulation of 4N cells. Time-lapse analysis revealed that binucleation is induced through the inhibition of cytokinesis, a final step of cell division. The localization of Mklp1, which is essential for cytokinesis, to the spindle midzone is inhibited in v-Src-expressing cells. Intriguingly, Aurora B, which regulates Mklp1 localization at the midzone, is delocalized from the spindle midzone and the midbody but not from the metaphase chromosomes upon v-Src expression. Mklp2, which is responsible for the relocation of Aurora B from the metaphase chromosomes to the spindle midzone, is also lost from the spindle midzone. These results suggest that v-Src inhibits cytokinesis through the delocalization of Mklp1 and Aurora B from the spindle midzone, resulting in binucleation. -- Highlights: • v-Src inhibits cell proliferation of HCT116, HeLa S3 and NIH3T3 cells. • v-Src induces binucleation together with cytokinesis failure. • v-Src causes delocalization of Mklp1, Aurora B and INCENP from the spindle midzone.

  9. The conserved apicomplexan Aurora kinase TgArk3 is involved in endodyogeny, duplication rate and parasite virulence.

    Science.gov (United States)

    Berry, Laurence; Chen, Chun-Ti; Reininger, Luc; Carvalho, Teresa G; El Hajj, Hiba; Morlon-Guyot, Juliette; Bordat, Yann; Lebrun, Maryse; Gubbels, Marc-Jan; Doerig, Christian; Daher, Wassim

    2016-08-01

    Aurora kinases are eukaryotic serine/threonine protein kinases that regulate key events associated with chromatin condensation, centrosome and spindle function and cytokinesis. Elucidating the roles of Aurora kinases in apicomplexan parasites is crucial to understand the cell cycle control during Plasmodium schizogony or Toxoplasma endodyogeny. Here, we report on the localization of two previously uncharacterized Toxoplasma Aurora-related kinases (Ark2 and Ark3) in tachyzoites and of the uncharacterized Ark3 orthologue in Plasmodium falciparum erythrocytic stages. In Toxoplasma gondii, we show that TgArk2 and TgArk3 concentrate at specific sub-cellular structures linked to parasite division: the mitotic spindle and intranuclear mitotic structures (TgArk2), and the outer core of the centrosome and the budding daughter cells cytoskeleton (TgArk3). By tagging the endogenous PfArk3 gene with the green fluorescent protein in live parasites, we show that PfArk3 protein expression peaks late in schizogony and localizes at the periphery of budding schizonts. Disruption of the TgArk2 gene reveals no essential function for tachyzoite propagation in vitro, which is surprising giving that the P. falciparum and P. berghei orthologues are essential for erythrocyte schizogony. In contrast, knock-down of TgArk3 protein results in pronounced defects in parasite division and a major growth deficiency. TgArk3-depleted parasites display several defects, such as reduced parasite growth rate, delayed egress and parasite duplication, defect in rosette formation, reduced parasite size and invasion efficiency and lack of virulence in mice. Our study provides new insights into cell cycle control in Toxoplasma and malaria parasites and highlights Aurora kinase 3 as potential drug target. PMID:26833682

  10. Anode glow and double layer in DC magnetron anode plasma

    International Nuclear Information System (INIS)

    Sputtering magnetron is widely used device in research and industry alike. DC planar magnetron employs series of magnets to create magnetic field above the electrode surface which traps electrons in closed E-bar x B-bar drift. Similar device used in reversed polarity power was reported for use in various applications. In contrast to its normal counterpart there is no closed drift effect in there. This device has very limited understanding. We here investigate this device for its discharge properties. Our device is dominated by anode glow. The anode glow is expected to have the electron sheath which provides energy to electron to excite the neutrals. Where as many experimental studies have been reported for anode glow and anode double layer, many of them uses auxiliary anode in the discharge. Most of the cases anode double layer (fire ball/fire rod) is small structures very near to anode surface which in itself is required to be small. The DC planar magnetron biased in reverse polarity have glow only near anode. Measurements confirm it as anode glow and the presence of electrons sheath is proven. The double layer structure was observed and measured in two mutually perpendicular directions. The double layer shows sub MHz oscillation that is typical of the unstable anode double layer. The dimension of anode glow is relatively large and is primarily in magnetic field free region making it easy to probe. The potential structure still shows large cathode fall but surprisingly visible cathode glow is not present. The device operates very stable for pressure bellow 0.01 mbar. But it shows instabilities such as unstable anode double layer above said pressure. (author)

  11. Application of a direct current glow discharge for fast silicon etching

    International Nuclear Information System (INIS)

    A direct current (dc) glow discharge with a silicon cathode is investigated. An etching rate of 170 nm/s is achieved when SF6 is used as a plasma-forming gas with an ion current density of 10 mA/cm2. The possibility to increase this value up to 400 nm/s is shown. It is found, that the treatment uniformity can be regulated effectively by changing the geometry of the discharge positive column. An oxygen gas jacket is used to prevent anode erosion and contamination

  12. Enhanced Glow Discharge Production of Oxygen

    Science.gov (United States)

    Ash, Robert; Zhong, Shi

    1998-01-01

    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.

  13. Glow rate technique for spectroscopy of complex thermostimulated relaxation processes

    International Nuclear Information System (INIS)

    The glow rate technique (GRT) developed for the analysis of complex trap spectra, is the extension of the known heating rate method to the full glow curve. It is shown that using two glow curves measured at different heating rate constants, a special mean activation energy of simultaneously emptied traps can be obtained as a function of temperature or emitted light sum to a good approximation. Expressions have been derived for the calculation of the mean activation energy function from data measured using a linear, logarithmic or a hyperbolic heating mode. Theoretical expressions for the mean activation energy function have been obtained and discussed for arbitrary trap distribution functions (TDF) in activation energy and frequency factor. The mean activation energy function additional to the glow curve gives direct quantitative information about the activation energies of traps involved in the thermostimulated relaxation. Application of the curve fit analysis to both the glow intensity and mean energy data offers a procedure for the advanced evaluation of parameters of the trap spectrum, which allows estimation of the true TDF as well as verifying the model used. The GRT can be applied down to very low intensities. (author)

  14. AC Glow Discharge Plasma in N2O

    International Nuclear Information System (INIS)

    This paper considers the optical and electrical characterization of AC glow discharge plasma in the abnormal glow mode used for optical emission spectroscopy. The total discharge current and applied voltage are measured using conventional techniques. The electrical characteristics of the planer-cathode glow discharge confirmed that the plasma is operating at abnormal discharge mode characterized by the increases in the operating voltage as the current was raised under given pressure. Optical emission spectroscopy was used to determine the main emission lines of the glow discharge plasma of N2O at pressures between 0.5 and 4.0 Torr. It shows that the discharge emission range is mainly within 300-400 nm. The emission lines correspond to NO, O2, and O2+ are the dominant lines in the glow discharge plasma in the present study. Intensity of the emission lines show linear increase with the discharge current up to 0.4 A followed by saturation at higher currents. No emission lines were observed in this work corresponding to atomic oxygen or nitrogen

  15. Observation of the glow-to-arc transitions

    Science.gov (United States)

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

    2002-10-01

    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.

  16. Aurorasaurus: A citizen science platform for viewing and reporting the aurora

    Science.gov (United States)

    MacDonald, E. A.; Case, N. A.; Clayton, J. H.; Hall, M. K.; Heavner, M.; Lalone, N.; Patel, K. G.; Tapia, A.

    2015-09-01

    A new, citizen science-based, aurora observing and reporting platform has been developed with the primary aim of collecting auroral observations made by the general public to further improve the modeling of the aurora. In addition, the real-time ability of this platform facilitates the combination of citizen science observations with auroral oval models to improve auroral visibility nowcasting. Aurorasaurus provides easily understandable aurora information, basic gamification, and real-time location-based notification of verified aurora activity to engage citizen scientists. The Aurorasaurus project is one of only a handful of space weather citizen science projects and can provide useful results for the space weather and citizen science communities. Early results are promising with over 2000 registered users submitting over 1000 aurora observations and verifying over 1700 aurora sightings posted on Twitter.

  17. Pulsating aurora induced by upper atmospheric barium releases

    Science.gov (United States)

    Deehr, C.; Romick, G.

    1977-01-01

    The paper reports the apparent generation of pulsating aurora by explosive releases of barium vapor near 250 km altitude. This effect occurred only when the explosions were in the path of precipitating electrons associated with the visible aurora. Each explosive charge was a standard 1.5 kg thermite mixture of Ba and CuO with an excess of Ba metal which was vaporized and dispersed by the thermite explosion. Traces of Sr, Na, and Li were added to some of the charges, and monitoring was achieved by ground-based spectrophotometric observations. On March 28, 1976, an increase in emission at 5577 A and at 4278 A was observed in association with the first two bursts, these emissions pulsating with roughly a 10 sec period for approximately 60 to 100 sec after the burst.

  18. Thermoluminescence glow curves and deconvoluted glow peaks of Ge doped flat fibers at ultra-high doses of electron radiation

    International Nuclear Information System (INIS)

    The behavior of Ge doped silica, SiO2 flat fibers (FF) irradiated with 2.5 MeV electron radiation at ultra-high dose (UHD) range, up to 1 MGy, has been investigated. The analyzed glow curves measured by the usage of the WinREMS software revealed that peak height and glow curve maximum temperature are highly dependent on the dose. The shape of the glow curves is constant with increasing dose. The supralinearity of all glow peaks increases to its f(D)max, which occurs around 50 kGy. No saturation occurs at f(D)max and further increases in dose, up to 1 MGy, exhibits a significant decrease in f(D). The glow peaks 2 (230 °C) and 4 (290 °C), deconvoluted by the usage of WinGCF software, are the first-order kinetic peaks and can be used as the main dosimetric peaks for high-dose measurements between 1 and 50 kGy in an industrial environment. - Highlights: • The supralinearity of FF was highly dependent on UHD. • f(D)max occurs around 50 kGy for 6 wt% Ge doped FF. • Peak 2 (230 °C) and peak 4 (290 °C) are the first-order kinetic peaks. • Sensitivity of FF decreases for doses >50 kGy

  19. Evidence of Low Dimensional Chaos in Glow Curves of Thermoluminescence

    CERN Document Server

    Conte, Elio

    2008-01-01

    Electron trapping following exposition to ionising radiations and consequent electron release during variation of temperature in solids represent processes happening at the quantum microphysical level. The interesting feature of the thermally stimulated process, that in fact deserves further investigation, is that the dynamic of electrons release during, variation of the temperature, here examined through the so called thermoluminescent Glow Curve, evidences chaotic and fractal regimes. Phase space reconstruction, Correlation Dimension, largest Lyapunov exponent, Recurrence Quantification Analysis(RQA) and fractal dimension analysis, developed by calculation of Hurst exponent, are performed on three samples. The results unequivocally fix that Glow Curves respond to a chaotic regime. RQA supports such results revealing the inner structure of Glow Curve signals in relation to their properties of recurrence, determinism and intermittency signed from laminarity as well as chaos-chaos and chaos order transitions.

  20. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  1. [The glow discharge as an atomization and ionization source

    International Nuclear Information System (INIS)

    This is to summarize the research progress in this project at the University of Florida over the past 13 months. In keeping with the directions of the Federal Demonstration Project, the report will be brief, presenting an overview of the major findings. We have continued the study of the glow discharge, primarily as an ionization source for elemental analysis. Glow discharge interest continues to grow in the analytical chemistry community as evidenced by the number of special symposia at major conferences, by the new researchers entering the field, and by the introduction of new instrumentation. There is little doubt that glow discharge mass spectrometry, for example, is now a major technique in the elemental analysis of solids

  2. Use of universal functional optimisation for TL glow curve analysis

    International Nuclear Information System (INIS)

    The effective use of any TL instrument requires an efficient software package to be able to fulfil different tasks required by research and practical applications. One of the standard features of the package used at the NPI Prague is the application of the interactive modular system Universal Functional Optimisation (UFO) for glow curve deconvolution. The whole system has been tested on standard glow curves using different models of the TL process (a single peak described by the Podgorsak approximation, first order kinetics and/or general order kinetics). Calculated values of basic TL parameters (E and s) show a good agreement with the results obtained by other authors. The main advantage of the system is in its modularity that enables flexible changes in the TL model and mathematical procedures of the glow curve analysis. (author)

  3. Glow discharge conditioning of the PDX vacuum vessel

    International Nuclear Information System (INIS)

    A glow discharge technique has been developed and applied to the conditioning of the large (38 m3) Poloidal Divertor Experiment (PDX) vacuum vessel. The discharge parameters and working gas (H2) 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 H2 at a pressure of 3 x 10-2 torr was flowed through PDX at approx. 10 t-l/s. The effectiveness of the glow discharge conditioning was monitored by measuring impurity gas (CH4, C2H4, and CO) exhaust rates by mass spectrometry and C and O surface removal rates by in-situ AES and XPS

  4. MLN8054 and Alisertib (MLN8237): Discovery of Selective Oral Aurora A Inhibitors.

    Science.gov (United States)

    Sells, Todd B; Chau, Ryan; Ecsedy, Jeffrey A; Gershman, Rachel E; Hoar, Kara; Huck, Jessica; Janowick, David A; Kadambi, Vivek J; LeRoy, Patrick J; Stirling, Matthew; Stroud, Stephen G; Vos, Tricia J; Weatherhead, Gabriel S; Wysong, Deborah R; Zhang, Mengkun; Balani, Suresh K; Bolen, Joseph B; Manfredi, Mark G; Claiborne, Christopher F

    2015-06-11

    The Aurora kinases are essential for cell mitosis, and the dysregulation of Aurora A and B have been linked to the etiology of human cancers. Investigational agents MLN8054 (8) and alisertib (MLN8237, 10) have been identified as high affinity, selective, orally bioavailable inhibitors of Aurora A that have advanced into human clinical trials. Alisertib (10) is currently being evaluated in multiple Phase II and III clinical trials in hematological malignancies and solid tumors. PMID:26101564

  5. The Discovery of Aurora Kinase Inhibitor by Multi-Docking-Based Virtual Screening

    Directory of Open Access Journals (Sweden)

    Jun-Tae Kim

    2014-11-01

    Full Text Available We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 μM against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.

  6. The Discovery of Aurora Kinase Inhibitor by Multi-Docking-Based Virtual Screening

    OpenAIRE

    Jun-Tae Kim; Seo Hee Jung; Sun Young Kang; Chung-Kyu Ryu; Nam Sook Kang

    2014-01-01

    We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 μM) against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.

  7. Aurorae of Io and Europa: Observations and Modeling

    OpenAIRE

    Roth, Lorenz

    2012-01-01

    In the present dissertation we study the auroral emissions emanating from the tenuous atmospheres of Jupiter's satellites Io and Europa. The satellites are embedded in a dense magnetospheric plasma environment. Due to Jupiter's fast rotation the corotating magnetospheric plasma particles constantly flow past Io and Europa causing a complex interaction and triggering auroral emission in the atmospheres. Therefore, aurora observations are a useful tool to explore both the magnetospheric environ...

  8. Planetary protection in the framework of the Aurora exploration program

    Science.gov (United States)

    Kminek, G.

    The Aurora Exploration Program will give ESA new responsibilities in the field of planetary protection. Until now, ESA had only limited exposure to planetary protection from its own missions. With the proposed ExoMars and MSR missions, however, ESA will enter the realm of the highest planetary protection categories. As a consequence, the Aurora Exploration Program has initiated a number of activities in the field of planetary protection. The first and most important step was to establish a Planetary Protection Working Group (PPWG) that is advising the Exploration Program Advisory Committee (EPAC) on all matters concerning planetary protection. The main task of the PPWG is to provide recommendations regarding: Planetary protection for robotic missions to Mars; Planetary protection for a potential human mission to Mars; Review/evaluate standards & procedures for planetary protection; Identify research needs in the field of planetary protection. As a result of the PPWG deliberations, a number of activities have been initiated: Evaluation of the Microbial Diversity in SC Facilities; Working paper on legal issues of planetary protection and astrobiology; Feasibility study on a Mars Sample Return Containment Facility; Research activities on sterilization procedures; Training course on planetary protection (May, 2004); Workshop on sterilization techniques (fall 2004). In parallel to the PPWG, the Aurora Exploration Program has established an Ethical Working Group (EWG). This working group will address ethical issues related to astrobiology, planetary protection, and manned interplanetary missions. The recommendations of the working groups and the results of the R&D activities form the basis for defining planetary protection specification for Aurora mission studies, and for proposing modification and new inputs to the COSPAR planetary protection policy. Close cooperation and free exchange of relevant information with the NASA planetary protection program is strongly

  9. Performance of the Aurora KrF ICF laser system

    International Nuclear Information System (INIS)

    Because short wavelength lasers are attractive for inertial confinement fusion (ICF), the Department of Energy is sponsoring work at Los Alamos National Laboratory in krypton-fluoride (KrF) laser technology. Aurora is a short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength ICF research. The system employs optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers. The 1 to 5 ns pulse of the Aurora front end is split into 96 beams which are angularly and temporally multiplexed to produce a 480 ns pulse train for amplification by four KrF laser amplifiers. In the present system configuration half (48) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. This paper discusses how the Aurora laser system has entered the initial operational phase by delivering pulse energies of greater than one kilojoule to target

  10. Doppler shifted H Ly α emission from Jupiter's aurora

    International Nuclear Information System (INIS)

    IUE observations of the aurora on Jupiter have been performed with high spectral resolution in a search for Doppler shifted H Ly α emission produced through charge exchange by fast precipitating protons, as observed in the Earth's aurora. No emission has been observed corresponding to proton energies greater than 200 eV, placing a strict upper limit on the contribution of KeV - MeV protons to the production of Jupiter's aurora. However, a large fraction of the H Ly α emission has appeared Doppler-shifted mainly toward the blue by roughly 50 km/sec, corresponding to a kinetic energy of 10-20 eV for a fast proton or H atom, and there are higher velocity wings on the line extending out to equivalent energies of 150-200 eV. The blue shift indicates motion up out of the atmosphere, and the authors suggest that the emission results from the in situ acceleration of ionospheric protons in Jupiter's auroral ionosphere by analogy to the ionospheric potentials observed in the Earth's auroral zones. These observations demonstrate that the acceleration of ionospheric plasma in an H2 atmosphere can lead to bright Ly α emission, with implications for the production of the outer planet airglow emissions

  11. The Grand Aurorae Borealis Seen in Colombia in 1859

    CERN Document Server

    Cárdenas, Freddy Moreno; Domínguez, Santiago Vargas

    2015-01-01

    On Thursday, September 1, 1859, the British astronomer Richard Carrington, for the first time ever, observes a spectacular gleam of visible light on the surface of the solar disk, the photosphere. The Carrington Event, as it is nowadays known by scientists, occurred because of the high solar activity that had visible consequences on Earth, in particular reports of outstanding aurorae activity that amazed thousands of people in the western hemisphere during the dawn of September 2. The geomagnetic storm, generated by the solar-terrestrial event, had such a magnitude that the auroral oval expanded towards the equator, allowing low latitudes, like Panama's 9$^\\circ$ N, to catch a sight of the aurorae. An expedition was carried out to review several historical reports and books from the northern cities of Colombia, allowing the identification of a narrative from Monter\\'ia, Colombia (8$^\\circ$ 45' N), that describes phenomena resembling those of an aurorae borealis, such as fire-like lights, blazing and dazzling ...

  12. Pulsating proton aurora caused by rising tone Pc1 waves

    Science.gov (United States)

    Nomura, R.; Shiokawa, K.; Omura, Y.; Ebihara, Y.; Miyoshi, Y.; Sakaguchi, K.; Otsuka, Y.; Connors, M.

    2016-02-01

    We found rising tone emissions with a dispersion of ˜1 Hz per several tens of seconds in the dynamic spectrum of a Pc1 geomagnetic pulsation (Pc1) observed on the ground. These Pc1 rising tones were successively observed over ˜30 min from 0250 UT on 14 October 2006 by an induction magnetometer at Athabasca, Canada (54.7°N, 246.7°E, magnetic latitude 61.7°N). Simultaneously, a Time History of Events and Macroscale Interactions during Substorms panchromatic (THEMIS) all-sky camera detected pulsations of an isolated proton aurora with a period of several tens of seconds, ˜10% variations in intensity, and fine structures of 3° in magnetic longitudes. The pulsations of the proton aurora close to the zenith of ATH have one-to-one correspondences with the Pc1 rising tones. This suggests that these rising tones scatter magnetospheric protons intermittently at the equatorial region. The radial motion of the magnetospheric source, of which the isolated proton aurora is a projection, can explain the central frequency increase of Pc1, but not the shorter period (tens of seconds) frequency increase of ˜1 Hz in Pc1 rising tones. We suggest that EMIC-triggered emissions generate the frequency increase of Pc1 rising tones on the ground and that they also cause the Pc1 pearl structure, which has a similar characteristic time.

  13. Realization of SOC behavior in a dc glow discharge plasma

    CERN Document Server

    Nurujjaman, M; Nurujjaman, Md.

    2006-01-01

    Experimental observations consistent with Self Organized Criticality (SOC) have been obtained in the electrostatic floating potential fluctuations of a dc glow discharge plasma. Power spectrum exhibits a power law which is compatible with the requirement for SOC systems. Also the estimated value of the Hurst exponent (self similarity parameter), H being greater than 0.5, along with an algebraic decay of the autocorrelation function, indicate the presence of temporal long-range correlations, as may be expected from SOC dynamics. This type of observations in our opinion has been reported for the first time in a glow discharge system.

  14. On the second kinetic order thermoluminescent glow curves

    International Nuclear Information System (INIS)

    The kinetic parameters of thermoluminescent material such as CaF2-N and CaSO4-Dy with the different grain sizes are investigated in detail using the least square method of fitting. It was found that the activation energy E (or trap depth) and peak temperature Tmax are changed with the elapsed time between the irradiation and read-out for the low temperature glow curve peaks. The similar TL glow curve shapes are obtained for the different CaSO4-Dy grain size. (author). 7 refs., 5 figs., 2 tabs

  15. Mitotic phosphorylation of SOX2 mediated by Aurora kinase A is critical for the stem-cell like cell maintenance in PA-1 cells.

    Science.gov (United States)

    Qi, Dandan; Wang, Qianqian; Yu, Min; Lan, Rongfeng; Li, Shuiming; Lu, Fei

    2016-08-01

    Transcription factor SOX2 is multiple phosphorylated. However, the kinase and the timing regulating SOX2 phosphorylation remains poorly understood. Here we reported mitotic phosphorylation of SOX2 by Aurora kinase A (AURKA). AURKA inhibitors (VX680, Aurora kinase Inhibitor I) but not PLK1 inhibitors (BI2536, CBB2001) eliminate the mitotic phosphorylation of SOX2. Consistently, siRNA inhibition of AURKA can eliminate mitotic SOX2 phosphorylation. Ser220 and Ser251 are two sites that identified for mitotic phosphorylation on SOX2. Moreover, SOX2 mutants (S220A and S251A) can promote SOX2 induced OCT4 re-expression in differentiated cells. These findings reveal a novel regulation mechanism of SOX2 phosphorylation mediated by AURKA in mitosis and its function in stem cell pluripotency maintenance in cancer cells. PMID:27249336

  16. Mps1 and Ipl1/Aurora B Act Sequentially to Correctly Orient Chromosomes on the Meiotic Spindle of Budding Yeast

    OpenAIRE

    Meyer, Régis E; Kim, Seoyoung; Obeso, David; Straight, Paul D.; Winey, Mark; Dawson, Dean S.

    2013-01-01

    The conserved kinases Mps1 and Ipl1/Aurora B are critical for enabling chromosomes to attach to microtubules such that partner chromosomes will be segregated correctly from each other, but the precise roles of these kinases have been unclear. Here, imaging of live yeast cells was performed to elucidate the stages of chromosome-microtubule interactions, and their regulation by Ipl1 and Mps1, through meiosis I. Ipl1 was found to release kinetochore-microtubule (kMT) associations following meiot...

  17. Temperature-sensitive ipl1-2/Aurora B mutation is suppressed by mutations in TOR complex 1 via the Glc7/PP1 phosphatase

    OpenAIRE

    Tatchell, Kelly; Makrantoni, Vasso; Stark, Michael J. R.; Robinson, Lucy C.

    2011-01-01

    Ipl1/Aurora B is the catalytic subunit of a complex that is required for chromosome segregation and nuclear division. Before anaphase, Ipl1 localizes to kinetochores, where it is required to establish proper kinetochore–microtubule associations and regulate the spindle assembly checkpoint. The protein phosphatase Glc7/PP1 opposes Ipl1 for some of these activities. To more thoroughly characterize the Glc7 phosphatase that opposes Ipl1, we have identified mutations that suppress the thermosensi...

  18. AURORA on MEGSAT 1 a photon counting observatory for the Earth UV night-sky background and Aurora emission

    CERN Document Server

    Monfardini, A; Stalio, R; Mahne, N; Battiston, R; Menichelli, M; Mazzinghi, P

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 sup + N sub 2 line (lambda sub c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 sup - N sup + sub 2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h sub a sub p sub o sub g sub e sub e =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of...

  19. AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

    International Nuclear Information System (INIS)

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2+N2 line (λc=337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1-N+2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (hapogee=648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of the techniques adopted is given in this paper

  20. AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

    Energy Technology Data Exchange (ETDEWEB)

    Monfardini, A. E-mail: monfardi@sci.area.trieste.it; Trampus, P.; Stalio, R.; Mahne, N.; Battiston, R.; Menichelli, M.; Mazzinghi, P

    2001-08-21

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2{sup +}N{sub 2} line ({lambda}{sub c}=337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1{sup -}N{sup +}{sub 2}), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h{sub apogee}=648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of the techniques adopted is given in this paper.

  1. AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

    Science.gov (United States)

    Monfardini, A.; Trampus, P.; Stalio, R.; Mahne, N.; Battiston, R.; Menichelli, M.; Mazzinghi, P.

    2001-08-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed ``Notte'' and the Aurora emission with ``Alba''. AURORA, this is the name of the experiment, will determine, with the ``Notte'' channel, the overall night-side photon background in the 300-400nm spectral range, together with a particular 2+N2 line (λc=337nm). The ``Alba'' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6nm) centered on: 367nm (continuum evaluation), 391nm (1-N+2), 535nm (continuum evaluation), 560nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 ``Satan'' rocket. The satellite orbit is nearly circular (hapogee=648km, /e=0.0022), and the inclination of the orbital plane is 64.56°. An overview of the techniques adopted is given in this paper.

  2. Camp GLOW (Girls Leading Our World): Handbook for Volunteers.

    Science.gov (United States)

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    Camp GLOW (Girls Leading Our World) began in Romania in 1995 as a weeklong leadership camp with the purpose of encouraging young women to become active citizens by building their self-esteem and confidence, increasing their self-awareness, and developing their skills in goal-setting, assertiveness, and career and life planning. Since that first…

  3. STS-45 Earth observation of the Aurora Australis or Southern Lights

    Science.gov (United States)

    1992-01-01

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The STS-45 crewmembers note the interesting spiralling or corkscrew appearance of this particular sighting. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  4. Spiral structures and regularities in magnetic field variations and auroras

    Science.gov (United States)

    Feldstein, Y. I.; Gromova, L. I.; Förster, M.; Levitin, A. E.

    2012-02-01

    The conception of spiral shaped precipitation regions, where solar corpuscles penetrate the upper atmosphere, was introduced into geophysics by C. Störmer and K. Birkeland at the beginning of the last century. Later, in the course of the XX-th century, spiral distributions were disclosed and studied in various geophysical phenomena. Most attention was devoted to spiral shapes in the analysis of regularities pertaining to the geomagnetic activity and auroras. We review the historical succession of perceptions about the number and positions of spiral shapes, that characterize the spatial-temporal distribution of magnetic disturbances. We describe the processes in the upper atmosphere, which are responsible for the appearance of spiral patterns. We considered the zones of maximal aurora frequency and of maximal particle precipitation intensity, as offered in the literature, in their connection with the spirals. We discuss the current system model, that is closely related to the spirals and that appears to be the source for geomagnetic field variations during magnetospheric substorms and storms. The currents in ionosphere and magnetosphere constitute together with field-aligned (along the geomagnetic field lines) currents (FACs) a common 3-D current system. At ionospheric heights, the westward and eastward electrojets represent characteristic elements of the current system. The westward electrojet covers the longitudinal range from the morning to the evening hours, while the eastward electrojet ranges from afternoon to near-midnight hours. The polar electrojet is positioned in the dayside sector at cusp latitudes. All these electrojets map along the magnetic field lines to certain plasma structures in the near-Earth space. The first spiral distribution of auroras was found based on observations in Antarctica for the nighttime-evening sector (N-spiral), and later in the nighttime-evening (N-spiral) and morning (M-spiral) sectors both in the Northern and Southern

  5. Model of the Crustal Magnetic Field in the Martian Aurora Zone

    Institute of Scientific and Technical Information of China (English)

    TONG Dong-Sheng; CHEN Chu-Xin

    2011-01-01

    It is well known that aurorae are prominent on planets with a global magnetic field and occur where open magnetic Geld lines converge. The UV spectrometer used for investigating the characteristics of the atmosphere of Mars (SPICAM) on board the Mars Express made the first observation of auroral-type emission in the cusp region of the strong crustal magnetic field on Mars and found that the arc of the Martian aurora zone is very narrow in width, which obviously differs from that of other planets. Based on the observation, we put forward a model of a crustal magnetic field on the Martian aurora zone through the morphology of Martian aurorae. In the model, equivalent currents are proposed; the topology and magnitude of the magnetic field generated by these equivalent currents are consistent with that of the crustal magnetic field in the Martian aurora zone. The morphology of the Martian aurora zone generated through the model matches well with the observations made by the Mars Express orbiter.%It is well known that aurorae are prominent on planets with a global magnetic field and occur where open magnetic field lines converge.The UV spectrometer used for investigating the characteristics of the atmosphere of Mars (SPICAM) on board the Mars Express made the first observation of auroral-type emission in the cusp region of the strong crustal magnetic field on Mars and found that the arc of the Martian aurora zone is very narrow in width,which obviously differs from that of other planets.Based on the observation,we put forward a model of a crustal magnetic field on the Martian aurora zone through the morphology of Martian aurorae.In the model,equivalent currents are proposed;the topology and magnitude of the magnetic field generated by these equivalent currents are consistent with that of the crustal magnetic field in the Martian aurora zone.The morphology of the Martian aurora zone generated through the model matches well with the observations made by the Mars Express

  6. Jupiter's Mid-Infrared Aurora: Solar Connection and Minor Constituents

    Science.gov (United States)

    Kostiuk, Theodore; Livengood, T.A.; Fast, K.E.; Hewagama, T.; Schmilling, F.; Sonnabend, G.; Delgado, J.

    2009-01-01

    High spectral resolution in the 12 pin region of the polar regions of Jupiter reveal unique information on auroral phenomena and upper stratospheric composition. Polar aurorae in Jupiter's atmosphere radiate; throughout the electromagnetic spectrum from X-ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based. spectroscopic measurements of Jupiter's northern mid-IR aurora acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane, emission brightness and solar 10.7-cm radar flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high scalar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. The spectra measured contain features that cannot be attributed to ethane and are most likely spectra of minor constituents whose molecular bands overlap the v9 band of ethane. Possible candidates are allene, propane, and other higher order hydrocarbons. These features appear to be enhanced in the active polar regions. Laboratory measurements at comparable spectral resolution of spectra of candidate molecules will be used to identify the constituents. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the NASA/ESA Europa Jupiter System Mission.

  7. First Terrestrial Soft X-ray Aurora Observations by Chandra

    Science.gov (United States)

    Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Waite, J. Hunter, Jr.; Cravens, Thomas E.; Ostgaard, Nikolai; Chang, Shen-Wu; Metzger, Albert E.; Majeed, Tariq

    2004-01-01

    Northern polar "auroral" regions of Earth was observed by High-Resolution Camera in imaging mode (T32C-I) aboard Chandra X-Ray Observatory (CXO) during mid December 2003 - mid April 2004. Ten CXO observations, each approximately 20 min duration, were made in a non-conventional method (due to CXO technical issues), such that Chandra was aimed at a fixed point in sky and the Earth's polar cusp was allowed to drift through the HRC-I field-of-view. The observations were performed when CXO was near apogee and timed during northern winter mostly near midnight (6 hr), except two observations which occurred around 1200 UT, so that northern polar region is entirely in dark and solar fluoresced x-ray contamination can be avoided. These observations were aimed at searching the Earth's soft x-ray aurora and to do a comparative study with Jupiter's x-ray aurora, where a pulsating x-ray hot-spot near the northern magnetic pole has been observed by Chandra that implies a particle source region near Jupiter's magnetopause, and entry of heavy solar wind ions due to high-latitude reconnection as a viable explanation for the soft x-ray emissions. The first Chandra soft (0.1-2 keV) x-ray observations of Earth's aurora show that it is highly variable (intense arc, multiple arcs, diffuse, at times almost absent). In at least one of the observations an isolated blob of emission is observed where we expect cusp to be: giving indication of solar wind charge-exchange signature in x-rays. We are comparing the Chandra x-ray observations with observations at other wavelengths and particle data from Earth-orbiting satellites and solar wind measurements from near-Earth ACE and SOH0 spacecraft. Preliminary results from these unique CXO-Earth observations will be presented and discussed.

  8. Expression of Aurora-B and FOXM1 predict poor survival in patients with nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pei-Yu; Luo, Dong-Hua; Mai, Hai-Qiang [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Nasopharyngeal Carcinoma, Guangzhou (China); Li, Yan; Zeng, Ting-Ting; Li, Meng-Qing [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Hou, Xue; Zhang, Li [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Medical Oncology, Guangzhou (China)

    2015-08-15

    The purpose of this work was to investigate the relationship between Aurora-B, FOXM1, and clinical outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with a combination of induction chemotherapy and radiotherapy. The expression of Aurora-B and FOXM1 were investigated by immunohistochemistry using a tissue microarray (TMA) containing samples from 166 NPC patients who were treated with cisplatin (DDP) + fluorouracil (5-FU) induction chemotherapy and radiotherapy between 1999 and 2005. The relationship of Aurora-B, FOXM1, and survival of these NPC patients was analyzed. Informative TMA results were obtained in 91 tumor cases for Aurora-B and 93 tumor cases for FOXM1. The 8-year failure-free survival rate (FFS) for the Aurora-B-negative and Aurora-B-positive group was 65.6 and 37.3 %, respectively (p = 0.024), and the 8-year distant FFS (D-FFS) rate was 65.6 and 41.5 %, respectively (p = 0.047). The 8-year overall survival (OS) in the FOXM1-negative group was moderately higher than in the FOXM1-positive group (58.4 vs 39.1 %, p = 0.081). Cox regression analysis revealed that for FFS, Aurora-B expression was a significant prognostic factor (p = 0.025), while for D-FFS, Aurora-B expression was a marginally significant prognostic factor (p = 0.056). When FOXM1 expression was analyzed, the Cox regression analyses showed that FOXM1 expression was a marginally significant prognostic factor (p = 0.056) for OS. Correlation analysis showed that Aurora-B and FOXM1 expression had no significant correlation. Aurora-B and FOXM1 were both adverse prognostic markers for NPC patients treated with chemoradiotherapy. However, the two markers had no significant correlation. (orig.) [German] Ziel war die Untersuchung der Beziehung zwischen Aurora-B, FOXM1 und den klinischen Ergebnissen bei Patienten mit nasopharyngealem Karzinom (NPC), die mit einer Kombinationstherapie aus Induktionschemotherapie und Radiotherapie behandelt wurden. Die Expression von Aurora-B und

  9. Expression of Aurora-B and FOXM1 predict poor survival in patients with nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    The purpose of this work was to investigate the relationship between Aurora-B, FOXM1, and clinical outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with a combination of induction chemotherapy and radiotherapy. The expression of Aurora-B and FOXM1 were investigated by immunohistochemistry using a tissue microarray (TMA) containing samples from 166 NPC patients who were treated with cisplatin (DDP) + fluorouracil (5-FU) induction chemotherapy and radiotherapy between 1999 and 2005. The relationship of Aurora-B, FOXM1, and survival of these NPC patients was analyzed. Informative TMA results were obtained in 91 tumor cases for Aurora-B and 93 tumor cases for FOXM1. The 8-year failure-free survival rate (FFS) for the Aurora-B-negative and Aurora-B-positive group was 65.6 and 37.3 %, respectively (p = 0.024), and the 8-year distant FFS (D-FFS) rate was 65.6 and 41.5 %, respectively (p = 0.047). The 8-year overall survival (OS) in the FOXM1-negative group was moderately higher than in the FOXM1-positive group (58.4 vs 39.1 %, p = 0.081). Cox regression analysis revealed that for FFS, Aurora-B expression was a significant prognostic factor (p = 0.025), while for D-FFS, Aurora-B expression was a marginally significant prognostic factor (p = 0.056). When FOXM1 expression was analyzed, the Cox regression analyses showed that FOXM1 expression was a marginally significant prognostic factor (p = 0.056) for OS. Correlation analysis showed that Aurora-B and FOXM1 expression had no significant correlation. Aurora-B and FOXM1 were both adverse prognostic markers for NPC patients treated with chemoradiotherapy. However, the two markers had no significant correlation. (orig.)

  10. Basal aurora kinase B activity is sufficient for histone H3 phosphorylation in prophase

    Directory of Open Access Journals (Sweden)

    Ly-Thuy-Tram Le

    2013-02-01

    Histone H3 phosphorylation is the hallmark of mitosis deposited by aurora kinase B. Benzo[e]pyridoindoles are a family of potent, broad, ATP-competitive aurora kinase inhibitors. However, benzo[e]pyridoindole C4 only inhibits histone H3 phosphorylation in prophase but not in metaphase. Under the C4 treatment, the cells enter into mitosis with dephosphorylated histone H3, assemble chromosomes normally and progress to metaphase, and then to anaphase. C4 also induces lagging chromosome in anaphase but we demonstrated that these chromosome compaction defects are not related to the absence of H3 phosphorylation in prophase. As a result of C4 action, mitosis lasts longer and the cell cycle is slowed down. We reproduced the mitotic defects with reduced concentrations of potent pan aurora kinase as well as with a specific aurora B ATP-competitive inhibitor; we therefore propose that histone H3 phosphorylation and anaphase chromosome compaction involve the basal activity of aurora kinase B. Our data suggest that aurora kinase B is progressively activated at mitosis entry and at anaphase onset. The full activation of aurora kinase B by its partners, in prometaphase, induces a shift in the catalytic domain of aurora B that modifies its affinity for ATP. These waves of activation/deactivation of aurora B correspond to different conformations of the chromosomal complex revealed by FRAP. The presence of lagging chromosomes may have deleterious consequences on the daughter cells and, unfortunately, the situation may be encountered in patients receiving treatment with aurora kinase inhibitors.

  11. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  12. Interpretation of electron spectra in morningside pulsating aurorae

    International Nuclear Information System (INIS)

    Energy spectra of precipitating electrons in morningside aurorae were obtained with instruments on the NOAA 6 satellite during several passes through the southern auroral zone in 1982. It is substantiated with the aid of coordinated data from particle detectors and a photometer in the Simulated Emission of Energetic Particles experiment payload on satellite S81-1 that the precipitation obserbed by NOAA 6 was probably in a region of pulsating aurorae. The particle detectors and forward/downward looking quadrant photometer onboard S81-1 all exhibited regular modulations at a period of about 5--15 s. The particle detectors on NOAA 6 showed fluctuating electron intensities over an energy range from several kiloelectronvolts to many tens of kiloelectronvolts, superimposed on a steady background component extending down to energies less than 1 keV. The NOAA 6 electron observations are in qualitative agreement with a time-dependent precipitation model that includes the production of backscattered and secondary electrons from the atmosphere. In this model the time variations imposed on the precipitation are restricted to the energetic portion of the electron spectrum, while the integrating effects inherent in the production of backscattered and secondary electrons, together with phase mixing introduced as those electrons transit between conjugate hemispheres, insure the existence of a nearly time independent population of low-energy electrons. A steady background precipitation is thereby created as a natural consequence of a time-variable primary precipitation. copyright American Geophysical Union 1987

  13. X-ray scanning of overhead aurorae from rockets

    International Nuclear Information System (INIS)

    Two Nike Tomahawk rocket payloads were launched into energetic auroral events to investigate their structure and effects on the atmosphere. The instrument complement included X-ray scintillation detectors with energy discrimination in four ranges to measure the deposition of bremsstrahlung produced X-rays within the stratosphere and mesosphere. For this purpose, each instrument was designed for wide angle viewing; however, properties of the rocket motion have permitted coarse observation of distinct spatial X-ray structure. The detectors were mounted at a 450 angle with respect to the payload axis to permit scanning of the upper hemisphere, with rocket spin rates near 5 c/s during the upleg portion of each flight. Here, atmospheric shielding reduced energetic particle contamination effects to insignificant values below 65 to 75 km. Iterative computer techniques were used to reconstruct X-ray source maps at 100 km, taking atmospheric absorption effects into account. Payload 18.178 was launched on 21 September (0302 LMT) into an aurora observed to have two distinct azimuthal regions of optical brightness. Payload 18.179 (23 September, 0147 LMT) was launched into an aurora of more diffuse character. The presence of a two component spectrum is indicated for each event with the hard component originating in the more diffuse, optically faint regions. (author)

  14. Glow discharge electron impact ionization source for miniature mass spectrometers.

    Science.gov (United States)

    Gao, Liang; Song, Qingyu; Noll, Robert J; Duncan, Jason; Cooks, R Graham; Ouyang, Zheng

    2007-05-01

    A glow discharge electron impact ionization (GDEI) source was developed for operation using air as the support gas. An alternative to the use of thermoemission from a resistively heated filament electron source for miniature mass spectrometers, the GDEI source is shown to have advantages of long lifetime under high-pressure operation and low power consumption. The GDEI source was characterized using our laboratory's handheld mass spectrometer, the Mini 10. The effects of the discharge voltage and pressure were investigated. Design considerations are illustrated with calculations. Performance is demonstrated in a set of experimental tests. The results show that the low power requirements, mechanical ruggedness, and quality of the data produced using the small glow discharge ion source make it well-suited for use with a portable handheld mass spectrometer. PMID:17441220

  15. Taylor discharge cleaning and glow discharge conditioning in Novillo tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Lopez C, R.; Valencia A, R.; Colunga S, S.; Melendez L, L.; Chavez A, E.; Olayo G, G.; Gaytan G, E.; Cruz C, G.; Flores O, A.

