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Sample records for brucei paraflagellar rod

  1. A protein-protein interaction map of the Trypanosoma brucei paraflagellar rod.

    Directory of Open Access Journals (Sweden)

    Sylvain Lacomble

    Full Text Available We have conducted a protein interaction study of components within a specific sub-compartment of a eukaryotic flagellum. The trypanosome flagellum contains a para-crystalline extra-axonemal structure termed the paraflagellar rod (PFR with around forty identified components. We have used a Gateway cloning approach coupled with yeast two-hybrid, RNAi and 2D DiGE to define a protein-protein interaction network taking place in this structure. We define two clusters of interactions; the first being characterised by two proteins with a shared domain which is not sufficient for maintaining the interaction. The other cohort is populated by eight proteins, a number of which possess a PFR domain and sub-populations of this network exhibit dependency relationships. Finally, we provide clues as to the structural organisation of the PFR at the molecular level. This multi-strand approach shows that protein interactome data can be generated for insoluble protein complexes.

  2. Generation of a Nanobody Targeting the Paraflagellar Rod Protein of Trypanosomes

    OpenAIRE

    Obishakin, Emmanuel; Stijlemans, Benoit; Santi-Rocca, Julien; Vandenberghe, Isabel; Devreese, Bart; Muldermans, Serge; Bastin, Philippe; Magez, Stefan

    2014-01-01

    Trypanosomes are protozoan parasites that cause diseases in humans and livestock for which no vaccines are available. Disease eradication requires sensitive diagnostic tools and efficient treatment strategies. Immunodiagnostics based on antigen detection are preferable to antibody detection because the latter cannot differentiate between active infection and cure. Classical monoclonal antibodies are inaccessible to cryptic epitopes (based on their size-150 kDa), costly to produce and require ...

  3. Taxonomy Icon Data: Trypanosoma brucei [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Trypanosoma brucei Trypanosoma brucei Trypanosoma_brucei_L.png Trypanosoma_brucei_NL.png Trypan...osoma_brucei_S.png Trypanosoma_brucei_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypan...osoma+brucei&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NL http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=S http://biosciencedbc.jp.../taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=121 ...

  4. Trypanosome Lytic Factor-1 Initiates Oxidation-stimulated Osmotic Lysis of Trypanosoma brucei brucei.

    Science.gov (United States)

    Greene, Amy Styer; Hajduk, Stephen L

    2016-02-01

    Human innate immunity against the veterinary pathogen Trypanosoma brucei brucei is conferred by trypanosome lytic factors (TLFs), against which human-infective T. brucei gambiense and T. brucei rhodesiense have evolved resistance. TLF-1 is a subclass of high density lipoprotein particles defined by two primate-specific apolipoproteins: the ion channel-forming toxin ApoL1 (apolipoprotein L1) and the hemoglobin (Hb) scavenger Hpr (haptoglobin-related protein). The role of oxidative stress in the TLF-1 lytic mechanism has been controversial. Here we show that oxidative processes are involved in TLF-1 killing of T. brucei brucei. The lipophilic antioxidant N,N'-diphenyl-p-phenylenediamine protected TLF-1-treated T. brucei brucei from lysis. Conversely, lysis of TLF-1-treated T. brucei brucei was increased by the addition of peroxides or thiol-conjugating agents. Previously, the Hpr-Hb complex was postulated to be a source of free radicals during TLF-1 lysis. However, we found that the iron-containing heme of the Hpr-Hb complex was not involved in TLF-1 lysis. Furthermore, neither high concentrations of transferrin nor knock-out of cytosolic lipid peroxidases prevented TLF-1 lysis. Instead, purified ApoL1 was sufficient to induce lysis, and ApoL1 lysis was inhibited by the antioxidant DPPD. Swelling of TLF-1-treated T. brucei brucei was reminiscent of swelling under hypotonic stress. Moreover, TLF-1-treated T. brucei brucei became rapidly susceptible to hypotonic lysis. T. brucei brucei cells exposed to peroxides or thiol-binding agents were also sensitized to hypotonic lysis in the absence of TLF-1. We postulate that ApoL1 initiates osmotic stress at the plasma membrane, which sensitizes T. brucei brucei to oxidation-stimulated osmotic lysis. PMID:26645690