    1993-12-31

    Both Taylor and Glow discharge conditioning techniques in Novillo Tokamak are applied. In each case the results are showed. The effectiveness of each one of these two conditioning techniques was monitored by measuring the gas impurities CH{sub 4}, C{sub 2}H{sub 4}, CO, C and O by means of mass spectrometry. In every case tokamak discharges were carried out after conditioning and the better plasma parameters obtained were used to determine the conditioning quality. A 20 kW, 17.5 kHz power oscillator was used for Taylor discharges. The oscillator energized the OHT, synchronized with a 200-700 G toroidal magnetic field. For the Glow discharges the same power oscillator DC voltage source was used to bias two SS electrodes with a 0-1500 V and 2 A maximum discharge current. (author) 5 refs., 2 figs.

  16. Glow Discharge Induced Hydroxyl Radical Degradation of 2-Naphthylamine

    Science.gov (United States)

    Lu, Quanfang; Yu, Jie; Gao, Jinzhang; Yang, Wu

    2005-06-01

    In an aqueous solution, normal electrolysis at high voltages switches over spontaneously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, and aqueous electron, as well as several other active species. Hydroxyl radical directly attacks organic contaminants to make them oxidized. In the present paper, 2-naphthylamine is eventually degraded into hydrogen carbonate and carbon dioxide. The degradation process is analyzed by using an Ultraviolet (UV) absorption spectrum, high-performance liquid chromatography (HPLC) and chemical oxygen demand (COD). It is demonstrated that 2-naphthylamine (c0 =30 mg·l-1) is completely converted within 2h at 30°C and 600 V by glow discharge electrolysis, and the degradation is strongly dependent upon the presence of ferrous ions. COD is ascended in the absence of ferrous ions and descended in the presence of them.

  17. Glow Discharge Induced Hydroxyl Radical Degradation of 2-Naphthylamine

    Institute of Scientific and Technical Information of China (English)

    Lu Quanfang; Yu Jie; Gao Jinzhang; Yang Wu

    2005-01-01

    In an aqueous solution, normal electrolysis at high voltages switches over sponta-neously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, andaqueous electron, as well as several other active species. Hydroxyl radical directly attacks or-ganic contaminants to make them oxidized. In the present paper, 2-naphthylamine is eventuallydegraded into hydrogen carbonate and carbon dioxide. The degradation process is analyzed byusing an Ultraviolet (UV) absorption spectrum, high-performance liquid chromatography (HPLC)and chemical oxygen demand (COD). It is demonstrated that 2-naphthylamine (c0 =30 mg.1-1) iscompletely converted within 2h at 30℃ and 600 V by glow discharge electrolysis, and the degra-dation is strongly dependent upon the presence of ferrous ions. COD is ascended in the absenceof ferrous ions and descended in the presence of them.

  18. Inception of Snapover and Gas Induced Glow Discharges

    Science.gov (United States)

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

    2000-01-01

    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.

  19. Effect of glow discharge air plasma on grain crops seed

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

    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.

  20. The Use of DC Glow Discharges as Undergraduate Educational Tools

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-09

    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.

  1. Analysis of polymers by pulsed RF glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Complete text of publication follows. Glow discharge spectroscopy is widely used for elemental analysis and depth profiling of various inorganic materials. Capacitively coupled RF glow discharges allow the analysis of non-conductive materials, and pulsed RF operation allows the analysis of thermally sensitive samples like glasses. However, the glow discharge technique has been rarely used for analysis of organic materials. The instrument recently developed by Tofwerk AG and Horiba Jobin Yvon combines the pulsed RF glow discharge with a fast time-of-flight mass spectrometer and can be used for simultaneous detection of a large number of mass peaks that occur with organic materials. The instrument can also be operated in negative ion mode thus eliminating some of the interferences that normally appear in positive ion mode due to the argon process gas and residual impurities. Furthermore, the negative ion detection mode offers greater sensitivity for halogens. The sputtering process and subsequent plasma reactions produce a unique mass spectrum of molecular fragments for each polymer and this fingerprint mass spectrum can be used for identifying polymers. We generated fingerprint mass spectra for a set of polymers (PTFE, CTFE, PE, PET, PMMA) and we demonstrated depth profiling of polymer multilayers on a silicon and glass substrates. Unlike in SIMS, the depth profiling with GD-MS is very quick, complete depth profiles can be recorded within minutes. The method can also be used to detect inorganic traces in polymers that are frequently present as contaminants or residuals of catalysts used during the fabrication process. Our measurements showed the presence of lead in polyethylene and antimony in PET commercial samples. We also measured zinc in ZnO-doped ethylene-propylene-diene rubbers. The authors acknowledge the financial support from the EC through the GLADNET Marie Curie Research Training Network (MRTN-CT-2006-035459) and the EMDPA project (STREP-NMP n deg 032202).

  2. Investigation and application of hollow anode glow discharge ion source

    Energy Technology Data Exchange (ETDEWEB)

    Abdelsalam, F.W.; Helal, A.G. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P.O. Box 13759 Inchas, Cairo (Egypt); Saddeek, Y.B. [Physics Dep., Faculty of Science, AL-Azhar University in Assuitt, Assuitt (Egypt); Abdelrahman, M.M., E-mail: moustafa82003@yahoo.co [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P.O. Box 13759 Inchas, Cairo (Egypt); Soliman, B.A. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P.O. Box 13759 Inchas, Cairo (Egypt)

    2010-11-15

    In the present work, a new shape of a glow discharge ion source has been designed, fabricated and constructed at Accelerators and Ion Sources Department, Nuclear Research Center, Egyptian Atomic Energy Authority, Egypt. The discharge and output beam characteristics of the ion source at different operating gas pressures have been measured at the optimum distance between the anode and the cathode (3.5 mm) using hydrogen and nitrogen gases. Furthermore, mixture of different gases was studied, e.g., addition of H{sub 2} gas to N{sub 2} gas with different ratios has been investigated. Finally, as an application of this new ion source, ion beam modification of insulators (glass) which depends on glass structure has been achieved. It has been found that, the transmission of light is decreased by coating the glass surface with Ar ion beam more than coating with plasma of Ar gas at the same pressure and the same exposure time. So we could use this ion source as a coating tool for borate glass surface. The parameters affected the glow discharge ion source efficiency have been examined carefully using a mixture of gases. Using helium gas, the glow discharge is in a turbulent state due to instabilities. An investigated H{sub 2}-N{sub 2} mixture has been used in order to obtain an optimum percentage of the mixture of the two gases to increase the electric field necessary for ionization balance.

  3. Study on the tokamak training technique by glow discharge

    International Nuclear Information System (INIS)

    Methods of vacuum chamber cleaning by glow and powerful discharges ahve been checked on the T-12 installation (the great radius is 36 cm, the small radius is 8 cm). The state of the inner wall surface of the chamber was analyzed by a diagnostic station, and the control of the residual gas spectrum in the installation was performed by omegatron analyzer. The diagnostic station consists of three main assemblies: a high-vacuum chambe of three main assemblies: a high-vacuum chamber in which the sample surface is analyzed, the system of sample transportation into the analyzer chamber and an autonomic system of vacuum pumping. The glow discharge was switched on in the atmosphere of hydrogen, helium, argon. It is found out that the technique of cleaning vacuum volumes by glow discharge is rather effective in comparison with other techniques. It permits to reduce the time of putting the tokamak into operational mode after filling the tokamak with atmosphere. The technique is notable for simplicity and a great safety as well

  4. Role of electronic mechanisms in surface erosion and glow phenomena

    International Nuclear Information System (INIS)

    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

  5. Glow discharge optical emission of plutonium and plutonium waste

    International Nuclear Information System (INIS)

    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

  6. A specific pharmacophore model of Aurora B kinase inhibitors and virtual screening studies based on it.

    Science.gov (United States)

    Wang, Hui-Yuan; Li, Lin-Li; Cao, Zhi-Xing; Luo, Shi-Dong; Wei, Yu-Quan; Yang, Sheng-Yong

    2009-01-01

    In this study, 3D-pharmacophore models of Aurora B kinase inhibitors have been developed by using HipHop and HypoGen modules in Catalyst software package. The best pharmacophore model, Hypo1, which has the highest correlation coefficient (0.9911), consists of one hydrogen-bond acceptor, one hydrogen-bond donor, one hydrophobic aliphatic moiety and one ring aromatic feature. Hypo1 was validated by test set and cross-validation methods. And the specificity of Hypo1 to Aurora B inhibitors was examined with the use of selective inhibitors against Aurora B and its paralogue Aurora A. The results clearly indicate that Hypo1 can differentiate selective inhibitors of Aurora B from those of Aurora A, and the ring aromatic feature likely plays some important roles for the specificity of Hypo1. Then Hypo1 was used as a 3D query to screen several databases including Specs, NCI, Maybridge and Chinese Nature Product Database (CNPD) for identifying new inhibitors of Aurora B. The hit compounds were subsequently subjected to filtering by Lipinski's rule of five and docking studies to refine the retrieved hits, and some compounds selected from the top ranked hits have been suggested for further experimental assay studies. PMID:19152640

  7. Survivin inhibits anti-growth effect of p53 activated by aurora B

    International Nuclear Information System (INIS)

    Genomic instability and apoptosis evasion are hallmarks of cancer, but the molecular mechanisms governing these processes remain elusive. Here, we found that survivin, a member of the apoptosis-inhibiting gene family, and aurora B kinase, a chromosomal passenger protein, were co-overexpressed in the various glioblastoma cell lines and tumors. Notably, exogenous introduction of the aurora B in human BJ cells was shown to decrease cell growth and increase the senescence-associated β-galactosidase activity by activation of p53 tumor suppressor. However, aurora B overexpression failed to inhibit cell proliferation in BJ and U87MG cells transduced with dominant-negative p53 as well as in p53-/- mouse astrocytes. Aurora B was shown to increase centrosome amplification in the p53-/- astrocytes. Survivin was shown to induce anchorage-independent growth and inhibit anti-proliferation and drug-sensitive apoptosis caused by aurora B. Overexpression of both survivin and aurora B further accelerated the proliferation of BJ cells. Taken together, the present study indicates that survivin should accelerate tumorigenesis by inhibiting the anti-proliferative effect of p53 tumor suppressor that is activated by aurora B in normal and glioblastoma cells containing intact p53

  8. Aurora candidates from the chronicle of Qíng dynasty in several degrees of relevance

    Science.gov (United States)

    Kawamura, Akito D.; Hayakawa, Hisashi; Tamazawa, Harufumi; Miyahara, Hiroko; Isobe, Hiroaki

    2016-08-01

    We present the result of a survey of sunspots and auroras in Qíngshǐgǎo (清史稿), a draft chronicle of Qíng dynasty, for the period of 1559-1912 CE. This is a sequel to a series of works surveying historical sunspot and aurora records, and providing online data to the scientific community regarding the attained results. In total of this Qíngshǐgǎo survey, we found 111 records of night-sky luminous events with such keywords as vapor (氣, qì), cloud (雲, yún), and light (光, guāng), which may indicate auroras as well as some other phenomena. Similarly, a keyword survey for sunspots was conducted, but no sunspot record was found. In comparison with the aurora records in the western world, we found that 14 of the 111 records have a corresponding record of simultaneous observation in the western world, and hence are very likely to be aurora. In order to investigate the likeliness of the remainder of the record being aurora, we calculated the lunar age and the phase of a solar cycle for each record. After these calculations, a notable fraction of these records clustered near the full moon were to be found statistically doubtful in considerations with atmospheric optics; meanwhile, a few records of observations near the new moon could be more likely interpreted as being auroras, including three records during the Maunder minimum.

  9. MLN-8237: A dual inhibitor of aurora A and B in soft tissue sarcomas

    Science.gov (United States)

    Nair, Jayasree S.; Schwartz, Gary K.

    2016-01-01

    Aurora kinases have become an attractive target in cancer therapy due to their deregulated expression in human tumors. Liposarcoma, a type of soft tissue sarcoma in adults, account for approximately 20% of all adult soft tissue sarcomas. There are no effective chemotherapies for majority of these tumors. Efforts made to define the molecular basis of liposarcomas lead to the finding that besides the amplifications of CDK4 and MDM2, Aurora Kinase A, also was shown to be overexpressed. Based on these as well as mathematic modeling, we have carried out a successful preclinical study using CDK4 and IGF1R inhibitors in liposarcoma. MLN8237 has been shown to be a potent and selective inhibitor of Aurora A. MLN-8237, as per our results, induces a differential inhibition of Aurora A and B in a dose dependent manner. At a low nanomolar dose, cellular effects such as induction of phospho-Histone H3 (Ser10) mimicked as that of the inhibition of Aurora kinase A followed by apoptosis. However, micromolar dose of MLN-8237 induced polyploidy, a hallmark effect of Aurora B inhibition. The dose dependent selectivity of inhibition was further confirmed by using siRNA specific inhibition of Aurora A and B. This was further tested by time lapse microscopy of GFP-H2B labelled cells treated with MLN-8237. LS141 xenograft model at a dose of 30 mg/kg also showed efficient growth suppression by selective inhibition of Aurora Kinase A. Based on our data, a dose that can target only Aurora A will be more beneficial in tumor suppression. PMID:26887042

  10. Radiation response of thermoluminescence glow peaks separated using a glow curve fitting method for red emission from quartz

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ki-Woung [Chungcheong Cultural Properties Research Institute, Gongju, Chungcheongnam-Do 314-923 (Korea, Republic of); Department of Physics, Kangwon National University, Chuncheon, Kangwon-Do 200-701 (Korea, Republic of); Yun, Kyong-Ku [Department of Civil Engineering, Kangwon National University, Chuncheon, Kangwon-Do 200-701 (Korea, Republic of); Hong, Duk-Geun [Department of Physics, Kangwon National University, Chuncheon, Kangwon-Do 200-701 (Korea, Republic of)], E-mail: dghong@kangwon.ac.kr

    2009-05-15

    Red thermoluminescence (TL) emission from quartz has attracted considerable attention in the fields of retrospective dosimetry and luminescence dating, due to the high dose saturation level and long-term stability of the TL signal. For two red emission quartz samples of volcanic origin (Yuda sample from Iwate Prefecture and Tazawa sample from Akita Prefecture in Japan), we investigated the radiation dose response of TL glow peaks separated using a glow curve fitting method. The radiation dose response of the separated peaks was examined using a growth curve based on the SAR TL protocol. The 260 deg. C, 290 deg. C and 320 deg. C peaks for the Yuda sample and the 270 deg. C and 320 deg. C peaks for the Tazawa sample showed a supralinear response up to 300 Gy, whereas the 370 deg. C peak for both samples behaved linearly.

  11. Topics under debate - The use of computerised glow curve analysis will optimise personal thermoluminescence dosimetry measurements

    International Nuclear Information System (INIS)

    Personal dosimetry is normally a regulated activity whose results must comply with established accuracy requirements. Although these requirements may not be extremely stringent, it is important to note that there are many factors influencing accuracy and therefore influencing results. These include the energy and angular dependence of dose equivalent response, signal reproducibility, stability and fading, along with other influence factors that tend to complicate the correct measurement of the low doses usually encountered in the monitoring of radiation workers. The statistical uncertainty associated with the measurement of dose equivalent in the workplace is dependent upon the reproducibility of the many conditions, and in the case of the readings produced by thermoluminescence (TL) dosemeters the analysis of the rather complex TL signals can be a source of uncertainty. Glow curve analysis may offer a method for reducing uncertainties, but it must be considered whether such an analysis can be accomplished in the context of a large scale worker dosimetry programme. (author)

  12. Dual Aurora A and JAK2 kinase blockade effectively suppresses malignant transformation

    OpenAIRE

    Hua YANG; Lawrence, Harshani R.; Kazi, Aslamuzzaman; Gevariya, Harsukh; Patel, Ronil; Luo, Yunting; Rix, Uwe; Schonbrunn, Ernst; Lawrence, Nicholas J.; Sebti, Said M.

    2014-01-01

    Aurora A and JAK2 kinases are involved in cell division and tumor cell survival, respectively. Here we demonstrate that ectopic expression of Aurora A and JAK2 together is more effective than each alone at inducing non-transformed cells to grow in an anchorage-independent manner and to invade. Furthermore, siRNA silencing or pharmacological inhibition of Aurora A and JAK2 with Alisertib and Ruxolitinib, respectively, is more effective than blocking each kinase alone at suppressing anchorage-d...

  13. NITROGEN POTENTIAL DURING ION NITRIDING PROCESS IN GLOW-DISCHARGE PLASMA

    Directory of Open Access Journals (Sweden)

    A. A. Kozlov

    2015-01-01

    Full Text Available The paper considers problems on regulation of phase composition of a nitrided layer during gas and ion nitriding process in a glow-discharge. It has been established that  available models for control of nitrided layer structure with the help of nitriding index (nitrogen potential can not be applied for nitriding process in the glow-discharge. Principal difference of the ion nitriding from the gas one is in the fact that chemically active nitrogen is formed in the discharge zone (cathode layer and its mass-transfer is carried out in the form of an active particle flow (ions, atoms, molecules which directed to the metal surface.Interrelation of chemical discharge activity with such characteristics of nitriding steel as nitrogen solubility in  α-solid solution and  coefficient diffusion during ion nitriding in low-discharge plasma. It has been shown that regulation of the nitride layer structure during ion nitriding is reached due to changes in nitrogen flow density in plasma. While supporting the flow at the level of nitrogen solubility in  one phase or another (α, γ′  it is possible to obtain the nitrided layer consisting only of α-solid solution or γ′-nitride layer and diffusion sub-layer. Moreover a specific range of nitrogen flow density values exists for every steel grade where it is possible to ensure a limiting nitrogen concentration in α-solid solution and the γ′-layer characterized by low diffusion  mobility is not formed on the surface.

  14. Ion diffusion into metals by double glow discharge. A new plasma surface alloying technique

    International Nuclear Information System (INIS)

    The diffusion of ions into a metal by double glow discharge--a new plasma surface alloying technique--is presented. An enhanced discharge caused by double glow cross-interaction is introduced as a special discharge. The conditions and physics of double glow cross-interaction are discussed. The effects of this cross-interaction on plasma surface alloying are also discussed. Experimental results and industrial applications as well as future industrialization and problems of application and promotion are mentioned

  15. Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO3 phosphor

    Science.gov (United States)

    Tiwari, Ratnesh; Chopra, Seema

    2016-05-01

    The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er3+ (1 mol%) doped CaZrO3 phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

  16. Exploring the Secrets of the Aurora Second Edition

    CERN Document Server

    Akasofu, Syun-Ichi

    2007-01-01

    This new edition of Exploring the Secrets of the Aurora is based on the author's own experiences as a scientist. It describes the history of progress made in auroral science and magnetospheric physics by providing examples of ideas, controversies, struggles, acceptance, and success. Although no general methodologies are mentioned, the hope is that the reader will learn about the history of progress in auroral science and examples of dealing with the many controversies. This book aims to help young scientific researchers learn how to persevere during periods of controversy and struggles for acceptance. In this second edition, by utilizing multiple examples, Akasofu is successful in demonstrating the importance and usefulness of Synthesis. "Probably the book's most valuable contribution to the history of space physics is precisely the narration of the discovery of substorms.---The book has special features.---Akasofu's coverage of the history of pre-space age solar-terrestrial relations is the most comprehensiv...

  17. Beam propagation considerations in the Aurora laser system

    International Nuclear Information System (INIS)

    Aurora is a high-power KrF laser system now being constructed for inertial confinement fusion (ICF) studies. It will use optical angular multiplexing and serial amplification by electron-beam-driven KrF amplifiers to deliver a stacked, multikilojoule 5-ns-duration laser pulse to ICF targets. The requirements of angular multiplexing KrF lasers at the multikilojoule level dictate path lengths on the order of 1 km. The inherent complicated path crossings produced by angular multiplexing and pulse stacking do not allow isolation of individual beam lines, so the optical quality of the long beam paths must be controlled. Propagation of the 248-nm light beams over long paths in air is affected by scattering, absorption thermal gradients and turbulence, beam alignment, and control and optical component figure errors

  18. Jupiter's north and south polar aurorae with IUE data

    International Nuclear Information System (INIS)

    Observations of Jupiter's auroral H2 emissions with the IUE spacecraft, from 1978 through 1990, show the aurorae at the two poles are similar in several respects: (a) emission intensity is modulated with magnetic longitude, north peak emission at λIII (1965) ∼ 200 degree, south peak at λIII (1965) ∼ 20 degree; (b) emission intensity and degree of modulation are comparable for both poles; (c) attenuation by hydrocarbons varies in phase with the intensity, peak attenuation coinciding approximately with peak emission. Increases in the hydrocarbon column are an indicator of either enhanced penetration depth and thus energy of the auroral primaries, or of increases in the high-altitude hydrocarbon content caused by modification of the local atmosphere

  19. The Aurora kinase inhibitors in cancer research and therapy.

    Science.gov (United States)

    Cicenas, Jonas

    2016-09-01

    Compounds that affect enzymatic function of kinases are valuable for the understanding of the complex biochemical processes in cells. Aurora kinases (AURKs) play a key role in the control of the mitosis. These kinases are frequently deregulated in different human cancers: overexpression, amplifications, translocations and deletions were reported in many cancer cell lines as well as patient tissues. These findings steered a rigorous hunt for small-molecule AURK inhibitors not only for research purposes as well as for therapeutic uses. In this review, we describe a number of AURK inhibitors and their use in cancer research and/or therapy. We hope to assist researchers and clinicians in deciding which inhibitor is most appropriate for their specific purpose. The review will also provide a broad overview of the clinical studies performed with some of these inhibitors (if such studies have been performed). PMID:26932147

  20. Field-aligned electron flux oscillations that produce flickering aurora

    International Nuclear Information System (INIS)

    Measurements of energetic electrons that produce flickering aurora were made by a pair of sounding rockets launched during a slowly evolving auroral breakup. Both payloads passed through a broad inverted-V structure. A component of the electron distribution function was closely aligned with the magnetic field over a broad energy range that extended form low energies up to the inverted-V differential energy flux peak. High time resolution measurements of the field-aligned component showed the presence of order to magnitude coherent flux oscillations. Source altitudes between 4,000 and 8,000 km were derived from velocity dispersion of the flux oscillations. A ground-based TV camera recorded visual flickering in the vicinity of the payloads' auroral footprints during periods when flux oscillations were present. Measurements are compared with previous observations of electron flux oscillations, and possible sources for the field-aligned component are discussed

  1. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  2. New contributions for the assessment of intelligence : the Aurora Battery

    OpenAIRE

    Salgado, Ana Manuela Faria

    2014-01-01

    Dissertação de mestrado integrado em Psicologia A avaliação da inteligência representa um dos domínios mais divulgados e controversos da Psicologia. Em resposta às críticas aos testes clássicos de inteligência emergiu a Bateria Aurora, destinada a crianças na faixa etária dos 9-12 anos e enquadrada na Teoria Triárquica de Robert Sternberg. Esta bateria visa o diagnóstico da sobredotação através da avaliação da inteligência prática, analítica e criativa, apresentando itens figur...

  3. Forecasting auroras from regional and global magnetic field measurements

    Science.gov (United States)

    Kauristie, Kirsti; Myllys, Minna; Partamies, Noora; Viljanen, Ari; Peitso, Pyry; Juusola, Liisa; Ahmadzai, Shabana; Singh, Vikramjit; Keil, Ralf; Martinez, Unai; Luginin, Alexej; Glover, Alexi; Navarro, Vicente; Raita, Tero

    2016-06-01

    We use the connection between auroral sightings and rapid geomagnetic field variations in a concept for a Regional Auroral Forecast (RAF) service. The service is based on statistical relationships between near-real-time alerts issued by the NOAA Space Weather Prediction Center and magnetic time derivative (dB/dt) values measured by five MIRACLE magnetometer stations located in Finland at auroral and sub-auroral latitudes. Our database contains NOAA alerts and dB/dt observations from the years 2002-2012. These data are used to create a set of conditional probabilities, which tell the service user when the probability of seeing auroras exceeds the average conditions in Fennoscandia during the coming 0-12 h. Favourable conditions for auroral displays are associated with ground magnetic field time derivative values (dB/dt) exceeding certain latitude-dependent threshold values. Our statistical analyses reveal that the probabilities of recording dB/dt exceeding the thresholds stay below 50 % after NOAA alerts on X-ray bursts or on energetic particle flux enhancements. Therefore, those alerts are not very useful for auroral forecasts if we want to keep the number of false alarms low. However, NOAA alerts on global geomagnetic storms (characterized with Kp values > 4) enable probability estimates of > 50 % with lead times of 3-12 h. RAF forecasts thus rely heavily on the well-known fact that bright auroras appear during geomagnetic storms. The additional new piece of information which RAF brings to the previous picture is the knowledge on typical storm durations at different latitudes. For example, the service users south of the Arctic Circle will learn that after a NOAA ALTK06 issuance in night, auroral spotting should be done within 12 h after the alert, while at higher latitudes conditions can remain favourable during the next night.

  4. Realidad, mito y deseo. La mirada grecolatina de Aurora Luque

    Directory of Open Access Journals (Sweden)

    Virtanen, Ricardo

    2011-08-01

    Full Text Available Aurora Luque’s poetry is one of the most representative of contemporary poetry, located within a Greek culturalism, where myth and reality blend into everyday life. Luque’s poetry is characterized by irony, nonchalance, frivolity and dedramatization. The article presents a series of poems where one can find a demystification of the classical element. A poetry stressed by some topoi such as carpe diem or Catullus’ odio et amo, which have been always represented from a light-hearted glance ruled by the spirit of Eros. The article also emphasizes the play on intertextuality –following Catullus– as well as the epicurean inclination/spirit/passion of the autor.

    La poesía de Aurora Luque representa una de las poéticas más representativas de nuestra contemporaneidad, ubicada dentro de un culturalismo grecista, donde mito y realidad se conjugan dentro de la cotidianidad. La poesía de Luque se caracteriza por su ironía, desenfado, frivolidad y desdramatización. El artículo presenta una serie de poemas donde se produce una desmitificación del elemento clásico. Una poesía marcada por algunos topoi como el carpe diem o el odio et amo catuliano, siempre representados desde una mirada desenfada y dominada por el espíritu del Eros. El artículo destaca además el juego de intertextualidad –en seguimiento de Catulo– así como la vocación epicúrea de la autora.

  5. From the Hubble Space Telescope to Juno, unraveling the secrets of Jupiter's UV aurorae

    OpenAIRE

    Bonfond, Bertrand

    2015-01-01

    The successive generations of instruments on board the Hubble Space Telescope (HST) have revealed an increasing amount of details concerning the aurorae of Jupiter. Among the most striking results is the finding that these aurorae are actually made of a multitude of components arising from a variety of processes, ranging from the local interaction of the Jovian moons with the magnetospheric plasma to solar-wind induced compression of the whole magnetosphere. In this presentation, I will revie...

  6. The aurora sign in a patient with type B Niemann-Pick disease

    International Nuclear Information System (INIS)

    The aurora sign, a sonographic sign found on the sagittal and transverse view, refers to multiple bands of ring-down artifacts posterior to the right hemidiaphragm. Parenchymal lung disease should be suspected when this is present. We report a case of type B Niemann-Pick disease with pulmonary involvement and the aurora sign on abdominal sonography. High-resolution CT of the chest showed corresponding thickened interlobular septa. (orig.)

  7. The aurora sign in a patient with type B Niemann-Pick disease

    Energy Technology Data Exchange (ETDEWEB)

    Costa e. Silva, Eduardo J. da [Instituto Materno Infantil Professor Fernando Figueira, Departamento de Radiologia, Recife, Pernambuco (Brazil); IMIP, Departamento de Radiologia-Rua dos Coelhos, Recife, PE (Brazil); Cavalcanti de Albuquerque, Silvio; Queiroz Praxedes, Eduardo L. de; Amaral, Fernando J. do [Instituto Materno Infantil Professor Fernando Figueira, Departamento de Radiologia, Recife, Pernambuco (Brazil)

    2007-01-15

    The aurora sign, a sonographic sign found on the sagittal and transverse view, refers to multiple bands of ring-down artifacts posterior to the right hemidiaphragm. Parenchymal lung disease should be suspected when this is present. We report a case of type B Niemann-Pick disease with pulmonary involvement and the aurora sign on abdominal sonography. High-resolution CT of the chest showed corresponding thickened interlobular septa. (orig.)

  8. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

    OpenAIRE

    En-Ju Chou; Liang-Yi Hung; Chieh-Ju C. Tang; Wen-Bin Hsu; Hsin-Yi Wu; Pao-Chi Liao; Tang K. Tang

    2016-01-01

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. In...

  9. A Market Analysis for PVD Coating System of Aurora North America

    OpenAIRE

    Chen, Wen-Hao Arthur

    2012-01-01

    Aurora North America, a venture founded by Dr. Da-Yung Wang, endeavours to offer its coating products while providing low-cost, quality solutions to North American manufacturers who apply thin-films to their goods. The objective of this proposed research is to provide a comprehensive analysis of the market opportunities for Aurora. This paper seeks to identify markets that have yet to fully adopt Physical Vapor Deposition (PVD) technology, as well as their potential customers. Market trend of...

  10. Mechanism of action and therapeutic efficacy of Aurora kinase B inhibition in MYC overexpressing medulloblastoma

    OpenAIRE

    Diaz, Roberto Jose; Golbourn, Brian; Faria, Claudia; Picard, Daniel; Shih, David; Raynaud, Denis; Leadly, Michael; MacKenzie, Danielle; Bryant, Melissa; Bebenek, Matthew; Smith, Christian A.; Taylor, Michael D.; Huang, Annie; Rutka, James T.

    2014-01-01

    Medulloblastoma comprises four molecular subgroups of which Group 3 medulloblastoma is characterized by MYC amplification and MYC overexpression. Lymphoma cells expressing high levels of MYC are susceptible to apoptosis following treatment with inhibitors of mitosis. One of the key regulatory kinases involved in multiple stages of mitosis is Aurora kinase B. We hypothesized that medulloblastoma cells that overexpress MYC would be uniquely sensitized to the apoptotic effects of Aurora B inhibi...

  11. Atmospheric response in aurora experiment: Observations of E and F region neutral winds in a region of postmidnight diffuse aurora

    Science.gov (United States)

    Larsen, M. F.; Marshall, T. R.; Mikkelsen, I. S.; Emery, B. A.; Christensen, A.; Kayser, D.; Hecht, J.; Lyons, L.; Walterscheid, R.

    1995-01-01

    The goal of the Atmospheric Response in Aurora (ARIA) experiment carried out at Poker Flat, Alaska, on March 3, 1992, was to determine the response of the neutral atmosphere to the long-lived, large-scale forcing that is characteristic of the diffuse aurora in the post midnight sector. A combination of chemical release rocket wind measurements, instrumented rocket composition measurements, and ground-based optical measurements were used to characterize the response of the neutral atmosphere. The rocket measurements were made at the end of a 90-min period of strong Joule heating. We focus on the neutral wind measurements made with the rocket. The forcing was determined by running the assimilated mapping of ionospheric electrodynamics (AMIE) analysis procedure developed at the National Center for Atmospheric Research. The winds expected at the latitude and longitude of the experiment were calculated using the spectral thermospheric general circulation model developed at the Danish Meteorological Institute. Comparisons of the observations and the model suggest that the neutral winds responded strongly in two height ranges. An eastward wind perturbation of approximately 100 m/s developed between 140 and 200 km altitude with a peak near 160 km. A southwestward wind with peak magnitude of approximately 150 m/s developed near 115 km altitude. The large amplitude winds at the lower altitude are particularly surprising. They appear to be associated with the upward propagating semidiurnal tide. However, the amplitude is much larger than predicted by any of the tidal models, and the shear found just below the peak in the winds was nominally unstable with a Richardson number of approximately 0.08.

  12. A SUMOylation Motif in Aurora-A: Implications in Spindle Dynamics and Oncogenesis

    Directory of Open Access Journals (Sweden)

    MarcosMalumbres

    2011-12-01

    Full Text Available Aurora-A is a serine/threonine kinase that plays critical roles in centrosome maturation, spindle dynamics and chromosome orientation and is frequently found overexpressed in human cancers. In this work, we show that Aurora-A interacts with the SUMO conjugating enzyme UBC9 and co-localizes with SUMO-1 in mitotic cells. Aurora-A can be SUMOylated in vitro and mutation in the highly conserved SUMOylation residue lysine 249 results in the induction of mitotic defects characterized by defective and multipolar spindles. The Aurora-AK249R mutant has normal kinase activity but it displays altered dynamics at the mitotic spindle. In addition, ectopic expression of the Aurora-AK249R mutant results in a significant increase in the susceptibility to malignant transformation induced by the Ras oncogene and an increased protection against apoptosis in tumor cells treated with mitotic poisons. These data suggest that modification by SUMO residues may control Aurora-A function at the spindle and suggest that deficient SUMOylation of this kinase may have relevant implications in tumor development or cancer therapy.

  13. East Asian Observations of Low Latitude Aurora during the Carrington Magnetic Storm

    CERN Document Server

    Hayakawa, Hisashi; Tamazawa, Harufumi; Isobe, Hiroaki; Kataoka, Ryuho; Ebihara, Yusuke; Miyahara, Hiroko; Kawamura, Akito Davis; Shibata, Kazunari

    2016-01-01

    The magnetic storm around 1859 September 2, caused by so-called Carrington flare, was the most intense in the history of modern scientific observations, and hence is considered to be the benchmark event for space weather. The magnetic storm caused worldwide observations of auroras even at very low latitudes such as Hawaii, Panama, or Santiago, and the available magnetic field measurement at Bombay, India, showed two peaks: the main was the Carrington event which occurred in day time in East Asia, and a second storm after the Carrington event which occurred at night in East Asia. In this paper, we present a result from surveys of aurora records in East Asia, which provides new information of the aurora activity of this important event. We found some new East Asian records of low latitude aurora observations caused by the storm which occurred after the Carrington event. The size of the aurora belt of the second peak of the Carrington magnetic storm was even wider than usual low-latitude aurora events.

  14. Comparative Spectroscopic Temperature Measurements In Hydrogen Hollow Cathode Glow Discharge

    Science.gov (United States)

    Majstorovic, G. Lj.; Šišovic, N. M.; Konjevic, N.

    2010-07-01

    We report results of optical emission spectroscopy measurements of rotational Trot and translational temperature Ttr of hydrogen molecules. The light source was hollow cathode glow discharge with titanium cathode operated in hydrogen at low pressure. The rotational temperature of excited electronic states of H2 was determined either from relative line intensities of the R branch of the GK ? B band or from the Q branch of the Fulcher-a diagonal band. The population of excited energy levels, determined from relative line intensities, was used to derive ro-vibronic temperature of the ground state of hydrogen molecule.

  15. Profiles of Methane Dimerization with a Glow Discharge Plasma System

    OpenAIRE

    Tanabe, Shuji; Okitsu, Kenji; Matsumoto, Hiroshige

    1999-01-01

    The dimerization of methane in the absence of oxygen has been investigated in order to evaluate a newly-developed glow-discharge plasma reactor operated at atmospheric pressure. A homogeneous circular plasma zone is observed between two electrodes of a rotor and a stator, the former of which is rotating at a high speed to make a larger reaction zone. It was recognized that in a stream of flowing helium that methane is converted to C 2 hydrocarbons at high selectivities which decreased with th...

  16. Glow discharge lamp: A light source for optical emission spectroscopy

    Science.gov (United States)

    Vishwanathan, K. S.; Srinivasan, V.; Nalini, S.; Mahalingam, T. R.

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emission spectrography by standardizing a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii, and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent.

  17. Glow discharge lamp: a light source for optical emission spectroscopy

    International Nuclear Information System (INIS)

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emmission spectrography by standardising a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent. (author). 19 re fs., 13 figs., 2 tabs

  18. Glow discharge assisted oxynitriding process of titanium for medical application

    Science.gov (United States)

    Wierzchoń, Tadeusz; Czarnowska, Elżbieta; Grzonka, Justyna; Sowińska, Agnieszka; Tarnowski, Michał; Kamiński, Janusz; Kulikowski, Krzysztof; Borowski, Tomasz; Kurzydłowski, Krzysztof J.

    2015-04-01

    The plasma oxynitriding process is a prospective method of producing titanium oxides as an integral part of a diffusive nitrided surface layer on titanium implants. This hybrid process, which combines glow discharge assisted nitriding and oxidizing, permits producing TiO2 + Ti2N + αTi(N)-type diffusive surface layers. The oxynitrided surface layers improve the corrosion and wear resistance of the substrate material. Additionally, the nanocrystalline titanium oxide TiO2 (rutile) improves the biological properties of titanium and its alloys when in contact with blood, whereas the TiN + Ti2N + αTi(N) zone eliminates the effect of metalosis.

  19. Reproducing continuous radio blackout using glow discharge plasma

    International Nuclear Information System (INIS)

    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 109 to 2.5 × 1011 cm−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

  20. Dual-frequency glow discharges in atmospheric helium

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojiang; Guo, Ying [College of Science, Donghua University, Shanghai 201620 (China); Magnetic Confinement Fusion Research Center, Ministry of Education of the People' s Republic of China, Shanghai 201620 (China); Dai, Lu [School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Zhang, Jing; Shi, J. J., E-mail: JShi@dhu.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); Magnetic Confinement Fusion Research Center, Ministry of Education of the People' s Republic of China, Shanghai 201620 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2015-10-15

    In this paper, the dual-frequency (DF) glow discharges in atmospheric helium were experimented by electrical and optical measurements in terms of current voltage characteristics and optical emission intensity. It is shown that the waveforms of applied voltages or discharge currents are the results of low frequency (LF) waveforms added to high frequency (HF) waveforms. The HF mainly influences discharge currents, and the LF mainly influences applied voltages. The gas temperatures of DF discharges are mainly affected by HF power rather than LF power.

  1. Dual-frequency glow discharges in atmospheric helium

    International Nuclear Information System (INIS)

    In this paper, the dual-frequency (DF) glow discharges in atmospheric helium were experimented by electrical and optical measurements in terms of current voltage characteristics and optical emission intensity. It is shown that the waveforms of applied voltages or discharge currents are the results of low frequency (LF) waveforms added to high frequency (HF) waveforms. The HF mainly influences discharge currents, and the LF mainly influences applied voltages. The gas temperatures of DF discharges are mainly affected by HF power rather than LF power

  2. miR-137 suppresses tumor growth of malignant melanoma by targeting aurora kinase A.

    Science.gov (United States)

    Chang, Xiao; Zhang, Haiping; Lian, Shi; Zhu, Wei

    2016-07-01

    As an oncogene, aurora kinase A (AURKA) is overexpressed in various types of human cancers. However, the expression and roles of AURKA in malignant melanoma are largely unknown. In this study, a miR-137-AURKA axis was revealed to regulate melanoma growth. We found a significant increase in levels of AURKA in melanoma. Both genetic knockdown and pharmacologic inhibition of AURKA decreased tumor cell growth in vitro and in vivo. Further found that miR-137 reduced AURKA expression through interaction with its 3' untranslated region (3'UTR) and that miR-137 was negatively correlated with AURKA expression in melanoma specimens. Overexpression of miR-137 decreased cell proliferation and colony formation in vitro. Notably, re-expression of AURKA significantly rescued miR-137-mediated suppression of cell growth and clonality. In summary, these results reveal that miR-137 functions as a tumor suppressor by targeting AURKA, providing new insights into investigation of therapeutic strategies against malignant melanoma. PMID:27233613

  3. A review on chemical effects in aqueous solution induced by plasma with glow discharge

    International Nuclear Information System (INIS)

    Chemical effects in different aqueous solutions induced by plasma with glow discharge electrolysis (GDE) and contact glow discharge electrolysis (CGDE) are described. The experimental and discharge characteristics are also reviewed. These are followed by a discussion of their mechanisms of both anodic and cathodic CGDE

  4. Simulation of the influence of thermal quenching on thermoluminescence glow-peaks

    Energy Technology Data Exchange (ETDEWEB)

    Subedi, B.; Kitis, G. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Pagonis, V. [Physics Department, McDaniel College, Westminster, MD 21157 (United States)

    2010-05-15

    The thermal quenching of luminescence efficiency is an effect which is present in many thermoluminescent (TL) materials. It causes a significant decrease of the luminescence signal and disturbs the shape of the glow-peaks. Therefore, in principle, the thermoluminescence kinetics theory cannot describe TL glow-peaks influenced by thermal quenching. In the present work a detailed simulation of the influence of the thermal quenching effect on thermoluminescence glow-peaks is presented. Specifically we study the shift of the quenched glow-peak with heating rate and the effect on the various heating rate methods, the influence on the symmetry factor and the kinetic order of the glow-peak, and the effect of thermal quenching on the initial rise and peak shape methods for evaluating kinetic parameters. Furthermore, the evaluation of the thermal quenching parameters using the quenched glow-peak and the possibility of using the conventional expression describing a single glow-peak to fit the quenched glow peaks are also investigated. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  5. Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J. M.; Delgado, A.