  5. Wild chimpanzees are infected by Trypanosoma brucei.

    Science.gov (United States)

    Jirků, Milan; Votýpka, Jan; Petrželková, Klára J; Jirků-Pomajbíková, Kateřina; Kriegová, Eva; Vodička, Roman; Lankester, Felix; Leendertz, Siv Aina J; Wittig, Roman M; Boesch, Christophe; Modrý, David; Ayala, Francisco J; Leendertz, Fabian H; Lukeš, Julius

    2015-12-01

    Although wild chimpanzees and other African great apes live in regions endemic for African sleeping sickness, very little is known about their trypanosome infections, mainly due to major difficulties in obtaining their blood samples. In present work, we established a diagnostic ITS1-based PCR assay that allows detection of the DNA of all four Trypanosoma brucei subspecies (Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma brucei gambiense, and Trypanosoma brucei evansi) in feces of experimentally infected mice. Next, using this assay we revealed the presence of trypanosomes in the fecal samples of wild chimpanzees and this finding was further supported by results obtained using a set of primate tissue samples. Phylogenetic analysis of the ITS1 region showed that the majority of obtained sequences fell into the robust T. brucei group, providing strong evidence that these infections were caused by T. b. rhodesiense and/or T. b. gambiense. The optimized technique of trypanosome detection in feces will improve our knowledge about the epidemiology of trypanosomes in primates and possibly also other endangered mammals, from which blood and tissue samples cannot be obtained. Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies. PMID:26110113

  6. Malleable Mitochondrion of Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Verner, Zdeněk; Basu, Somuvro; Benz, C.; Dixit, S.; Dobáková, Eva; Faktorová, Drahomíra; Hashimi, Hassan; Horáková, Eva; Huang, Zhenqiu; Paris, Zdeněk; Peña-Diaz, Priscila; Ridlon, L.; Týč, Jiří; Wildridge, David; Zíková, Alena; Lukeš, Julius

    2015-01-01

    Roč. 315, 2015 Feb 07 (2015), s. 73-151. ISSN 1937-6448 R&D Projects: GA ČR GAP302/12/2513; GA MŠk LL1205; GA MŠk(CZ) EE2.3.30.0032; GA MŠk LH12104; GA ČR GAP305/12/2261 EU Projects: European Commission(XE) 316304 Institutional support: RVO:60077344 Keywords : Kinetoplast * Metabolism * Mitochondrial transport * Mitochondrion * RNA import * T. brucei * Trypanosome * kDNA Subject RIV: EE - Microbiology, Virology Impact factor: 3.419, year: 2014

  7. Mapping of VSG similarities in Trypanosoma brucei

    OpenAIRE

    Weirather, Jason L.; Wilson, Mary E; Donelson, John E.

    2011-01-01

    The protozoan parasite Trypanosoma brucei switches its variant surface glycoprotein (VSG) to subvert its mammalian hosts’ immune responses. The T. brucei genome contains as many as 1600 VSG genes (VSGs), but most are silent noncoding pseudogenes. Only one functional VSG, located in a telomere-linked expression site, is transcribed at a time. Silent VSGs are copied into a VSG expression site through gene conversion. Truncated gene conversion events can generate new mosaic VSGs with segments of...

  8. What happens when Trypanosoma brucei leaves Africa

    OpenAIRE

    Jensen, Robert E.; Simpson, Larry; Englund, Paul T.

    2008-01-01

    Julius Lukeš and co-workers evaluated the evolutionary origin of Trypanosoma equiperdum and Trypanosoma evansi, parasites that cause horse and camel diseases. Although similar to T. brucei, the sleeping-sickness parasite, these trypanosomes do not cycle through the tsetse fly and have been able to spread beyond Africa. Transmission occurs sexually, or via blood-sucking flies or vampire bats. They concluded that these parasites, which resemble yeast petite mutants, are T. brucei sub-species, w...

  9. Multiple Triclosan Targets in Trypanosoma brucei

    OpenAIRE

    Paul, Kimberly S.; Bacchi, Cyrus J.; Englund, Paul T.