    1989-07-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

  6. Multiple solutions in the theory of dc glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2010-04-15

    Multiple steady-state solutions existing in the theory of dc glow discharges are computed for the first time. The simulations are performed in 2D in the framework of the simplest self-consistent model, which accounts for a single ion species and employs the drift-diffusion approximation. Solutions describing up to nine different modes were found in the case where losses of the ions and the electrons due to diffusion to the wall were neglected. One mode is 1D, exists at all values of the discharge current, and represents in essence the well-known solution of von Engel and Steenbeck. The other eight modes are axially symmetric, exist in limited ranges of the discharge current, and are associated with different patterns of current spots on the cathode. The mode with a spot at the centre of the cathode exhibits a well pronounced effect of normal current density. Account of diffusion losses affects the solutions dramatically: the number of solutions is reduced, a mode appears that exists at all discharge currents and comprises the Townsend, subnormal, normal and abnormal discharges. The solutions that exist in limited current ranges describe patterns, and these patterns seem to represent axially symmetric analogues of the 3D patterns observed in dc glow microdischarges in xenon.

  7. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; HE Zhi-yong; ZHANG Gao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%.Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  8. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANGPing-ze; XUZhong; HEZhi-yong; ZHANGGao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%. Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  9. A statistical study of dayside diffuse aurora observed at Yellow River Station in Ny-Ålesund, Svalbard

    Science.gov (United States)

    Han, D.; Hu, Z.; Hu, H.; Yang, H.; Huang, D. H.; Chen, X.

    2014-12-01

    Chinese Yellow River Station (YRS), at Ny-Alesund, Svalbard is one of the few stations that can make longtime optical auroral observation at the cusp latitude in the dayside during the boreal winter season on the Earth. Since November 2003, an optical observation system consisting of three identical all-sky imagers supplied with the narrow band filters centered at 427.8, 557.5 and 630.0nm, has been installed at YRS, and the continuous observations providing us with an unprecedented opportunity to investigate some new properties of dayside aurora. Optical diffuse auroras are normally observed at the sub-aurora latitude in nightside on the ground. However, by using 7-year continuous observations obtained at YRS, we found that the diffuse auroras are very frequently observed on the dayside at the high latitude, i.e., near the cusp. We classified the dayside diffuse aurora into four primary categories. They are (1) Veiling Diffuse Aurora, which has no obvious morphological structure and clear boundaries, sometimes likes a thick cloud cover the entire sky, (2) Patch Diffuse Aurora, which is an aurora patch normally in ~10-100km in width and usually owns pulsating property; (3) Diffuse Arcs, which looks like an arc but is apparently different from the discrete auroral arcs in morphology, and (4) Pulsating Aurora, occurring with sparkling forms. We statistical studied how the occurrence of the four types of dayside diffuse auroras depends on the local time, magnetic activity, and solar wind conditions. We found that the occurrence of each type of dayside diffuse aurora shows a unimodal distribution with magnetic local time and their peaks are mostly appeared near the magnetic local noon. We also noted that ~92.2% of the dayside diffuse auroras is observed under low magnetic activity, i.e., Kp ≤ 3, and the dayside diffuse auroras prefer to be observed under IMF By0. Although previous studies suggested that the dayside diffuse aurora should be caused by wave scattering of

  10. Glow curve analysis of composite peak 5 in LiF:Mg,Ti (TLD-100) using optical bleaching, thermal annealing and computerised glow curve deconvolution

    International Nuclear Information System (INIS)

    The relative intensity of glow peak 5a in the composite glow peak 5 of LiF:Mg,Ti (TLD-100) is very weak following gamma irradiation, and has been estimated at approximately 0.1 of the intensity of peak 5. Typical glow curve analysis using computerised glow curve deconvolution with unconstrained variation of the peak shape parameters, yields values of the relative intensity of glow peak 5a varying from 0 to 15%. Due to the potential of peak 5a to fulfil the criteria of a quasi-tissue-equivalent nanodosemeter which estimates quality factor, considerable efforts have been invested in ancillary techniques to improve the reliability of the estimation of the intensity of peak 5a. Optical bleaching and thermal annealing techniques were used to obtain single-peak glow curves consisting of peak 4 only and peak 5 only. A multi-stage CGCD protocol was then constructed using these peak shape parameters for peaks 4 and 5, which allows more accurate estimation of the relative intensity of peak 5a. Following 60Co irradiation of ten chips to a dose level of 1 Gy, the technique yields a relative intensity of 0.08±0.008 (1 SD). (author)

  11. Characteristics of north jovian aurora from STIS FUV spectral images

    Science.gov (United States)

    Gustin, J.; Grodent, D.; Ray, L. C.; Bonfond, B.; Bunce, E. J.; Nichols, J. D.; Ozak, N.

    2016-04-01

    We analyzed two observations obtained in Jan. 2013, consisting of spatial scans of the jovian north ultraviolet aurora with the HST Space Telescope Imaging Spectrograph (STIS) in the spectroscopic mode. The color ratio (CR) method, which relates the wavelength-dependent absorption of the FUV spectra to the mean energy of the precipitating electrons, allowed us to determine important characteristics of the entire auroral region. The results show that the spatial distribution of the precipitating electron energy is far from uniform. The morning main emission arc is associated with mean energies of around 265 keV, the afternoon main emission (kink region) has energies near 105 keV, while the 'flare' emissions poleward of the main oval are characterized by electrons in the 50-85 keV range. A small scale structure observed in the discontinuity region is related to electrons of 232 keV and the Ganymede footprint shows energies of 157 keV. Interestingly, each specific region shows very similar behavior for the two separate observations. The Io footprint shows a weak but undeniable hydrocarbon absorption, which is not consistent with altitudes of the Io emission profiles (∼900 km relative to the 1 bar level) determined from HST-ACS observations. An upward shift of the hydrocarbon homopause of at least 100 km is required to reconcile the high altitude of the emission and hydrocarbon absorption. The relationship between the energy fluxes and the electron energies has been compared to curves obtained from Knight's theory of field-aligned currents. Assuming a fixed electron temperature of 2.5 keV, an electron source population density of ∼800 m-3 and ∼2400 m-3 is obtained for the morning main emission and kink regions, respectively. Magnetospheric electron densities are lowered for the morning main emission (∼600 m-3) if the relativistic version of Knight's theory is applied. Lyman and Werner H2 emission profiles, resulting from secondary electrons produced by

  12. AURORA BOREALIS: a polar-dedicated European Research Platform

    Science.gov (United States)

    Wolff-Boenisch, Bonnie; Egerton, Paul; Thiede, Joern; Roberto, Azzolini; Lembke-Jene, Lester

    2010-05-01

    Polar research and in particular the properties of northern and southern high latitude oceans are currently a subject of intense scientific debate and investigations, because they are subject to rapid and dramatic climatic variations. Polar regions react more rapidly and intensively to global change than other regions of the earth. A shrinking of the Arctic sea-ice cover, potentially leading to an opening of sea passages to the north of North America and Eurasia, on the long to a "blue" Arctic Ocean would additionally have a strong impact on transport, commerce and tourism bearing potential risk for humans and complex ecosystems in the future. In spite of their critical role processes and feedbacks, especially in winter but not exclusively, are virtually unknown: The Arctic Ocean for example, it is the only basin of the world's oceans that has essentially not been sampled by the drill ships of the Deep-Sea Drilling Project (DSDP) or the Ocean Drilling Program (ODP) and its long-term environmental history and tectonic structure is therefore poorly known. Exceptions are the ODP Leg 151 and the more recent very successful ACEX-expedition of the Integrated Ocean Drilling Program (IODP) in 2004. To help to address the most pressing questions regarding climate change and related processes, a Pan-European initiative in the field of Earth system science has been put in place: AURORA BOREALIS is the largest environmental research infrastructure on the ESFRI roadmap of the European Community. AURORA BOREALIS is a very powerful research icebreaker, which will enable year-round operations in the Arctic and the Antarctic as well as in the adjacent ocean basins. Equipped with its drilling rig, the vessel is also capable to explore the presently completely unknown Arctic deep-sea floor. Last but not least, the ship is a floating observatory and mobile monitoring platform that permits to measure on a long-term basis comprehensive time series in all research fields relevant to

  13. GCAFIT-A new tool for glow curve analysis in thermoluminescence nanodosimetry

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2011-05-01

    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

  15. Evolution of resistance to Aurora kinase B inhibitors in leukaemia cells.

    Directory of Open Access Journals (Sweden)

    Timothy W Failes

    Full Text Available Aurora kinase inhibitors are new mitosis-targeting drugs currently in clinical trials for the treatment of haematological and solid malignancies. However, knowledge of the molecular factors that influence sensitivity and resistance remains limited. Herein, we developed and characterised an in vitro leukaemia model of resistance to the Aurora B inhibitor ZM447439. Human T-cell acute lymphoblastic leukaemia cells, CCRF-CEM, were selected for resistance in 4 µM ZM447439. CEM/AKB4 cells showed no cross-resistance to tubulin-targeted and DNA-damaging agents, but were hypersensitive to an Aurora kinase A inhibitor. Sequencing revealed a mutation in the Aurora B kinase domain corresponding to a G160E amino acid substitution. Molecular modelling of drug binding in Aurora B containing this mutation suggested that resistance is mediated by the glutamate substitution preventing formation of an active drug-binding motif. Progression of resistance in the more highly selected CEM/AKB8 and CEM/AKB16 cells, derived sequentially from CEM/AKB4 in 8 and 16 µM ZM447439 respectively, was mediated by additional defects. These defects were independent of Aurora B and multi-drug resistance pathways and are associated with reduced apoptosis mostly likely due to reduced inhibition of the catalytic activity of aurora kinase B in the presence of drug. Our findings are important in the context of the use of these new targeted agents in treatment regimes against leukaemia and suggest resistance to therapy may arise through multiple independent mechanisms.

  16. HST/STIS Ultraviolet Imaging of Polar Aurora on Ganymede

    CERN Document Server

    Feldman, P D; Strobel, D F; Moos, H W; Retherford, K D; Wolven, B C; Feldman, Paul D.; Grath, Melissa A. Mc; Strobel, Darrell F.; Retherford, Kurt D.; Wolven, Brian C.

    2000-01-01

    We report new observations of the spectrum of Ganymede in the spectral range 1160 - 1720 A made with the Space Telescope Imaging Spectrograph (STIS) on HST on 1998 October 30. The observations were undertaken to locate the regions of the atomic oxygen emissions at 1304 and 1356 A, previously observed with the GHRS on HST, that Hall et al. (1998) claimed indicated the presence of polar aurorae on Ganymede. The use of the 2" wide STIS slit, slightly wider than the disk diameter of Ganymede, produced objective spectra with images of the two oxygen emissions clearly separated. The OI emissions appear in both hemispheres, at latitudes above 40 degrees, in accordance with recent Galileo magnetometer data that indicate the presence of an intrinsic magnetic field such that Jovian magnetic field lines are linked to the surface of Ganymede only at high latitudes. Both the brightness and relative north-south intensity of the emissions varied considerably over the four contiguous orbits (5.5 hours) of observation, presum...

  17. Spatial scaling of optical fluctuations during substorm-time aurora

    Directory of Open Access Journals (Sweden)

    B. V. Kozelov

    2007-05-01

    Full Text Available A study of statistical features of auroras during substorm activity is presented, emphasizing characteristics which are commonly applied to turbulent flows. Data from all-sky television (TV observations from the Barentsburg observatory (Svalbard have been used. Features of the probability density function (PDF of auroral fluctuations have been examined at different spatial scales. We find that the observed PDFs generally have a non-Gaussian, heavy-tailed shape. The generalized structure function (GSF for the auroral luminosity fluctuations has been analyzed to determine the scaling properties of the higher (up to 6 order moments, and the evolution of the scaling indices during the actual substorm event has been determined. The scaling features obtained can be interpreted as signatures of turbulent motion of the magnetosphere-ionosphere plasma. Relations to previously obtained results of avalanche analysis of the same event, as well as possible implications for the validity of self-organized criticality models and turbulence models of the substorm activity, are discussed.

  18. Ezekiel and the Northern Lights: Biblical aurora seems plausible

    Science.gov (United States)

    Siscoe, George L.; Silverman, Samuel M.; Siebert, Keith D.

    Auroral specialists have suggested that in the Bible's Old Testament book of Ezekiel, the opening vision of a "storm cloud out of the north" depicts imagery inspired by a low-latitude auroral display [Link, 1967; Eather, 1980; Silverman, 1998]. Naturally, other interpretations have been suggested, including a true epiphany, a sandstorm, a thunderstorm, a tornado, a solar halo, a hallucination, and a UFO. Biblical scholars place the site of the Ezekiel's vision about 100 km south of Babylon near Nippur, latitude ˜32°, longitude ˜45°, and the date is within a year or two of 593 B.C., or about 2600 years ago.An auroral interpretation of the vision is subject to possible refutation due to several geophysical considerations. Can auroras be seen at Ezekiel's latitude? More important, can they reach a coronal stage of development, which is what the vision requires? Was the tilt of the dipole axis favorable? Was the general level of solar activity favorable? And finally, What effect does a larger dipole moment in Ezekiel's time have on the question? All but the last question could have been answered on the basis of geophysical data a decade ago or earlier.

  19. Aurora 7 the Mercury space flight of M. Scott Carpenter

    CERN Document Server

    Burgess, Colin

    2016-01-01

    TO A NATION enthralled by the heroic exploits of the Mercury astronauts, the launch of Lt. Cmdr. Scott Carpenter on NASA’s second orbital space flight was a renewed cause for pride, jubilation and celebration. Within hours, that excitement had given way to stunned disbelief and anxiety as shaken broadcasters began preparing the American public for the very real possibility that an American astronaut and his spacecraft may have been lost at sea. In fact, it had been a very close call. Completely out of fuel and forced to manually guide Aurora 7 through the frightening inferno of re-entry, Carpenter brought the Mercury spacecraft down to a safe splashdown in the ocean. In doing so, he controversially overshot the intended landing zone. Despite his efforts, Carpenter’s performance on the MA-7 mission was later derided by powerful figures within NASA. He would never fly into space again. Taking temporary leave of NASA, Carpenter participated in the U.S. Navy’s pioneering Sealab program. For a record 30 days...

  20. Aurora Candidates from the Chronicle of Q\\={i}ng Dynasty in Several Degrees of Relevance

    CERN Document Server

    Kawamura, Akito D; Tamazawa, Harufumi; Miyahara, Hiroko; Isobe, Hiroaki

    2016-01-01

    We present the result of the survey of sunspots and auroras in ${\\it Q\\bar{\\imath}ngsh\\check{\\imath}ga\\check{o}}$, the draft chronicle of ${\\it Q\\bar{\\imath}ng}$ dynasty, for the period of 1559-1912 CE, as a sequel of the series of works surveying historical sunspot and aurora records, and providing online data to the scientific community regarding the attained results. In total of this ${\\it Q\\bar{\\imath}ngsh\\check{\\imath}ga\\check{o}}$ survey, we found 111 records of night-sky luminous events with the keywords such as vapor (${\\it q\\grave{\\imath}}$), cloud (${\\it y\\acute{u}n}$), and light (${\\it gu\\bar{a}ng}$), which may indicate auroras as well as some other phenomena. Similarly keyword survey for sunspots were done, but no sunspot record was found. In comparison with the aurora records in the western world, we found 14 of the 111 records have a corresponding record of simultaneous observation in the western world and hence are very likely to be aurora. In order to investigate the likeliness of the rest of ...

  1. A simulation study of the current-voltage relationship of the Io tail aurora

    Science.gov (United States)

    Matsuda, K.; Terada, N.; Katoh, Y.; Misawa, H.

    2012-10-01

    The Io tail aurora extends for approximately 100 degrees downstream in longitude from the Io footprint aurora. Observations indicate that the brightness of the Io tail aurora continuously decreases along the footpath while its peak altitude remains constant. According to the quasi-steady theoretical frame, this suggests that the field-aligned voltage is constant while the parallel current density decreases in the downstream direction. The mechanism that realizes the current-voltage relationship of the Io tail aurora remains unresolved. In this paper, we apply a new multimagnetofluid code to the Io-Jupiter system to clarify the origin of the current-voltage relationship. The code solves a set of equations that includes the electron convection term in Ohm's law, which enables us to simulate the current-driven ion acoustic instability in the fluid frame. The instability forms a transition layer at a high altitude, which accelerates the magnetospheric electrons and blocks the magnetospheric ions, leading to the formation of a density depleted region called an auroral cavity. We find that if the ionospheric proton density decreases at the same rate as the parallel current density, the timescale on which the transition layer disappears is consistent with the longitudinal extent of the tail aurora, and the potential gap is constant all along the tail. We discuss the possibility that the fringe, wideband repetitive bursts of the Io-related Jovian decametric radiation, is excited in the auroral cavity.

  2. Syncrude's Aurora Mine : the key to future Athabasca oil sands development

    International Nuclear Information System (INIS)

    Syncrude's newest mine, the Aurora mine is located 35 km northeast of Syncrude's existing Mildred Lake plant, across the Athabasca River. It has a potential to produce more than 2.5 billion barrels of bitumen. Aurora will eventually consist of two surface mines, the Aurora North and Aurora South. Mining and extraction will occur at Aurora with the resulting bitumen transported as a froth by pipeline back to the existing plant for upgrading to Syncrude Sweet Blend. A total of 120 km of pipeline will be used. Syncrude has developed a new method of sending oilsand from its Athabasca deposit to the extraction plant. The company plans to phase out the dragline, bucketwheel reclaimer, and conveyor ore mining and delivery system in favour of shovel, truck, and hydrotransport technology. The advantages of hydrotransport include significant energy savings and considerably less plant infrastructure. A hydrotransport prototype is at work at Syncrude's base mine where it is responsible for 15 per cent of the production

  3. Syncrude`s Aurora Mine : the key to future Athabasca oil sands development

    Energy Technology Data Exchange (ETDEWEB)

    Kershaw, D. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    1998-09-01

    Syncrude`s newest mine, the Aurora mine is located 35 km northeast of Syncrude`s existing Mildred Lake plant, across the Athabasca River. It has a potential to produce more than 2.5 billion barrels of bitumen. Aurora will eventually consist of two surface mines, the Aurora North and Aurora South. Mining and extraction will occur at Aurora with the resulting bitumen transported as a froth by pipeline back to the existing plant for upgrading to Syncrude Sweet Blend. A total of 120 km of pipeline will be used. Syncrude has developed a new method of sending oilsand from its Athabasca deposit to the extraction plant. The company plans to phase out the dragline, bucketwheel reclaimer, and conveyor ore mining and delivery system in favour of shovel, truck, and hydrotransport technology. The advantages of hydrotransport include significant energy savings and considerably less plant infrastructure. A hydrotransport prototype is at work at Syncrude`s base mine where it is responsible for 15 per cent of the production.

  4. Intrinsic Noise Induced Coherence Resonance in a Glow discharge Plasma

    CERN Document Server

    Shaw, Pankaj Kumar; Ghosh, S; Janaki, M S; Iyengar, A N S

    2014-01-01

    Experimental evidence of intrinsic noise induced coherence resonance in a glow discharge plasma is being reported. Initially the system is started at a discharge voltage (DV) where it exhibited fixed point dynamics, and then with the subsequent increase in the DV spikes were excited which were few in number and with further increase of DV the number of spikes as well as their regularity increased. The regularity in the interspike interval of the spikes is estimated using normalized variance (NV). Coherence resonance was determined using normalized variance curve and also corroborated by Hurst exponent and power spectrum plots. We show that the regularity of the excitable spikes in the floating potential fluctuation increases with the increase in the DV, upto a particular value of DV. Using a Wiener filter, we separated the noise component which was observed to increase with DV and hence conjectured that noise can be playing an important role in the generation of the coherence resonance. From an anharmonic osc...

  5. Accurate models of collisions in glow discharge simulation

    International Nuclear Information System (INIS)

    Very detailed, self-consistent kinetic glow discharge simulations are used to examine the effect of various models of collisional processes. The effects of allowing anisotropy in elastic electron collisions with neutral atoms instead of using the momentum transfer cross-section, the effects of using an isotropic distribution in inelastic electron-atom collisions, and the effects of including a Coulomb electron-electron collision operator are all described. It is shown that changes in any of the collisional models, especially the second and third described above, can make a profound difference in the simulation results. This confirms that many discharge simulations have great sensitivity to the physical and numerical approximations used. The results reinforce the importance of using a kinetic theory approach with highly realistic models of various collisional processes

  6. High-pressure dc glow discharges in hollow diamond cathodes

    Science.gov (United States)

    Truscott, B. S.; Turner, C.; May, P. W.

    2016-04-01

    We report the generation and characterization of dc helium microdischarges at several times atmospheric pressure in monolithic diamond hollow-cathode devices having cavity diameters on the order of 100 μm. I-V characteristics indicated operation in the glow discharge regime even at nearly 10 atm, while spectroscopic measurements of the N2 C3Πu  →  B3Πg emission returned rotational temperatures always around 420 K, with a pressure-dependent vibrational population distribution. The variation of breakdown voltage with pressure closely followed Paschen’s law, but with offsets in both axes that we tentatively ascribe to strong diffusive loss and a partial thermalization of electron energies under the high pressures considered here.

  7. Measuring Anthropogenic Sky Glow Using a Natural Sky Brightness Model

    Science.gov (United States)

    Duriscoe, Dan M.

    2013-11-01

    Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth's surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.

  8. Efficiency of surface cleaning by a glow discharge for plasma spraying coating

    Science.gov (United States)

    Kadyrmetov, A. M.; Kashapov, N. F.; Sharifullin, S. N.; Saifutdinov, A. I.; Fadeev, S. A.

    2016-06-01

    The article presents the results of experimental studies of the quality of cleaning steel surfaces by a glow discharge for plasma spraying. Shows the results of measurements of the angle of surface wetting and bond strength of the plasma coating to the surface treated. The dependence of the influence of the glow discharge power, chamber pressure, distance between the electrodes and the processing time of the surface on cleaning efficiency. Optimal fields of factors is found. It is shown increase joint strength coating and base by 30-80% as a result of cleaning the substrate surface by a glow discharge plasma spraying.

  9. Note: Rapid reduction of graphene oxide paper by glow discharge plasma

    International Nuclear Information System (INIS)

    This note reports on a novel method for the rapid reduction of graphene oxide (GO) paper using a glow discharge plasma reactor. Glow discharge is produced and sustained between two parallel-plate graphite electrodes at a pressure of 240 mTorr. By exposing GO paper at the junction of negative-glow and Faraday-dark area for 4 min, the oxygen-containing groups can be effectively removed (C/O ratio increases from 2.6 to 7.9), while the material integrality and flexibility are kept well. Electrochemical measurements demonstrate that the as-obtained reduced GO paper can be potentially used for supercapacitor application

  10. Aspects of Metal Surface Glowing Mechanisms with Intensive Electron Beam Bombardment

    Directory of Open Access Journals (Sweden)

    I.V. Barsuk

    2012-06-01

    Full Text Available The paper gives a brief description and analysis of the main physical processes which can have an effect on the glowing nature of metal element surfaces in different electric vacuum devices when they are bombarded by electron beams. It has been found that the electron glowing effects on metal surfaces according to the electron energy can be explained with the help of the transition scattering on plasma waves or just with the classical transition radiation effect. This fact is rather important in terms of classical physics interpretation of the observed glowing effects on metal surface elements and techniques optimization of metal and electron beams diagnostics as well.

  11. Non-local model of hollow cathode and glow discharge - theory calculations and experiment comparison

    OpenAIRE

    Gorin, Vladimir V.

    2009-01-01

    General form of the non-local equation for an ionization source in glow discharge and hollow cathode 3D-simulation is formulated. It is a fundamental equation in a hollow cathode theory, which allows to make up a complete set of field equations for a self-consistent problem in a stationary glow discharge and a hollow cathode. It enables to describe adequately the region of negative glow and the hollow cathode effect. Here you can see first attempts to compare calculation results of electrical...

  12. Thermoluminescence glow curve deconvolution and its statistical analysis using the flexibility of spreadsheet programs

    International Nuclear Information System (INIS)

    Analysing thermoluminescence glow curves involves the solving of a system of non-linear equations. These equations are either differential equations that must be solved numerically or functional approximations for their solution. The current paper presents software with the functions needed for the study of glow curves that is not a stand-alone computer program but an extension of MS Excel. It supplies functions that solve the general one trap model for the thermoluminescence process without the use of approximating functions. Combined with the Solver utility of Excel this gives a very flexible system for the analysis of glow curves. Functions for analysing the statistics of the deconvolution results are included. (authors)

  13. Control of glow discharge parameters using transverse supersonic gas flow - numerical experiment

    International Nuclear Information System (INIS)

    A low pressure glow discharge in a transverse supersonic gas flow was studied by numerical modelling for the case where the flow only partially fills the interelectrode gap. It's shown that by organizing a supersonic gas flow in a limited region of the interelectrode space can be controlled combustion conditions of the glow discharge, and its parameters. It is shown that it is possible to achieve stable combustion glow discharge at low and superlow pressures, when the parameter pL lies on the left branch of the Paschen curve

  14. Note: Rapid reduction of graphene oxide paper by glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Zheng; Qian, Jiajing; Duan, Liangping; Qiu, Kunzan, E-mail: qiukz@zju.edu.cn; Yan, Jianhua; Cen, Kefa [State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Han, Zhao Jun [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Ostrikov, Kostya [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Institute for Future Environments and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia)

    2015-05-15

    This note reports on a novel method for the rapid reduction of graphene oxide (GO) paper using a glow discharge plasma reactor. Glow discharge is produced and sustained between two parallel-plate graphite electrodes at a pressure of 240 mTorr. By exposing GO paper at the junction of negative-glow and Faraday-dark area for 4 min, the oxygen-containing groups can be effectively removed (C/O ratio increases from 2.6 to 7.9), while the material integrality and flexibility are kept well. Electrochemical measurements demonstrate that the as-obtained reduced GO paper can be potentially used for supercapacitor application.

  15. Two Universities and Two Eras of Catholicism in China: Fu Jen University and Aurora University, 1903-1937

    Science.gov (United States)

    Xian, Liu

    2009-01-01

    This paper compares Fu Jen University in Beijing and Aurora University in Shanghai--the two comprehensive Catholic universities located in the two largest cities of China in modern history--and analyzes four aspects: identity, educational idea, curriculum, and campus culture. It was found that the differences between Aurora and Fu Jen resulted…

  16. Signatures in the dayside aurora of plasma transfer from the magnetosheath

    International Nuclear Information System (INIS)

    Continuous ground-based observations of the dayside aurora provide important information, complementary to the in situ measurements from satellites, on plasma transport and electromagnetic coupling between the magnetosheath and the magnetosphere. In this study observations of the polar cusp/dayside oval aurora from Svalbard,Norway, simultaneous observations of the nightside aurora from Poker Flat, Alaska, and the interplanetary magnetic field from satellites, are used to identify the ionospheric signatures of plasma transfer from the solar wind to the magnetosphere. The characteristics of motion, spatial scale, time of duration and repetition frequency of certain dayside auroral forms which occur at the time of large-scale oval expansions (IMF Bsub(z) < 0), are observed to be consistent with the expected optical signatures of plasma transfer through the dayside magnetopause boundary layer, in association with flux transfer events. Similarly, more large-scale (time and space) events are tentatively explained by the quasi steady-state reconnection process

  17. A High Resolution Magnetohydrodynamic Simulation Study of Kronian Field-Aligned Currents and Aurora

    Science.gov (United States)

    Fukazawa, K.; Ogino, T.; Walker, R. J.

    2011-12-01

    Magnetohydrodynamic simulations of the interaction of Saturn's magnetosphere with the solar wind indicate that Kelvin-Helmholtz (K-H) waves can form on the dayside magnetopause when the interplanetary magnetic field (IMF) is northward. Dayside magnetic reconnection occurs at Saturn for northward IMF. The combination of K-H waves and reconnection caused enhanced vorticity in Saturn's magnetosphere. We have used a very high resolution version (grid interval is 0.1 RS) of our simulation code to study the consequences of the vortices and reconnection for the generation of field aligned currents (FAC) and aurorae in Saturn's ionosphere. We found three bands of alternating FAC toward and away from the dawn side of the ionosphere and two sets on the dusk side. The K-H waves generated a series of toward and away currents along the dayside side magnetopause. In the ionosphere they appear as a series of spots of up and down current. The K-H field aligned currents are adjacent to nearly continuous currents located from 1600 LT around past midnight to about 0700 LT The largest currents (jpara> 5×10-8 A /m-2) are found are at the highest latitudes. They map to the magnetopause and to the near-Earth tail region. In analogy with the Earth's ionosphere the field aligned currents away from Saturn can serve as a proxy for discrete aurorae. We used the away current density and the Knight relationship to estimate the energy flux from discrete aurorae and obtained ~1 mW /m-2 in the region with the strongest currents. Similar energy fluxes were found in the K-H related aurorae. This gave approximately 70 GW for the auroral power. We also investigated diffuse aurorae by using the energy flux in the absence of the field aligned currents. We found a region of enhanced thermal energy flux in the region where cusp aurorae are observed.

  18. A review of East Asian reports of aurorae and comets circa AD 775

    Science.gov (United States)

    Chapman, J.; Neuhäuser, D. L.; Neuhäuser, R.; Csikszentmihalyi, M.

    2015-08-01

    Given that a strong 14C variation in AD 775 has recently been suggested to be due to the largest solar flare ever recorded in history, it is relevant to investigate whether celestial events observed around that time may have been aurorae, possibly even very strong aurorae, or otherwise related to the 14C variation (e.g. a suggested comet impact with Earth's atmosphere). We critically review several celestial observations from AD 757 to the end of the 770s, most of which were previously considered to be true, and in some cases, strong aurorae; we discuss in detail the East Asian records and their wording. We conclude that probably none among the events after AD 770 was actually an aurora, including the event in AD 776 Jan, which was misdated for AD 774 or 775; the observed white qi phenomenon that happened above the moon in the south-east was most probably a halo effect near the full Moon - too late in any case to be related to the 14C variation in AD 774/5. There is another report of a similar (or identical) white qi phenomenon above the moon, reported just before a comet observation and dated to AD 776 Jan; the reported comet observed by the Chinese was misdated to AD 776, but actually sighted in AD 767. Our critical review of East Asian reports of aurorae circa AD 775 shows some very likely true Chinese auroral displays observed and reported for AD 762; there were also several events prior to AD 771 that may have been aurorae but are questionable.

  19. Europa's far ultraviolet oxygen aurora from a comprehensive set of HST observations

    Science.gov (United States)

    Roth, Lorenz; Saur, Joachim; Retherford, Kurt D.; Strobel, Darrell F.; Feldman, Paul D.; McGrath, Melissa A.; Spencer, John R.; Blöcker, Aljona; Ivchenko, Nickolay

    2016-03-01

    We analyze a large set of far ultraviolet oxygen aurora images of Europa's atmosphere taken by Hubble's Space Telescope Imaging Spectrograph (HST/STIS) in 1999 and on 19 occasions between 2012 and 2015. We find that both brightness and aurora morphology undergo systematic variations correlated to the periodically changing plasma environment. The time variable morphology seems to be strongly affected by Europa's interaction with the magnetospheric plasma. The brightest emissions are often found in the polar region where the ambient Jovian magnetic field line is normal to Europa's disk. Near the equator, where bright spots are found at Io, Europa's aurora is faint suggesting a general difference in how the plasma interaction shapes the aurora at Io and Europa. The dusk side is consistently brighter than the dawnside with only few exceptions, which cannot be readily explained by obvious plasma physical or known atmospheric effects. Brightness ratios of the near-surface OI] 1356 Što OI 1304 Šemissions between 1.5 and 2.8 with a mean ratio of 2.0 are measured, confirming that Europa's bound atmosphere is dominated by O2. The 1356/1304 ratio decreases with increasing altitude in agreement with a more extended atomic O corona, but O2 prevails at least up to altitudes of ˜900 km. Differing 1356/1304 line ratios on the plasma upstream and downstream hemispheres are explained by a differing O mixing ratio in the near-surface O2 atmosphere of ˜5% (upstream) and ≲1% (downstream), respectively. During several eclipse observations, the aurora does not reveal any signs of systematic changes compared to the sunlit images suggesting no or only weak influence of sunlight on the aurora and an optically thin atmosphere.

  20. Aurora-A overexpression enhances cell-aggregation of Ha-ras transformants through the MEK/ERK signaling pathway

    International Nuclear Information System (INIS)

    Overexpression of Aurora-A and mutant Ras (RasV12) together has been detected in human bladder cancer tissue. However, it is not clear whether this phenomenon is a general event or not. Although crosstalk between Aurora-A and Ras signaling pathways has been reported, the role of these two genes acting together in tumorigenesis remains unclear. Real-time PCR and sequence analysis were utilized to identify Ha- and Ki-ras mutation (Gly -> Val). Immunohistochemistry staining was used to measure the level of Aurora-A expression in bladder and colon cancer specimens. To reveal the effect of overexpression of the above two genes on cellular responses, mouse NIH3T3 fibroblast derived cell lines over-expressing either RasV12and wild-type Aurora-A (designated WT) or RasV12 and kinase-inactivated Aurora-A (KD) were established. MTT and focus formation assays were conducted to measure proliferation rate and focus formation capability of the cells. Small interfering RNA, pharmacological inhibitors and dominant negative genes were used to dissect the signaling pathways involved. Overexpression of wild-type Aurora-A and mutation of RasV12 were detected in human bladder and colon cancer tissues. Wild-type Aurora-A induces focus formation and aggregation of the RasV12 transformants. Aurora-A activates Ral A and the phosphorylation of AKT as well as enhances the phosphorylation of MEK, ERK of WT cells. Finally, the Ras/MEK/ERK signaling pathway is responsible for Aurora-A induced aggregation of the RasV12 transformants. Wild-type-Aurora-A enhances focus formation and aggregation of the RasV12 transformants and the latter occurs through modulating the Ras/MEK/ERK signaling pathway

  1. Unidentified emission lines in Jupiter's northern and southern 2 micron aurorae

    International Nuclear Information System (INIS)

    The detection of a number of unidentified emission lines in Jupiter's 2 micron spectral region for both the northern and southern aurorae is reported. Spectra taken as far back as September 1987 show that at least some of these features are long-lived. Some emission features are present in both the aurorae while others appear to reside only in one or the other. Certain emission lines are detected only at low latitudes. Altogether, two or more species besides H2 are inferred. 13 refs

  2. BOOK REVIEW: Electron acceleration in the aurora and beyond

    Science.gov (United States)

    McClements, K. G.

    1999-08-01

    Duncan Bryant is a retired space plasma physicist who spent most of his career at the Rutherford-Appleton Laboratory in Oxfordshire, England. For many years he has been challenging a widely accepted theory, that auroral electrons are accelerated by double layers, on the grounds that it contains a fundamental error (allegedly, an implicit assumption that charged particles can gain energy from conservative fields). It is, of course, right that models of particle acceleration in natural plasmas should be scrutinized carefully in terms of their consistency with basic physical principles, and I believe that Dr Bryant has performed a valuable service by highlighting this issue. He maintains that auroral electron acceleration by double layers is fundamentally untenable, and that acceleration takes place instead via resonant interactions with lower hybrid waves. In successive chapters, he asserts that essentially the same process can account for electron acceleration observed at the Earth's bow shock, in the neighbourhood of an `artificial comet' produced as part of the Active Magnetospheric Particle Explorers (AMPTE) space mission in 1984/85, in the solar wind, at the Earth's magnetopause, and in the Earth's magneto- sphere. The evidence for this is not always convincing: waves with frequencies of the order of the lower hybrid resonance are often observed in these plasma environments, but in general it is difficult to identify clearly which wave mode is being observed (whistlers, for example, have frequencies in approximately the same range as lower hybrid waves). Moreover, it is not at all clear that the waves which are observed, even if they were of the appropriate type, would have sufficient intensity to accelerate electrons to the extent observed. The author makes a persuasive case, however, that acceleration in the aurora, and in other plasma environments accessible to in situ measurements, involves some form of wave turbulence. In Chapter 2 it is pointed out that

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

    International Nuclear Information System (INIS)

    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

  4. A single TiO2-coated side-glowing optical fiber for photocatalytic wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    HU Yan; XU Jingjing; YUAN Chunwei; LIN Jian; YIN Zhidong

    2005-01-01

    By means of TiO2-layer-on-SiO2-layer, anatase TiO2 was deposited on novel side- glowing optical fibers, which can provide side UV radiation along the whole fiber length. FE-SEM images show that the double layers adhered well to the side-glowing optical fiber, and the TiO2 coating was homogeneous and smooth. The decomposition reaction of reactive brilliant red dye X-3B on a single TiO2-coated side-glowing optical fiber indicated that the side-scattering UV light intensity was strong enough for photocatalytic oxidation reaction. Therefore, TiO2-coated side-glowing optical fibers open up a new way to use the optical fiber reactor in photocatalytic wastewater treatment.

  5. Microhollow Glow Discharge Instrument for In Situ Lunar Surface Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge plasma emission for the...

  6. A computerized glow curve analysis (GCA) method for WinREMS thermoluminescent dosimeter data using MATLAB

    International Nuclear Information System (INIS)

    A computerized glow curve analysis (GCA) program for handling of thermoluminescence data originating from WinREMS is presented. The MATLAB program fits the glow peaks using the first-order kinetics model. Tested materials are LiF:Mg,Ti, CaF2:Dy, CaF2:Tm, CaF2:Mn, LiF:Mg,Cu,P, and CaSO4:Dy, with most having an average figure of merit (FOM) of 1.3% or less, with CaSO4:Dy 2.2% or less. Output is a list of fit parameters, peak areas, and graphs for each fit, evaluating each glow curve in 1.5 s or less. - Highlights: → Robust algorithm for performing thermoluminescent dosimeter glow curve analysis. → Written in MATLAB so readily implemented on variety of computers. → Usage of figure of merit demonstrated for six different materials.

  7. Effect of Ne Glow Discharge on Ion Density Control in LHD

    Institute of Scientific and Technical Information of China (English)

    S.Morita; M. Goto; S. Masuzaki; H. Suzuki; K. Tanaka; H. Nozato; Y. Takeiri; J. Miyazawa; LHD esperimental group

    2004-01-01

    Neon glow discharge cleaning was firstly attempted in Large Helical Device (LHD) instead of He glow discharge to remove hydrogen neutrals and to control the ion density, ni. The Ne glow discharge continued for 8 hours overnight after a three-day experiment. At the second night Halpha emission became weaker than the emission usually observed in the He glow discharge. A clear reduction of the hydrogen influx was also observed in neutral beam injection (NBI) discharges with Ne puff, whereas the neon recycling was strongly enhanced with appearance of a flat density profile. As a result, the lowest density limit was further reduced down to 0.2 times10 13 ,cm-3. The use of Ar puff formed a peaked density profile with a high Ti of 7 keV.

  8. CALCULATION OF BIMETAL PLATE BENDING FORCE OF A GLOW DISCHARGE STARTER

    OpenAIRE

    Akimov, V.; Mukha, L.

    2005-01-01

    Calculation techniques of bending power of bimetal plate electrode causing its displacement in the direction of the electrode of glow discharge starter have been represented. Calculation of bimetal electrode displacement has been conducted in correspondence with the chosen scheme.

  9. A new algorithm for identifying abnormal glow curves in thermoluminescence personal dosimetry

    International Nuclear Information System (INIS)

    In this paper an algorithm for the investigation of routine curves in thermoluminescence personnel dosimetry is presented. In rare cases, the luminescence glow curves do not exhibit the expected form. They have an abnormal shape as a result of, for example, external contamination, hardware problems, and poor heat transfer. So, glow curves from a monthly exposure period are compared with regular glow curves. Each curve is divided into four regions of interest (ROIs) and the relationship between the different ROIs are analysed. There are few criteria combining all four ROIs, which are necessary to distinguish between normal and abnormal glow curves. For that, the numerical value and the channel of the curves maximum also need to be considered. In most cases an additional set of criteria permits the identification of the ROI in which the irregularity occurs. (author)

  10. Does exclusion of protest zeros and warm-glow bidders cause selection bias in Contingent Valuation?

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye; Pouta, Eija

    the true WTP due to protest behavior. We conduct a contingent valuation study to estimate the WTP for conserving a Natura 2000 wetland area in Greece. We find that 54% of the positive bidders exert warm glow motivations while 29% of all responses can be classified as protest zero bids. We employ three...... different models to test for the potential impacts of how these positive warm glow and protest zero bidders are treated. We first exclude the warm glow cases, secondly we include them, and, finally, we correct for selection bias by using the Full Information Maximum Likelihood method for grouped data model....... Our findings show that removal of warm glow positive bidders does not distort the WTP estimate in any significant way. However, using the same approach for protest zero bidders, we find strong evidence of selection bias associated with removal of protest zero responses. Specifically, WTP estimates...

  11. Influence of longitudinal argon flow on DC glow discharge at atmospheric pressure

    Science.gov (United States)

    Zhu, Sha; Jiang, Weiman; Tang, Jie; Xu, Yonggang; Wang, Yishan; Zhao, Wei; Duan, Yixiang

    2016-05-01

    A one-dimensional self-consistent fluid model was employed to investigate the influence of longitudinal argon flow on the DC glow discharge at atmospheric pressure. It is found that the charges exhibit distinct dynamic behaviors at different argon flow velocities, accompanied by a considerable change in the discharge structure. The positive argon flow allows for the reduction of charge densities in the positive column and negative glow regions, and even leads to the disappearance of negative glow. The negative argon flow gives rise to the enhancement of charge densities in the positive column and negative glow regions. These observations are attributed to the fact that the gas flow convection influences the transport of charges through different manners by comparing the argon flow velocity with the ion drift velocity. The findings are important for improving the chemical activity and work efficiency of the plasma source by controlling the gas flow in practical applications.

  12. Short-term low-temperature glow discharge nitriding of 316L austenitic steel

    OpenAIRE

    T. Frączek; Olejnik, M.; Jasiñski, J.; Skuza, Z.

    2011-01-01

    The AISI 316L austenitic steel after glow discharge nitriding at temperature of T = 673 K and duration of τ=14,4 ks, for two different variants of specimen arrangement in the glow-discharge chamber was investigated. In order to assess the effectiveness of nitriding process, the surface layers profile analysis examination, surface hardness and hardness profile examination, the analysis of surface layer structures and corrosion resistance tests were performed. It has been found that application...

  13. Surface modification of austenitic steel by various glow-discharge nitriding methods

    OpenAIRE

    Tomasz Borowski; Bogusława Adamczyk-Cieślak; Agnieszka Brojanowska; Krzysztof Kulikowski; Tadeusz Wierzchoń

    2015-01-01

    Recent years have seen intensive research on modifying glow-discharge nitriding processes. One of the most commonly used glow-discharge methods includes cathodic potential nitriding (conventional method), and active screen plasma nitriding. Each of these methods has a number of advantages. One very important, common feature of these techniques is full control of the microstructure, chemical and phase composition, thickness and the surface topography of the layers formed. Another advantage inc...

  14. Effects of norms, warm-glow and time use on household recycling

    OpenAIRE

    Halvorsen, Bente

    2004-01-01

    Abstract: The aim of this paper is to quantify the relative importance of motivations based on warm-glow, social and moral norms and cost of time used recycling on household recycling efforts. We also test for crowding-out of intrinsic motivations when recycling is perceived as mandatory. We find that the most important variable increasing household recycling efforts is agreeing that recycling is a pleasant activity in itself, which may be interpreted as a warm-glow effect. The...

  15. Kinetic parameters, bleaching and radiation response of thermoluminescence glow peaks separated by deconvolution on Korean calcite

    Science.gov (United States)

    Kim, Ki-Bum; Hong, Duk-Geun

    2014-10-01

    Calcite has been of particular interest in studies of thermoluminescence (TL) because of its geological and archeological importance. Although extensive research on the TL glow curves of calcite has been conducted, most previous works have been based on the TL intensity integrated over a particular temperature range on the glow curve, without any separation of peaks. In this paper, the physical characteristics of the overlapping peaks in the TL glow curves of a calcite sample are investigated. These properties can provide useful information for determining the radiation dose absorbed to the sample in radiation dosimetry and luminescence dating research. The Tm-Tstop method is employed to identify the number of hidden glow peaks, and the kinetic parameters of each separated glow peak, including the thermal activation energy, kinetic order, and frequency factor, are evaluated using a computerized glow curve deconvolution (CGCD) method. The Tm-Tstop method indicates that the glow curve of calcite is the superposition of at least four components (P1 - P4) in the temperature range between room temperature and 450 °C. A bleaching experiment for two separated glow peaks (P3 and P4) using a solar simulator revealed that the bleaching rates of peak P3 show two exponential decays, and after bleaching, the TL intensity of peak P3 is reduced to approximately 4% of the initial value. In contrast, peak P4 is bleached exponentially to approximately 30% of the initial TL intensity and thereafter shows no detectable change in intensity. In addition, in a study of the radiation dose response of the two peaks, both peaks have a similar pattern, exhibiting a linear increment up to the maximum dose investigated, 520 Gy.

  16. DC normal glow discharges in atmospheric pressure atomic and molecular gases

    International Nuclear Information System (INIS)

    DC glow discharges were experimentally investigated in atmospheric pressure helium, argon, hydrogen, nitrogen and air. The discharges were characterized by visualization of the discharges and voltage and current measurements for current of up to several milliamperes. Significant differences are seen in the gas temperature; however all the discharges appear to operate as temperature and pressure scaled versions of low pressure discharges. In the normal glow discharges, features such as negative glow, Faraday dark space and positive column regions are clearly observable. In hydrogen and to a lesser degree in helium and argon standing striations of the positive column were visible in the normal glow regime. Normal glow characteristics such as normal current density at the cathode and constant electric field in the positive column are observed although there are some unexplained effects. The emission spectra for each of the discharges were studied. Also the rotational and vibrational temperature of the discharges were measured by adding trace amounts of N2 to the discharge gas and comparing modeled optical emission spectra of the N2 2nd positive system with spectroscopic measurements from the discharge. The gas temperatures for a 3.5 mA normal glow discharge were around 420 K, 680 K, 750 K, 890 K and 1320 K in helium, argon, hydrogen, nitrogen and air, respectively. Measured vibrational and excitation temperatures indicate non-thermal discharge operation. Mixtures of gases achieved intermediate temperatures.

  17. TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

    Directory of Open Access Journals (Sweden)

    Vikas Dubey

    2015-01-01

    Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

  18. Pulsed RF discharges, glow and filamentary mode at atmospheric pressure in argon

    International Nuclear Information System (INIS)

    The properties of a pulsed radio frequency capacitive discharge are investigated at atmospheric pressure in argon. The discharge can operate in two different modes: a homogeneous glow discharge or turn into filaments. By pulsing the 13.56 MHz generator both the filamentary and the glow modes can be selected depending on the pulse width and period. For a 5 μs pulse width (∼70 RF cycles in the pulse), short pulse periods (less than 100 μs) result in a filamentary discharge while long pulse periods (greater than 1 ms) result in a glow discharge. Optical emission spectroscopy and power measurements were performed to estimate the plasma temperature and density. Water vapour was introduced to the discharge as a source of hydrogen and the Stark broadening of the Balmer Hβ line was measured to allow the plasma density to be estimated as 1015 cm-3 in the filamentary mode. The estimation of the glow mode density was based on power balance and yielded a density of 5 x 1011 cm-3. Emission line ratio measurements coupled with the Saha equation resulted in an estimate of electron temperature of approximatively 1.3 eV for the glow mode and 1.7 eV for the filaments. Using the glow mode at a duty cycle of 10% is effective in decreasing the hydrophobicity of polymer films while keeping the temperature low

  19. Study of the glow curve structure of the minerals separated from black pepper (Piper nigrum L.)

    Science.gov (United States)

    Guzmán, S.; Ruiz Gurrola, B.; Cruz-Zaragoza, E.; Tufiño, A.; Furetta, C.; Favalli, A.; Brown, F.

    2011-04-01

    The inorganic mineral fraction extracted from black pepper (Piper nigrum L.) has been analysed using a thermoluminescence (TL) method, investigating the glow curve structure, including an evaluation of the kinetic parameters. Different grain sizes, i.e. 10, 74, and 149 μm, were selected from commercial black pepper. The X-ray diffraction of the inorganic fraction shows that quartz is the main mineral present in it. The samples were exposed to 1-25 kGy doses by gamma rays of 60Co in order to analyse the thermally stimulated luminescence response as a function of the delivered dose. The glow curves show a complex structure for different grain sizes of the pepper mineral samples. The fading of the TL signal at room temperature was obtained after irradiation, and it was observed that the maximum peaks of the glow curves shift towards higher values of the temperature when the elapsed time from irradiation increases. It seems that the fading characteristic may be related to a continuous trap distribution responsible for the complex structure of the glow curve. Similar glow curves structure behaviour was found under ultraviolet irradiation of the samples. The activation energy and the frequency factor were determined from the glow curves of different grain sizes using a deconvolution programme because of the evident complexity of the structure.

  20. The effect of glow discharge plasma surface modification of polymers on the osteogenic differentiation of committed human mesenchymal stem cells.

    Science.gov (United States)

    Mwale, Fackson; Wang, Hong Tian; Nelea, Valentin; Luo, Li; Antoniou, John; Wertheimer, Michael R

    2006-04-01

    Little is known of the effect of material surfaces on stem cell differentiation. The present study has addressed the hypothesis that the interaction of mesenchymal stem cells (MSCs) with material surfaces modified by glow discharge plasma is a major regulator of osteogenic differentiation. We found that biaxially oriented polypropylene (BOPP) plasma treated in ammonia significantly reduced up-regulation of expression of osteogenic marker genes, such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). In contrast, ALP expression was up-regulated when cultured on treated Nylon-6 polyamide (Ny-t) but was substantially reduced when cultured on its pristine counterpart (Ny-p) on day 3. On day 7, ALP expression was down-regulated with MSCs cultured on Ny-t although its expression level was up again on day 14. BSP was expressed weakly on day 3, but was up-regulated when cultured on Ny-t and Ny-p. Its expression reached its maximum on day 14 when cultured on a polystyrene control, while it was cyclically up-regulated on Ny-t. Similarly, there was a slight increase in OC expression when MSCs were cultured on Ny-t and Ny-p on day 3, when compared to control. Thus, the nature of the surface can directly influence MSCs differentiation, ultimately affecting the quality of new tissue formation with BOPP-t suppressing osteogenic differentiation. PMID:16313952

  1. Is this an arc or a glow discharge?

    International Nuclear Information System (INIS)

    A well known criterion for distinguishing an arc discharge from a glow discharge is a low voltage drop (10--30 V) and a high current density that varies from a few tens to 106 A/cm2 depending on arc type. The high current density is an attribute of arcs with cathode spots. The authors report here a study of the mechanism of emission in cathode spot arc where they realized a spotless discharge with a low voltage drop (30--50 V) and a high mean current density (104--106 A/cm2). The discharge was initiated between a broad cathode and point anode. The cathode was a smooth tungsten sphere electrode of about 100 μm in diameter. The point anode was made of various materials (Mo, Cu, Cd) with initial radius 1 μm. Before the experiment the cathode was cleaned by heating at 2,000 K at high vacuum (10-8 Torr). The discharge was initiated by self-breakdown when electrodes under the voltage 200--500 V were brought to close proximity with each other. The cathode-anode spacing d at the moment of breakdown was estimated to be < 1 μm. The discharge current was varied within 1--3 A by changing the applied voltage and impedance of coaxial cable generator. The discharge burned during 100--1,000 ns. After the single discharge the cathode and anode were examined with a scanning electron microscope. The cathode surface exposed to the discharge was smooth, i.e. no erosion pits similar to arc craters were found on the cathode surface. The anode was shortened after discharge by 5--50 μm depending on current, material and cone angle. A high current density and low voltage drop implies that this is an arc discharge, while the cold cathode and the absence f cathode spot trace are pertinent to a dense glow discharge. The mechanism of emission involving secondary electron emission is to be discussed

  2. Preliminary Results from a Coordinated Hisaki/Chandra/XMM-Newton Study of the Jovian Aurora and Io Plasma Torus

    Science.gov (United States)

    Kraft, Ralph; Kimura, Tomoki; Elsner, Ronald; Branduardi-Raymont, Graziella; Gladstone, Randy; Badman, Sarah Victoria; Ezoe, Yuichiro; Murakami, Go; Murray, Stephen S.; Roediger, Elke; Tsuchiya, Fuminori; Yamazaki, Atsushi; Yoshikawa, Ichiro; Yoshioka, Kazuo

    2014-01-01

    We present preliminary results from a coordinated Hisaki/Chandra/XMM-Newton observational campaign of the Jovian aurora and Io plasma torus. The data were taken over a three week period in April, 2014. Jupiter was observed continuously with Hisaki, six times with the Chandra/HRC instrument for roughly 12 hours per observation, and twice by XMM-Newton. The goal of this observational campaign was to understand how energy and matter are exchanged between the Jovian aurora, the IPT, and the Solar wind. X-ray observations provide key diagnostics on highly stripped ions and keV electrons in the Jovian magnetosphere. We use the temporal, spatial, and spectral capabilities of the three instruments to search for correlated variability between the Solar wind, the EUV-emitting plasma of the IPT and UV aurora, and the ions responsible for the X-ray aurora. Preliminary analysis suggests a strong 45 min periodicity in the EUV emission from the electron aurora. There is some evidence for complex variability of the X-ray auroras on scales of tens of minutes. There is also clear morphological changes in the X-ray aurora that do not appear to be correlated with either variations in the IPT or Solar wind.

  3. Recent laser experiments on the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    The Aurora KrF/ICF Laser Facility at Los Alamos is operational at the kilojoule-level for both laser and target experiments. We report on recent laser experiments on the system and resulting system improvements. 3 refs., 4 figs

  4. Polo‐like kinase 1 and Aurora A cooperate in spindle assembly during meiotic

    Czech Academy of Sciences Publication Activity Database

    Böhmová, Tereza; Mayer, Alexandra; Šolc, Petr; Baran, Vladimír; Motlík, Jan

    Liběchov : Institute of Animal Physiology and Genetics AS CR, v.v ,, 2010. s. 52-52. [Czech-Japan Joint Symposium for Animal Reproduction. 20.09.2010-21.09.2010, Liblice] Institutional research plan: CEZ:AV0Z50450515 Keywords : Polo-like kinase 1 * Aurora A * mouse oocytes Subject RIV: EB - Genetics ; Molecular Biology

  5. 76 FR 65216 - Beacon Medical Services, LLC, Aurora, CO; Notice of Negative Determination Regarding Application...

    Science.gov (United States)

    2011-10-20

    ... (76 FR 40401). The workers of Beacon Medical Services are engaged in activities related ] to the... Employment and Training Administration Beacon Medical Services, LLC, Aurora, CO; Notice of Negative... apply for Trade Adjustment Assistance (TAA) applicable to workers and former workers of Beacon...

  6. Control of Jupiter's Radio Emission and Aurorae by the Solar Wind

    Science.gov (United States)

    Gurnett, D. A.; Kurth, W. S.; Hospodarsky, G. B.; Persoon, A. M.; Zarka, P.; Lecacheux, A.; Bolton, S. J.; Desch, . D.; Farrell, W. W.; Kaiser, M. L.

    2002-01-01

    Radio emissions from Jupiter provided the first evidence that this giant planet has a strong magnetic field and a large magnetosphere. Jupiter also has polar aurorae, which are similar in many respects to Earth's aurorae. The radio emissions are believed to be generated along the high-latitude magnetic field lines by the same electrons that produce the aurorae, and both the radio emission in the hectometric frequency range and the aurorae vary considerably. The origin of the variability, however, has been poorly understood. Here we report simultaneous observations using the Cassini and Galileo spacecraft of hectometric radio emissions and extreme ultraviolet auroral emissions from Jupiter. Our results show that both of these emissions are triggered by interplanetary shocks propagating outward from the Sun. When such a shock arrives at Jupiter, it seems to cause a major compression and reconfiguration of the magnetosphere, which produces strong electric fields and therefore electron acceleration along the auroral field lines, similar to the processes that occur during geomagnetic storms at the Earth.

  7. Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence.

    Science.gov (United States)

    Hallinan, G; Littlefair, S P; Cotter, G; Bourke, S; Harding, L K; Pineda, J S; Butler, R P; Golden, A; Basri, G; Doyle, J G; Kao, M M; Berdyugina, S V; Kuznetsov, A; Rupen, M P; Antonova, A

    2015-07-30

    Aurorae are detected from all the magnetized planets in our Solar System, including Earth. They are powered by magnetospheric current systems that lead to the precipitation of energetic electrons into the high-latitude regions of the upper atmosphere. In the case of the gas-giant planets, these aurorae include highly polarized radio emission at kilohertz and megahertz frequencies produced by the precipitating electrons, as well as continuum and line emission in the infrared, optical, ultraviolet and X-ray parts of the spectrum, associated with the collisional excitation and heating of the hydrogen-dominated atmosphere. Here we report simultaneous radio and optical spectroscopic observations of an object at the end of the stellar main sequence, located right at the boundary between stars and brown dwarfs, from which we have detected radio and optical auroral emissions both powered by magnetospheric currents. Whereas the magnetic activity of stars like our Sun is powered by processes that occur in their lower atmospheres, these aurorae are powered by processes originating much further out in the magnetosphere of the dwarf star that couple energy into the lower atmosphere. The dissipated power is at least four orders of magnitude larger than what is produced in the Jovian magnetosphere, revealing aurorae to be a potentially ubiquitous signature of large-scale magnetospheres that can scale to luminosities far greater than those observed in our Solar System. These magnetospheric current systems may also play a part in powering some of the weather phenomena reported on brown dwarfs. PMID:26223623

  8. Aurora T: a Monte Carlo code for transportation of neutral atoms in a toroidal plasma

    International Nuclear Information System (INIS)

    This paper contains a short description of Aurora code. This code have been developed at Princeton with Monte Carlo method for calculating neutral gas in cylindrical plasma. In this work subroutines such one can take in account toroidal geometry are developed

  9. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

    Czech Academy of Sciences Publication Activity Database

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolík, Ondřej; Clilverd, M.; Rodger, C. J.; Turunen, E.; Tsuchiya, F.

    2015-01-01

    Roč. 120, č. 4 (2015), s. 2754-2766. ISSN 2169-9380 Institutional support: RVO:68378289 Keywords : pulsating aurora * EISCAT * Van Allen Probes * pitch angle scattering Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.440, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020690/abstract

  10. Cancer Cell Resistance to Aurora Kinase Inhibitors: Identification of Novel Targets for Cancer Therapy

    Czech Academy of Sciences Publication Activity Database

    Hrabáková, Rita; Kollaredy, M.; Tylečková, Jiřina; Halada, Petr; Hajdúch, M.; Gadher, S. J.; Kovářová, Hana

    2013-01-01

    Roč. 12, č. 1 (2013), s. 455-469. ISSN 1535-3893 R&D Projects: GA MŠk LC07017 Institutional support: RVO:67985904 ; RVO:61388971 Keywords : Aurora kinase inhibitors * resistance * p53 * apoptosis Subject RIV: CE - Biochemistry Impact factor: 5.001, year: 2013

  11. A review of East Asian reports of aurorae and comets circa AD 775

    CERN Document Server

    Chapman, Jesse; Neuhaeuser, Ralph; Csikszentmihalyi, Mark

    2015-01-01

    Given that a strong 14C variation in AD 775 has recently been suggested to be due to the largest solar flare ever recorded in history, it is relevant to investigate whether celestial events observed around that time may have been aurorae, possibly even very strong aurorae, or otherwise related to the 14C variation (e.g. a suggested comet impact with Earth's atmosphere). We critically review several celestial observations from AD 757 to the end of the 770s, most of which were previously considered to be true, and in some cases, strong aurorae; we discuss in detail the East Asian records and their wording. We conclude that probably none among the events after AD 770 was actually an aurora, including the event in AD 776 Jan, which was misdated for AD 774 or 775; the observed white qi phenomenon that happened "above the moon" in the south-east was most probably a halo effect near the full moon - too late in any case to be related to the 14C variation in AD 774/5. There is another report of a similar (or identical...

  12. Allosteric inhibition of Aurora-A kinase by a synthetic vNAR domain.

    Science.gov (United States)

    Burgess, Selena G; Oleksy, Arkadiusz; Cavazza, Tommaso; Richards, Mark W; Vernos, Isabelle; Matthews, David; Bayliss, Richard

    2016-07-01

    The vast majority of clinically approved protein kinase inhibitors target the ATP-binding pocket directly. Consequently, many inhibitors have broad selectivity profiles and most have significant off-target effects. Allosteric inhibitors are generally more selective, but are difficult to identify because allosteric binding sites are often unknown or poorly characterized. Aurora-A is activated through binding of TPX2 to an allosteric site on the kinase catalytic domain, and this knowledge could be exploited to generate an inhibitor. Here, we generated an allosteric inhibitor of Aurora-A kinase based on a synthetic, vNAR single domain scaffold, vNAR-D01. Biochemical studies and a crystal structure of the Aurora-A/vNAR-D01 complex show that the vNAR domain overlaps with the TPX2 binding site. In contrast with the binding of TPX2, which stabilizes an active conformation of the kinase, binding of the vNAR domain stabilizes an inactive conformation, in which the αC-helix is distorted, the canonical Lys-Glu salt bridge is broken and the regulatory (R-) spine is disrupted by an additional hydrophobic side chain from the activation loop. These studies illustrate how single domain antibodies can be used to characterize the regulatory mechanisms of kinases and provide a rational basis for structure-guided design of allosteric Aurora-A kinase inhibitors. PMID:27411893

  13. Temporal evolution of the after glow plasma conductivity

    International Nuclear Information System (INIS)

    Due to their exhibited advantages over continuous and RF glows, the pulsed discharges gain more attention in a wide variety of application fields, like film deposition, plasma chemistry, semiconductor processing, etc. For this reason, fast time-resolved experimental methods need to be developed in order to control the main parameters of the high voltage pulsed plasmas. It is well known that electric probes present major advantages over many other diagnostic techniques for studying plasma parameters, but the use of these probes in the high voltage pulsed plasmas encounters enormous difficulties. One of them is the issue of galvanic insulation of the probe during the high voltage pulse. Also, the plasma potential may change rapidly, inducing spurious currents in the probe. Other problems could arise in the afterglow when the probe can exert great influence over the plasma potential by the current that it draws from the plasma. In this paper, we proposed a new method for the determination of the electrical conductivity of the afterglow of the high voltage pulsed discharges, using a low frequency RF plane probe. The application of a small low frequency signal to the plane probe could successfully eliminate all the disadvantages mentioned above. (authors)

  14. Study on the onset of DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    In this paper, the DC diaphragm glow discharge (DGD) occurred around the small hole on quartz tube between two submersed graphite electrodes and the onset of DGD was systematically investigated. It was found that critical voltage (VD) decreased with the increasing conductivity, and then maintained at about 620 V. When the hole diameter increased from 1.0 mm to 2.5 mm, H2O2 formation and AO discoloration in anolyte increased with the increase of the hole diameter. In addition, the effect of electrolyte constituents on H2O2 formation and AO discoloration in anolyte induced by DGD was also studied. The concentration of H2O2 and AO discoloration in anolyte was close in inert electrolyte such as Na2SO4 and Na2HPO4 solution. The concentration of H2O2 and AO discoloration rate in Na2CO3 and NaAc solution was lower than those in Na2SO4 and Na2HPO4 solution, due to their capture ability for ·OH. However, NaCl showed enhancing effect on AO discoloration, although it consumed a certain amount of H2O2. The energy efficiencies of AO discoloration and H2O2 formation were also compared with those of other DGD reactor.

  15. Glow curve analysis by Gauss-Lorentz function

    Directory of Open Access Journals (Sweden)

    Vejnović Zdravko M.

    2013-01-01

    Full Text Available A new method for fitting glow curves, described in a mixed order kinetics model, with Gauss-Lorentz function is shown. Theoretical expressions of the mixed order kinetics model are shown in a new way, so that the values of kinetic parameters can be obtained through the geometric parameters. When the model is described in this way it is possible to calculate precisely the kinetic parameters such as activation energy, pre-exponential factor and the factor a= n0/(h + n0. At the same time, obtained values of geometric parameters of the experimental curve, which is described with the Gauss-Lorentz function, can be used to estimate the kinetic model, in which thermoluminescence relaxation occurs. This gives a possibility of a new application of Gauss-Lorentz function to be used as a criterion for assessing model of relaxation, when it is not known in advance. The accuracy of fitting is studied, for the specific cases of computer simulated thermoluminescent curves with one peak.

  16. Platinum and Iridium Coatings Obtained by Double Glow Plasma Technology

    Institute of Scientific and Technical Information of China (English)

    WU Wangping; CHEN Zhaofeng; CHEN Zhou; CONG Xiangna; QIU Jinlian

    2012-01-01

    Pt and Ir coatings were produced by double glow plasma technology on the surface of Ti alloy substrates.The chemical compositions of the coatings were determined by X-ray diffraction and X-ray photoelectron spectroscopy.The microstructure and morphology of the coatings were observed by scanning electron microscopy.The hardness and elastic modulus of the coatings were estimated by nanoindentation.The measurements of adhesive forces of the coatings were performed with scratch tester.The results indicated that the Pt and Ir coatings displayed the preferred (220) orientation due to the initial nuclei with preferred growth on the surface of the substrates.The interface between the Pt coating and substrate exhibited no evidence of delamination.The Ir coating was composed of irregular columnar grains with many nanovoids at the interface between the coating and substrate.The mean values of hardness for Pt and Ir coatings were 0.9 GPa and 9 GPa,respectively.The elastic modulus of Pt and Ir coatings were 178 GPa and 339 GPa,respectively.The adhesive forces of the Pt and Ir coatings were about 66.4 N and 55 N,respectively.The Pt and Ir coatings adhered well to the Ti alloy substrates.

  17. Glow-Discharge Production of Oxygen from the Martian Atmosphere

    Science.gov (United States)

    Hughes, Caleb; Outlaw, Ronald

    One of the most crucial aspects of any mission to Mars is a continual supply of oxygen for astronaut respiration on site. The most popular approach to this problem favors in-situ oxygen production on Mars, utilizing the CO2 Martian atmosphere. However, this requires a large energy budget. NASA's current plans for Mars include sending a system called MOXIE, which produces oxygen through solid oxide electrolysis at high temperatures. An alternative approach utilizes the 6 Torr Martian atmosphere to provide a continual source of oxygen by breaking down the molecule into CO and O using a glow-discharge. After dissociation, a thin film Agmembrane uniquely permeates the atomic oxygen which then recombines to O2 on the downstream side, where it is subsequently stored. By taking advantage of recent advances in thin film technology to reduce the thickness of the film to many orders of magnitude less than used in the initial study, a corresponding increase in O2 flux can be realized. The Ag thin film requires the support of a porous ceramic substructure. With this system, it is shown that this method produces a viable energy efficient alternative to MOXIE.

  18. Bulk plasma properties in the pulsed glow discharge

    International Nuclear Information System (INIS)

    This work focuses on the spatial and temporal characteristics of a glow discharge plasma operated with power pulses of 5 ms in duration at 25% duty cycle. Interpretation of emission data provides insight into the nature of the plasma at each instant of a typical pulse cycle and at each position in space. Because the bulk plasma properties affect the distribution of excited energy levels of the sputtered atoms, an improved understanding of the plasma affords the ability to select conditions that enhance analytically important emission lines. Optical emission spectroscopy was used to determine the relative populations of excited states for atoms and ions during the initial breakdown, the steady state and the recombining periods of the discharge pulse cycle. The plasma is highly ionizing in nature at the time of breakdown--with lower excited states being overpopulated--before reaching the steady state, or plateau, period, also ionizing in nature. These behaviors arise from a loss of charged particles and photons to the surroundings that shifts the plasma away from Saha and Boltzmann balances during these periods. The post-pulse period typically displays recombining behavior, characterized by population inversion for selected species--except for regions close to the cathode, where electrons and ions are lost by diffusion and are not available for recombination. The sputtered analyte atom emissions closely mimic those of the plasma bath gas, except that their emissions persevere for longer in the recombining after-peak period than do the discharge gas species

  19. Radio frequency glow discharge-induced acidification of fluoropolymers.

    Science.gov (United States)

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

    2011-12-01

    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

  20. Ultrasonic nebulization atmospheric pressure glow discharge - Preliminary study

    Science.gov (United States)

    Greda, Krzysztof; Jamroz, Piotr; Pohl, Pawel

    2016-07-01

    Atmospheric pressure glow microdischarge (μAPGD) generated between a small-sized He nozzle jet anode and a flowing liquid cathode was coupled with ultrasonic nebulization (USN) for analytical optical emission spectrometry (OES). The spatial distributions of the emitted spectra from the novel coupled USN-μAPGD system and the conventional μAPGD system were compared. In the μAPGD, the maxima of the intensity distribution profiles of the atomic emission lines Ca, Cd, In, K, Li, Mg, Mn, Na and Sr were observed in the near cathode region, whereas, in the case of the USN-μAPGD, they were shifted towards the anode. In the novel system, the intensities of the analytical lines of the studied metals were boosted from several to 35 times. As compared to the conventional μAPGD-OES with the introduction of analytes through the sputtering and/or the electrospray-like nebulization of the flowing liquid cathode solution, the proposed method with the USN introduction of analytes in the form of a dry aerosol provides improved detectability of the studied metals. The detection limits of metals achieved with the USN-μAPGD-OES method were in the range from 0.08 μg L- 1 for Li to 52 μg L- 1 for Mn.

  1. Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials

    Science.gov (United States)

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

    2006-01-01

    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.

  2. Study on Glow Discharge Plasma Used in Polyester Surface Modification

    Science.gov (United States)

    Liu, Wenzheng; Lei, Xiao; Zhao, Qiang

    2016-01-01

    To achieve an atmospheric pressure glow discharge (APGD) in air and modify the surface of polyester thread using plasma, the electric field distribution and discharge characteristics under different conditions were studied. We found that the region with a strong electric field, which was formed in a tiny gap between two electrodes constituting a line-line contact electrode structure, provided the initial electron for the entire discharge process. Thus, the discharge voltage was reduced. The dielectric barrier of the line-line contact electrodes can inhibit the generation of secondary electrons. Thus, the transient current pulse discharge was reduced significantly, and an APGD in air was achieved. We designed double layer line-line contact electrodes, which can generate the APGD on the surface of a material under treatment directly. A noticeable change in the surface morphology of polyester fiber was visualized with the aid of a scanning electron microscope (SEM). Two electrode structures - the multi-row line-line and double-helix line-line contact electrodes - were designed. A large area of the APGD plasma with flat and curved surfaces can be formed in air using these contact electrodes. This can improve the efficiency of surface treatment and is significant for the application of the APGD plasma in industries.

  3. GCAFIT-A new tool for glow curve analysis in thermoluminescence nanodosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Hafez, A.I., E-mail: nis_arafa@yahoo.co [National Institute for Standards, Tersa Street, El-Harm, P.O. 136, Code No. 12211, Giza (Egypt); Yasin, M.N. [Fayoum University, Faculty of Science, Physics Department (Egypt); Sadek, A.M. [National Institute for Standards, Tersa Street, El-Harm, P.O. 136, Code No. 12211, Giza (Egypt)

    2011-05-01

    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, E{sub eff,} and an effective frequency factor, S{sub eff}. The temperature value for peak 5 was also treated as an

  4. The deconvolution of thermoluminescence glow-curves using general expressions derived from the one trap-one recombination (OTOR) level model

    International Nuclear Information System (INIS)

    The new developed thermoluminescence (TL) glow-peak expressions derived from the one trap-one recombination (OTOR) level model were used to analyze the TL glow-curves recorded with linear and exponential heating function profiles under various experimental conditions. The results showed that these expressions can, accurately, analyze the TL glow-curves even with the overlapped glow-peaks. Low values of R=An/Am were reported for glow-peaks in different TL materials. A glow-peak with the possibility of An>Am was also pointed out. - Highlights: • The accuracy of the TL expressions derived from the OTOR model was verified. • EHF and LHF glow-curves were deconvoluted using TL expressions based on OTOR model. • Low values of R=An/Am were reported for some glow-peaks. • A glow-peak with the possibility of An>Am was pointed out

  5. In vivo FRET imaging revealed a regulatory role of RanGTP in kinetochore-microtubule attachments via Aurora B kinase.

    Directory of Open Access Journals (Sweden)

    Yoke-Peng Lee

    Full Text Available Under the fluctuating circumstances provided by the innate dynamics of microtubules and opposing tensions resulted from microtubule-associated motors, it is vital to ensure stable kinetochore-microtubule attachments for accurate segregation. However, a comprehensive understanding of how this regulation is mechanistically achieved remains elusive. Using our newly designed live cell FRET time-lapse imaging, we found that post-metaphase RanGTP is crucial in the maintenance of stable kinetochore-microtubule attachments by regulating Aurora B kinase via the NES-bearing Mst1. More importantly, our study demonstrates that by ensuring stable alignment of metaphase chromosomes prior to segregation, RanGTP is indispensible in governing the genomic integrity and the fidelity of cell cycle progression. Our findings suggest an additional role of RanGTP beyond its known function in mitotic spindle assembly during the prometaphase-metaphase transition.

  6. The production of large concentrations of molecular ions in the lengthened negative glow region of a discharge

    OpenAIRE

    De Lucia, Frank C.; Herbst, Eric; Plummer, Grant M.; Blake, Geoffrey A.

    1983-01-01

    A technique for enhancement of positive molecular ion concentrations in a glow discharge is presented. The technique consists of modifying an anomalous glow discharge by the addition of a longitudinal magnetic field of up to 300 G. Enhancements in the ion signal strength, as measured by millimeter and submillimeter wave spectroscopy, are approximately two orders of magnitude. Evidence is presented that the magnetic field increases the length of the ion rich negative glow by restricting inside...

  7. Aurora: Los Alamos multikilojoule angular-multiplexed KrF driver prototype for ICF

    International Nuclear Information System (INIS)

    The Los Alamos National Laboratory (LANL) has participated in programs to apply high-power gas lasers to inertial confinement fusion (ICF). The bulk of this effort has been in the development of CO/sub 2/ laser systems and laser-plasma interaction experiments at a 10.6-μm wavelength. The main hardware element in this program is the Aurora KrF laser system, which is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to study KrF systems as potential fusion drivers. Aurora will serve as a test-bed for specific laser, optical, and electron-beam-pumping technology aspects of larger KrF fusion systems. The Aurora system is being built in two phases. The first-phase portion of the Aurora system contains all the main optical and laser elements from the front end to the final amplifier output. In the first phase, the front end output is replicated using aperture slicers and beam splitters to produce a 480-ns long pulse train consisting of 96 separate 5-ns pulses. This pulse train is encoded in angular separation, relayed through the amplifier chain by means of the centered optical system and the computer-controlled alignment station, and delivered to a diagnostic station which follows the main power amplifier [large aperture module (LAM)]. The second phase of the system contains the first-phase portion and the additional optical and target hardware needed to stack 48 of the 96 multiplexed and amplified beams into a single multikilojoule 5-ns pulse at the fusion target. The authors give a description of the Aurora system and discuss its present status

  8. Protein tyrosine phosphatase receptor delta acts as a neuroblastoma tumor suppressor by destabilizing the aurora kinase a oncogene

    LENUS (Irish Health Repository)

    Meehan, Maria

    2012-02-05

    Abstract Background Protein tyrosine phosphatase receptor delta (PTPRD) is a member of a large family of protein tyrosine phosphatases which negatively regulate tyrosine phosphorylation. Neuroblastoma is a major childhood cancer arising from precursor cells of the sympathetic nervous system which is known to acquire deletions and alterations in the expression patterns of PTPRD, indicating a potential tumor suppressor function for this gene. The molecular mechanism, however, by which PTPRD renders a tumor suppressor effect in neuroblastoma is unknown. Results As a molecular mechanism, we demonstrate that PTPRD interacts with aurora kinase A (AURKA), an oncogenic protein that is over-expressed in multiple forms of cancer, including neuroblastoma. Ectopic up-regulation of PTPRD in neuroblastoma dephosphorylates tyrosine residues in AURKA resulting in a destabilization of this protein culminating in interfering with one of AURKA\\'s primary functions in neuroblastoma, the stabilization of MYCN protein, the gene of which is amplified in approximately 25 to 30% of high risk neuroblastoma. Conclusions PTPRD has a tumor suppressor function in neuroblastoma through AURKA dephosphorylation and destabilization and a downstream destabilization of MYCN protein, representing a novel mechanism for the function of PTPRD in neuroblastoma.

  9. Glow-curve deconvolution of thermoluminescence curves in the simplified OTOR equation using the Hybrid Genetic Algorithm

    International Nuclear Information System (INIS)

    Highlights: • Use of Hybrid Genetic Algorithm in TL analysis. • Deconvolution in simplified OTOR equation. • Glow curve analysis. -- Abstract: A novel method of analyzing thermoluminescence TL glow curves is presented here. This method is based on the recently derived simplified OTOR equation. It employs the Hybrid Genetic Algorithm for the extraction of the TL parameters. This method has been tested against theoretical glow-curve data that were generated using the full iteration method without any prior approximation in the OTOR model, and it has also been tested using the complex glow curve of NaCl

  10. SWIR air glow mapping of the night sky

    Science.gov (United States)

    Myers, Michael M.; Dayton, David C.; Gonglewski, John D.; Fertig, Gregory; Allen, Jeff; Nolasco, Rudolf; Burns, Dennis; Mons, Ishan

    2010-08-01

    It is well known that luminance from photo-chemical reactions of hydroxyl ions in the upper atmosphere (~85 km altitude) produces a significant amount of night time radiation in the short wave infra-red (SWIR) band of wave length 0.9 to 1.7 μm. Numerous studies of these phenomena have demonstrated that the irradiance shows significant temporal and spatial variations in the night sky. Changes in weather patterns, seasons, sun angle, moonlight, etc have the propensity to alter the SWIR air glow irradiance pattern. By performing multiple SWIR measurements a mosaic representation of the celestial hemisphere was constructed and used to investigate these variations over time and space. The experimental setup consisted of two sensors, an InGaAs SWIR detector and a visible astronomical camera, co-located and bore sighted on an AZ-EL gimbal. This gimbal was programmed to view most of the sky using forty five discrete azimuth and elevation locations. The dwell time at each location was 30 seconds with a total cycle time of less than 30 minutes. The visible astronomical camera collected image data simultaneous with the SWIR camera in order to distinguish SWIR patterns from clouds. Data was reduced through batch processing producing polar representations of the sky irradiance as a function of azimuth, elevation, and time. These spatiotemporal variations in the irradiance, both short and long term, can be used to validate and calibrate physical models of atmospheric chemistry and turbulence. In this paper we describe our experimental setup and present some results of our measurements made over several months in a rural marine environment on the Islands of Kauai and Maui Hawaii.

  11. SWIR Hemispherical Air-Glow Plotting System SHAPS

    Science.gov (United States)

    Gonglewski, John D.; Myers, Michael M.; Dayton, David C.; Fertig, Gregory; Allen, Jeffrey; Nolasco, Rudolph; Maia, Franscisco

    2010-10-01

    It is well known that luminance from photo-chemical reactions of hydroxyl ions in the upper atmosphere (~85 km altitude) produces a significant amount of night time radiation in the short wave infra-red (SWIR) band of wave length 0.9 to 1.7 μm. Numerous studies of these phenomena have demonstrated that the irradiance shows significant temporal and spatial variations in the night sky. Changes in weather patterns, seasons, sun angle, moonlight, etc have the propensity to alter the SWIR air glow irradiance pattern. By performing multiple SWIR measurements a mosaic representation of the celestial hemisphere was constructed and used to investigate these variations over time and space. The experimental setup consisted of two sensors, an InGaAs SWIR detector and a visible astronomical camera, co-located and bore sighted on an AZ-EL gimbal. This gimbal was programmed to view most of the sky using forty five discrete azimuth and elevation locations. The dwell time at each location was 30 seconds with a total cycle time of less than 30 minutes. The visible astronomical camera collected image data simultaneous with the SWIR camera in order to distinguish SWIR patterns from clouds. Data was reduced through batch processing producing polar representations of the sky irradiance as a function of azimuth, elevation, and time. These spatiotemporal variations in the irradiance, both short and long term, can be used to validate and calibrate physical models of atmospheric chemistry and turbulence. In this paper we describe our experimental setup and present some results of our measurements made over several months in a rural marine environment on the Island of Kauai Hawaii.