    2004-01-01

    Trypanosoma brucei genes encoding putative fatty acid synthesis enzymes are homologous to those encoding type II enzymes found in bacteria and organelles such as chloroplasts and mitochondria. It was therefore not surprising that triclosan, an inhibitor of type II enoyl-acyl carrier protein (enoyl-ACP) reductase, killed both procyclic forms and bloodstream forms of T. brucei in culture with 50% effective concentrations (EC50s) of 10 and 13 μM, respectively. Triclosan also inhibited cell-free ...

  10. Effects of tea on survival rates and liver pathology of Trypanosoma brucei brucei infected mice

    OpenAIRE

    Mbuthia, S.K; Wachira, N.W; Ngure, R.M; Ouma, J; Kagira, J. M.

    2011-01-01

    The current study investigated the effects of different types of Kenyan tea extracts on the pathogenesis ofTrypanosoma brucei brucei in a Swiss White mice model. Following infection with trypanosomes, the micewere monitored for survival and liver pathology. Tea significantly (P

  11. Genetic control of resistance to Trypanosoma brucei brucei infection in mice

    Czech Academy of Sciences Publication Activity Database

    Šíma, Matyáš; Havelková, Helena; Quan, L.; Svobodová, M.; Jarošíková, T.; Vojtíšková, Jarmila; Stassen, A. P. M.; Demant, P.; Lipoldová, Marie

    2011-01-01

    Roč. 5, č. 6 (2011), e1173. ISSN 1935-2735 R&D Projects: GA AV ČR IAA500520606; GA MŠk(CZ) LC06009 Grant ostatní: NIH-NCI(US) 1R01CA127162-01 Institutional research plan: CEZ:AV0Z50520514 Keywords : Trypanosoma brucei brucei * mouse recombinant congenic strains * Tbbr Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.716, year: 2011

  12. CHARACTERIZATION AND ANTIPARASITIC ACTIVITY OF BENZOPHENONE THIOSEMICARBAZONES ON Trypanosoma brucei brucei

    OpenAIRE

    Georges C. Accrombessi; Jacques Poupaert; Raymond H. Fatondji; Salomé D. S. Kpoviessi; Gbaguidi, Fernand A.; Bienvenu Glinma

    2011-01-01

    The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50) = 8.48 micromolar (µM). Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate a...

  13. An evaluation of Minor Groove Binders as anti-Trypanosoma brucei brucei therapeutics.

    Science.gov (United States)

    Scott, Fraser J; Khalaf, Abedawn I; Giordani, Federica; Wong, Pui Ee; Duffy, Sandra; Barrett, Michael; Avery, Vicky M; Suckling, Colin J

    2016-06-30

    A series of 32 structurally diverse MGBs, derived from the natural product distamycin, was evaluated for activity against Trypanosoma brucei brucei. Four compounds have been found to possess significant activity, in the nanomolar range, and represent hits for further optimisation towards novel treatments for Human and Animal African Trypanosomiases. Moreover, SAR indicates that the head group linking moiety is a significant modulator of biological activity. PMID:27060763

  14. Mitochondrial pyruvate carrier in Trypanosoma brucei.

    Science.gov (United States)

    Štáfková, Jitka; Mach, Jan; Biran, Marc; Verner, Zdeněk; Bringaud, Frédéric; Tachezy, Jan

    2016-05-01

    Pyruvate is a key product of glycolysis that regulates the energy metabolism of cells. In Trypanosoma brucei, the causative agent of sleeping sickness, the fate of pyruvate varies dramatically during the parasite life cycle. In bloodstream forms, pyruvate is mainly excreted, whereas in tsetse fly forms, pyruvate is metabolized in mitochondria yielding additional ATP molecules. The character of the molecular machinery that mediates pyruvate transport across mitochondrial membrane was elusive until the recent discovery of mitochondrial pyruvate carrier (MPC) in yeast and mammals. Here, we characterized pyruvate import into mitochondrion of T. brucei. We identified mpc1 and mpc2 homologs in the T. brucei genome with attributes of MPC protein family and we demonstrated that both proteins are present in the mitochondrial membrane of the parasite. Investigations of mpc1 or mpc2 gene knock-out cells proved that T. brucei MPC1/2 proteins facilitate mitochondrial pyruvate transport. Interestingly, MPC is expressed not only in procyclic trypanosomes with fully activated mitochondria but also in bloodstream trypanosomes in which most of pyruvate is excreted. Moreover, MPC appears to be essential for bloodstream forms, supporting the recently emerging picture that the functions of mitochondria in bloodstream forms are more diverse than it was originally thought. PMID:26748989

  15. Wild chimpanzees are infected by Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Milan Jirků

    2015-12-01

    Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies.