  12. Dusty plasma structures in He-Kr DC glow discharge

    International Nuclear Information System (INIS)

    Complete text of publication follows. 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 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 argon), (helium and krypton) are performed, and results of numerical simulations of ion and electron drift in the mixture are presented. The model of electron-atom collisions is considered taking into account non-elastic collisions in electron energy balance. On the basis of numerical simulation the characteristics of electron velocity distribution function, the energy characteristics of electron drift in constant electric field in He-Kr discharge were tabulated. Values of drift velocity, average electron energy, Townsend characteristic energy, and average electron energy leading to excitation and ionization of atoms, ratio between energy losses in elastic and nonelastic collisions, Townsend ionization coefficient were obtained. For the experiment conditions calculations of dust particle charging characteristics are also conducted - values of an average dust charge, charge fluctuation, and number of the bounded ions are calculated. These calculations have shown that dust charging in a mix of a 'light' gas with a small additive of a 'heavy' gas and ions has a number of features which lead, in particular, to considerable (up to thousand times) increase of dust kinetic energy - this effect was observed in the experiments.

  13. The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

    Directory of Open Access Journals (Sweden)

    Chodun Rafal

    2016-06-01

    Full Text Available In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case. In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field seem to confirm the validity of the research assumption. What is the most spectacular - the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction.

  14. The power supplies for the glow discharge electrodes in Wendelstein 7-X

    Energy Technology Data Exchange (ETDEWEB)

    Rummel, Thomas, E-mail: thomas.rummel@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Wendelsteinstr. 1, D-17491 Greifswald (Germany); Fuellenbach, Frank [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Wendelsteinstr. 1, D-17491 Greifswald (Germany); Boehm, Guenther; Kaesler, Wolfgang; Burek, Rainer [PPT Puls-Plasmatechnik GmbH, Feldstr. 56, D-44141 Dortmund (Germany); Pingel, Steffen; Spring, Anett; Schacht, Joerg; Woelk, Andreas [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, Wendelsteinstr. 1, D-17491 Greifswald (Germany)

    2011-10-15

    The conditioning of the Wendelstein 7-X (W7-X) plasma vessel will be done by glow discharges. Ten electrodes are placed inside of the vessel. Due to the three dimensional geometry the conditions for the ignition and the stabilization of a glow discharge can vary from one electrode to the other electrode. Therefore ten individual power supplies with maximum ratings of 3 kV and 3 A will be used. The ten power supplies are individually controlled by a PLC based control system. This control system is a major part of the overall glow discharge system, because it has to allow the combination of two or more power supplies to groups, which can be controlled in a similar way. The glow discharge is planned to run up to a week in steady state mode. This requires a sophisticated monitoring system of the parameters of the power supplies and the implementation of a proper matrix of reaction after failures. One aim of the Wendelstein 7-X control system is the remote control of all activities from the W7-X main control room. The glow discharge power supply control has to allow such operation and special procedures for exchange of control rights were implemented. The power supply system was developed, manufactured installed and tested in collaboration between IPP and PPT.

  15. Non-Thermal Equilibrium Atmospheric Pressure Glow-Like Discharge Plasma Jet

    Science.gov (United States)

    Chang, Zhengshi; Yao, Congwei; Zhang, Guanjun

    2016-01-01

    Non-thermal equilibrium atmospheric pressure plasma jet (APPJ) is a cold plasma source that promises various innovative applications, and the uniform APPJ is more favored. Glow discharge is one of the most effective methods to obtain the uniform discharge. Compared with the glow dielectric barrier discharge (DBD) in atmospheric pressure, pure helium APPJ shows partial characteristics of both the glow discharge and the streamer. In this paper, considering the influence of the Penning effect, the electrical and optical properties of He APPJ and Ar/NH3 APPJ were researched. A word “Glow-like APPJ” is used to characterize the uniformity of APPJ, and it was obtained that the basic characteristics of the glow-like APPJ are driven by the kHz AC high voltage. The results can provide a support for generating uniform APPJ, and lay a foundation for its applications. supported by National Natural Science Foundation of China (Nos. 51307133, 51125029, 51221005) and the Fundamental Research Funds for the Central Universities of China (Nos. xjj2012132, xkjc2013004)

  16. The measurement and analysis of electric fields in glow discharge plasmas

    International Nuclear Information System (INIS)

    Interest in glow discharge plasmas has remained high for many decades because of their widespread application as a source of incoherent and coherent light, in plasma processing materials, in pulsed power devices, and in other technologies. Plasma etching of semiconductors and various plasma deposition process emerged as major applications during the 1980s. The technological significance of plasma processing is described in Plasma Processing of Materials. More fundamental work on glow discharges also advanced greatly during the 1980s. For example, substantial progress was made through the use of laser diagnostics to study glow discharges and as a result of the dramatically increased computing power that became available in the 1980s to model glow discharges. Many of the laser diagnostics are described in Radiative Processes in Discharge Plasmas. Kinetic theory models, in particular, became far more sophisticated and realistic during the 1980s. This article is a review of recent work that used optical diagnostics to study electric fields in glow discharge plasmas. Alternative methods for measuring electric electric fields in plasmas include electron beam deflection and electrostatic probes. Optical techniques have important advantages over these methods: They can be used at higher pressures and discharge current densities than electron beam deflection; and they are noninvasive, unlike electrostatic probes. In addition, optical techniques are usually easier to apply in a highly pure system than either of the alternative methods. 46 refs., 23 figs., 1 tab

  17. Anomalous behaviour of thermoluminescence from quartz: A case of glow peaks from a Nigerian quartz

    Energy Technology Data Exchange (ETDEWEB)

    Ogundare, F.O. [Department of Physics, Rhodes University, P.O. Box 94, Grahamstown 6140 (South Africa) and Physics Department, University of Ibadan, Ibadan (Nigeria)]. E-mail: ogun_dare@yahoo.com; Chithambo, M.L. [Department of Physics, Rhodes University, P.O. Box 94, Grahamstown 6140 (South Africa); Oniya, E.O. [Department of Physics and Electronics, Adekunle Ajasin University, Akungba-Akoko, Ondo State (Nigeria)

    2006-05-15

    Anomalous behaviour displayed by a thermoluminescence (TL) glow peak as radiation dose increases in a Nigerian quartz is presented. The glow curves of the phosphor have four clear glow peaks. The peak temperatures of the first three glow peaks were found to be constant with change in radiation dose at 82, 148 and 200 deg. C for the sample readout at a heating rate of 1 deg. Cs{sup -1}. The peak temperature of the fourth peak, which is at around 320 deg. for a sample irradiated to a dose of 63Gy and heated at 1 deg. Cs{sup -1}, displays anomalous behaviour with increase in dose relative to the first three peaks. The temperature at which this peak occurs increases with dose to about 335 deg. C for 177Gy and then decreases thereafter as dose is further increased. The change is explained on the assumption that the peak may be complex consisting of several overlapping first-order glow peaks each with different TL behaviour.

  18. Anomalous behaviour of thermoluminescence from quartz: A case of glow peaks from a Nigerian quartz

    International Nuclear Information System (INIS)

    Anomalous behaviour displayed by a thermoluminescence (TL) glow peak as radiation dose increases in a Nigerian quartz is presented. The glow curves of the phosphor have four clear glow peaks. The peak temperatures of the first three glow peaks were found to be constant with change in radiation dose at 82, 148 and 200 deg. C for the sample readout at a heating rate of 1 deg. Cs-1. The peak temperature of the fourth peak, which is at around 320 deg. for a sample irradiated to a dose of 63Gy and heated at 1 deg. Cs-1, displays anomalous behaviour with increase in dose relative to the first three peaks. The temperature at which this peak occurs increases with dose to about 335 deg. C for 177Gy and then decreases thereafter as dose is further increased. The change is explained on the assumption that the peak may be complex consisting of several overlapping first-order glow peaks each with different TL behaviour

  19. Determination of trap parameters for thermoluminescence glow peaks of red thermoluminescence of quartz from Japan

    Science.gov (United States)

    Song, K. W.; Kim, K. B.; Hong, D. G.

    Red thermoluminescence in quartz has been generally observed in samples from volcanic deposits or archaeological burnt materials. Red thermoluminescence emission quartz has gained attention as a radiation dosimeter for thermoluminescence dating due to the high-dose saturation level and long-term stability of the thermoluminescence signal. The technique for this application can be improved with an understanding of various trap parameters associated with thermoluminescence glow peaks. The repeated initial rise and computerized glow curve deconvolution methods are used to determine the number of thermoluminescence glow peaks and trap parameters for red thermoluminescence from two types of quartz (Tazawa and Yuda samples) from Japan. For both quartz samples, the glow curves were best described as a superposition of seven glow peaks with activation energies of 0.76-1.95 eV and 0.89-1.91 eV for the Tazawa and Yuda samples, respectively. These results provide useful information for the investigation of the intrinsic characteristics of quartz crystals in the research fields relevant to dating and dosimetry.

  20. Design and performance of large area monolithic electron guns for the Aurora KrF laser system

    International Nuclear Information System (INIS)

    Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy

  1. Daurinol Enhances the Efficacy of Radiotherapy in Lung Cancer via Suppression of Aurora Kinase A/B Expression.

    Science.gov (United States)

    Woo, Jong Kyu; Kang, Ju-Hee; Shin, DongYun; Park, Seong-Hyeok; Kang, Kyungsu; Nho, Chu Won; Seong, Je Kyung; Lee, Sang-Jin; Oh, Seung Hyun

    2015-07-01

    The aurora kinases constitute one family of serine/threonine kinases whose activity is essential for mitotic progression. The aurora kinases are frequently upregulated in human cancers and are associated with sensitivity to chemotherapy in certain ones. In the present study, we investigated whether aurora kinases could be a target to overcome radioresistance or enhance the radiosensitivity of lung cancer. For that purpose, we determined the therapeutic potential of daurinol, an investigational topoisomerase inhibitor, alone and in combination with radiation, by observing its effect on aurora kinases. Daurinol decreased cell viability and proliferation in human colon and lung cancer cells. Gene expression in daurinol-treated human colon cancer cells was evaluated using RNA microarray. The mRNA expression of 18 genes involved in the mitotic spindle check point, including aurora kinase A (AURKA) and aurora kinase B (AURKB), was decreased in daurinol-treated human colon cancer cells as compared with vehicle-treated cells. As expected, radiation increased expression levels of AURKA and AURKB. This increase was effectively attenuated by siRNAs against AURKA and AURKB, which suppressed cell growth and increased apoptosis under radiation. Furthermore, the expression of AURKA and AURKB was suppressed by daurinol in the presence or absence of radiation in colon and lung cancer cells. Daurinol alone or in combination with radiation decreased lung cancer growth in xenograft mouse models. Our data clearly confirm the antitumor and radiosensitizing activity of daurinol in human lung cancer cells through the inhibition of AURKA and AURKB. PMID:25882311

  2. Apocenter glow in eccentric debris disks: implications for Fomalhaut and $\\epsilon$ Eridani

    CERN Document Server

    Pan, Margaret; Kuchner, Marc J

    2016-01-01

    Debris disks often take the form of eccentric rings with azimuthal asymmetries in surface brightness. Such disks are often described as showing "pericenter glow", an enhancement of the disk brightness in regions nearest the central star. At long wavelengths, however, the disk apocenters should appear brighter than their pericenters: in the long wavelength limit, we find the apocenter/pericenter flux ratio scales as 1+e for disk eccentricity e. We produce new models of this "apocenter glow" to explore its causes and wavelength dependence and study its potential as a probe of dust grain properties. Based on our models, we argue that several far-infrared and (sub)millimeter images of the Fomalhaut and epsilon Eridani debris rings obtained with Herschel, JCMT, SHARC II, ALMA, and ACTA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks' dust grain properties and size distributions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fucheng, E-mail: hdlfc@hbu.cn; He, Yafeng; Dong, Lifang [Hebei Key Lab of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2014-12-15

    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.

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

    International Nuclear Information System (INIS)

    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

  5. Physics of self-sustained oscillations in the positive glow corona

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung Nae [Micro Devices Group, Micro Systems Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd, Mt. 14-1 Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of)

    2012-07-15

    The physics of self-sustained oscillations in the phenomenon of positive glow corona is presented. The dynamics of charged-particle oscillation under static electric field has been briefly outlined; and, the resulting self-sustained current oscillations in the electrodes have been compared with the measurements from the positive glow corona experiments. The profile of self-sustained electrode current oscillations predicted by the presented theory qualitatively agrees with the experimental measurements. For instance, the experimentally observed saw-tooth shaped electrode current pulses are reproduced by the presented theory. Further, the theory correctly predicts the pulses of radiation accompanying the abrupt rises in the saw-tooth shaped current oscillations, as verified from the various glow corona experiments.

  6. Thermal glow curves from quenched pure and doped potassium chloride single crystal

    International Nuclear Information System (INIS)

    Thermoluminescence property of quenched potassium chloride, pure and doped with PbCl2, has been studied. Quenching from 650degC enhances the glow output by a much larger amount than can be explained on the basis of enhancement of F-centres formation in quenched samples. Moreover, the glow peaks which are associated with divalent impurities and first stage of colouration are amply intensified due to quenching. Electrolytic colouration, which involved quenching, however, diminishes the integrated light output, when the coloured crystal is exposed to X-rays and warmed up. These results have been explained on the basis of the fact that the recombination efficiency of electrons and holes can be changed by various pretreatment of the samples. A new peak in the glow curve of quenched has also been observed. (author)

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

    Science.gov (United States)

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

    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.

  8. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, C.P. 52750, Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

    2011-10-15

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I{sub M}) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: >Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. > The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. > The peak intensity at the maximum (I{sub M}) of the glow curves decreases. > Shifts to higher temperature were observed as the heating rate increased. > Similar behavior of the kinetics parameters was noticed.

  9. Decomposition Characteristics of an Artificial Biogas in a Low-Pressure DC Glow Discharge

    Science.gov (United States)

    Itoh, Yasuhiro; Oshita, Takamasa; Satoh, Kohki; Itoh, Hidenori

    The decomposition characteristics of an artificial biogas, which is a mixture of CH4, CO2 and H2S, using a low pressure DC glow discharge have been investigated. It is found that H2, CO, C2H2, H2O, CS2 and COS are produced from the artificial biogas in the glow discharge. About 65 % of hydrogen atoms in CH4 are converted into H2 at the input energy of 800 J, at which CH4 is completely decomposed, and the decomposition characteristics of the artificial biogas has little dependency on H2S additive. Farther, H2S has a tendency to be decomposed earlier than the other components of the artificial biogas. When the glow discharge is generated in the artificial biogas with H2S, some of carbon atoms are found to deposit on electrodes and the wall of a discharge chamber.

  10. Discharge Characteristics in Atmospheric Pressure Glow Surface Discharge in Helium Gas

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Chen; WANG Long

    2005-01-01

    @@ Atmospheric pressure glow discharge is observed for the first time in a surface discharge generator in flowing helium. Electrical and optical methods are used to measure the characteristics of atmospheric pressure glow discharge for different voltages. The results show that discharge current waveforms are asymmetric for the different polarities of the applied voltage. A continuous discharge profile with a width of several microseconds appears for per half cycle of the applied voltage when the voltage is increased to a certain value. The short-pulsed discharge and the continuous current would result from the Townsend breakdown and glow discharge mechanisms respectively. The properties of surface discharge in stagnant helium are completely different from that in flowing helium.

  11. Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure

    Science.gov (United States)

    Liu, Xinkun; Xu, Jinzhou; Cui, Tongfei; Guo, Ying; Zhang, Jing; Shi, Jianjun

    2013-07-01

    A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm-1Torr-1, which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap.

  12. Deuterium retention in graphite and its removal by inert gas glow discharge

    International Nuclear Information System (INIS)

    The hydrogen isotope retention and its removal by inert gas glow discharge for graphite was investigated by residual gas analysis. The amount of retained hydrogen isotope in graphite during the deuterium glow discharge was about 1.0×1017 cm2, which was one order of magnitude larger than that in 316L stainless steel or tungsten. The removal ratio of hydrogen isotope by helium, neon and argon glow discharge cleaning were 49%, 22% and 6% respectively. These removal ratios were similar to those for the stainless steel, but larger than the tungsten. The removal ratio in graphite can be explained by both the depth distribution of incident deuterium in the materials and the etching depth. (author)

  13. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.;

    2010-01-01

    discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F(-) and TaO(2)F(-) are enhanced relative to positive ion signals and can be......A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime of the...... the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed....

  14. Repetitive nanosecond glow discharge in atmospheric pressure air

    Science.gov (United States)

    Packan, Denis

    Nonequilibrium, weakly ionized plasmas are widely used in the industry, but they are restricted to the domain of continuous discharges at low gas pressure or with specialty gases because of stability and power budget constraints. In this study, repetitively pulsed discharges were investigated as a way to decrease the power budget of atmospheric air plasmas by several orders of magnitude compared to continuous discharges, for an electron density of 1012 cm-3. The principle of the pulsed scheme is to use nanosecond electrical pulses to ionize air diffusely and with high efficiency, and to match the pulse interval with the recombination time of the plasma in order to maintain an elevated average electron density. Maxwellian and non-Maxwellian models of the physical processes in the discharge were examined, and the discharge parameters were chosen to minimize the power. Using a 10 ns, 12 kV, 100 kHz repetitive pulse generator, it was found that a repetitive nanosecond glow discharge could be operated in stable manner in atmospheric pressure air at 2000 K at an electron density of about 10 12 cm-3. Two pulsed discharges, with repetition frequencies of 100 kHz and 30 kHz, are described in this work. The electrode gap is 1 cm and the pulsed voltage is about 5 kV/cm. Electrical and optical methods were developed to measure the electron density in the discharge. The electron density was measured from the electrical conductivity during both the pulse and recombination phases, from the absolute intensity of the N2 Second Positive system during the pulse phase, and from the NO-gamma system during the recombination phase. The average electron density was found to be 1.4 x 1012 cm -3 for the 100 kHz discharge, and 1.8 x 102 cm-3 for the 30 kHz discharge, with peak values of 2 x 1012 cm-3 and 1013 cm-3, respectively. The power budget for the 30 kHz discharge was measured, from the voltage and current during the pulse phase, to be about 10 W/cm3, which represents an improvement of

  15. The effect of the impact of comet Shoemaker Levy-9 on Jupiter's aurorae

    Science.gov (United States)

    Miller, S.; Achilleos, N.; Dinelli, B. M.; Lam, H. A.; Tennyson, J.; Jagod, M.-F.; Geballe, T. R.; Trafton, L. M.; Joseph, R. D.; Ballester, G. E.; Baines, K.; Brooke, T. Y.; Orton, G.

    We present infrared spectra and images of the jovian aurorae taken at wavelengths sensitive to the H3+ molecular ion during the period around the impact of Comet Shoemaker Levy-9. The spectra were obtained using CGS4 on the United Kingdom Infrared Telescope and the images using NSFcam on NASA's Infrared Telescope Facility. Comparison with spectra obtained in May, 1993, shows that while the relative intensities of the northern and southern auroral zones prior to and during impact week (July 16-22, 1994) were broadly comparable with those of 1993, a few days after the last collision the northern aurora was considerably enhanced and its southern counterpart somewhat depressed. The north/south auroral ratio was returning to more normal values a week later. The effect of material drifting from the impact sites to the southern auroral zone is discussed in relation to these results.

  16. Aurora multikilojoule KrF laser system prototype for inertial confinement fusion

    International Nuclear Information System (INIS)

    Aurora is the Los Alamos National Laboratory short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration for large-scale ultraviolet laser systems of interest for short wavelength, inertial confinement fusion (ICF) investigations. The systems is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF targets using an --1-km-long optical beam path. The entire Aurora KrF laser system is described and the design features of the following major system components are summarized: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, target irradiation apparatus, and alignment and controls systems

  17. Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence

    CERN Document Server

    Hallinan, G; Cotter, G; Bourke, S; Harding, L K; Pineda, J S; Butler, R P; Golden, A; Basri, G; Doyle, J G; Kao, M M; Berdyugina, S V; Kuznetsov, A; Rupen, M P; Antonova, A

    2015-01-01

    Aurorae are detected from all the magnetized planets in our Solar System, including Earth. They are powered by magnetospheric current systems that lead to the precipitation of energetic electrons into the high-latitude regions of the upper atmosphere. In the case of the gas-giant planets, these aurorae include highly polarized radio emission at kilohertz and megahertz frequencies produced by the precipitating electrons, as well as continuum and line emission in the infrared, optical, ultraviolet and X-ray parts of the spectrum, associated with the collisional excitation and heating of the hydrogen-dominated atmosphere. Here we report simultaneous radio and optical spectroscopic observations of an object at the end of the stellar main sequence, located right at the boundary between stars and brown dwarfs, from which we have detected radio and optical auroral emissions both powered by magnetospheric currents. Whereas the magnetic activity of stars like our Sun is powered by processes that occur in their lower a...

  18. Time sequence analysis of flickering auroras. I - Application of Fourier analysis. [in atmosphere

    Science.gov (United States)

    Berkey, F. T.; Silevitch, M. B.; Parsons, N. R.

    1980-01-01

    Using a technique that enables one to digitize the brightness of auroral displays from individual fields of a video signal, we have analyzed the frequency content of flickering aurora. Through the application of Fourier analysis to our data, we have found that flickering aurora contains a wide range of enhanced frequencies, although the dominant frequency enhancement generally occurs in the range 6-12 Hz. Each incidence of flickering that we observed was associated with increased radio wave absorption. Furthermore, we have found that flickering occurs in bright auroral surges, the occurrence of which is not limited to the 'breakup' phase of auroral substorms. Our results are interpreted in terms of a recently proposed theory of fluctuating double layers that accounts for a number of the observational features.

  19. Phase-locked coaxial reflex diodes for Aurora and other drivers

    Science.gov (United States)

    Phelps, David A.

    1990-04-01

    High power microwave (11PM) experiments with Aurora reflex diodes (ARDs) are analyzed. In particular the multi-wave guide logistics 11PM peak envelope power (PEP) and waveform consistency problems associated with multi-guide radial extraction are reviewed. A novel design involving an outer coaxial cavity to extract power from the ARD cavity via 2535 appropriately placed ports or an equivalently loaded peripheral opening (sideshoot aperture) is described. Tmproved extraction mode selection phase locking frequency stabilization and waveform smoothing via this coaxial ARD (or CARD) is predicted. Staged physics studies and scaling experiments to validate the 11PM operation of a full-scale CARD on a Pocobeam and Aurora are recommended. 1.

  20. 110° C thermoluminescence glow peak of quartz – A brief review

    Indian Academy of Sciences (India)

    D K Koul

    2008-12-01

    The 110°C glow peak of quartz, though unstable at room temperature, has worked wonderfully in archaeology and retrospective dosimetry due to its pre-dose sensitization property. Various aspects of the peak, like its nature, defect centres involved, the impact of different stimuli and its application have been extensively studied. The main aims of this review are to (i) summarize briefly the work carried out on the various facets of this TL glow peak during the last four decades and (ii) identify the areas which need further attention in order to have a better understanding of the luminescence characteristics of this TL peak.

  1. PIC/MCC Simulation of Glow Discharge Plasma in Four-Anode Device

    Institute of Scientific and Technical Information of China (English)

    YUAN Zhongcai; SHI Jiaming; XU Bo

    2007-01-01

    Numerical simulations by the code of Object-Oriented PIC (Particle-in-Cell) and the Monte Carlo Collision (MCC) method were carried out in order to obtain an insight into the characteristics of plasmas generated by glow discharges in low pressure helium in a four-anode DC glow discharge device. The results show that, the pressure, the external mirror magnetic field, and the virtual breadth of the annular electrode affect the radial distribution of the plasma density and temperature. The simulations are instructive for further experiments.

  2. Thermoluminescence glow-curve deconvolution functions for mixed order of kinetics and continuous trap distribution

    CERN Document Server

    Kitis, G

    2000-01-01

    New glow-curve deconvolution functions are proposed for mixed order of kinetics and for continuous-trap distribution. The only free parameters of the presented glow-curve deconvolution functions are the maximum peak intensity (I sub m) and the maximum peak temperature (T sub m), which can be estimated experimentally together with the activation energy (E). The other free parameter is the activation energy range (DELTA E) for the case of the continuous-trap distribution or a constant alpha for the case of mixed-order kinetics.

  3. Wavelet based time-frequency and multifractal analysis of the glow discharge plasma instabilities

    CERN Document Server

    Nurujjaman, Md; Iyengar, A N Sekar

    2009-01-01

    Wavelet based ridge patterns and multifractal analysis have been carried out of the anode glow related floating potential fluctuations of a glow discharge plasma. Wavelet based ridge plots and multifractal spectrum were constructed for the fluctuations for different discharge voltages. Presence of the strong and weak chaos has been explained qualitatively from the ridge plots and from the multifractal spectrum different quantities like correlation and fractal dimension, degree of multifractality, etc., have been estimated at different discharge voltages. Wavelet based analysis is very much consistent with nonlinear time series analysis.

  4. Second Order Fluid Glow Discharge Model Sustained by Different Source Terms

    International Nuclear Information System (INIS)

    Behavior of charged particles in a DC low pressure glow discharge is studied. The electric properties of the glow discharge in argon, maintained by a constant source term with uniform electron and ion generation, between two plane electrodes or by secondary electron emission at the cathode, are determined. A fluid model is used to solve self-consistently the first three moments of the Boltzmann equation coupled with the Poisson equation. The stationary spatial distribution of the electron and ion densities, the electric potential, the electric field, and the electron energy, in a two-dimensional (2D) configuration, are presented.

  5. Gas flow effects on the submicrosecond pulsed atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    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.

  6. Thermoluminescence glow curve involving any extent of retrapping or any order of kinetics

    Indian Academy of Sciences (India)

    Jai Prakash

    2013-09-01

    Adirovitch set of equations has been modified to explain the mechanisms involved in thermoluminescence (TL) glow curve. A simple model is proposed which explains the occurrence of TL glow curve involving any extent of retrapping or any order of kinetics. It has been observed that the extents of recombination and simultaneous rewrapping decide the order of kinetics involved. TL decay parameters, order of kinetics and initial concentration of trapped electrons per unit volume are evaluated easily and conveniently. It has been observed that retrapping increases with increasing order of kinetics.

  7. Short-term low-temperature glow discharge nitriding of 316L austenitic steel

    Directory of Open Access Journals (Sweden)

    T. Frączek

    2011-07-01

    Full Text Available The AISI 316L austenitic steel after glow discharge nitriding at temperature of T = 673 K and duration of τ=14,4 ks, for two different variants of specimen arrangement in the glow-discharge chamber was investigated. In order to assess the effectiveness of nitriding process, the surface layers profile analysis examination, surface hardness and hardness profile examination, the analysis of surface layer structures and corrosion resistance tests were performed. It has been found that application of a booster screen effects in a nitrogen diffusion depth increment into the 316L austenitic steel surface, what results in the surface layer thickness escalation.

  8. Overheating Willingness to Pay: Who Gets Warm Glow and What It Means for Valuation

    OpenAIRE

    Interis, Matthew G.; Haab, Timothy C.

    2014-01-01

    In traditional contingent valuation, the researcher seeks the amount a respondent is willing, ceteris paribus, to pay to obtain something. But if a respondent receives a “warm glow†from a yes response, ceteris is not paribus. In estimating willingness to pay (WTP) to reduce environmental impacts from consumption of transportation fuel, we find that respondents who were relatively less environmentally focused in the past receive greater warm-glow benefits from a “yes†response and have ...

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

    International Nuclear Information System (INIS)

    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

  10. An Assessment of Using Glow Curve Fitting Procedures for Obtaining Information on Exposure History

    International Nuclear Information System (INIS)

    A detailed analysis has been performed of the usefulness of glow peak area ratios to determine when, during a dosemeter assignment period, an exposure has taken place. Several heating rates, including the fast rates usually used in routine dosimetry, have been used to quantify the impact of heating rate on such analysis. Large differences in glow peak positions and smaller changes in peak widths resulted from different heating rates. The results indicate that curve fitting techniques and determination of peak area ratios to determine exposure history have very limited usefulness at heating rates generally used in routine dosimetry. (author)

  11. Pilot study on the application of computerised glow curve analysis in TL based personal dosimetry services

    International Nuclear Information System (INIS)

    Preliminary results of an inter-laboratory collaborative work on the application of computerised glow curve analysis to TL personal dosimetry are presented. Very simple analysis methods have proved to be useful for the evaluation of glow curves similar to those encountered in the dosimetric control of radiation workers. A first result obtained in the study has been the possibility of simplifying the TL working procedures by eliminating pre-annealing or pre-heating steps employed in conventional systems to avoid low temperature peaks. The presence of these unwanted peaks can be detected by the computerised evaluation methods, discriminating their contribution to the dosimetric TL data. (author)

  12. Status of the Aurora laser system: Angular-multiplexed multikilojoule krypton fluoride prototype for inertial fusion

    International Nuclear Information System (INIS)

    In this presentation, the authors report on the present status of the Aurora system including: The operation of the final stage 1-X 1-m laser at the 10-kJ level; the generation of 5-ns pulses by the front end; integration of the front end, multiplexer, amplifiers, and the extraction of long-pulse energy from the amplifier chain. Progress on the design and construction of the demultiplexer are also reported

  13. Localization of Aurorae with 10 m High Power Radar Technique, using a Rotating Antenna

    OpenAIRE

    Hellgren, Gösta; Meos, Johan

    2011-01-01

    The paper describes the 10 m high power recorder with a rotating antenna that is used since May 1951 for the localization of aurorae at the Radio Wave Propagation Laboratory of the Kiruna Geophysical Observatory (67.8° N, 20.5° E). Continuous observations during the time May 1951–March 1952 have disclosed periods of auroral activity. The preliminary results from these observations indicate that there is a good correlation between the auroral activity, the magnetic activity, and ...

  14. Bora and Aurora-A continue to activate Plk1 in mitosis

    Czech Academy of Sciences Publication Activity Database

    Bruinsma, W.; Macůrek, Libor; Freire, R.; Lindqvist, A.; Medema, R.H.

    2014-01-01

    Roč. 127, č. 4 (2014), s. 801-811. ISSN 0021-9533 R&D Projects: GA ČR GA13-18392S Grant ostatní: Ministerio de Economía y Competitividad(ES) SAF2010-22357; CONSOLIDER-Ingenio(NL) CDS2007-0015 Keywords : Aurora-A * Bora * Mitosis * Plk1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.432, year: 2014

  15. New Treatment of Medullary and Papillary Human Thyroid Cancer: Biological Effects of Hyaluronic Acid Hydrogel Loaded With Quercetin Alone or in Combination to an Inhibitor of Aurora Kinase.

    Science.gov (United States)

    Quagliariello, Vincenzo; Armenia, Emilia; Aurilio, Caterina; Rosso, Francesco; Clemente, Ottavia; de Sena, Gabriele; Barbarisi, Manlio; Barbarisi, Alfonso

    2016-08-01

    The aim of this paper is based on the use of a hyaluronic acid hydrogel of Quercetin tested alone and in combination to an inhibitor of Aurora Kinase type A and B (SNS-314) on human medullary and papillary thyroid cancer cells. Biological investigations were focused on the cellular uptake of the hydrogel, cell viability, antioxidant, and cytokines secretion studies. Quercetin delivered from hydrogel show a time and CD44 dependent interaction with both cell lines with significant anti-inflammatory effects. Combination of Quercetin and SNS-314 leads to a synergistic cytotoxic effect on medullary TT and papillary BCPAP cell lines with a significant reduction of the IC50 value. These results, highlights the importance of synergistic effect of the hyaluronic acid hydrogel of Quercetin with SNS-314 in the regulation of human thyroid cancer cell proliferation and emphasize the anti-tumor activity of these molecules. J. Cell. Physiol. 231: 1784-1795, 2016. © 2015 Wiley Periodicals, Inc. PMID:26660542

  16. Effect of acidic lake water on survival of aurora trout (Salvelinus fontinalis) embryos and alevins

    Energy Technology Data Exchange (ETDEWEB)

    Snucins, E.J.; Liimatainen, V.A.; Gale, P.A.

    1988-01-01

    During the 1960s the aurora trout, a rare color variant of the brook trout, disappeared from its native waters in northeastern Ontario. Its disappearance was attributed to acidification of the waters by atmospheric deposition of industrial emissions from metal smelters at Sudbury, Ontario. Recently, water quality in the Sudbury area has improved due to emission reductions. These experiments were designed to assess the toxicity of current water quality in the native lakes of aurora trout. During May 1984, hatchery-reared aurora trout alevins were held for 4 days in 3 of their native lakes (Whiligig, Whitepine and Wilderness with pH 4.5-4.8) and a control lake, Regan Lake (pH 6.5), and survival rates were assessed. In a second bioassay, embryos and alevins were buried in the substrate at 3 groundwater upwelling sites, and survival rates were assessed. The final test involved a 14-day exposure of groundwater-reared fish to ambient conditions.

  17. Features of the polar cap aurorae in the southern polar region

    International Nuclear Information System (INIS)

    The data of the all-sky camera and photometer at Vostok station in the Antarctic nearpole region have been used for analysis of the auroral features in the southern polar cap. It is shown that the sun-aligned arcs appear in the polar cap with a delay-time of about an hour relative to the northward turning of the interplanetary magnetic field (IMF) and that they can remain for many hours provided the IMF is invariable. The distribution of these aurorae in the dayside polar cap displays a θ-shaped pattern which is clearly separated from the latitude-oriented arcs in the auroral oval. Disappearance of the sun-aligned arcs after the southward turning of the IMF occurs much faster: in 10-15 min. The observation of the polar cap arcs immersed in a wide band of diffuse luminescence implies that the sun-aligned arcs should be located within the θ-aurora transpolar band. It is concluded that the distribution of the aurorae in the polar cap, auroral oval and in the day-side cusp requires a closed structure for the magnetosphere. The convection pattern corresponding to a closed magnetosphere suggests the formation of closed cavities with a stagnation plasma regime in the distant tail of the magnetosphere. (author)

  18. Pulsating aurora observed on the ground and in-situ by the Van Allen Probes

    Science.gov (United States)

    Lessard, M.; Cohen, I. J.; Denton, R. E.; Engebretson, M. J.; Kletzing, C.; Wygant, J. R.; Bounds, S. R.; Smith, C. W.; MacDowall, R. J.; Kurth, W. S.

    2013-12-01

    Early observations and theory related to pulsating aurora suggested that the electrons that drive this aurora originate from the equatorial region of the magnetosphere and that a likely process that can scatter these electrons would involve chorus waves. Recent satellite observations during pulsating auroral events have provided important "firsts", including evidence of strong correlations between pulsating auroral patches and in-situ lower-band chorus (THEMIS), as well as correlations with energetic electron precipitation in the vicinity of geosynchronous orbit (GOES). These results provide important information regarding particle dynamics, leading to a question about how the chorus might be driven. We present observations of the Van Allen Probes in conjunction with a pulsating aurora event, as confirmed by observations on the ground. The in-situ data again show the presence of lower-band chorus. However, magnetic and electric field data also show that the wave bursts coincide with an apparent poloidal field-line resonance, begging the question of whether the resonance might be responsible for driving the VLF waves.

  19. A compact SR light source for x-ray lithography 'AURORA'

    International Nuclear Information System (INIS)

    A compact synchrotron radiation (SR) light source called AURORA has been developed for industrial use. It is specially designed for X-ray lithography. AURORA consists of a storage ring, injector microtron and SR light beam lines. The storage ring is a superconducting single magnet machine, designed to accelerate a 150 MeV electron beam to 650 MeV and to store as high as 300 mA current. The injector is a racetrack microtron (RTM) producing a pulsed 150 MeV beam. As many as 16 SR light beam channels are available for AURORA. Prototypes of the storage ring and RTM are constructed, and beam commissioning is performed. A hundred and fifty MeV electron beam of a pulsed current 10 μA from the RTM is successfully injected to the ring and accelerated to 600 MeV and 10 mA current stored with a lifetime of more than 20 hours. The half-integer method investigated is shown to work well with the injection efficiency being found to be very high. Improvement of the design is now under way. (N.K.)

  20. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis.

    Science.gov (United States)

    Chou, En-Ju; Hung, Liang-Yi; Tang, Chieh-Ju C; Hsu, Wen-Bin; Wu, Hsin-Yi; Liao, Pao-Chi; Tang, Tang K

    2016-03-29

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity. PMID:26997271

  1. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

    Directory of Open Access Journals (Sweden)

    En-Ju Chou

    2016-03-01

    Full Text Available CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity.

  2. Inter-domain Cooperation in INCENP Promotes Aurora B Relocation from Centromeres to Microtubules

    Directory of Open Access Journals (Sweden)

    Armando van der Horst

    2015-07-01

    Full Text Available The chromosomal passenger complex is essential for error-free chromosome segregation and proper execution of cytokinesis. To coordinate nuclear division with cytoplasmic division, its enzymatic subunit, Aurora B, relocalizes from centromeres in metaphase to the spindle midzone in anaphase. In budding yeast, this requires dephosphorylation of the microtubule-binding (MTB domain of the INCENP analog Sli15. The mechanistic basis for this relocalization in metazoans is incompletely understood. We demonstrate that the putative coiled-coil domain within INCENP drives midzone localization of Aurora B via a direct, electrostatic interaction with microtubules. Furthermore, we provide evidence that the CPC multimerizes via INCENP’s centromere-targeting domain (CEN box, which increases the MTB affinity of INCENP. In (prometaphase, the MTB affinity of INCENP is outcompeted by the affinity of its CEN box for centromeres, while at anaphase onset—when the histone mark H2AT120 is dephosphorylated—INCENP and Aurora B switch from centromere to microtubule localization.

  3. Interplanetary magnetic field structure at Saturn inferred from nanodust measurements during the 2013 aurora campaign

    Science.gov (United States)

    Hsu, H.-W.; Kempf, S.; Badman, S. V.; Kurth, W. S.; Postberg, F.; Srama, R.

    2016-01-01

    Interactions between the solar wind and planetary magnetospheres provide important diagnostic information about the magnetospheric dynamics. The lack of monitoring of upstream solar wind conditions at the outer planets, however, restrains the overall scientific output. Here we apply a new method, using Cassini nanodust stream measurements, to derive the interplanetary magnetic field structure during the 2013 Saturn aurora campaign. Due to the complex dynamical interactions with the interplanetary magnetic field, a fraction of fast nanodust particles emerging from the Saturnian system is sent back into the magnetosphere and can be detected by a spacecraft located within. The time-dependent directionality caused by the variable interplanetary magnetic field enable these particles to probe the solar wind structure remotely. Information about the arrival time of solar wind compression regions (coupled with the heliospheric current sheet crossings) as well as the field direction associated with the solar wind sector structure can be inferred. Here we present a tentative identification of the interplanetary magnetic field sector structure based on Cassini nanodust and radio emission measurements during the 2013 Saturn aurora campaign. Our results show that, the interplanetary magnetic field near Saturn during 2013-080 to 176 was consistent with a two-sector structure. The intensifications of aurora and the radio emission on 2013-095, 112 and 140 coincide with the IMF sector boundaries, indicating that the encounter of the compressed solar wind is the main cause of the observed activities.

  4. Presumable European aurorae in the mid AD 770s were halo displays

    CERN Document Server

    Neuhaeuser, Dagmar

    2015-01-01

    The interpretation of the strong 14-C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A "red cross/crucifix" in AD 773/4/6 from the Anglo-Saxon Chronicle, "inflamed shields" in AD 776 (both listed in the aurora catalogue of Link 1962), and "riders on white horses" in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three were halo displays: The "red cross" or "crucifix" is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the "inflamed shields" and the "riders on white horses" were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2...

  5. Observation of O+ (4P-4D0 lines in electron aurora over Svalbard

    Directory of Open Access Journals (Sweden)

    K. Throp

    2004-09-01

    Full Text Available This work reports on observations of O+ lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (Hβ, N+2 1N(0,2 and N+2 1N(1,3. The oxygen ion multiplet (4639-4696Å is blended with the band. It is found that in electron aurora, the brightness of this multiplet, is on average, about 0.1 of the total brightness. A joint optical and incoherent scatter radar study of an electron aurora event shows that the ratio is enhanced when the ionisation in the upper E-layer (140-190km is significant with respect to the E-layer peak below 130km. Rayed arcs were observed on one such occasion, whereas on other occasions the auroral intensity was below the threshold of the imager. A one-dimensional electron transport model is used to estimate the cross section for production of the multiplet in electron collisions, yielding 0.18x10-18cm2.

  6. The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays.

    Science.gov (United States)

    Alawiah, A; Bauk, S; Marashdeh, M W; Nazura, M Z N; Abdul-Rashid, H A; Yusoff, Z; Gieszczyk, W; Noramaliza, M N; Adikan, F R Mahamd; Mahdiraji, G A; Tamchek, N; Muhd-Yassin, S Z; Mat-Sharif, K A; Zulkifli, M I; Omar, N; Wan Abdullah, W S; Bradley, D A

    2015-10-01

    In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF. PMID:26188687

  7. Iridium Coating Deposited by Double Glow Plasma Technique — Effect of Glow Plasma on Structure of Coating at Single Substrate Edge

    International Nuclear Information System (INIS)

    Double glow plasma technique has a high deposition rate for preparing iridium coating. However, the glow plasma can influence the structure of the coating at the single substrate edge. In this study, the iridium coating was prepared by double glow plasma on the surface of single niobium substrate. The microstructure of iridium coating at the substrate edge was observed by scanning electron microscopy. The composition of the coating was confirmed by energy dispersive spectroscopy and X-ray diffraction. There was a boundary between the coating and the substrate edge. The covered area for the iridium coating at the substrate edge became fewer and fewer from the inner area to the outer flange-area. The bamboo sprout-like particles on the surface of the substrate edge were composed of elemental niobium. The substrate edge was composed of the Nb coating and there was a transition zone between the Ir coating and the Nb coating. The interesting phenomenon of the substrate edge could be attributed to the effects of the bias voltages and the plasma cloud in the deposition chamber. The substrate edge effect could be mitigated or eliminated by adding lots of small niobium plates around the substrate in a deposition process. (plasma technology)

  8. Injúrias mecânicas e seus efeitos em pêssegos 'Aurora-1' Effect of mechanical injuries on 'Aurora-1' peaches

    Directory of Open Access Journals (Sweden)

    Giorgia Fernanda Kasat

    2007-08-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos das injúrias mecânicas por corte, compressão e impacto na qualidade pós-colheita de pêssegos 'Aurora-1'. Na injúria por impacto, os pêssegos foram deixados cair duas vezes de uma altura de 1,20 m. Por compressão, os frutos foram colocados sob um bloco exercendo um peso constante de 3 kg por 10 minutos. Para a injúria por corte, promoveram-se três incisões longitudinalmente. Manteve-se, ainda, um lote de pêssegos intactos, correspondente ao controle. Após esses tratamentos, os frutos foram armazenados a 10±1,5 °C e 85±2% UR por 8 dias. Avaliaram-se o teor de sólidos solúveis (SS, de acidez titulável (AT e a relação SS/AT, a perda de massa fresca, a aparência, a coloração, a firmeza e o conteúdo de carboidratos solúveis. As injúrias mecânicas promoveram marcas nos pêssegos 'Aurora-1', afetando a aparência dos mesmos, que obtiveram nota ruim a partir do sexto dia de armazenamento. Esses pêssegos, quando submetidos à injúria de impacto, apresentaram maior perda de massa fresca que os do controle, da compressão e do corte. As áreas lesionadas apresentaram-se mais escurecidas, menos amareladas, com menor cromaticidade e menos firmes que as áreas dos frutos não-submetidas às injúrias. Esse efeito deletério também foi verificado quando os frutos eram submetidos à injúria por Impacto, quando comparado com os demais tratamentos. As injúrias mecânicas promoveram um amadurecimento mais rápido dos frutos, verificado pelos maiores valores da relação SS/AT.This work aimed to evaluate the effect of mechanical injuries, impact, compression and cut on the postharvest quality of peaches cv. Aurora-1. Impact injury was obtained dropping fruit, twice, from a height of 1.20 m. Compression injury was performed with the fruit submitted to weight (3 kg for 10 minutes. Cut injury was obtained cutting fruits, three times, in the longitudinal direction. after these treatments

  9. The dayside ultraviolet aurora and convection responses to a southward turning of the interplanetary magnetic field

    Directory of Open Access Journals (Sweden)

    K. A. McWilliams

    Full Text Available We examine the large-scale ultraviolet aurora and convection responses to a series of flux transfer events that immediately followed a sharp and isolated southward turning of the IMF. During the interval of interest, SuperDARN was monitoring the plasma convection in the dayside northern ionosphere, while the VIS Earth Camera and the Far Ul-traviolet Imager (UVI were monitoring the northern hemisphere’s ultraviolet aurora. Reconnection signatures were seen in the SuperDARN HF radar data in the postnoon sector following a sharp southward turning of the IMF. The presence of flux transfer events is supported by measurements of a classic dispersed ion signature in the low-altitude cusp from the DMSP spacecraft. Subsequent to the onset of reconnection, the postnoon convection and ultraviolet aurora expanded in concert, reaching 18 MLT in half an hour. The auroral oval was found to move equatorward at the convection speed in the 16–18 MLT sector, implying that it was related directly to an adiaroic magnetospheric boundary. In the present study, we have estimated the field-aligned current response to magnetic reconnection in terms of the vorticity of the ionospheric plasma convection velocity. The convection velocities were obtained using two methods: (a direct reconstruction of the full vector velocities from bistatic measurements of the convection by the SuperDARN HF radars in a relatively small region of the auroral zone, and (b from global-scale spherical harmonic fits to the SuperDARN velocities deduced from the map potential model. Regions of high vorticity, which were predicted to be an estimate of a component of the total field-aligned current, agree extremely well with the images of the dayside UV aurora, indicating that, in this case, the plasma vorticity is an excellent estimator of the morphology of dayside field-aligned currents (FACs. The morphology of the aurora and ionospheric electric field in the postnoon sector supports the

  10. Auroras and Space Weather Celebrating the International Heliophysics Year in Classroom

    Science.gov (United States)

    Craig, N.; Peticolas, L. M.; Angelopoulos, V.; Thompson, B.

    2007-05-01

    2007 Celebrates the International Heliophysics year and its outreach has a primary objective, to "demonstrate the beauty, relevance and significance of Space and Earth Science to the world." NASA's first five-satellite mission, THEMIS (Time History of Events and Macroscale Interactions during Substorms), was launched on February 17, 2007 and is to investigate a key mystery surrounding the dynamics of the auroras- when, where, and how are they triggered? When the five probes align perfectly over the North American continent- every four days - and with 20 ground stations in Northern Canada and Alaska with automated, all-sky cameras will document the auroras from Earth. To monitor the large-scale local effects of the currents in space, THEMIS Education and Outreach program has installed 10 ground magnetometers, instruments that measure Earth's magnetic field, in competitively selected rural schools around the country and receive data. The THEMIS Education and Outreach Program shares the IHY objective by bringing in this live local space weather data in the classrooms and engaging the teachers and students on authentic research in the classroom. The data are displayed on the school computer monitors as well as on the THEMIS E/PO website providing the local data to the science mission as well as schools. Teachers use the data to teach about the aurora not only in math and science, but also in Earth science, history and art. These students and their teachers are our ambassadors to rural America and share the excitement of learning and teaching with their regional teachers. We will share how authentic space science data related to Earth's magnetic field and auroras can be understood, researched, predicted and shared via the internet to any school around the globe that wished to be part of tracking solar storms. Complimenting IHY, World Space Week will take place from October 4-10th and this year. World Space week is "an international celebration of science and technology

  11. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    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 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

  12. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    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 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

  13. Dependence of the transition from Townsend to glow discharge on secondary emission

    NARCIS (Netherlands)

    Raizer, Y.P.; Ebert, U.; Sijacic, D.

    2004-01-01

    In a recent paper Sijacic and Ebert have systematically studied the transition from Townsend to glow discharge, refering to older work from von Engel (1934) up to Raizer (1991), and they stated a strong dependendence on secondary emission gamma from the cathode. We here show that the earlier results

  14. Surface analysis by glow discharge spectrometry: cathode zone and sputtering yield

    International Nuclear Information System (INIS)

    Applications of the glow discharge optical spectroscopy for surface analysis are numerous. Moreover, this method enables to get qualitative and semi-quantitative results which are already significant. However, we should improve our knowledge of the physical parameters involved in the glow discharge lamp mechanisms and learn to handle such phenomena. The problems can be divided into two categories: sputtering of the target under argon ions accelerated in the cathode dark space, and luminous emission of torn away species which reach the negative glow region. Our aim was to take stock of the present theoretical knowledge which can be applied to the specific self-maintained glow discharge plasma. Moreover, we tried to link together (often roughly) the basic discharge parameters, i.e. current intensity I, voltage of the lamp Vg, pressure of the gas p. Specially a comparison between theoretical and experimental results was established concerning the pure target sputtering yields. The contribution of the argon ions striking the cathode is estimated taking into account their energetic distribution. The role of the fast argon neutrals produced by charge exchange with the ions is important; we evaluated their energetic distribution and their contribution to sputtering. The total theoretical sputtering yield is inferred: the comparison with experimental results is presented. The role of the gas temperature is emphasized

  15. Analysis of TLD-900 glow curves: results on single peak properties

    International Nuclear Information System (INIS)

    In this paper we present fading experimental measurements on CaSO4:Dy (TLD-900) ribbons and computer calculated evaluations of single glow peak characteristics and their time dependence. The same method is also used to identify the time elapsed since an anomalous irradiation superposed to the normal one. (author)

  16. SkyGlowNet: an Internet-Enabled Light at Night Monitoring System

    Science.gov (United States)

    Craine, Erin M.; Craine, Eric R.; Craine, Brian L.; Crawford, David L.

    2013-05-01

    The "Sky Glow Network" (SkyGlowNet) is an internet connected depository of photometric light at night (LAN) data that are collected automatically by static, internet-enabled Sky Brightness Meters (iSBMs). The data are collected nightly at high temporal frequency and can be used to monitor extended areas of sky brightness on hourly, nightly, monthly, seasonal, and annual cycles over long periods of time. The photometry can be used for scientific and community planning purposes, as well as a powerful tool for science, technology, engineering, and mathematics (STEM) educational outreach programs. The effective and efficient use of light in modern society has become an important and contentious issue that urgently requires better technical and societal understanding. It is important to us as astronomers, and will become increasingly relevant as dark sky areas shrink as a result of poorly implemented lighting. We outline the structure of SkyGlowNet, describe the iSBM unit, and discuss how to interact with the SkyGlowNet website. We discuss how these data can help us preserve observing sites in the future.

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

    Science.gov (United States)

    Reece Roth, J.

    2000-10-01

    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.

  18. Thermoluminescence glow curves of Ca2+ and Sr2+ doped LiCl single crystals

    International Nuclear Information System (INIS)

    Effects of Ca2+ and Sr2+ dopants on the thermoluminescence glow curves of LiCl monocrystals have been studied. The crystals containing different amounts of Sr2+ and Ca2+, resp., were irradiated either by 60Co γ-radiation or by 90Sr beta particles

  19. Effect of rf power on the electrical properties of glow-discharge a-Si:H

    OpenAIRE

    TOLUNAY, Hüseyin

    2002-01-01

    Hydrogenated amorphous silicon films were prepared in an rf glow-discharge system by decomposing undiluted silane at various rf power densities. Dark conductivity and photoconductivity of the films have been measured in the temperature range 420K-100K at four different photon fluxes. It was observed that both dark conductivity and photoconductivity increase with increasing rf power density.

  20. Quantitative Analysis on Carbon Migration in Double-Glow Discharge Plasma Surface Alloying Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhen-xia; WANG Cong-zeng; ZHANG Wen-quan; SU Xue-kuan

    2004-01-01

    Carbon migration is of great significance in double-glow discharge plasma surface alloying process, but literature of quantitative analysis about carbon migration is relatively scarce. In this paper differential equations of the carbon and metal concentration distribution were established. By means of differential equations carbon migration was described and a numerical solution was acquired. The computational results fit the experiment results quite well.

  1. A study on water treatment induced by plasma with contact glow discharge electrolysis

    International Nuclear Information System (INIS)

    Oxidative degradation of eight kinds of dyes induced by plasma in aqueous solution was investigated with contract glow discharge electrolysis (CGDE). It has been demonstrated that these eight dyes underwent degradation in CGDE, where Fe2+ could be utilised to raise the efficiency of degradation of dyes

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-02-01

    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.

  3. Direct solar-thermal hydrogen production from water using nozzle/skimmer and glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Pyle, W.R.; Hayes, M.H.; Spivak, A.L. [H-Ion Solar Co., Richmond, CA (United States)

    1996-12-31

    An investigation of direct solar-thermal hydrogen and oxygen production from water is described. Nozzle jets and skimmers have been used for separation of the products and suppression of recombination. The dissociation of water vapor and the separation of its products was conducted in plasma-enhanced, non-equilibrium glow discharges.

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

    International Nuclear Information System (INIS)

    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/cm2 at low discharge power of 175 W where ion density of plasma ball is estimated to be over 3.7x1012 cm-3.

  5. Thermoluminescence glow-curve deconvolution functions for first, second and general orders of kinetics

    International Nuclear Information System (INIS)

    Thermoluminescence glow-curve deconvolution (GCD) functions are proposed for first, second and general orders of kinetics. The free parameters of the GCD functions are the maximum peak intensity (Im) and the maximum peak temperature (Tm), which can be obtained experimentally. The activation energy (E) and the order of kinetics (b) in the case of general order kinetics are the additional free parameters. (author)

  6. A Functionally Superior Second-Generation Vector Expressing an Aurora Kinase-A-Specific T-Cell Receptor for Anti-Leukaemia Adoptive Immunotherapy.

    Science.gov (United States)

    Casey, Nicholas Paul; Fujiwara, Hiroshi; Tanimoto, Kazushi; Okamoto, Sachiko; Mineno, Junichi; Kuzushima, Kiyotaka; Shiku, Hiroshi; Yasukawa, Masaki

    2016-01-01

    Aurora Kinase A is a cancer-associated protein normally involved in the regulation of mitosis. Being over-expressed in a range of cancers, it is a suitable target for cell-based immunotherapy. Gene transfer of T-cell receptor sequences cognisant of HLA-A*0201-restricted Aurora Kinase A antigen has previously been shown to transfer specific immunoreactivity against the target peptide in a Human Lymphocyte Antigen-restricted manner. While T cell receptor gene-transfer has great potential in overcoming the difficulties of isolating and expanding tumour-reactive lymphocytes from a patient's own cells, one hurdle is potential mispairing and competition between exogenous and endogenous T cell receptor chains. We have used a retroviral vector design bearing a short-interfering RNA that downregulates endogenous T cell receptor chains, without affecting expression of the transgenic T cell receptor sequences. The T cell receptor expression cassette also includes a 2A self-cleaving peptide, resulting in equimolar expression of the T cell receptor alpha and beta chains, further enhancing formation of the desired T cell receptor. Via a simple, modular cloning method, we have cloned the alpha and beta chains of the anti-Aurora Kinase A-reactive T cell receptor into this 'siTCR' vector. We then compared the activity of this vector against the original, 'conventional' vector across a panel of assays. T cell receptors expressed from the siTCR-vector retained the cytotoxic functionality of the original vector, with evidence of reduced off-target reactivity. The rate of expression of correctly-formed T cell receptors was superior using the siTCR design, and this was achieved at lower vector copy numbers. Maintaining T cell receptor efficacy with a reduced vector copy number reduces the risk of genotoxicity. The siTCR design also reduces the risk of mispairing and cross-reactivity, while increasing the functional titre. Such improvements in the safety of T cell receptor gene

  7. A Functionally Superior Second-Generation Vector Expressing an Aurora Kinase-A-Specific T-Cell Receptor for Anti-Leukaemia Adoptive Immunotherapy.

    Directory of Open Access Journals (Sweden)

    Nicholas Paul Casey

    Full Text Available Aurora Kinase A is a cancer-associated protein normally involved in the regulation of mitosis. Being over-expressed in a range of cancers, it is a suitable target for cell-based immunotherapy. Gene transfer of T-cell receptor sequences cognisant of HLA-A*0201-restricted Aurora Kinase A antigen has previously been shown to transfer specific immunoreactivity against the target peptide in a Human Lymphocyte Antigen-restricted manner. While T cell receptor gene-transfer has great potential in overcoming the difficulties of isolating and expanding tumour-reactive lymphocytes from a patient's own cells, one hurdle is potential mispairing and competition between exogenous and endogenous T cell receptor chains. We have used a retroviral vector design bearing a short-interfering RNA that downregulates endogenous T cell receptor chains, without affecting expression of the transgenic T cell receptor sequences. The T cell receptor expression cassette also includes a 2A self-cleaving peptide, resulting in equimolar expression of the T cell receptor alpha and beta chains, further enhancing formation of the desired T cell receptor. Via a simple, modular cloning method, we have cloned the alpha and beta chains of the anti-Aurora Kinase A-reactive T cell receptor into this 'siTCR' vector. We then compared the activity of this vector against the original, 'conventional' vector across a panel of assays. T cell receptors expressed from the siTCR-vector retained the cytotoxic functionality of the original vector, with evidence of reduced off-target reactivity. The rate of expression of correctly-formed T cell receptors was superior using the siTCR design, and this was achieved at lower vector copy numbers. Maintaining T cell receptor efficacy with a reduced vector copy number reduces the risk of genotoxicity. The siTCR design also reduces the risk of mispairing and cross-reactivity, while increasing the functional titre. Such improvements in the safety of T cell

  8. P-glycoprotein and breast cancer resistance protein in acute myeloid leukaemia cells treated with the Aurora-B Kinase Inhibitor barasertib-hQPA

    International Nuclear Information System (INIS)

    Aurora kinases play an essential role in orchestrating chromosome alignment, segregation and cytokinesis during mitotic progression, with both aurora-A and B frequently over-expressed in a variety of human malignancies. Over-expression of the ABC drug transporter proteins P-glycoprotein (Pgp) and Breast cancer resistance protein (BCRP) is a major obstacle for chemotherapy in many tumour types with Pgp conferring particularly poor prognosis in acute myeloid leukaemia (AML). Barasertib-hQPA is a highly selective inhibitor of aurora-B kinase that has shown tumouricidal activity against a range tumour cell lines including those of leukaemic AML origin. Effect of barasertib-hQPA on the pHH3 biomarker and cell viability was measured in a panel of leukaemic cell lines and 37 primary AML samples by flow cytometry. Pgp status was determined by flow cytometry and BCRP status by flow cytometry and real-time PCR. In this study we report the creation of the cell line OCI-AML3DNR, which over-expresses Pgp but not BCRP or multidrug resistance-associated protein (MRP), through prolonged treatment of OCI-AML3 cells with daunorubicin. We demonstrate that Pgp (OCI-AML3DNR and KG-1a) and BCRP (OCI-AML6.2) expressing AML cell lines are less sensitive to barasertib-hQPA induced pHH3 inhibition and subsequent loss of viability compared to transporter negative cell lines. We also show that barasertib-hQPA resistance in these cell lines can be reversed using known Pgp and BCRP inhibitors. We report that barasertib-hQPA is not an inhibitor of Pgp or BCRP, but by using 14[C]-barasertib-hQPA that it is effluxed by these transporters. Using phosphoHistone H3 (pHH3) as a biomarker of barasertib-hQPA responsiveness in primary AML blasts we determined that Pgp and BCRP positive primary samples were less sensitive to barasertib-hQPA induced pHH3 inhibition (p = <0.001) than samples without these transporters. However, we demonstrate that IC50 inhibition of pHH3 by barasertib-hQPA was achieved in

  9. P-glycoprotein and breast cancer resistance protein in acute myeloid leukaemia cells treated with the Aurora-B Kinase Inhibitor barasertib-hQPA

    Directory of Open Access Journals (Sweden)

    Russell Nigel H

    2011-06-01

    Full Text Available Abstract Background Aurora kinases play an essential role in orchestrating chromosome alignment, segregation and cytokinesis during mitotic progression, with both aurora-A and B frequently over-expressed in a variety of human malignancies. Over-expression of the ABC drug transporter proteins P-glycoprotein (Pgp and Breast cancer resistance protein (BCRP is a major obstacle for chemotherapy in many tumour types with Pgp conferring particularly poor prognosis in acute myeloid leukaemia (AML. Barasertib-hQPA is a highly selective inhibitor of aurora-B kinase that has shown tumouricidal activity against a range tumour cell lines including those of leukaemic AML origin. Methods Effect of barasertib-hQPA on the pHH3 biomarker and cell viability was measured in a panel of leukaemic cell lines and 37 primary AML samples by flow cytometry. Pgp status was determined by flow cytometry and BCRP status by flow cytometry and real-time PCR. Results In this study we report the creation of the cell line OCI-AML3DNR, which over-expresses Pgp but not BCRP or multidrug resistance-associated protein (MRP, through prolonged treatment of OCI-AML3 cells with daunorubicin. We demonstrate that Pgp (OCI-AML3DNR and KG-1a and BCRP (OCI-AML6.2 expressing AML cell lines are less sensitive to barasertib-hQPA induced pHH3 inhibition and subsequent loss of viability compared to transporter negative cell lines. We also show that barasertib-hQPA resistance in these cell lines can be reversed using known Pgp and BCRP inhibitors. We report that barasertib-hQPA is not an inhibitor of Pgp or BCRP, but by using 14[C]-barasertib-hQPA that it is effluxed by these transporters. Using phosphoHistone H3 (pHH3 as a biomarker of barasertib-hQPA responsiveness in primary AML blasts we determined that Pgp and BCRP positive primary samples were less sensitive to barasertib-hQPA induced pHH3 inhibition (p = 50 inhibition of pHH3 by barasertib-hQPA was achieved in 94.6% of these samples after 1

  10. Stereoscopic determination of all-sky altitude map of aurora using two ground-based Nikon DSLR cameras

    Science.gov (United States)

    Kataoka, R.; Miyoshi, Y.; Shigematsu, K.; Hampton, D.; Mori, Y.; Kubo, T.; Yamashita, A.; Tanaka, M.; Takahei, T.; Nakai, T.; Miyahara, H.; Shiokawa, K.

    2013-09-01

    A new stereoscopic measurement technique is developed to obtain an all-sky altitude map of aurora using two ground-based digital single-lens reflex (DSLR) cameras. Two identical full-color all-sky cameras were set with an 8 km separation across the Chatanika area in Alaska (Poker Flat Research Range and Aurora Borealis Lodge) to find localized emission height with the maximum correlation of the apparent patterns in the localized pixels applying a method of the geographical coordinate transform. It is found that a typical ray structure of discrete aurora shows the broad altitude distribution above 100 km, while a typical patchy structure of pulsating aurora shows the narrow altitude distribution of less than 100 km. Because of its portability and low cost of the DSLR camera systems, the new technique may open a unique opportunity not only for scientists but also for night-sky photographers to complementarily attend the aurora science to potentially form a dense observation network.

  11. Selected personal highlights from experimental space studies of the aurora (Hannes Alfvén Medal Lecture)

    Science.gov (United States)

    Marklund, Göran

    2013-04-01

    Aurora is a most spectacular and frequently occurring scenery in the winter polar sky, occurring on Earth and many other planets. To further our understanding of the physics of the aurora, numerous sounding rocket and satellite projects have been carried out since the 1960's. Results are presented for a small selection of these where the author and his research team at KTH were strongly engaged in the research, namely a series of rocket experiments and small satellite missions, and the European Space Agency Cluster multi-satellite mission. The electric field plays a fundamental role in the physics of the magnetosphere and of the aurora, such as for the acceleration of electrons and ions producing bright aurora and outflow of energetic plasma. The results include: An arc classification scheme based on the electric field variation across arcs; A method to derive global distributions of electrodynamical parameters for a given auroral oval distribution; The discovery of intense diverging electric fields and of their characteristics in the auroral downward current region; Using Cluster data to reveal how such diverging electric fields evolve in time and are closely tied to the formation of ionospheric density cavities; Reconstruction of an experimentally verified acceleration potential pattern of the aurora, being stable on a 5 min time scale. Finally, acceleration signatures and electrodynamics of large-scale auroral forms, such as spirals, surges, and polar boundary intensifications are discussed based on recent Cluster and DMSP satellite conjunctions.

  12. The real-time state of the aurora -- a research to operations need with a citizen science solution?

    Science.gov (United States)

    Heavner, M.; MacDonald, E.; Case, N.; McCloat, S.

    2015-12-01

    A prototype citizen science application called Aurorasaurus has been developed and launched in 2014. The goal of this platform is crowdsourcing observations of the aurora in real-time in order to assess global visibility of the aurora for the public. Users can submit observations, verify relevant social media observations, learn about the aurora, and receive location-based alerts based on verified reports, all in near real-time. The size and distribution of the citizen scientist community around the world has tremendous potential both for documenting the visible manifestations of global space weather impacts as well as providing quality control on the reported sightings. Information with high spatial and temporal resolution of the largest, most dynamic and mysterious space weather events is made possible by this solution, and this data can be integrated with other ground and space based measures of auroral activity. We will present initial results during the large geomagnetic events of 2015 and comparison to other measures of auroral activity. Our findings indicate the prototype application can be a valuable tool for real-time aurora knowledge and should be included in discussions of real-time aurora nowcasting needs. We will discuss those needs and assess the feasibility of available systems for meeting them.

  13. Records of sunspot and aurora during CE 960-1279 in the Chinese chronicle of the Song dynasty

    CERN Document Server

    Hayakawa, Hisashi; Kawamura, Akito D; Isobe, Hiroaki

    2015-01-01

    Records of sunspots and aurora observations in pre-telescopic historical documents can provide useful information about solar activity in the past. This is also true for extreme space weather events, as they may have been recorded as large sunspots observed by the naked eye or as low-latitude auroras. In this paper, we present the results of a comprehensive survey of records of sunspots and auroras in the Songshi, a Chinese formal chronicle spanning the tenth to the thirteenth century. This chronicle contains a record of continuous observations with well-formatted reports conducted as a policy of the government. A brief comparison of the frequency of observations of sunspots and auroras and the observations of radioisotopes as an indicator of the solar activity during corresponding periods is provided. This paper is the first step of our project in which we survey and compile the records of sunspots and aurora in historical documents from various locations and languages, ultimately providing it to the science...

  14. Thermal quenching in calcite and evaluation of quenching parameters from composite glow curve by a computerized resolved peak technique

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, J.M., E-mail: jitukalita09@gmail.com; Wary, G.

    2015-04-15

    Thermoluminescence (TL) glow curves of X-ray irradiated micro-grain calcite mineral were recorded at various heating rates (2, 4, 6, 8 and 10 K/s) under same linear temperature profile from 300 to 520 K. By using a Computerized Glow Curve Deconvolution technique, all composite glow curves of calcite were analyzed and the glow curves were found to be a combination of three distinct overlapping peaks. Activation energies corresponding to these three peaks were found to be 0.70, 0.60 and 1.30 eV respectively. For each set of computerized resolved peak, variation of peak maximum temperature, FWHM and peak area with heating rate were studied. Entire glow curves were found to be influenced by thermal quenching. Thermal quenching activation energy, W and the pre-exponential unitless constant, C were evaluated from each resolved peak individually. Thermal quenching activation energies for the three peaks were found to be 1.36±0.54, 1.14±0.73 and 1.38±0.40 eV respectively. The significance of determining the individual value of quenching parameters related to each peak for a composite glow curve is reported. - Highlights: • TL of X-ray irradiated calcite mineral was recorded at various heating rates. • Composite glow curves were found to be a combination of three overlapping peaks. • Glow curves were found to be influenced by thermal quenching. • Thermal quenching parameters were evaluated from the composite glow curves.

  15. R. B. Cunninghame Graham’s “Aurora La Cujiñi” (1898 : An Exploration / Aurora La Cujiñi” (1898 de R. B. Cunninghame Graham - Una indagación

    Directory of Open Access Journals (Sweden)

    John C. Mc Intyre

    2011-06-01

    Full Text Available Abstract: In Aurora La Cujiñi-A realistic sketch in Seville, published by the Scottish writer R. B. Cunninghame Graham in 1898, the frontispiece showed the sepia image of a female flamenco dancer. What might ‘La Cujiñi’ mean? Charles Davillier and Gustave Doré in 1862-63 note the existence of a Sevillan dancer with this name. In 2011 the present writer was gifted an old lithograph, in colour, published in Seville ‘c. 1850’ and entitled ‘Aurora La Cujiñí’ - with ñ and í. The two images are supplied. ‘Aurora La Cujiñi’ really existed. Graham’s sketch has five phases: Seville; the bullfight; the crowd’s return to town; a low-quality flamenco show; and the highly stirring performance by an initially anonymous female dancer - the dead Aurora brought back to life. Graham emphasises the Seville blend of blood and sensuality in a realist style also capable of mockery and criticism. Graham’s writing includes a good variety of well-controlled Spanish vocabulary, his empathy with horses and a deep nostalgia for times past. W. H. Hudson, writer and friend of Graham, in 1894 recommended that Graham should read the Argentine sketches published by Alfred Ébélot in 1890. In Aurora La Cujiñi Graham in 1898 is beginning to show mastery of the literary sketch. Question: Might Lorca have read Aurora La Cujiñi before drafting “Teoría y juego del duende”? Resumen: En Aurora La Cujiñi-A realistic sketch in Seville (1898 del escritor escocés R. B. Cunninghame Graham, el frontispicio llevaba la imagen en sepia de una bailadora de flamenco. ¿Qué podría significar ‘La Cujiñi’? Charles Davillier y Gustave Doré en 1862-1863 apuntan la existencia de una bailaora sevillana con este nombre. En 2011 al que esto escribe le regalaron una litografía antigua, en color, publicada en Sevilla ‘hacia 1850’ e intitulada ‘Aurora la Cujiñí’ - con ñ y con í. Se incluyen las dos imágenes. ‘Aurora La Cujiñi’ realmente

  16. Conservação de pêssego 'Aurora-1' armazenados sob refrigeração Keeping quality of peaches 'Aurora-1' stored under refrigeration

    OpenAIRE

    Luis Carlos Cunha Junior; Maria Fernanda Berlingieri Durigan; Ben-Hur Mattiuz

    2010-01-01

    Avaliou-se o comportamento pós-colheita de pêssegos da cv. Aurora-1 armazenados sob refrigeração. Os frutos foram colhidos em dois estádios de maturação, verde maduro (de vez) e maduro. Os lotes foram armazenados em três temperaturas (2°C; 6°C e 12°C), por 35 dias, e avaliados a cada sete dias: quanto à coloração da casca, perda acumulada de massa fresca (PMF), firmeza (FIR), aparência, teores de acidez titulável (AT), sólidos solúveis (SS), açúcares solúveis (AS) e redutores (AR), pectina so...

  17. Conservação de pêssego 'Aurora-1' armazenados sob refrigeração Keeping quality of peaches 'Aurora-1' stored under refrigeration

    Directory of Open Access Journals (Sweden)

    Luis Carlos Cunha Junior

    2010-06-01

    Full Text Available Avaliou-se o comportamento pós-colheita de pêssegos da cv. Aurora-1 armazenados sob refrigeração. Os frutos foram colhidos em dois estádios de maturação, verde maduro (de vez e maduro. Os lotes foram armazenados em três temperaturas (2°C; 6°C e 12°C, por 35 dias, e avaliados a cada sete dias: quanto à coloração da casca, perda acumulada de massa fresca (PMF, firmeza (FIR, aparência, teores de acidez titulável (AT, sólidos solúveis (SS, açúcares solúveis (AS e redutores (AR, pectina solúvel (PS e total (PT, além da porcentagem de solubilização de pectinas (SOL. A menor temperatura de armazenamento elevou o tempo de prateleira dos pêssegos, e os frutos "de vez" apresentaram melhor aparência. A PMF demonstrou um gradiente em função do aumento da temperatura, e os frutos "de vez" apresentaram menor perda ao final do armazenamento sob todas as temperaturas, quando comparados aos maduros. A coloração da casca dos frutos "de vez", a 2°C, teve pouca alteração, conferindo-lhes mudança de coloração de verde-amarelada para amarelo-clara; enquanto nas temperaturas de 6°C e 12°C esse gradiente foi mais intenso. O mesmo efeito foi verificado nos pêssegos maduros. A FIR sofreu efeito da temperatura, pois temperaturas menores sofreram redução mais lenta e AT dos pêssegos maduros foi superior aos "de vez". Não houve influência dos tratamentos nos teores de SS, AS e AR. Os pêssegos 'Aurora-1' não demonstraram sensibilidade ao frio, e os "de vez", armazenados a 2°C, tiveram vida útil de 35 dias.This work aimed to evaluate the postharvest of peaches cv. Aurora-1 stored under refrigeration. The fruit were harvested in two stages ("mature green" and ripe. The lots were stored at three temperatures (2°C, 6°C, and 12°C, for 35 days and evaluated every seven days for skin color, loss of fresh mass (PMF, firmness (FIR, appearance, titratable acidity (TA, soluble solids (SS, soluble (AS and reducing (AR sugars, soluble

  18. Ultraviolet aurora on outer planets: morphology and remote sensing of electron precipitation

    Science.gov (United States)

    Gerard, Jean-Claude; Bisikalo, Dmitry; Shematovich, Valery; Soret, Lauriane

    2016-07-01

    The aurora is the result of the interaction between energetic particles and the upper atmosphere of a planet. Generally, energetic particles from the magnetosphere penetrate the atmosphere, partly deposit their energy and are partly reflected. Their collisional interactions with the atmospheric atoms and molecules heat the atmosphere and produce auroral emissions. Consequently, the aurora then bears the signature of both the acceleration mechanism and the atmospheric structure and composition. Jupiter's UV auroral H2 and H emissions are generally divided into several components. The main auroral emission at Jupiter is associated with the giant current loop connecting the region of co-rotation breakdown in the middle magnetosphere with the ionosphere. The polar emissions observed inside the main emission are very variable over short timescales. The observed diffuse emission equatorward of the main emission is most likely related to precipitation resulting from wave-particle interactions. Finally, the satellite magnetic footprints are created by accelerated electrons resulting from the interaction between the Galilean moons and the plasma in the Jovian magnetosphere. Saturn's magnetosphere and its aurorae appear to be both solar wind driven as the terrestrial magnetosphere and rotationally dominated, similarly to Jupiter. In addition to the main auroral ring, transient features have been recently identified. Uranus displays aurorae quite different from the other two with faint small-size structures appearing following solar storm activity. These different processes are probably associated with different energy spectra of the precipitated electrons. We present an overview of recent results concerning the relation between morphology, variability and remote sensing of the auroral electron energy in the different components. We show that mapping the UV color ratio is a powerful tool to globally characterize the electron precipitation and the flux-energy relation

  19. Aurora kinase B is important for antiestrogen resistant cell growth and a potential biomarker for tamoxifen resistant breast cancer

    DEFF Research Database (Denmark)

    Larsen, Sarah L; Yde, Christina W; Laenkholm, Anne-Vibeke;

    2015-01-01

    endocrine resistance, immunohistochemistry was performed on archival primary tumor tissue from breast cancer patients who have received adjuvant endocrine treatment with tamoxifen. RESULTS: The selective Aurora kinase B inhibitor barasertib was identified to preferentially inhibit growth of fulvestrant...... and PARP cleavage in the fulvestrant resistant cells. Barasertib also exerted preferential growth inhibition of tamoxifen resistant T47D cell lines. Finally, high percentage of Aurora kinase B positive tumor cells was significantly associated with reduced disease-free and overall survival in 261 ER......-positive breast cancer patients, who have received tamoxifen as first-line adjuvant endocrine treatment. CONCLUSIONS: Our results indicate that Aurora kinase B is a driving factor for growth of antiestrogen resistant T47D breast cancer cell lines, and a biomarker for reduced benefit of tamoxifen treatment. Thus...

  20. The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70–130 kVp x-rays

    International Nuclear Information System (INIS)

    In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF. - Highlights: • Supralinearity was not observed within the dose range of 0.1–0.7 Gy. • Er doped silica CF showed a sub-linear response. • The peak height and Tmax showed a significant dependency on dose. • The kinetics parameters were highly dependence on dose

  1. Volumetric characterization of the Aurora magnetic tracker system for image-guided transorbital endoscopic procedures

    International Nuclear Information System (INIS)

    In some medical procedures, it is difficult or impossible to maintain a line of sight for a guidance system. For such applications, people have begun to use electromagnetic trackers. Before a localizer can be effectively used for an image-guided procedure, a characterization of the localizer is required. The purpose of this work is to perform a volumetric characterization of the fiducial localization error (FLE) in the working volume of the Aurora magnetic tracker by sampling the magnetic field using a tomographic grid. Since the Aurora magnetic tracker will be used for image-guided transorbital procedures we chose a working volume that was close to the average size of the human head. A Plexiglass grid phantom was constructed and used for the characterization of the Aurora magnetic tracker. A volumetric map of the magnetic space was performed by moving the flat Plexiglass phantom up in increments of 38.4 mm from 9.6 mm to 201.6 mm. The relative spatial and the random FLE were then calculated. Since the target of our endoscopic guidance is the orbital space behind the optic nerve, the maximum distance between the field generator and the sensor was calculated depending on the placement of the field generator from the skull. For the different field generator placements we found the average random FLE to be less than 0.06 mm for the 6D probe and 0.2 mm for the 5D probe. We also observed an average relative spatial FLE of less than 0.7 mm for the 6D probe and 1.3 mm for the 5D probe. We observed that the error increased as the distance between the field generator and the sensor increased. We also observed a minimum error occurring between 48 mm and 86 mm from the base of the tracker

  2. Large-scale KrF systems for inertial confinement fusion based on Aurora experience

    International Nuclear Information System (INIS)

    The ultimate amplifier in the Aurora system was originally conceived as a stackable module suitable for construction of much larger systems. The name habitually used to describe it, large aperture module (LAM), is derived from this concept. The principal initial objective of what is now named Aurora was to test the viability of this module and obtain working experience with it. Although it is no longer clear that this is the largest feasible amplifier size, or even that a large amplifier size is advantageous, it is still true that the working experience gained in Aurora creates a special place for this particular module size. It is valuable to examine the limitations and difficulties of stacking LAMs. The key concept is aperture combination. This reduces the complexity of the decoder by combining the outputs of several amplifiers in each time channel so that they can be directed to a common large delay mirror. For this to be effective, the relevant group of amplifiers must be placed close together. A layout containing 128 parallel LAMs in its ultimate gain stage is displayed and explained in detail. An improved version of the LAM might be capable of producing 25 kJ at its output window. This array would then produce 3.2 MJ, of which perhaps 2.8 MJ would reach the target. This layout contains eight separate decoders, each handling the output of a group of sixteen LAMs, arranged symmetrically around a central target chamber. This giant system divides naturally into subsystems which could be built to meet interim objectives

  3. A magnetohydrodynamic simulation study of Kronian field-aligned currents and auroras

    Science.gov (United States)

    Fukazawa, Keiichiro; Ogino, Tatsuki; Walker, Raymond J.

    2012-02-01

    Magnetohydrodynamic simulations of the interaction of Saturn's magnetosphere with the solar wind indicate that Kelvin-Helmholtz (K-H) waves can form on the dayside magnetopause when the interplanetary magnetic field (IMF) is northward. Dayside magnetic reconnection occurs at Saturn for northward IMF, and the combination of K-H waves and reconnection caused enhanced vorticity in Saturn's magnetosphere. We have used a very high resolution version (Δx = 0.1 RS) of our simulation code to study the consequences of the vortices and reconnection for the generation of field-aligned currents (FACs) and auroras in Saturn's ionosphere. We found three bands of alternating FACs toward and away from the dawn side of the ionosphere and two sets on the dusk side. The K-H waves generated a series of toward and away currents along the dayside magnetopause. In the ionosphere they appear as a series of spots of up and down currents. The K-H field-aligned currents are adjacent to nearly continuous currents located from 16:00 LT, to around past midnight, and to about 07:00 LT. The largest currents densities (j∥ > 5 × 10-8 A m-2) are found at the highest latitudes. They map to the magnetopause and to the near-Saturn tail region. We used the away current density and the Knight relationship to estimate the energy flux related to discrete auroras and obtained ˜1 mW m-2 in the region with the strongest currents. This gives approximately 7 GW for the auroral UV emitted power. We found a region of enhanced thermal energy flux in the region where cusp auroras are observed.

  4. Properties of thermoluminescence glow curves from tunneling recombination processes in random distributions of defects

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Pagonis, Vasilis, E-mail: vpagonis@mcdaniel.edu [Physics Department, McDaniel College, Westminster, MD 21157 (United States)

    2014-09-15

    Localized electronic recombination processes in donor–acceptor pairs of luminescent materials have been recently modeled using a new kinetic model based on tunneling. Within this model, recombination is assumed to take place via the excited state of the donor, and nearest-neighbor recombinations take place within a random distribution of centers. An approximate semi-analytical version of the model has been shown to simulate successfully thermally and optically stimulated luminescence (TL and OSL), linearly modulated OSL (LM-OSL) and isothermal TL processes. This paper presents a detailed analysis of the geometrical properties of the TL glow curves obtained within three different published versions of the model. The dependence of the shape of the TL glow curves on the kinetic parameters of the model is examined by allowing simultaneous random variations of the parameters, within wide ranges of physically reasonable values covering several orders of magnitude. It is found that the TL glow curves can be characterized according to their shape factors μ{sub g}, as commonly done in TL theory of delocalized transitions. The values of the shape factor are found to depend rather weakly on the activation energy E and the frequency factor s, but they have a strong dependence on the parameter ρ′ which characterizes the concentration of acceptors in the model. It is also shown by simulation that both the variable heating rate and initial rise methods are applicable in this type of model and can yield the correct value of the activation energy E. However, the initial rise method of analysis for the semianalytical version of the model fails to yield the correct E value, since it underestimates the low temperature part of the TL glow curves. Two analytical expressions are given for the TL intensity, which can be used on an empirical basis for computerized glow curve deconvolution analysis (CGCD). - Highlights: • Detailed study of TL glow curves in a tunneling model for

  5. Properties of thermoluminescence glow curves from tunneling recombination processes in random distributions of defects

    International Nuclear Information System (INIS)

    Localized electronic recombination processes in donor–acceptor pairs of luminescent materials have been recently modeled using a new kinetic model based on tunneling. Within this model, recombination is assumed to take place via the excited state of the donor, and nearest-neighbor recombinations take place within a random distribution of centers. An approximate semi-analytical version of the model has been shown to simulate successfully thermally and optically stimulated luminescence (TL and OSL), linearly modulated OSL (LM-OSL) and isothermal TL processes. This paper presents a detailed analysis of the geometrical properties of the TL glow curves obtained within three different published versions of the model. The dependence of the shape of the TL glow curves on the kinetic parameters of the model is examined by allowing simultaneous random variations of the parameters, within wide ranges of physically reasonable values covering several orders of magnitude. It is found that the TL glow curves can be characterized according to their shape factors μg, as commonly done in TL theory of delocalized transitions. The values of the shape factor are found to depend rather weakly on the activation energy E and the frequency factor s, but they have a strong dependence on the parameter ρ′ which characterizes the concentration of acceptors in the model. It is also shown by simulation that both the variable heating rate and initial rise methods are applicable in this type of model and can yield the correct value of the activation energy E. However, the initial rise method of analysis for the semianalytical version of the model fails to yield the correct E value, since it underestimates the low temperature part of the TL glow curves. Two analytical expressions are given for the TL intensity, which can be used on an empirical basis for computerized glow curve deconvolution analysis (CGCD). - Highlights: • Detailed study of TL glow curves in a tunneling model for random

  6. Stratospheric temperature and composition of Jupiter's polar aurora from IRTF-TEXES

    Science.gov (United States)

    Sinclair, J.; Orton, G. S.; Greathouse, T. K.; Fletcher, L. N.; Irwin, P. G. J.