  16. Sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, J.; Preis, L.

    1987-12-08

    The sucker rod system in a deep well sucker rod pump consists of a plurality of unidirectionally reinforced composite fiber rods extending substantially parallel but not in contact with each other, the cross-sectional area of which rods is less than 1 cm/sup 2/. This enables the advantageous material properties to be utilized to a high degree. The sucker rod system can be assembled on site. The individual composite fiber rods can be monitored when they are in the working position.

  17. Rodding Surgery

    Science.gov (United States)

    ... a rod or nail into the internal cavity (medullary canal) of a long bone. Purpose of Rodding ... Osteogenesis Imperfecta: A Translational Approach to Brittle Bone Disease 1 st edition. New York, NY: Elsevier Academic ...

  18. Motility modes of the parasite Trypanosoma brucei

    Science.gov (United States)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

    2015-11-01

    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  19. Mechanism of Trypanosoma brucei gambiense resistance to human serum

    DEFF Research Database (Denmark)

    Uzureau, Pierrick; Uzureau, Sophie; Lecordier, Laurence;

    2013-01-01

    The African parasite Trypanosoma brucei gambiense accounts for 97% of human sleeping sickness cases. T. b. gambiense resists the specific human innate immunity acting against several other tsetse-fly-transmitted trypanosome species such as T. b. brucei, the causative agent of nagana disease in...

  20. Trypanosoma evansi is alike to Trypanosoma brucei brucei in the subcellular localisation of glycolytic enzymes

    Directory of Open Access Journals (Sweden)

    S Andrea Moreno

    2015-06-01

    Full Text Available Trypanosoma evansi, which causes surra, is descended from Trypanosoma brucei brucei, which causes nagana. Although both parasites are presumed to be metabolically similar, insufficient knowledge of T. evansi precludes a full comparison. Herein, we provide the first report on the subcellular localisation of the glycolytic enzymes in T. evansi, which is a alike to that of the bloodstream form (BSF of T. b. brucei: (i fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, hexokinase, phosphofructokinase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase (glycolytic enzymes and glycerol-3-phosphate dehydrogenase (a glycolysis-auxiliary enzyme in glycosomes, (ii enolase, phosphoglycerate mutase, pyruvate kinase (glycolytic enzymes and a GAPDH isoenzyme in the cytosol, (iii malate dehydrogenase in cytosol and (iv glucose-6-phosphate dehydrogenase in both glycosomes and the cytosol. Specific enzymatic activities also suggest that T. evansi is alike to the BSF of T. b. brucei in glycolytic flux, which is much faster than the pentose phosphate pathway flux, and in the involvement of cytosolic GAPDH in the NAD+/NADH balance. These similarities were expected based on the close phylogenetic relationship of both parasites.

  1. Mapping of VSG similarities in Trypanosoma brucei.

    Science.gov (United States)

    Weirather, Jason L; Wilson, Mary E; Donelson, John E

    2012-02-01

    The protozoan parasite Trypanosoma brucei switches its variant surface glycoprotein (VSG) to subvert its mammalian hosts' immune responses. The T. brucei genome contains as many as 1600 VSG genes (VSGs), but most are silent noncoding pseudogenes. Only one functional VSG, located in a telomere-linked expression site, is transcribed at a time. Silent VSGs are copied into a VSG expression site through gene conversion. Truncated gene conversion events can generate new mosaic VSGs with segments of sequence identity to other VSGs. To examine the VSG family sub-structure within which these events occur, we combined the available VSG sequences and annotations with scripted BLAST searches to map the relationships among VSGs in the T. brucei genome. Clusters of related VSGs were visualized in 2- and 3-dimensions for different N- and C-terminal regions. Five types of N-termini (N1-N5) were observed, within which gene recombinational events are likely to occur, often with fully-coding 'functional' or 'atypical'VSGs centrally located between more dissimilar VSGs. Members of types N1, N3 and N4 are most closely related in the middle of the N-terminal region, whereas type N2 members are more similar near the N-terminus. Some preference occurs in pairing between specific N- and C-terminal types. Statistical analyses indicated no overall tendency for more related VSGs to be located closer in the genome than less related VSGs, although exceptions were noted. Many potential mosaic gene formation events within each N-terminal type were identified, contrasted by only one possible mosaic gene formation between N-terminal types (N1 and N2). These data suggest that mosaic gene formation is a major contributor to the overall VSG diversity, even though gene recombinational events between members of different N-terminal types occur only rarely. PMID:22079099