    2015-10-01

    We perform an analysis of TEXES (Texas Echelon Cross Echelle Spectrograph, 5- to 25- μm,[1]) spectra of Jupiter's high latitudes observed in December 2014 in order to study the jovian polar aurora. The high resolving power (R˜85000) of TEXES allows a large altitude range (10 mbar to 0.01 mbar) in Jupiter's stratosphere to be sounded. Retrievals of temperature and stratospheric composition of these measurements therefore: 1) allow the vertical deposition of auroral energy to be determined and 2) quantify how the auro-ral processes modify the thermal structure and composition of the jovian stratosphere.

  7. Saturn’s UV aurora: the (high latitude) point of view of Cassini

    OpenAIRE

    Grodent, Denis; Bonfond, Bertrand; Gustin, Jacques; Radioti, Aikaterini; Gérard, Jean-Claude; Pryor, Wayne

    2013-01-01

    The high latitude vantage point of Cassini and its short distance to Saturn give rise to a unique opportunity for obtaining exceptional spectral images of the aurorae, along with in situ observations of the associated particles and magnetic field. Cassini’s T83 flyby of Titan significantly changed the inclination of the spacecraft’s orbit and marked the beginning of the XXM inclined phase 1 which will last until March 16, 2015. We will give an overview of the auroral emissions observed so ...

  8. Correlation between TL and OSL signals in KMgF3:Ce3+: Bleaching study of individual glow-peaks

    International Nuclear Information System (INIS)

    KMgF3:Ce3+ is an ultra sensitive Thermoluminescence (TL) material with a complex TL and OSL glow-curve structure. The aim of the present work is to attempt a one-to-one correspondence between specific TL glow-peaks and OSL components in KMgF3:Ce3+. The correlation study involves the deconvolution of the TL curves and the estimation of the bleaching decay constants for individual glow-peaks followed by the deconvolution of the LM-OSL curve using the estimated decay constants. It was found that the bleaching of each individual glow-peak takes place in three different rates; namely in a fast, medium and slow rate.

  9. Development of On-Line Direct Current Glow Discharge Source for Analysis of Isotope Ratio of Hydrogen

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The present research is focused on the analysis of isotope ratio of the hydrogen by measuring an intensity ratio of hydrogen/deuterium/tritium fluxes. The direct current glow discharge tube may provide a

  10. Expression of aurora kinase A is associated with metastasis-free survival in node-negative breast cancer patients

    International Nuclear Information System (INIS)

    Inhibitors targeting the cell cycle-regulated aurora kinase A (AURKA) are currently being developed. Here, we examine the prognostic impact of AURKA in node-negative breast cancer patients without adjuvant systemic therapy (n = 766). AURKA was analyzed using microarray-based gene-expression data from three independent cohorts of node-negative breast cancer patients. In multivariate Cox analyses, the prognostic impact of age, histological grade, tumor size, estrogen receptor (ER), and HER2 were considered. Patients with higher AURKA expression had a shorter metastasis-free survival (MFS) in the Mainz (HR 1.93; 95% CI 1.34 – 2.78; P < 0.001), Rotterdam (HR 1.95; 95% CI 1.45– 2.63; P<0.001) and Transbig (HR 1.52; 95% CI 1.14–2.04; P=0.005) cohorts. AURKA was also associated with MFS in the molecular subtype ER+/HER2- carcinomas (HR 2.10; 95% CI 1.70–2.59; P<0.001), but not in ER-/HER2- nor in HER2+ carcinomas. In the multivariate Cox regression adjusted to age, grade and tumor size, AURKA showed independent prognostic significance in the ER+/HER2- subtype (HR 1.73; 95% CI 1.24–2.42; P=0.001). Prognosis of patients in the highest quartile of AURKA expression was particularly poor. In addition, AURKA correlated with the proliferation metagene (R=0.880; P<0.001), showed a positive association with grade (P<0.001), tumor size (P<0.001) and HER2 (P<0.001), and was inversely associated with ER status (P<0.001). AURKA is associated with worse prognosis in estrogen receptor positive breast carcinomas. Patients with the highest AURKA expression (>75% percentile) have a particularly bad prognosis and may profit from therapy with AURKA inhibitors

  11. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determi...

  12. Simulation of gas breakdown in high pressure molecular lasers and study role of preionization in glow discharge by percolation theory

    International Nuclear Information System (INIS)

    In this paper, electrical breakdown in gases is simulated and the necessary condition for formation of a high pressure homogenous glow discharge is investigated by the percolation theory. In this simulation, a resistor network is used to simulate the electrical breakdown and then this resistor network is solved by percolation theory. The minimum initial electron density for formation of a glow discharge is calculated. Results are in agreement with published experimental results.

  13. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp

    OpenAIRE

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surfa...

  14. Analysis of the different zones of glow discharge of ethyl alcohol (C2H6O)

    International Nuclear Information System (INIS)

    The aim of this work is to explore the emission spectroscopy of ethyl alcohol in some regions, also is determine the result elements of the glow discharge, the spectrums were observed in a range of 200 at 1100 nm in the different zones inside of the tube at different distances of 20 and 30 cm. The elements are: in anode region C6H5 (483.02 nm), CHO (519.56 nm) and H2 (560.47 nm), in the positive column CO2+ (315.52 y 337.00 nm), O+ (357.48 nm), CH+ (380.61 nm) and CO+ (399.73 nm); in the cathode region we observed O+ (391.19 nm), CHOCHO (428.00 nm), CO+ (471.12 nm) and H2 (656.52 nm). C6H5, CHO y H2 species occurring in all regions analyzed varying the glow discharge emission intensity.

  15. Fading prediction in thermoluminescent materials using computerised glow curve deconvolution (CGCD)

    CERN Document Server

    Furetta, C; Weng, P S

    1999-01-01

    The fading of three different thermoluminescent (TL) materials, CaF sub 2 : Tm (TLD-300), manocrystalline LiF : Mg,Ti (DTG-4) and MgB sub 4 O sub 7 : Dy,Na has been studied at room temperature and at 50 deg. C of storage. The evolution as a function of the elapsed time of the whole glow curve as well as of the individual peaks has been analysed using the Computerised Glow Curve Deconvolution (CGCD) program developed at the NTHU. The analysis allows to predict the loss of the dosimetric information and to make any correction is necessary for using the TL dosimeters in practical applications. Furthermore, it is well demonstrated that using CGCD it is not necessary to anneal the peaks having a rapid fading to avoid, then, any interfering effect on the more stable peaks.

  16. Electrostatic analyzer for electron and ion energy in glow discharge tube

    International Nuclear Information System (INIS)

    The project, the construction and use of an electrostatic energy analyser (Faraday Cup) are described explaining physically its working mechanism. The analyser was used in a glow discharge tube with air and an air-argon mixture. A chapter with the theory of the glow discharge is included. The ion and electron temperatures, the plasma potential and the distribution function for ions and electrons were measured. The electron temperature and plasma potential were also measured using a Langmuir probe and the results show reasonable agreement with the results of the analyser. Good fits of the experimental electron and ion distribution functions were obtained with Maxwellian distributions centered values near the plasma potential. Finally, we discuss the performance of the analyser compared to Langmuir probes. (author)

  17. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    International Nuclear Information System (INIS)

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  18. Glow Discharge Mass Spectrometry Analysis of LX-17 and PBX-9502 High Explosive Samples

    Energy Technology Data Exchange (ETDEWEB)

    Nilsen, J; Castor, J I; Lane, M A; Overturf, G E

    2002-12-16

    As part of the Campaign 4 effort in A Division we have done an analysis of several high explosives that are used in the current nuclear stockpile. In particular we have looked at samples of LX-17 and PBX-9502. The analysis was done using the glow discharge mass spectrometer that is currently located in B132N and operated by Mark Lane of the Chemistry and Material Science (CMS) Directorate. George Overturf from CMS obtained small samples of high explosive for the measurements. From the analysis we wanted to verify the actual atomic composition of the high explosive, see how that compared with the nominal composition, and understand whether any significant impurities existed in the samples. We present the analysis of several LX-17 and PBX-9502 samples using the glow discharge mass spectrometer to measure both the main constituents of the high explosive as well as any trace materials that may be present.

  19. On the feasibility of inversion methods based on models of urban sky glow

    International Nuclear Information System (INIS)

    Multi-wavelength imaging luminance photometry of sky glow provides a huge amount of information on light pollution. However, the understanding of the measured data involves the combination of different processes and data of radiation transfer, atmospheric physics and atmospheric constitution. State-of-the-art numerical radiation transfer models provide the possibility to define an inverse problem to obtain information on the emission intensity distribution of a city and perhaps the physical properties of the atmosphere. We provide numerical tests on the solvability and feasibility of such procedures. - Highlights: • A method of urban sky glow inversion is introduced based on Monte-Carlo calculations. • Imaging photometry can provide enough information for basic inversions. • The inversion technique can be used to construct maps of light pollution. • The inclusion of multiple scattering in the models plays an important role

  20. The impact of light source spectral power distribution on sky glow

    Science.gov (United States)

    Luginbuhl, Christian B.; Boley, Paul A.; Davis, Donald R.

    2014-05-01

    The effect of light source spectral power distribution on the visual brightness of anthropogenic sky glow is described. Under visual adaptation levels relevant to observing the night sky, namely with dark-adapted (scotopic) vision, blue-rich (“white”) sources produce a dramatically greater sky brightness than yellow-rich sources. High correlated color temperature LEDs and metal halide sources produce a visual brightness up to 8× brighter than low-pressure sodium and 3× brighter than high-pressure sodium when matched lumen-for-lumen and observed nearby. Though the sky brightness arising from blue-rich sources decreases more strongly with distance, the visual sky glow resulting from such sources remains significantly brighter than from yellow sources out to the limits of this study at 300 km.

  1. Double Glow Plasma Hydrogen-free Carburizing on Commercial Purity Titanium

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gaohui; PAN Junde; HE Zhiyong; ZHANG Pingze; GAO Yuan; XU Zhong

    2005-01-01

    A carburized layer with special physical and chemical properties was formed on the surface of commercial purity titanium by a double glow plasma hydrogen-free carburizing technique. High-purity netlike solid graphite was used as a raw material and commercial purity titanium was used as the substrate material. Argon gas was used as the working gas. The carburized layer can be obviously observed under a microscope. X-ray diffraction indicates that TiC phase with higher hardness and dissociate state carbon phase was formed in the carburized layer. The glow discharge spectrum (GDS) analysis shows that the carbon concentration distributes gradiently along the depth of carburized layer. The surface hardness of the substrate increases obviously. The hardness distributes gradiently from the surface to inner of carburized layer. The friction coefficient reduces by more than 1/2, the ratio wear rate decreases by above three orders of magnitude. The wear resistance of the substrate material is improved consumedly.

  2. Glow corona generation and streamer inception at the tip of grounded objects during thunderstorms: revisited

    International Nuclear Information System (INIS)

    The initiation of streamers prior to a lightning strike can be reportedly inhibited by glow corona discharges generated from tall objects. In contrast to previous studies based on a simplified one-dimensional model of glow corona, a two-dimensional evaluation of the corona ion drift from tall objects is used here to analyse this effect quantitatively. Proper estimates for the corona space charge distribution generated during both the charging process of a thundercloud and the descent of the downward stepped leader are thus calculated. It is found that the shielding effect of the corona space charge on the streamer inception is not as severe as previously reported. Estimations of the effective height of the downward leader tip at which streamer inception takes place are presented and discussed for lightning rods and dissipation array systems. (paper)

  3. Analysis of non-conducting powders by glow-discharge atomic emission spectrography

    International Nuclear Information System (INIS)

    An analytical method for control of the impurity levels of non-conducting powders during their preparation (particularly milling processes) is proposed. Impurity concentrations between some hundredths and a few percent as well as admixtures concentrations higher than 10% are determined. The glow discharge emission spectrography is applied after briquetting the samples with an excess of copper powder using a Grimm-type glow discharge lamp and a grating plan spectrograph with photographic detection. Difficulties arise from the band spectra due to non-metallic elements in the sample and from insufficient grain sizes, mixture homogeneity and compactness of the briquettes. The efficiency and detection limits in determination of SiO2 and ZrO2 in Al2O3 and of SiO2 in Bi2Ru2O7 are described. (author)

  4. A reflex glow discharge as a plasma source for broad area electron beam generation

    International Nuclear Information System (INIS)

    The authors demonstrated an electron beam generation scheme in which two glow discharge electron guns are used in a reflex configuration to create a dense and cold plasma in a large volume. The thermal electrons from this plasma, created mainly by electron beam ionization, are subsequently accelerated in the gap between two grids by an externally applied electric field to produce a broad area electron beam. This electron beam current density and energy are independently controlled by the voltage applied to the glow discharge guns and by the electric field sustained between the grids respectively. They present a schematic representation of the electron gun used in the experimental demonstration of the concept reported here

  5. Uniqueness theorem for the non-local ionization source in glow discharge and hollow cathode

    CERN Document Server

    Gorin, Vladimir V

    2012-01-01

    The paper is devoted to the proof of the uniqueness theorem for solution of the equation for the non-local ionization source in a glow discharge and a hollow cathode in general 3D geometry. The theorem is applied to wide class of electric field configurations, and to the walls of discharge volume, which have a property of incomplete absorption of the electrons. Cathode is regarded as interior singular source, which is placed arbitrarily close to the wall. The existence of solution is considered also. During the proof of the theorem many of useful structure formulae are obtained. Elements of the proof structure, which have arisen, are found to have physical sense. It makes clear physical construction of non-local electron avalanche, which builds a source of ionization in glow discharge at low pressures. Last has decisive significance to understand the hollow cathode discharge configuration and the hollow cathode effect.

  6. A PC-based technique for creating 3D plots from monochromatic TL glow curves

    International Nuclear Information System (INIS)

    Recording of thermoluminescence emission spectra of many minerals is beset with the problem of detecting low (TL) emission intensities at high temperatures where the thermal noise is competing. Although very expensive techniques have been described in literature to obtain elegantly isometric plots of temperature, wavelength and TL intensity of weakly emitting minerals, the present work describes a very simple method of creating 3D projections of TL emission from measurements of monochromatic TL glow curves and using a commercially available PC software. A microprocessor-based data acquisition system has been indigenously developed and interfaced to the conventional TL glow-curve recorder. The digitised data are directly fed into an IBM compatible PC-XT and the 3D plots are created using a commercially available software named 'SURFER'. The programme can also generate contour maps. Typical plots are presented for the case of minerals like Scapolite, Spodumene an Kunzite. (author). 4 refs., 6 figs

  7. Numerical Study on Characteristics of Argon Radio-Frequency Glow Discharge with Varying gas Pressure

    Institute of Scientific and Technical Information of China (English)

    YU Qian; DENG Yong-Feng; LIU Yue; HAN Xian-Wei

    2008-01-01

    A one-dimensional fluid simulation on argon rf glow discharge with varying linearly gas pressure from 1 Torr to 100 Torr is performed. The model based on mass conservation equations for electron and ion under diffusion and mobility approximation, and the electron energy conservation equation is solved numerically by finite volume method. The numerical results show that a uniform plasma with high density can be obtained from rf glow discharge with varying gas pressure, and the density of plasma becomes higher as the gas pressure varies from 1 Torr to 100 Torr. It is also shown that in the range of the gas pressure from 1 Torr to 100 Torr with the slower rate of varying gas pressure, higher density of plasma can be obtained.

  8. Self-Organization of a Laminar Structure of a Normal Glow Discharge

    Science.gov (United States)

    Timerkaev, B. A.; Petrova, O. A.; Saifutdinov, A. I.

    2016-03-01

    The behavior of a glow discharge at low pressures is considered. A combined experimental and theoretical method for determining the distributions of electron and ion concentrations in the discharge chamber is proposed. It is shown that the concentrations of charged particles in the negative glow rise not due to the intense ionization by fast electrons from the cathode regions, but instead due to the slowing down of their drift motion. The use of an experimental curve of the potential distribution along a discharge chamber and account of the nonlocal dependence of the Townsend coefficient on the electric field strength have allowed obtaining the distribution of the electric field strength and determining the exact character of variation in the concentration of charged particles along the discharge axis.

  9. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, M.; Kondo, M.; Noda, N. [Hydrogen Isotope Research Center, University of Toyama, Gofuku, Toyama (Japan); Tanaka, M.; Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu (Japan)

    2015-03-15

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

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

    Science.gov (United States)

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

    2014-07-01

    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.

  11. Inner Surface Modification of a Tube by Magnetic Glow-Arc Plasma Source Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gu-Ling; YANG Si-Ze; WANG Jiu-Li; WU Xing-Fang; FENG Wen-Ran; CHEN Guang-Liang; GU Wei-Chao; NIU Er-Wu; FAN Song-Hua; LIU Chi-Zi

    2006-01-01

    @@ A new method named the magnetic glow-arc plasma source ion implantation (MCA-PSⅡ) is proposed for inner surface modification of tubes. In MGA-PSⅡ, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90mm and length 600mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.

  12. Inner Surface Modification of a Tube by Magnetic Glow-Arc Plasma Source Ion Implantation

    Science.gov (United States)

    Zhang, Gu-Ling; Wang, Jiu-Li; Wu, Xing-Fang; Feng, Wen-Ran; Chen, Guang-Liang; Gu, Wei-Chao; Niu, Er-Wu; Fan, Song-Hua; Liu, Chi-Zi; Yang, Si-Ze

    2006-05-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.

  13. COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES

    International Nuclear Information System (INIS)

    OAK A271 COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES. Targets for the National Ignition Facility (NIF) need to be about 200 (micro)m thick and 2 mm in diameter. These dimensions are well beyond those currently fabricated on a routine basis. They have investigated fabrication of near NIF scale targets using the depolymerizable mandrel technique. Poly-alpha-methylstyrene (PAMS) mandrels, about 2 mm in diameter, of varying qualities were coated with as much as 125 (micro)m of glow discharge polymer (GDP). The surface finish of the final shells was examined using a variety of techniques. A clear dependence of the modal spectrum of final GDP shell on the quality of the initial PAMS mandrels was observed. isolated features were found to be the greatest cause for a shell not meeting the NIF standard

  14. Chaotic-to-ordered state transition of cathode-sheath instabilities in DC glow discharge plasmas

    Indian Academy of Sciences (India)

    Md Nurujjaman; A N Sekar Iyengar

    2006-08-01

    Transition from chaotic to ordered state has been observed during the initial stage of a discharge in a cylindrical DC glow discharge plasma. Initially it shows a chaotic behavior but increasing the discharge voltage changes the characteristics of the discharge glow and shows a period subtraction of order 7 period → 5 period → 3 period → 1 period, i.e. the system goes to single mode through odd cycle subtraction. On further increasing the discharge voltage, the system goes through period doubling, like 1 period → 2 period → 4 period. On further increasing the voltage, the system goes to stable state through two period subtraction, like 4 period → 2 period → stable.

  15. Polarity functions' characterization and the mechanism of starch modification by DC glow discharge plasma.

    Science.gov (United States)

    Khorram, S; Zakerhamidi, M S; Karimzadeh, Z

    2015-01-01

    The wheat starch was investigated, before and after exposure to the argon and oxygen glow discharge plasma, without any added chemical reagents, using a novel media polarity functions method. The mechanisms of modification of starch in plasma discharge irradiation were explained using some methods such as; NMR, IR spectroscopy, Kamlet-Abboud-Taft polarity functions (specific and nonspecific interaction) of modified starch. The starch modification, by plasma treatment, shows valuable changes with plasma gas and relative ionized or active species. Characterizations indicate that argon glow discharge plasma increases crosslink in C-2 site of starch. Also, oxygen plasma discharge irradiation tends to oxidize the OH group in C-6 site of carbonyl group. Furthermore, the reported mechanisms show the highest efficiency, because of the stereo-chemical orientation of active sites of starch and plasma potential of wall in plasma media. PMID:25965458

  16. Classification of mixed-radiation fields using the vector representation of thermoluminescent glow curves

    International Nuclear Information System (INIS)

    A novel and robust technique, vector representation (VR), was developed for classifying the glow curves of thermoluminescent dosimeters (TLDs) exposed to proton, photon, and mixed proton-photon fields produced by two types of TLDs:LiF:Mg,Ti (TLD-100) and CaF2:Tm (TLD-300). Vectors were constructed from glow curve points and classified based on the TL vector inner product with a unit vector and TL vector magnitude. The goal was to perform two-category (proton or mixed/photon) and three-category (proton, photon, or mixed) classification. The method was tested for accuracy using leave-one-out validation (LOOV) with classification based on the smallest Mahalanobis distance. Using the high-temperature peaks of each material, correct classification rates exceeding 92% in all cases were obtained

  17. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  18. The glow duration time influence on the ionization rate detected in the diodes filled with noble gases on mbar pressures

    Directory of Open Access Journals (Sweden)

    Stepanović Olivera M.

    2003-01-01

    Full Text Available The results of the glow current duration time (glowing-time influence on the ionization rate detected in the gas filled diodes are presented. The electrical breakdown was detected as the minimal current impulse. After that diode glow from the minimal glowing-time (10-3 s, up to the maximal 103 s which overlap the time of the stationary regime formation in the gas diode tube. The diodes were with volumes of 300 cm3, but with a diode gap volume of about 1 cm3 and filled with helium, neon, argon or krypton, at the pressures of the order of mbar. The ionization rates were detected as the residual ionization after the glowing was interrupted, using the electrical breakdown time delay measuring method. The influence of the gap distance stationary current values and the relaxation period were also investigated. The result shows that the stationary regime in such a gas diode is established after the glowing time of 1-3 s, although the breakdown formative times were smaller then 1 ms.

  19. Decomposition of polychlorinated biphenyls (PCB's) in a radio-frequency glow discharge plasma

    International Nuclear Information System (INIS)

    A study was made on the decomposition of PCB's in a radio-frequency glow discharge plasma. When PCB's were decomposed in a plasma of oxygen at a few Torr, they were completely decomposed to gaseous products: carbon monoxide, carbon dioxide, water, hydrogen chloride, chlorine, and chlorine dioxide. Hazardous compounds such as phosgene and vinyl chloride were not detected by a GC-MS analysis. (author)

  20. Aligned Carbon Nano tubes Array by DC Glow Plasma Etching for Super capacitor

    International Nuclear Information System (INIS)

    To open the end of carbon nano tubes and make these ends connect with functional carboxyl group, aligned carbon nano tubes (CNTs) arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nano tubes array as electrode materials to build super capacitor, we found that the capacity (32.2 F/g) increased significantly than that of pure carbon nano tubes (6.7 F/g)

  1. Investigation of complexity dynamics of inverse and normal homoclinic bifurcation in a glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Debajyoti, E-mail: debajyoti.saha@saha.ac.in; Kumar Shaw, Pankaj; Janaki, M. S.; Sekar Iyengar, A. N.; Ghosh, Sabuj; Mitra, Vramori, E-mail: vramorimitra@yahoo.com; Michael Wharton, Alpha [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2014-03-15

    Order-chaos-order was observed in the relaxation oscillations of a glow discharge plasma with variation in the discharge voltage. The first transition exhibits an inverse homoclinic bifurcation followed by a homoclinic bifurcation in the second transition. For the two regimes of observations, a detailed analysis of correlation dimension, Lyapunov exponent, and Renyi entropy was carried out to explore the complex dynamics of the system.

  2. Influence of gap width on discharge asymmetry in atmospheric pressure glow dielectric barrier discharges

    International Nuclear Information System (INIS)

    In this letter, a one-dimensional fluid model is used to investigate the mechanism of discharge asymmetry in atmospheric pressure helium glow dielectric barrier discharges (GDBDs). By observing the evolutionary process between the successive peak currents, the effect of the gap width on the discharge asymmetry is thoroughly discussed. It is shown that when the gap width is too large, the very severe nonuniformity of electric field distribution over the gas gap leads to the discharge asymmetry.

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

    Science.gov (United States)

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

    2011-10-01

    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

  4. Effect of Atmospheric Pressure Glow Discharge Treatment on Polymerization of Acrylic Fabric and Its Printing Behavior

    Directory of Open Access Journals (Sweden)

    D M El-Zeer

    2014-03-01

    Full Text Available Acrylic fibers have been treated by atmospheric pressure glow discharge (APGD plasma in open air to enhance surface antistatic properties. The treated surfaces are investigated by scanning electron microscopy (SEM, Fourier-Transition Infrared Spectroscopy (FTIR and Atomic Force Microscope (AFM. Plasma treatment of acrylic fabric has been found to increase the surface roughness, modify the nature and density of surface functionalities, and drastically improve the wettability and antistatic ability of acrylic fibers.

  5. CORRELATION BETWEEN ELECTRICAL AND VIBRATIONAL PROPERTIES OF CHLORINATED AND HYDROGENATED AMORPHOUS SILICON PREPARED BY GLOW DISCHARGE

    OpenAIRE

    Al Dallal, S.; Chevallier, J.; Kalem, S; Bourneix, J.

    1982-01-01

    Electrical conductivity and infrared transmission measurements have been carried out on chlorinated and hydrogenated amorphous silicon films prepared by glow discharge. Upon increasing the plasma power, we observed a change of transport mechanism, accompanied by an evolution of hydrogen and chlorine related bands. From this correlation between the transport and the infrared data we suggest that the evolution of SiCl2 species with the plasma power is mainly responsible for the change in bandga...

  6. Study on the Dyeing Behaviors of Low Temperature Glow Discharge Treated Wool

    Institute of Scientific and Technical Information of China (English)

    JIN Jun-chao; LU Wang; DAI Jin-jin

    2002-01-01

    Wool tops was modified by low temperature glow discharge (LTGD). The inputted power, the treating time and the pressure or vacuum were found to play an important role. The wool tops were dyed with reactive dye under a constant dyeing temperature after plasma treatment. Then the dyeing behaviors were studied based on the data of uptake, fixation, dyeing rate and fixing rate. The results revealed the possibility of low temperature dyeing and the suitable parameter of LTGD treatment.

  7. Production of nanometric particles in radio frequency glow discharges in mixtures of silane and methane

    OpenAIRE

    Bertrán Serra, Enric; Costa i Balanzat, Josep; Viera Mármol, Gregorio; Zhang, R. Q.

    1996-01-01

    The formation of silicon particles in rf glow discharges has attracted attention due to their effect as a contaminant during film deposition or etching. However, silicon and silicon alloy powders produced by plasma¿enhanced chemical vapor deposition (PECVD) are promising new materials for sintering ceramics, for making nanoscale filters, or for supporting catalytic surfaces. Common characteristics of these powders are their high purity and the easy control of their stoichiometry through the c...

  8. Heat and Radiofrequency Plasma Glow Discharge Pretreatment of a Titanium Alloy Promote Bone Formation and Osseointegration

    OpenAIRE

    MacDonald, Daniel E.; Rapuano, Bruce E.; Vyas, Parth; Lane, Joseph M.; Meyers, Kathleen; Wright, Timothy

    2013-01-01

    Orthopedic and dental implants manifest increased failure rates when inserted into low density bone. We determined whether chemical pretreatments of a titanium alloy implant material stimulated new bone formation to increase osseointegration in vivo in trabecular bone using a rat model. Titanium alloy rods were untreated or pretreated with heat (600°C) or radiofrequency plasma glow discharge (RFGD). The rods were then coated with the extracellular matrix protein fibronectin (1 nM) or left unc...

  9. Glow Worms as a Tourist Attraction in Springbrook National Park: Visitor Attitudes and Economic Issues

    OpenAIRE

    Wilson, Clevo; Tisdell, Clement A.; Merritt, David

    2004-01-01

    Insect-based tourism mainly caters to a niche market, but its popularity has been growing in recent years. Despite its popularity this form of tourism has remained under-researched and in a sense its contribution to the tourism industry has gone mostly unnoticed. This paper reports the results of a study undertaken on one form of popular insect-based tourism, namely glow worms. The study was undertaken in Springbrook National Park (Natural Bridge section) southeast Queensland, which has one o...

  10. Dynamic Contraction of the Positive Column of a Self-Sustained Glow Discharge in Air Flow

    OpenAIRE

    Shneider, M. N.; Mokrov, M. S.; Milikh, G. M.

    2013-01-01

    We study the dynamic contraction 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 co...

  11. Investigation of Stream Flow Distribution and Its Condensation in Glow Discharge Electron Beam Installation for Evaporation

    International Nuclear Information System (INIS)

    Glow discharge electron guns are widely used for realising different technological operation in the soft vacuum. Its may be successfully applied for reactive evaporation of thin film of oxides and nitrides, which are used for covering of mechanical instruments and for obtaining of dielectric films in microelectronics. In the present work the mathematical model of steam flow distribution and its condensation in the substrate is proposed and realised and its experimental verification provided. (author)

  12. Surface modification of polyethylene and polypropylene in atmospheric pressure glow discharge

    Czech Academy of Sciences Publication Activity Database

    Šíra, M.; Trunec, D.; Sťahel, P.; Buršíková, V.; Navrátil, Z.; Buršík, Jiří

    2005-01-01

    Roč. 38, č. 4 (2005), s. 621-627. ISSN 0022-3727 R&D Projects: GA ČR(CZ) GA202/02/0880; GA ČR(CZ) GP202/02/D097 Institutional research plan: CEZ:AV0Z20410507 Keywords : glow discharge * surface * electron microscopy Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.957, year: 2005

  13. Aligned Carbon Nanotubes Array by DC Glow Plasma Etching for Supercapacitor

    OpenAIRE

    Yongfeng Luo; Xi Li; Zhiqiang Gong; Zhongzhi Sheng; Xiaofang Peng; Qunying Mou; Mengdong He; Xianjun Li; Hong Chen

    2013-01-01

    To open the end of carbon nanotubes and make these ends connect with functional carboxyl group, aligned carbon nanotubes (CNTs) arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nanotubes array as electrode materials to build supercapacitor, we found that the capacity (32.2 F/g) increased significantly than that of pure carbon nanotubes (6.7 F/g).

  14. Occurrence of multipolar mitoses and association with Aurora-A/-B kinases and p53 mutations in aneuploid esophageal carcinoma cells

    Directory of Open Access Journals (Sweden)

    Münch Claudia

    2011-04-01

    Full Text Available Abstract Background Aurora kinases and loss of p53 function are implicated in the carcinogenesis of aneuploid esophageal cancers. Their association with occurrence of multipolar mitoses in the two main histotypes of aneuploid esophageal squamous cell carcinoma (ESCC and Barrett's adenocarcinoma (BAC remains unclear. Here, we investigated the occurrence of multipolar mitoses, Aurora-A/-B gene copy numbers and expression/activation as well as p53 alterations in aneuploid ESCC and BAC cancer cell lines. Results A control esophageal epithelial cell line (EPC-hTERT had normal Aurora-A and -B gene copy numbers and expression, was p53 wild type and displayed bipolar mitoses. In contrast, both ESCC (OE21, Kyse-410 and BAC (OE33, OE19 cell lines were aneuploid and displayed elevated gene copy numbers of Aurora-A (chromosome 20 polysomy: OE21, OE33, OE19; gene amplification: Kyse-410 and Aurora-B (chromosome 17 polysomy: OE21, Kyse-410. Aurora-B gene copy numbers were not elevated in OE19 and OE33 cells despite chromosome 17 polysomy. Aurora-A expression and activity (Aurora-A/phosphoT288 was not directly linked to gene copy numbers and was highest in Kyse-410 and OE33 cells. Aurora-B expression and activity (Aurora-B/phosphoT232 was higher in OE21 and Kyse-410 than in OE33 and OE19 cells. The mitotic index was highest in OE21, followed by OE33 > OE19 > Kyse-410 and EPC-hTERT cells. Multipolar mitoses occurred with high frequency in OE33 (13.8 ± 4.2%, followed by OE21 (7.7 ± 5.0% and Kyse-410 (6.3 ± 2.0% cells. Single multipolar mitoses occurred in OE19 (1.0 ± 1.0% cells. Distinct p53 mutations and p53 protein expression patterns were found in all esophageal cancer cell lines, but complete functional p53 inactivation occurred in OE21 and OE33 only. Conclusions High Aurora-A expression alone is not associated with overt multipolar mitoses in aneuploid ESCC and BAC cancer cells, as specifically shown here for OE21 and OE33 cells, respectively

  15. Solar wind-Magnetosphere-Ionosphere Coupling and Aurora at Jupiter and Saturn

    Science.gov (United States)

    Bunce, E. J.; Cowley, S. W. H.

    2015-10-01

    Solar wind-magnetosphere-ionosphere coupling is accomplished through the existence of largescale field-aligned currents which are generated in a source region and end in a sink region, and which transfer momentum (and energy) between the regions. Therefore, to move beyond a theoretical picture of how this works at Jupiter and Saturn we require in-situ measurements of these regions primarily in the form of magnetic field measurements, but importantly combined with in-situ plasma, plasma wave data, and remote auroral observations. Since the arrival of Cassini at Saturn in 2004 we have had many opportunities to sample the high-latitude magnetosphere and aurora and have learned a great deal about how this giant magnetosphere works. We also await the "proximal" orbit phase of Cassini where we will obtain information on the high-latitude magnetosphere very close to Saturn. In the case of Jupiter, we eagerly anticipate the first high-latitude observations from the Juno mission, due to arrive in the Jupiter system in 2016. The simultaneous observations from Cassini at Saturn in the final phase of the mission until 2017, and Juno at Jupiter during 2016/17, will be a first in planetary science, and we expect to learn a great deal about both planetary magnetospheres individually and by comparison. Here then, we will give an overview of what we have learned so far from Cassini at Saturn, and how it might apply to Juno at Jupiter. A principal "source" of the field-aligned currents is the planetary neutral atmosphere, that at Saturn imposes both sub-corotation (and is axi-symmetric to a first approximation), as well as an m=1 rotating twin-vortex perturbation of comparable magnitude. The Cassini data have revealed that there are two separate systems in the Northern and Southern hemispheres rotating with slowly-changing separate periods. These have been systematically studied, principally in the pre-equinox (2008) Cassini data on the nightside. The sub-corotation system of field

  16. Integration of the Aurora KrF ICF laser system at Los Alamos

    International Nuclear Information System (INIS)

    The Aurora laser system, under construction at the Los Alamos National Laboratory for the past few years, is now being integrated into a working system for examining the applicability of high-power KrF lasers to inertial confinement fusion (ICF). The design principles of the system have been described in detail in earlier publications and conferences. Multikilojoule 248-nm 5-ns duration laser pulses, which have been derived from angular-multiplexed electron-beam-driven KrF amplifiers, are to be delivered to ICF targets when the system is fully integrated. The authors describe the progress of the Aurora system toward the goal of delivering energy (MkJ/48 pulses stacked into one 5-ns pulse/200-μm spot) to ICF targets. Integrated performance to date of the front end optical multiplexer/demultiplexer e-beam-driven amplifiers and alignment hardware are discussed in particular. They have concentrated on the demonstration of system integration at a modest (--100-J) level of energy on-target (without the final amplifier stage). They discuss the amplifier gain measurements, the extraction of energy from a chain of three e-beam-driven machines, and progress toward the delivery of on-target energy

  17. Recent progress on the Los Alamos Aurora ICF [inertial confinement fusion] laser system

    International Nuclear Information System (INIS)

    Aurora is the Los Alamos short-pulse, high-power, krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF-relevant targets. This paper presents a summary of the Aurora system and a discussion of the progress achieved in the construction and integration of the laser system. We concentrate on the main features of the following major system components: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, and the associated optical alignment system. During the past year, two major construction and integration tasks have been accomplished. The first task is the demonstration of 96-beam multiplexing and amplified energy extraction, as evidenced by the integrated operation of the front end, the multiplexer (12-fold and 8-fold encoders), the optical relay train, and three electron-beam-driven amplifiers. The second task is the assembly and installation of the demultiplexer optical hardware, which consists of over 300 optical components ranging in size from several centimeters square to over a meter square. 13 refs., 13 figs

  18. Generation of ninety-six angularly multiplexed KrF beams at Aurora

    International Nuclear Information System (INIS)

    The Aurora KrF laser facility is designed to produce ninety-six laser beams at 248 nm with total energy of -- 10 kJ. The 5-ns duration beams are angularly multiplexed to allow sequential amplification in electron-beam-pumped amplifiers. These amplifiers operated over a half-microsecond period. Previous to this investigation, all individual components of the Aurora system have been operated independently. As a first step toward integration of the full system, the author operated the front end, beam slicer, small-aperture module (SAM), and angle encoder to generate ninety-six angularly multiplexed beams. These beams have been delivered to the first of the three large amplifiers, which will boost the pulse train energy from <1 J to 10 kJ. Measurements to date have concentrated on the total energy of the pulse train and pulse shapes of the individual beams at positions preceding and following SAM. Measured gain through SAM is -- 13 with 20 the target figure. Relative pulse heights are preserved through SAM with the exception of the first pulse of the 12

  19. Improved performance of the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    This paper reports on Aurora the Los Alamos National Laboratory short pulse high power krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large scale UV laser systems for short wavelength inertial confinement fusion (ICF) research. The system employs optical angular multiplexing and serial amplification by electron-beam driven KrF laser amplifiers. The 1-5-ns pulse of the Aurora front end is split into ninety-six beams which are angularly and temporally multiplexed to produce a 480-ns pulse train for amplification by four KrF laser amplifiers. The largest amplifier, the large aperture module (LAM), has a 1-m square aperture and a gain length of 2 m. In the present system configuration half (forty-eight) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. The system has not been optimized, and several near term improvements are expected to result in significant increases in both delivered energy and target irradiance. Removing the twelve calorimeters from the lens plate and allowing forty-eight beams to go to target will increase delivered energy by 33%. Relatively minor modifications to the front end should result in a 30% increase in system output energy. Replacement of damaged optics will increase transmission into the preamplifier by at least 25%. New optics and reduction of retro-pulses will allow the preamplifier stage gain to be increased by 50%

  20. Imaging-based observations of low-latitude auroras during 2001-2004 at Nayoro, Japan

    Science.gov (United States)

    Suzuki, Hidehiko; Chino, Haruka; Sano, Yasuo; Kadokura, Akira; Ejiri, Mitsumu K.; Taguchi, Makoto

    2015-07-01

    Color images of six low-latitude auroral events observed using color digital cameras at Nayoro (142.5° E, 44.4° N), Hokkaido, Japan, from 2001 to 2004, were analyzed to determine the events' locations and times of occurrence. Geographical azimuthal and elevation angles of the images' pixels were determined precisely by using the positions of the stars captured in the images. Horizontal regions covered by these auroral events were directly indicated by mapping the color images onto geographical maps and assuming that the emission layer's altitude is the lowest or highest value of a visible-level red aurora, as determined by the OI 630.0nm emission. The estimated geomagnetic latitudes and L values of these low-latitude auroral events were in the 39-50° range and below L reported previously based on high-sensitivity optical observations at other sites on Hokkaido (Rikubetsu and Moshiri). Although the previous study is lacking information about the maximal brightness level of the red auroral events, the present investigation suggests that these four low-latitude auroral events reached the visible level. In addition, two new events were reported in this study. The present work provides essential information such as the morphology and appearance of visible auroras, which are extremely rare in mid- or low-latitude regions.

  1. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania K [Los Alamos National Laboratory; Miyoshi, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [SEC/NOAA; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  2. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C2). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  3. Atmospheric sampling glow discharge ionizataion and triple quadrupole tandem mass spectrometry for explosives vapor detection

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G.; Hart, K.J.; Glish, G.L.; Grant, B.C.; Chambers, D.M.