  2. CHARACTERIZATION AND ANTIPARASITIC ACTIVITY OF BENZOPHENONE THIOSEMICARBAZONES ON Trypanosoma brucei brucei

    Directory of Open Access Journals (Sweden)

    Georges C. Accrombessi

    2011-02-01

    Full Text Available The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50 = 8.48 micromolar (µM. Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate anti-trypanosomal activity with IC50 values equal to 23.27 µM and 67.17 µM respectively. Benzophenone 2 methyl-3-thiosemicarbazone 2 showed no activity up to IC50 = 371.74 µM.

  3. Classical clinical signs in rats experimemtally infected with Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Nwoha Rosemary Ijeoma Ogechi

    2015-02-01

    Full Text Available Objective: To investigate clinical signs in Trypanosoma brucei infection in albino rats. Methods: Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats. Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei. Results: Parasitaemia was recorded in Group B by (3.86±0.34 d and the peak of parasitaemia was observed at Day 5 post infection. Classical signs observed included squint eyes, raised whiskers, lethargy, no weight loss, pyrexia, isolation from the other rats, and starry hair coat. Conclusions: These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.

  4. Classical clinical signs in rats experimemtally infected with Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omolathebu

    2015-01-01

    Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats. Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats. Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei. Results:Parasitaemia was recorded in Group B by (3.86±0.34) d and the peak of parasitaemia was observed at Day 5 post infection. Classical signs observed included squint eyes, raised whiskers, lethargy, no weight loss, pyrexia, isolation from the other rats, and starry hair coat. Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.

  5. Control rod

    International Nuclear Information System (INIS)

    In a control rod of a nuclear reactor, B-10 is distributed such that the concentration of B-10 in boron carbide is lowered from the outer side to the inner side of the control rod. Alternatively, the inside of a blade is radially divided into a plurality of regions, and the amount of boron carbide loaded in the regions is reduced from the outer side to the inner side of the control rod. Alternatively, a plurality of sintered products of boron carbide are disposed radially in the blade, and the sintered product is divided to a first region where the B-10 content is relatively low and a second region having a higher B-10 content than the first region, and the sintered product disposed on the inner side is constituted such that the position of the first region in the sintered product is localized to the inner side of the control rod. Then, improvement of reliability and reduction of cost can be attained while maintaining an effective neutron absorbing performance of control rods taking neutron flux distribution into consideration. (N.H.)

  6. Role of expression site switching in the development of resistance to human Trypanosome Lytic Factor-1 in Trypanosoma brucei brucei.

    Science.gov (United States)

    Kieft, Rudo; Stephens, Natalie A; Capewell, Paul; MacLeod, Annette; Hajduk, Stephen L

    2012-05-01

    Human high-density lipoproteins (HDLs) play an important role in human innate immunity to infection by African trypanosomes with a minor subclass, Trypanosome Lytic Factor-1 (TLF-1), displaying highly selective cytotoxicity to the veterinary pathogen Trypanosoma brucei brucei but not against the human sleeping sickness pathogens Trypanosoma brucei gambiense or Trypanosoma brucei rhodesiense. T. b. rhodesiense has evolved the serum resistance associated protein (SRA) that binds and confers resistance to TLF-1 while T. b. gambiense lacks the gene for SRA indicating that these parasites have diverse mechanisms of resistance to TLF-1. Recently, we have shown that T. b. gambiense (group 1) resistance to TLF-1 correlated with the loss of the haptoglobin/hemoglobin receptor (HpHbR) expression, the protein responsible for high affinity binding and uptake of TLF-1. In the course of these studies we also examined TLF-1 resistant T. b. brucei cell lines, generated by long-term in vitro selection. We found that changes in TLF-1 susceptibility in T. b. brucei correlated with changes in variant surface glycoprotein (VSG) expression in addition to reduced TLF-1 binding and uptake. To determine whether the expressed VSG or expression site associated genes (ESAGs) contribute to TLF-1 resistance we prepared a TLF-1 resistant T. b. brucei with a selectable marker in a silent bloodstream expression site (BES). Drug treatment allowed rapid selection of trypanosomes that activated the tagged BES. These studies show that TLF-1 resistance in T. b. brucei is largely independent of the expressed VSG or ESAGs further supporting the central role of HpHbR expression in TLF-1 susceptibility in these cells. PMID:22226682

  7. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei.

    Science.gov (United States)

    Sun, Ya Nan; No, Joo Hwan; Lee, Ga Young; Li, Wei; Yang, Seo Young; Yang, Gyongseon; Schmidt, Thomas J; Kang, Jong Seong; Kim, Young Ho

    2016-01-01

    Neglected tropical diseases (NTDs) affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness), caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds-4, 7, 11, 14, 15, 18, 20, and 21-showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT. PMID:27077842

  8. Regulation and spatial organization of PCNA in Trypanosoma brucei

    International Nuclear Information System (INIS)

    Highlights: ► Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). ► TbPCNA is a suitable marker to detect replication in T. brucei. ► TbPCNA distribution and regulation is different compared to closely related parasites T. cruzi and Leishmania donovani. -- Abstract: As in most eukaryotic cells, replication is regulated by a conserved group of proteins in the early-diverged parasite Trypanosoma brucei. Only a few components of the replication machinery have been described in this parasite and regulation, sub-nuclear localization and timing of replication are not well understood. We characterized the proliferating cell nuclear antigen in T. brucei (TbPCNA) to establish a spatial and temporal marker for replication. Interestingly, PCNA distribution and regulation is different compared to the closely related parasites Trypanosoma cruzi and Leishmania donovani. TbPCNA foci are clearly detectable during S phase of the cell cycle but in contrast to T. cruzi they are not preferentially located at the nuclear periphery. Furthermore, PCNA seems to be degraded when cells enter G2 phase in T. brucei suggesting different modes of replication regulation or functions of PCNA in these closely related eukaryotes.

  9. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Ya Nan Sun

    2016-04-01

    Full Text Available Neglected tropical diseases (NTDs affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness, caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds—4, 7, 11, 14, 15, 18, 20, and 21—showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.

  10. Regulation and spatial organization of PCNA in Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Doris; Gassen, Alwine [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Maiser, Andreas; Leonhardt, Heinrich [University of Munich (LMU), Department Biology II, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Janzen, Christian J., E-mail: christian.janzen@uni-wuerzburg.de [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). Black-Right-Pointing-Pointer TbPCNA is a suitable marker to detect replication in T. brucei. Black-Right-Pointing-Pointer TbPCNA distribution and regulation is different compared to closely related parasites T. cruzi and Leishmania donovani. -- Abstract: As in most eukaryotic cells, replication is regulated by a conserved group of proteins in the early-diverged parasite Trypanosoma brucei. Only a few components of the replication machinery have been described in this parasite and regulation, sub-nuclear localization and timing of replication are not well understood. We characterized the proliferating cell nuclear antigen in T. brucei (TbPCNA) to establish a spatial and temporal marker for replication. Interestingly, PCNA distribution and regulation is different compared to the closely related parasites Trypanosoma cruzi and Leishmania donovani. TbPCNA foci are clearly detectable during S phase of the cell cycle but in contrast to T. cruzi they are not preferentially located at the nuclear periphery. Furthermore, PCNA seems to be degraded when cells enter G2 phase in T. brucei suggesting different modes of replication regulation or functions of PCNA in these closely related eukaryotes.

  11. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi.

    Science.gov (United States)

    Habila, Nathan; Agbaji, Abel S; Ladan, Zakari; Bello, Isaac A; Haruna, Emmanuel; Dakare, Monday A; Atolagbe, Taofiq O

    2010-01-01

    Essential oils (EOs) from Cymbopogon citratus (CC), Eucalyptus citriodora (EC), Eucalyptus camaldulensis (ED), and Citrus sinensis (CS) were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb) and Trypanosoma evansi (T. evansi). The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09%) in CS, 6-octenal (77.11%) in EC, Eucalyptol (75%) in ED, and Citral (38.32%) in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy. PMID:20700425

  12. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

    Science.gov (United States)

    Habila, Nathan; Agbaji, Abel S.; Ladan, Zakari; Bello, Isaac A.; Haruna, Emmanuel; Dakare, Monday A.; Atolagbe, Taofiq O.