    1993-08-01

    The detection and identification of trace vapors of hidden high explosives is an excellent example of a targeted analysis problem. It is desirable to push to ever lower levels the quantity or concentration of explosives material that provides an analytical signal, while at the same time discriminating against all other uninteresting material. The detection system must therefore combine high sensitivity with high specificity. This report describes the philosophy behind the use of atmospheric sampling glow discharge ionization, which is a sensitive, rugged, and convenient means for forming anions from explosives molecules, with tandem mass spectrometry, which provides unparalleled specificity in the identification of explosives-related ions. Forms of tandem mass spectrometry are compared and contrasted to provide a summary of the characteristics to be expected from an explosives detector employing mass spectrometry/mass spectrometry. The instrument developed for the FAA, an atmospheric sampling glow discharge/triple quadrupole mass spectrometer, is described in detail with particular emphasis on the ion source/spectrometer interface and on the capabilities of the spectrometer. Performance characteristics of the system are also described as they pertain to explosives of interest including a description of an automated procedure for the detection and identification of specific explosives. A comparison of various tandem mass spectrometers mated with atmospheric sampling glow discharge is then described and preliminary studies with a vapor preconcentration system provided by the FAA will be described.

  4. Development of a glow curve measuring system of TLDs and its applications

    International Nuclear Information System (INIS)

    A glow curve measurement apparatus of TLDs with a constant heating rate and a wide measurable range has been developed to study the characteristics of TLDs and to apply them to synchrotron radiation dosimetry. The heating rates of 0.5, 1, 2, 3, and 5 degC/s are controlled within an accuracy of ± 2 % from room temperature up to 450degC and the TL output corresponding to the photomultiplier current from 0.01 nA to 100 μA can be measured as digital values per every 1 msec through a current digitizer, in which the linearity of the current digitizer is guaranteed with an accuracy less than 0.1 %. The glow curve and the dose response of LiF, Li2B4O7 (Mn), and Li2B4O7 (Cu) TLDs have been measured for 60Co gamma-rays and synchrotron radiations of 10 to 40 keV up to a couple of 103 Gy using the present system. Apparent differences among the glow curves and the dose responses have been observed with respect to the photon energy and the exposure. Consequently, the high performance of the present measuring system has been demonstrated. (author)

  5. Advanced trap spectroscopy using the glow rate technique based on bleaching of color centers

    International Nuclear Information System (INIS)

    The glow rate technique (GRT) is the extension of the known heating rate method to the full glow curve. The GRT like the fractional glow technique (FGT) offers a procedure for evaluation of the mean activation energy as a function of temperature in the case of arbitrary thermostimulated relaxation kinetics represented by trap distribution function. The experimental procedure involves at least two subsequent measurements of thermostimulated recombination kinetics at different heating rates. The extension of the GRT to the direct measurements of thermostimulated bleaching of the radiation-induced color centers is presented. The experimental procedure involves measurements of the decay of radiation-induced absorption spectra of color centers in preliminary irradiated materials during linear heating. Procedure for evaluation of the trap energy and frequency factor spectrum is considered in the paper. Results of the application of GRT for analysis of the parameters of thermostimulated decay of color centers are presented in the case of decay of the radiation-induced defects in LiBaF3 crystals irradiated by X-rays. It is shown that decay of F-type centers occurs in two steps, the activation energy slightly decreasing from 0.660±0.003 eV in the first step (300-370 K) to 0.615±0.003 eV (400-480 K) in the second step

  6. Methane Conversion to C2 Hydrocarbons by Abnormal Glow Discharge at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    Dai Wei; Yu Hui; Chen Qi; Yin Yongxiang; Dai Xiaoyan

    2005-01-01

    Methane conversion to C2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%,where the coke increases gradually along with the increase of CH4/H2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH4/H2= 2:8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge.A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C2 hydrocarbon products. Therefore, the deposition of coke is restrained.

  7. Mechanism behind self-sustained oscillations in direct current glow discharges and dusty plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung Nae [Devices R and D Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Mt. 14-1 Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of)

    2013-04-15

    An alternative explanation to the mechanism behind self-sustained oscillations of ions in direct current (DC) glow discharges is provided. Such description is distinguished from the one provided by the fluid models, where oscillations are attributed to the positive feedback mechanism associated with photoionization of particles and photoemission of electrons from the cathode. Here, oscillations arise as consequence of interaction between an ion and the surface charges induced by it at the bounding electrodes. Such mechanism provides an elegant explanation to why self-sustained oscillations occur only in the negative resistance region of the voltage-current characteristic curve in the DC glow discharges. Furthermore, this alternative description provides an elegant explanation to the formation of plasma fireballs in the laboratory plasma. It has been found that oscillation frequencies increase with ion's surface charge density, but at the rate which is significantly slower than it does with the electric field. The presented mechanism also describes self-sustained oscillations of ions in dusty plasmas, which demonstrates that self-sustained oscillations in dusty plasmas and DC glow discharges involve common physical processes.

  8. Mixed- and general-order kinetics applied to selected thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Mixed-order (MO) and general-order (GO) kinetics expressions are applied to experimental glow curves of CaSO4Ce, LiNaSO4: Eu, BaF2:Ce and SrF2:Er. The purpose is to compare the activation energies derived from the two models to investigate the correlation between the order of kinetics, b, and the parameter α of the MO model for real systems and to explore the validity of the correlation between b and α derived from the analysis of synthetic glow peaks or experimentally isolated single peak for complex glow curves. The two alternative routes resulted in clean fits with very close values of the sum of squared residuals. The general conclusions are: (1) the activation energies derived from the MO model are slightly higher than the ones derived from the GO model, but the difference appears to be insignificant, (2) the correlation between b and α is not smooth and the scatter in the b values for a given α is within the theoretically expected spread in the b value and (3) the MO expression is capable of evaluating the shape parameters as accurately as the GO expression with the advantage that it has a physical basis contrary to the purely empirical GO model. (authors)

  9. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge

    Indian Academy of Sciences (India)

    Raju Bhai Tyata; Deepak Prasad Subedi; Rajendra Shrestha; Chiow San Wong

    2013-03-01

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge system is investigated by means of electrical and optical measurements. Using a high voltage (0–20 kV) power supply operating at 10–30 kHz, homogeneous and steady APGD has been observed between the electrodes with gap spacing from 0.5 mm to 2 mm and with a dielectric barrier of thickness 2 mm while argon gas is fed at a controlled flow rate of 11/min. The electron temperature and electron density of the plasma are determined by means of optical emission spectroscopy. Our results show that the electron density of the discharge obtained is of the order of 1016 cm-3 while the electron temperature is estimated to be 0.65 eV. The important result is that electron density determined from the line intensity ratio method and stark broadening method are in very good agreement. The Lissajous figure is used to estimate the energy deposited to the glow discharge. It is found that the energy deposited to the discharge is in the range of 20 to 25 $\\$J with a discharge voltage of 1.85 kV. The energy deposited to the discharge is observed to be higher at smaller gas spacing. The glow discharge plasma is tested to be effective in reducing the hydrophobicity of polyethylene film significantly.

  10. Numerical studies of atmospheric pressure glow discharge controlled by a dielectric barrier between two coaxial electrodes

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong-Yan; Wang De-Zhen; Wang Xiao-Gang

    2007-01-01

    The glow discharge in pure helium at atmospheric pressure, controlled by a dielectric barrier between coaxial electrodes, is investigated based on a one-dimensional self-consistent fluid model. By solving the continuity equations for electrons, ions, and excited atoms, with the current conservation equation and the electric field profile, the time evolution of the discharge current, gas voltage and the surface density of charged particles on the dielectric barrier are calculated. The simulation results show that the peak values of the discharge current, gas voltage and electric field in the first half period are asymmetric to the second half. When the current reaches its positive or negative maximum,the electric field profile, and the electron and ion densities represent similar properties to the typical glow discharge at low pressures. Obviously there exist a cathode fall, a negative glow region, and a positive column. Effects of the barrier position in between the two coaxial electrodes and the discharge gap width on discharge current characteristics are also analysed. The result indicates that, in the case when the dielectric covering the outer electrode only, the gas is punctured earlier during the former half period and later during the latter half period than other cases, also the current peak value is higher, and the difference of pulse width between the two half periods is more obvious. On reducing the gap width, the multiple current pulse discharge happens.

  11. Radio frequency atmospheric pressure glow discharge in α and γ modes between two coaxial electrodes

    Science.gov (United States)

    Shang, Wanli; Wang, Dezhen; Zhang, Yuantao

    2008-09-01

    The discharge in pure helium and the influence of small nitrogen impurities at atmospheric pressure are investigated based on a one-dimensional self-consistent fluid model controlled by a dielectric barrier between two coaxial electrodes. The simulation of the radiofrequency (rf) discharge is based on the one-dimensional continuity equations for electrons, ions, metastable atoms, and molecules, with the much simpler current conservation law replacing the Poisson equation for electric field. Through a computational study of rf atmospheric glow discharges over a wide range of current density, this paper presents evidence of at least two glow discharge modes, namely the α mode and the γ mode. The simulation results show the asymmetry of the discharge set exercises great influence on the discharge mechanisms compared to that with parallel-plane electrodes. It is shown that the particle densities are not uniform in the discharge region but increase gradually from the outer to the inner electrode in both modes. The contrasting dynamic behaviors of the two glow modes are studied. Secondary electron emission strongly influences gas ionization in the γ mode yet matters little in the α mode.

  12. A comparison of hydrogen vs. helium glow discharge effects on fusion device first-wall conditioning

    International Nuclear Information System (INIS)

    Hydrogen- and deuterium-fueled glow discharges are used for the initial conditioning of magnetic fusion device vacuum vessels following evacuation from atmospheric pressure. Hydrogenic glow discharge conditioning (GDC) significantly reduces the near-surface concentration of simple adsorbates, such as H2O, CO, and CH4, and lowers ion-induced desorption coefficients by typically three orders of magnitude. The time evolution of the residual gas production observed during hydrogen-glow discharge conditioning of the carbon first-wall structure of the TFTR device is similar to the time evolution observed during hydrogen GDC of the initial first-wall configuration in TFTR, which was primarily stainless steel. Recently, helium GDC has been investigated for several wall-conditioning tasks on a number of tokamaks including TFTR. Helium GDC shows negligible impurity removal with stainless steel walls. For impurity conditioning with carbon walls, helium GDC shows significant desorption of H2O, CO, and CO2; however, the total desorption yield is limited to the monolayer range. In addition, helium GDC can be used to displace hydrogen isotopes from the near-surface region of carbon first-walls in order to lower hydrogenic retention and recycling. 38 refs., 6 figs

  13. Independencia y su expresión léxica en la Aurora de Chile Independence and its lexical expression in the Aurora de Chile

    Directory of Open Access Journals (Sweden)

    Mariano Franco Figueroa

    2010-01-01

    Full Text Available Tomando como base documental el semanario Aurora de Chile, se realiza un análisis lingüístico que describe las caracterizaciones léxicas acomodadas a los nuevos contextos sociolingüísticos en esta época histórica de la independencia colonial y los fenómenos gramaticales que permiten observar rasgos diferenciadores en la lengua que se asienta en esta sociedad chilena. Por una parte, resulta interesante constatar la variación léxica que este texto periodístico, portavoz de una ideología ilustrada, proporciona para alcanzar un mejor conocimiento del grado de penetración del nuevo léxico político-social, con voces en muchos casos recreadas con las acepciones dominantes en las comunidades insurgentes. Por otra, la descripción de los fenómenos gramaticales y del léxico general de este corpus aporta datos concretos acerca de la preferencia de estas variantes lingüísticas y del grado de estandarización que van adquiriendo, como usos emergentes de la lengua española en Chile, bien como asentamientos de estructuras sintácticas y de léxico tradicionales o bien como mecanismos innovadores en la gramática y en el vocabulario diferencial americano.Based on the weekly newspaper Aurora de Chile, a linguistic analysis is here introduced including both the description of lexical characterizations as they adapted to the new sociolinguistic contexts in the historical period of the colonial emancipation and the grammatical phenomena that allow for the observation of differentiating features of the language being established in the Chilean society of the time. On the one hand, it is of interest to observe the lexical variation displayed in this journalistic text, which represents an illustrated ideology, in order to better understand the degree of penetration of the new political and social vocabulary, with voices in many cases recreated with uses dominating the insurgent communities. On the other hand, the description of the grammatical

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

    Science.gov (United States)

    Reece Roth, J.

    2004-11-01

    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

  15. Dithiocarbamate promoted practical synthesis of N-Aryl-2-aminobenzazoles: Synthesis of novel Aurora-A kinase inhibitor

    Indian Academy of Sciences (India)

    Naresh Kumar Katari; M Venkatanarayana; Kummari Srinivas

    2015-03-01

    Various N-aryl-2-aminobenzoxazoles and N-aryl-2-aminobenzothiazoles were synthesized from o-aminophenol and o-aminothiophenol, respectively, mediated by dithiocarbamate in one step. The salient features of this method include mild reaction condition, high yield and large scale synthesis. Application of this methodology has been demonstrated by synthesizing potent Aurora kinase-A inhibitors.

  16. 3D-QSAR (CoMFA, CoMFA-RG, CoMSIA) and molecular docking study of thienopyrimidine and thienopyridine derivatives to explore structural requirements for aurora-B kinase inhibition.

    Science.gov (United States)

    Borisa, Ankit; Bhatt, Hardik

    2015-11-15

    Aurora-B kinase plays a crucial role in cell cycle events and is identified as an important factor in regulation of spindle check point assembly. Thus, it can be proved as an important target in the field of oncology. 3D-QSAR model was generated using 54 molecules reported in literature containing thienopyrimidine and thienopyridine as scaffolds. All molecules were aligned using Distill function in Sybyl X1.2. This generated best model of CoMFA-RG (Region focusing) and CoMSIA were statistically significant with correlation coefficient r(2)ncv of 0.97, for both & Leave one out coefficient (LOO) q(2) of 0.70 and 0.72, respectively. Best CoMSIA model was built up using various combination of descriptors and proved statistical significant among all models. Best CoMFA-RG and CoMSIA models were validated by 12 test set molecules giving satisfactory prediction (r(2)pred) values of 0.86 and 0.88, respectively. External test set validation was performed using 20 molecules and satisfactory prediction of their biological activity was found. Active compounds were docked on protein (PDB ID: 4C2V) by GOLD module and revealed important interactions with amino acids at ATP-binding region. These data explored insight requirements for Aurora-B inhibition which might be fruitful for understanding mechanisms with kinase ligand interactions. PMID:26343315

  17. Drilling Polar Oceans with the European Research Icebreaker AURORA BOREALIS: the IODP Context

    Science.gov (United States)

    Lembke-Jene, Lester; Wolff-Boenisch, Bonnie; Azzolini, Roberto; Thiede, Joern; Biebow, Nicole; Eldholm, Olav; Egerton, Paul

    2010-05-01

    Polar oceans are characterized by extreme environmental conditions for humans and materials, and have remained the least accessible regions to scientists of the IODP. DSDP and ODP have for long faced specific technical and logistical problems when attempting to drill in ice-covered polar deep-sea basins. The Arctic Ocean and large areas of the high-latitude Southern Ocean remained largely un-sampled by ODP and remain one of the major scientific and technological challenges for IODP. Drilling in these regions has been discussed and anticipated for decades and the scientific rationales are reflected in the science plans of the international Nansen Arctic Drilling Program (NAD) or the Arctic Program Planning Group (APPG) of ODP/IODP, amongst others. More recently, the rationale to investigate the polar oceans in a holistic approach has been outlined by workshops, leading to strategic assessments of the scientific potential and new drilling proposals. The European Polar Board took the initiative to develop a plan for a novel and dedicated research icebreaker with technical capabilities hitherto unrealised. This research icebreaker will enable autonomous operations in the central Arctic Ocean and the Southern Ocean, even during the severest ice conditions in the deep winter, serving all marine disciplines of polar research including scientific drilling: The European Research Icebreaker and Deep-Sea Drilling Vessel AURORA BOREALIS. AURORA BOREALIS is presently planned as a multi-purpose vessel. The ship can be deployed as a research icebreaker in all polar waters during any season of the year, as it shall meet the specifications of the highest ice-class attainable (IACS Polar Code 1) for icebreakers. During the times when it is not employed for drilling, it will operate as the most technically advanced multi-disciplinary research vessel in the Arctic or polar Southern Ocean. AURORA BOREALIS will be a "European scientific flagship facility" (fully open to non

  18. Epithelial Cell Transforming 2 and Aurora Kinase B Modulate Formation of Stress Granule-Containing Transcripts from Diverse Cellular Pathways in Astrocytoma Cells.

    Science.gov (United States)

    Weeks, Adrienne; Agnihotri, Sameer; Lymer, Jennifer; Chalil, Alan; Diaz, Roberto; Isik, Semra; Smith, Christian; Rutka, James T

    2016-06-01

    Stress granules are small RNA-protein granules that modify the translational landscape during cellular stress to promote survival. The RhoGTPase RhoA is implicated in the formation of RNA stress granules. Our data demonstrate that the cytokinetic proteins epithelial cell transforming 2 and Aurora kinase B (AurkB) are localized to stress granules in human astrocytoma cells. AurkB and its downstream target histone-3 are phosphorylated during arsenite-induced stress. Chemical (AZD1152-HQPA) and siRNA inhibition of AurkB results in fewer and smaller stress granules when analyzed using high-throughput fluorescent-based cellomics assays. RNA immunoprecipitation with the known stress granule aggregates TIAR and G3BP1 was performed on astrocytoma cells, and subsequent analysis revealed that astrocytoma stress granules harbor unique mRNAs for various cellular pathways, including cellular migration, metabolism, translation, and transcriptional regulation. Human astrocytoma cell stress granules contain mRNAs that are known to be involved in glioma signaling and the mammalian target of rapamycin pathway. These data provide evidence that RNA stress granules are a novel form of epigenetic regulation in astrocytoma cells, which may be targetable by chemical inhibitors and enhance astrocytoma susceptibility to conventional therapy, such as radiation and chemotherapy. PMID:27106762

  19. Breaking the Ice: Strategies for Future European Research in the Polar Oceans - The AURORA BOREALIS Concept

    Science.gov (United States)

    Lembke-Jene, L.; Biebow, N.; Wolff-Boenisch, B.; Thiede, J.; European Research Icebreaker Consortium

    2011-12-01

    Research vessels dedicated to work in polar ice-covered waters have only rarely been built. Their history began with Fritjof Nansen's FRAM, which he used for his famous first crossing of the Arctic Ocean 1893-1896. She served as example for the first generation of polar research vessels, at their time being modern instruments planned with foresight. Ice breaker technology has developed substantially since then. However, it took almost 80 years until this technical advance also reached polar research, when the Russian AKADEMIK FEDEROV, the German POLARSTERN, the Swedish ODEN and the USCG Cutter HEALY were built. All of these house modern laboratories, are ice-breakers capable to move into the deep-Arctic during the summer time and represent the second generation of dedicated polar research vessels. Still, the increasing demand in polar marine research capacities by societies that call for action to better understand climate change, especially in the high latitudes is not matched by adequate facilities and resources. Today, no icebreaker platform exists that is permanently available to the international science community for year-round expeditions into the central Arctic Ocean or heavily ice-infested waters of the polar Southern Ocean around Antarctica. The AURORA BOREALIS concept plans for a heavy research icebreaker, which will enable polar scientists around the world to launch international research expeditions into the central Arctic Ocean and the Antarctic continental shelf seas autonomously during all seasons of the year. The European Research Icebreaker Consortium - AURORA BOREALIS (ERICON-AB) was established in 2008 to plan the scientific, governance, financial, and legal frameworks needed for the construction and operation of this first multi-nationally owned and operated research icebreaker and polar scientific drilling platform. By collaborating together and sharing common infrastructures it is envisioned that European nations make a major contribution to

  20. Aurora A反义寡核苷酸对肺癌细胞A549的作用和对紫杉醇化疗敏感性的影响%The effect of antisense oligodeoxynucleotides targeting Aurora A kinase on cell proliferation and chemosensitivity to paclitaxel in human lung cancer cell line A549

    Institute of Scientific and Technical Information of China (English)

    Rui Meng; Gang Wu; Jing Cheng; Tao Wang

    2007-01-01

    Objective:Aurora A kinase representing a family of evolutionarily conserved mitotic serine/threonine kinases has been found elevated in human lung adenocarcinoma cell line A549.It is suggested that the overexpression of Aurora A contributes to the carcinogenesis,chromosomal instability (CIN),and de-differentiation of lung cancers.To address its possibility as a therapeutic target for lung cancer,we employed the antisense oligodeoxynucleotide (ASODN) technique to inhibi Aurora A expression and investigate its effects on tumor growth and cell cycle of A549.as well as the chemosensitivilty to paclitaxel.Methods:Aurora A ASODN was synthesized and transfected into A549 cells by lipofectAMINE 2000.Aurora A mRNA and protein expression were examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot respectively.Cell cycle distribution was observed by flow cytometer.MTT assay was used to evaluate cell inhibition ratio before and after transfection.Results:The proliferation of the A549 cell swas inhibited by Aurora AASODN dose and time dependently.It was also observed thal the IC50 of A549 cells after 48 hours'treatmenl of ASODN was about 300 nmol/L and under such circumstances,the Aurora A mRNA and protein expression significantly decreased(P<0.05),along with the induction of accumulation of cells in S phase and the G2-M transition.Furlhermore.cell inhibition ratio of the combination of Aurora AASODN and paclitaxel was higher significantly than paclitaxel(P<0.05)or Aurora AASODN alone (P<0.05).Conclusion:Inhibition of Aurora A expression can result in the suppression of cell growth and chemosensilizina activity to paclitaxel in human lung cancer cell line A549.

  1. Substorm aurora and magnetic tail dynamics during interplanetary shock compression: THEMIS observations

    Science.gov (United States)

    Angelopoulos, Vassilis; Zhou, Xiaoyan

    2012-07-01

    Fast and forward interplanetary shocks compress and squeeze the Earth magnetosphere and cause a series of magnetospheric and ionospheric reactions. In addition to the enhancement of chorus, electromagnetic ion cyclotron (EMIC) waves and magnetospheric hiss, the ionospheric convection is enhanced as well. Shock aurora is generated, which is a phenomenon first an auroral brightness onset near local noon right after the shock impingement then followed by a fast anti-sunward auroral propagation along the oval. It has been found that substorm auroral activity can be significantly intensified by the shock compression when the shock upstream magnetic field was in southward in a certain period of time. This paper will present recent results based on the THEMIS spacecraft and ground-based observations. With multiple spacecraft in the magnetotail, the complex dynamics of the compressed tail is identified and analyzed. Correlations between the tail dynamics and substorm auroral variations will be discussed. *On-leave from Jet Propulsion Laboratory

  2. The Morphology of the X-ray Emission above 2 keV from Jupiter's Aurorae

    Science.gov (United States)

    Elsner, R.; Branduardi-Raymont, G.; Galand, M.; Grodent, D.; Gladstone, G. R.; Waite, J. H.; Cravens, T.; Ford, P.

    2007-01-01

    The discovery in XMM-Newton X-ray data of X-ray emission above 2 keY from Jupiter's aurorae has led us to reexamine the Chandra ACIS-S observations taken in Feb 2003. Chandra's superior spatial resolution has revealed that the auroral X-rays with E > 2 keV are emitted from the periphery of the region emitting those with E < 1 keV. We are presently exploring the relationship of this morphology to that of the FUV emission from the main auroral oval and the polar cap. The low energy emission has previously been established as due to charge exchange between energetic precipitating ions of oxygen and either sulfur or carbon. It seems likely to us that the higher energy emission is due to precipitation of energetic electrons, possibly the same population of electrons responsible for the FUV emission. We discuss our analysis and interpretation.

  3. Plant Aurora kinases play a role in maintenance of primary meristems and control of endoreduplication

    Czech Academy of Sciences Publication Activity Database

    Petrovská, Beáta; Cenklová, Věra; Pochylová, Žaneta; Kourová, Hana; Doskočilová, Anna; Plíhal, Ondřej; Binarová, Lenka; Binarová, Pavla

    2012-01-01

    Roč. 193, č. 3 (2012), s. 590-604. ISSN 0028-646X R&D Projects: GA ČR(CZ) GA204/07/1169; GA ČR GP204/09/P155; GA ČR(CZ) GD204/09/H084; GA MŠk(CZ) LC06034; GA MŠk LC545; GA AV ČR IAA500200719 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : Arabidopsis thaliana * AtTPX2 (targeting protein for Xklp2) * Aurora kinases Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.736, year: 2012

  4. An extensive survey of dayside diffuse aurora based on optical observations at Yellow River Station

    CERN Document Server

    Han, De-Sheng; Liu, Jian-Jun; Qiu, Qi; Keika, K; Hu, Ze-Jun; Liu, Jun-Ming; Hu, Hong-Qiao; Yang, Hui-Gen

    2016-01-01

    By using 7 years optical auroral observations obtained at Yellow River Station (magnetic latitude $76.24\\,^{\\circ}{\\rm C}$N) at Ny-Alesund, Svalbard, we performed the first extensive survey for the dayside diffuse auroras (DDAs) and acquired observational results as follows. (1) The DDAs can be classified into two broad categories, i.e., unstructured and structured DDAs. The unstructured DDAs are mainly distributed in the morning and afternoon, but the structured DDAs predominantly occurred around the magnetic local noon (MLN). (2) The unstructured DDAs observed in morning and afternoon present obviously different properties. The afternoon ones are much stable and seldom show pulsating property. (3) The DDAs are more easily observed under geomagnetically quiet times. (4) The structured DDAsmainly show patchy, stripy, and irregular forms and are often pulsating and drifting. The drifting directions are mostly westward (with speed $\\sim$5km/s), but there are cases showing eastward or poleward drifting. (5) The ...

  5. Observations of a travelling aurorae curvature to the west in the dayside polar cap

    International Nuclear Information System (INIS)

    Results of visual and photometrical observations at the Vostok antarctic station are presented. The data obtained testify to the fact that during strong magnetic disturbanel auroral curvature and auroral crinkle associated with it can penetrate deeply nto the dayside polar cap. These extraordinary auroral were observed at the Vostok station during the world storm on the 13-th-15-th of July 1982. Aurorae with characteristics typical for auroral curvature were detected twice at the Vostok station on the 14-th of July 1982 at the moment of development of explosive phases of two substorms. Region limited by auroral oval was compressed to the minimum in these periods and it was locatel in the region of dayside cusp

  6. Tomographic Imaging of Water Content and Mine-Induced Stress Distribution in North Aurora, Illinois

    Science.gov (United States)

    Meulemans, A. J.; Fratta, D.; Wang, H. F.

    2013-12-01

    Located in North Aurora, Illinois, the Lafarge-Conco plant is a room-and-pillar mine that is in active production of aggregates, taken from the Galena-Platteville formations. To better understand how stresses are distributed among the pillars over periods of mining production, tomographic images of the interior of the pillar using seismic data collected in November 2012 and March 2013 were created. Seismic tomographic images showed changes in seismic velocity between the two surveys, which is interpreted as change in stress. The southeast corner pillar showed a significant stress increase, and could indicate a possible area of very high stresses within the pillar. While the ground-penetrating radar (GPR) tomographic image was used to assess a very uniform water content and porosity distribution within the pillar. Understanding how stress and moisture distribution changes within pillars during excavation is valuable to mine design and to the maintenance of mine safety.

  7. The analysis of thermoluminescent glow peaks of CaF2 : Dy (TLD-200) after β-irradiation

    International Nuclear Information System (INIS)

    Variable dose (VD), Tm-Tstop, initial rise (IR), variable heating rate (VHR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods are used to determine the number of peaks, the order of kinetics (b), the activation energy (Ea) and attempt-to-escape frequency (s) associated with the glow peaks in CaF2 : Dy (TLD-200) after β-irradiation between the dose level 0.1 and 110 Gy. The Tm-Tstop procedure indicates that the glow curve of this crystal consists of at least nine glow peaks. The dose variation experiment indicates that seven of them, namely peaks 1-6 and 8, are of first-order kinetics and peaks 7 and 9 are of general-order kinetics. However, the Tm-Tstop procedure and the CGCD method have indicated that peak 6 has general-order kinetics too. The activation energy found with the IR, VHR, PS and CGCD methods for peak 4 yield very close values. For all other peaks, there is no agreement between the results of all the applied methods. This work also indicates that the post-irradiation annealing and the heating rate have pronounced effects on the evaluated kinetic parameters of all glow peaks

  8. An algorithm for the deconvolution of the optically stimulated luminescence glow curves involving the mutual interactions among the electron traps

    International Nuclear Information System (INIS)

    The most of the algorithms reported on the deconvolution of the OSL/TL glow curve is basically based on the one trap one recombination center (OTOR) model. In the OTOR model, each individual trap is considered to be independent with each other (mutually exclusive with each other), and the total glow curve is produced solely by the summation of the glow peaks generated from the luminescence emitted by the electrons in one individual trap when transferring to other trap(s). Therefore, there could be a major difference between the model and real physical process of the OSL/TL mechanism. Because the electrons being excited to be in the conduction band barely have past recollection of the original traps, it is widely believed that electrons in one trap can be easily transferred to other trap via the conduction band. Particularly in case of the OSL, the effects of mutual interactions among the traps could be more dominant than those in case of the TL. An algorithm, which can be used to numerically analyze the OSL/TL curves with reflecting the mutual interactions among the individual traps via the conduction band, is developed. This algorithm is able to promptly generate the glow curves for a system with numerous electron traps and recombination centers. Thus, the algorithm can be used to effectively deconvolute the glow curve of a given measurement data.

  9. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

    Science.gov (United States)

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined. PMID:25184109

  10. Dayside aurorae and polar arcs under south-east IMF orientation

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2006-12-01

    Full Text Available We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135° ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auroral forms/activities corresponding to merging and lobe convection cells obtained from SuperDARN convection data and Greenland magnetograms. The ground optical instruments at Ny Ålesund, Svalbard (76° MLAT recorded different auroral forms/activities as the station moved to higher magnetic local times (MLTs in the 13:00–17:00 MLT sector. Whereas the 13:00–15:00 MLT sector is characterized by classical poleward moving auroral forms (PMAFs associated with merging cell transients, the aurora in the 15:00–17:00 MLT sector shows instead a characteristic latitudinal bifurcation consisting of standard oval forms and polar arcs, and a corresponding composite pattern of merging and lobe convection cells. The merging and lobe cells respond to the southward and northward IMF transitions by activation/fading and fading/activation, respectively. A sequence of brightening events is characterized by successive activations progressing in latitude from the merging cell regime to the lobe cell regime. Emphasis is placed on the association between polar arc brightenings and the activation of the channel of enhanced sunward flow in the lobe cell. The observations are discussed in relation to recent work on solar wind-magnetosphere-ionosphere interconnection topology.

  11. Reconstruction of recent climate change in Alaska from the Aurora Peak ice core, central Alaska

    Science.gov (United States)

    Tsushima, A.; Matoba, S.; Shiraiwa, T.; Okamoto, S.; Sasaki, H.; Solie, D. J.; Yoshikawa, K.

    2015-02-01

    A 180.17 m ice core was drilled at Aurora Peak in the central part of the Alaska Range, Alaska, in 2008 to allow reconstruction of centennial-scale climate change in the northern North Pacific. The 10 m depth temperature in the borehole was -2.2 °C, which corresponded to the annual mean air temperature at the drilling site. In this ice core, there were many melt-refreeze layers due to high temperature and/or strong insolation during summer seasons. We analyzed stable hydrogen isotopes (δD) and chemical species in the ice core. The ice core age was determined by annual counts of δD and seasonal cycles of Na+, and we used reference horizons of tritium peaks in 1963 and 1964, major volcanic eruptions of Mount Spurr in 1992 and Mount Katmai in 1912, and a large forest fire in 2004 as age controls. Here, we show that the chronology of the Aurora Peak ice core from 95.61 m to the top corresponds to the period from 1900 to the summer season of 2008, with a dating error of ± 3 years. We estimated that the mean accumulation rate from 1997 to 2007 (except for 2004) was 2.04 m w.eq. yr-1. Our results suggest that temporal variations in δD and annual accumulation rates are strongly related to shifts in the Pacific Decadal Oscillation index (PDOI). The remarkable increase in annual precipitation since the 1970s has likely been the result of enhanced storm activity associated with shifts in the PDOI during winter in the Gulf of Alaska.

  12. Electrodynamics and energy characteristics of aurora at high resolution by optical methods

    Science.gov (United States)

    Dahlgren, H.; Lanchester, B. S.; Ivchenko, N.; Whiter, D. K.

    2016-06-01

    Technological advances leading to improved sensitivity of optical detectors have revealed that aurora contains a richness of dynamic and thin filamentary structures, but the source of the structured emissions is not fully understood. In addition, high-resolution radar data have indicated that thin auroral arcs can be correlated with highly varying and large electric fields, but the detailed picture of the electrodynamics of auroral filaments is yet incomplete. The Auroral Structure and Kinetics (ASK) instrument is a state-of-the-art ground-based instrument designed to investigate these smallest auroral features at very high spatial and temporal resolution, by using three electron multiplying CCDs in parallel for three different narrow spectral regions. ASK is specifically designed to utilize a new optical technique to determine the ionospheric electric fields. By imaging the long-lived O+ line at 732 nm, the plasma flow in the region can be traced, and since the plasma motion is controlled by the electric field, the field strength and direction can be estimated at unprecedented resolution. The method is a powerful tool to investigate the detailed electrodynamics and current systems around the thin auroral filaments. The two other ASK cameras provide information on the precipitation by imaging prompt emissions, and the emission brightness ratio of the two emissions, together with ion chemistry modeling, is used to give information on the energy and energy flux of the precipitating electrons. In this paper, we discuss these measuring techniques and give a few examples of how they are used to reveal the nature and source of fine-scale structuring in the aurora.

  13. Pitch angle scattering and particle precipitation in a pulsating aurora - an experimental study

    International Nuclear Information System (INIS)

    A pulsating aurora occurring during the recovery phase of a substorm on January 27, 1979 was monitored by a large set of instruments. The Swedish sounding rocket S23-L2 was launched at magnetic midnight over pulsating patches, some of which exhibited 3+-1 Hz modulation. The ground based instrumentation included auroral TV cameras, all sky cameras, photometers and magnetometers. The geostationary satellite GEOS-2 was located in the equatorial plane, approximately conjugate to the rocket. The central experiment of this study is the particle experiment on the rocket. Several aspects of pulsating auroras have been investigated. The auroral luminosity variations were very well correlated to variations in the flux of precipitating hot electrons. The 1-20 second pulsations were caused by increased fluxes of 4-40 keV electrons. The 3+-1 Hz modulation was detected in 7-200 keV electrons, but the biggest energy flux modulation occurred for electrons of about 60 keV. Model calculations involving the electron distributions measured by the sounding rocket and GEOS-2, consistently show that the electrons may have been scattered into the loss cone through the Doppler shifted gyroresonance with whistler mode waves. The scattering was not a pure pitch angle scattering as in the classical Coroniti and Kennel theory, but involved also a systematic energy loss from the particles. The waves were probably hiss with some chorus elements. The equatorial plane plasma density was estimated in two independent ways to be about 2x106 m-3. The 3+-1 Hz modulation was measured both by the particle experiment on the rocket and by the wave experiment on GEOS-2. Properties of the modulated fluxes are described and a qualitative model for the cause of the modulation is proposed. (author)

  14. Distribution of energetic positive ion species above a diffuse midnight aurora

    International Nuclear Information System (INIS)

    Observational approaches to the problem of magnetospheric plasma origin usually depend upon mass-discriminating measurements of ion distribution functions. A new instrument for this purpose has been developed and flown via sounding rockets above a diffuse midnight aurora during geomagnetically quiet conditions. The instrument combines wide mass and energy ranges (2.5+ and He++ were detected, and the He++ was not clearly above background, having an upper limit of 2--4% of the H+ intensity. All other ions, including the ionospheric species He+ and O+, had upper limits at a similar or smaller level. This situation contrasts sharply with a number of recently reported observations of large intensities of O+ during magnetic storms and may be characteristic of undisturbed periods. Though these results suggest a solar wind source for the ions, an admixture including an appreciable fraction of polar wind material (predominantly H+) is not precluded. The measured proton distribution was nearly isotropic over downcoming pitch angles at all energies and showed a depleted atmospheric source cone. The proton energy distribution had a best fit temperature of 4.5 keV and a number density of 0.17 cm-3, corresponding to a peak intensity just over 105 cm-2 s-1 keV-1. Altitudinal variations observed during the flight are consistent with the theory of charge exchange of a time steady incident proton population. These ion observations, taken together with electron observations reported in a companion paper, appear to be consistent with the model of diffuse auroras in which trapped plasma precipitates owing to strong pitch angle diffusion on auroral field lines linking the near-earth plasma sheet

  15. Modeling Spectra of the North and South Jovian X-ray Auroras

    International Nuclear Information System (INIS)

    Spectra of Jovian X-ray auroras observed from the North and South poles with the Chandra X-ray telescope are analyzed and compared with predicted spectra of the charge-exchange mechanism. To determine the theoretical spectra of Jovian X-ray auroras, we model numerically the collisionally induced evolution of energy and charge distributions of Oq+ and Sq+ ions, precipitating into the Jovian atmosphere. Monte Carlo simulations of the energy and charge relaxation of the precipitating ions are carried out with updated cross-sections of the ion stripping, electron capture, and gas-ionization collisions. X-ray and Extreme Ultraviolet (EUV) spectra of cascading radiation induced by individual energetic sulfur and oxygen ions are calculated, and relative intensities of X-ray emission lines are determined. Synthetic spectra of X-ray and EUV photons are computed at different initial kinetic energies and compositions of ion-precipitating fluxes. Theoretical spectra with adjustable initial energies and relative fraction of sulfur and oxygen ions are shown to be in good agreement with the spectra of X rays detected from the South and North polar regions. The abundances and initial energies of the precipitating ions are inferred by comparing synthetic and observed X-ray spectra. Comparisons are performed independently for the North and South pole emissions. Abundances of the precipitating sulfur ions are found to be four to five times smaller than those of oxygen ions, and averaged ion energies are determined to lie between 1 and 2 MeV/amu. Slightly different ion flux compositions are found to describe the observed spectra of X-ray emission from the North and South poles

  16. Application of computerised glow curve analysis in a TLD based personnel dosimetry service

    International Nuclear Information System (INIS)

    The methods and techniques of computerised Glow Curve Analysis (GCA) have clearly a potential for improvement of the thermoluminescence dosimetry (TLD) performance still to be exploited for practical work. Particularly personal dosimetry, whose results must comply with specific quality criteria, can be benefited from the more accurate handling of the usually complex glow curves, including several peaks with different properties and also different interest for dosimetry, notably their different intensity and thermal stability. Most of the so called standard procedures for TLD were proposed in the 70s aiming to obtain a sufficiently stable response for the usual integration periods, one to three months, in personal or environmental dosimetry. Mostly these procedures consisted in more or less complex annealing procedures applied before or after irradiation but having a common objective: the modification of the natural glow curve structure trying to eliminate the unstable low temperature peaks favouring the presence of high temperature peaks with better long term stability. In these initial stages of the employment of TLD, the physics behind the thermally activated light emissions in the materials employed for dosimetry was not properly understood and so these standard procedures were mainly of phenomenological nature, presenting important differences among laboratories. Since these early times and in parallel with an impressive increase of the practical use of TLD, an important research effort has been developed that have clarified many of the features of the TL physical processes in dosimetric materials, particularly LiF(Mg,Ti) and more recently also LiF(Mg,Cu,P). On the light of the accumulated knowledge, the old standard procedures should be revised and simplified. If achieved, this simplification will be excellent for TLD routine measurements

  17. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2011-11-15

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

  18. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    International Nuclear Information System (INIS)

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3–6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3–4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: ► This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. ► A Boltzmann distribution is studied among iron lines of various excitation levels. ► We find an overpopulation of the high-lying energy levels from the normal distribution. ► It is caused through Penning-type collision of iron atom with argon metastable atom.

  19. Oxidative Degradation of o-Chlorophenol with Contact Glow Discharges in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    高锦章; 杨武; 刘永军; 陈平; 纳鹏君; 陆泉芳

    2003-01-01

    Contact glow discharge electrolysis (CGDE) of o-chlorophenol (2-CP) was investi-gated under different pH, voltages and initial concentrations. And the mechanism of the oxidationwas explored. The results suggested that the degradation followed the first order kinetic law;Fe2+ had a remarkable catalytic effect on the removal rate of o-chloropenol. In the presence ofFe2+, 2-CP underwent an exhaustive degradation, from which the major intermediates includedo-dihydroxybenze, p-hydroxybenze, p-benzoquione and carboxlic acids.

  20. Transition from Spark Discharge to Constricted Glow Discharge in Atmospheric Air by Capacitor Coupled Discharge

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yutao; REN Chunsheng; XU Zhenfeng; MA Tengcai; QI Bing; WANG Dezhen; WANG Younian

    2007-01-01

    The transition from a spark discharge to a constricted glow discharge in atmospheric air was studied with a capacitor coupled pin-to-water plasma reactor. The reason of the transition is considered to be of various factors, namely the change of the air gap due to the polarization of water molecules by the electric field, the feedback effect of the capacitors, and the ion trapping mechanism. The effects of the frequency of the power supply, inter-electrode gap, and coupled capacitance on the discharge transition were also investigated.