    2010-01-01

    Essential oils (EOs) from Cymbopogon citratus (CC), Eucalyptus citriodora (EC), Eucalyptus camaldulensis (ED), and Citrus sinensis (CS) were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb) and Trypanosoma evansi (T. evansi). The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09%) in CS, 6-octenal (77.11%) in EC, Eucalyptol (75%) in ED, and Citral (38.32%) in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy. PMID:20700425

  13. A comparative study on the susceptibility of male and female albino mice to Trypanosoma brucei brucei

    Directory of Open Access Journals (Sweden)

    A.A. Turay, G.O. Nwobu, G.R.A. Okogun, C.U. Igwe, K. Adeyeye, K.E. Aghatise, H.O. Okpal & Y.M. Tatfeng

    2005-03-01

    Full Text Available Background & objectives: Trypanosomiasis has remained a major set-back in the development oflivestock farming in tropical Africa. Thus the need for ascertaining the trypanotolerant levels ofdomestic animal breeds and possible improvement on them cannot be over-emphasised.Methods: Level of trypanotolerance in animals was compared between sexes using albino mice infectedwith a Nigerian strain of Trypanosoma brucei brucei at a 50% mouse lethal dose (MLD50.Results: The male mice showed unrestrained parasite growth with a prepatent period (PP of two daysand a mean survival period (MSP of six days corresponding to a gradual decrease in packed cellvolume (PCV, body weight, diet response and white blood cells (WBC count to the time of death.Their female counterparts showed a PP of three days and MSP of ten days with a similar PCV gradientbut a refractory WBC count. There was no significant difference in the differential leucocytes countin both sexes. However, the eosinophils count was significantly higher in the infected animals. It wasfound that female albino mice exercised more parasite restraint than their male counterparts.Interpretation & conclusion: The result suggests that the female animals may be more trypanotoleranthence may be more useful in protein production in trypanosomiasis endemic areas. However, furtherresearch using large domestic breeds like goats and sheep may be required to confirm the hypothesis.

  14. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

    Directory of Open Access Journals (Sweden)

    Nathan Habila

    2010-01-01

    Full Text Available Essential oils (EOs from Cymbopogon citratus (CC, Eucalyptus citriodora (EC, Eucalyptus camaldulensis (ED, and Citrus sinensis (CS were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb and Trypanosoma evansi (T. evansi. The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09% in CS, 6-octenal (77.11% in EC, Eucalyptol (75% in ED, and Citral (38.32% in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy.

  15. Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.

    Science.gov (United States)

    Allmann, Stefan; Mazet, Muriel; Ziebart, Nicole; Bouyssou, Guillaume; Fouillen, Laetitia; Dupuy, Jean-William; Bonneu, Marc; Moreau, Patrick; Bringaud, Frédéric; Boshart, Michael

    2014-01-01

    Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development and migration in the tsetse. Lipid droplets are candidates for this function. This report shows that feeding of T. brucei with oleate results in a 4-5 fold increase in the number of lipid droplets, as quantified by confocal fluorescence microscopy and by flow cytometry of BODIPY 493/503-stained cells. The triacylglycerol (TAG) content also increased 4-5 fold, and labeled oleate is incorporated into TAG. Fatty acid carbon can thus be stored as TAG in lipid droplets under physiological growth conditions in procyclic T. brucei. β-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEα1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEα1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEα1 gene knock-out mutant still expressed wild-type levels of previously reported NADP-dependent 3-hydroxyacyl-CoA dehydrogenase activity, and therefore, another gene encodes this enzymatic activity. Homozygous Δtfeα1/Δtfeα1 null mutant cells show a normal growth rate and an unchanged glycosomal proteome in procyclic T. brucei. The decay kinetics of accumulated lipid droplets upon oleate withdrawal can be fully accounted for by the dilution effect of cell division in wild-type and Δtfeα1/Δtfeα1 cells. The absence of net catabolism of stored TAG in procyclic T. brucei, even under strictly glucose-free conditions, does not formally exclude a flux through TAG, in which biosynthesis equals catabolism. Also, the possibility remains that TAG catabolism is completely repressed by other carbon sources in culture media or developmentally activated in post-procyclic stages in the tsetse. PMID:25493940

  16. Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Stefan Allmann

    Full Text Available Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development and migration in the tsetse. Lipid droplets are candidates for this function. This report shows that feeding of T. brucei with oleate results in a 4-5 fold increase in the number of lipid droplets, as quantified by confocal fluorescence microscopy and by flow cytometry of BODIPY 493/503-stained cells. The triacylglycerol (TAG content also increased 4-5 fold, and labeled oleate is incorporated into TAG. Fatty acid carbon can thus be stored as TAG in lipid droplets under physiological growth conditions in procyclic T. brucei. β-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEα1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEα1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEα1 gene knock-out mutant still expressed wild-type levels of previously reported NADP-dependent 3-hydroxyacyl-CoA dehydrogenase activity, and therefore, another gene encodes this enzymatic activity. Homozygous Δtfeα1/Δtfeα1 null mutant cells show a normal growth rate and an unchanged glycosomal proteome in procyclic T. brucei. The decay kinetics of accumulated lipid droplets upon oleate withdrawal can be fully accounted for by the dilution effect of cell division in wild-type and Δtfeα1/Δtfeα1 cells. The absence of net catabolism of stored TAG in procyclic T. brucei, even under strictly glucose-free conditions, does not formally exclude a flux through TAG, in which biosynthesis equals catabolism. Also, the possibility remains that TAG catabolism is completely repressed by other carbon sources in culture media or developmentally activated in post-procyclic stages in the tsetse.

  17. Fuel rod

    International Nuclear Information System (INIS)

    The present invention provide a fuel rod used in a BWR type reactor, preventing the occurrence of defects of weld portions and improving the operationability of test and assembling operation to improve the quality of weld portions. Namely, the fuel rod is formed by loading a plurality of fuel pellets in a cladding tube. The outer diameter of a groove portion of a tightly sealing end plug to be inserted and welded to the open end of the cladding tube is made substantially identical with the inner diameter of the cladding tube. A neck portion having a diameter smaller than the outer diameter of the groove portion is disposed between an end plug main body and the groove portion. As a result, since the outer diameter of the groove portion is substantially identical with the inner diameter of the cladding tube, the positioning is facilitated. Since the neck portion having a smaller diameter than the outer diameter of the groove portion is disposed in the groove portion, a gap is formed in the welded portion thereby enabling to facilitate the confirmation of weld sag for confirming integrity of the weld by a non-destructive test. (I.S.)

  18. Testicular pathology, gonadal and epididymal sperm reserves of Yankasa rams infected with experimental Trypanosoma brucei brucei and Trypanosoma evansi

    Directory of Open Access Journals (Sweden)

    Yunusa A. Wada

    2016-07-01

    Full Text Available Aim: The study was conducted to evaluate the pathological effects of trypanosomosis on the testes, gonadal, and epididymal sperm reserves of Yankasa rams for 98 days. Materials and Methods: A total of 16 Yankasa rams, aged between 24 and 30 months and weighed between 22 and 25 kg, were acclimatized for a period of 2-months in a clean fly proof house and were adequately fed and given water ad-libitum. Of the 16 rams, 12 that were clinically fit for the experiment at the end of the acclimatization period were randomly divided into four groups: Groups I, II, III, and IV, each having 3 rams. Groups I and II were each challenged singly with experimental Trypanosoma brucei brucei (Federer strain and Trypanosoma evansi (Sokoto strain, respectively, while Group III was challenged with mixed T. brucei brucei and T. evansi parasites (50% of each species in the infective inoculum and Group IV was left as an uninfected control. Each infected ram received 2 mL of the infected blood containing 2×106 trypomastigotes via the jugular vein, while the control group received 2 mL each, normal saline. Results: All the infected rams developed clinical signs typical of trypanosomosis at varying pre-patent periods. The gross lesions observed in the infected rams in Group II were moderate and more severe in those of Groups I and III. Histological sections of the testes of infected rams (Groups I, II, and III showed moderate (T. evansi-infected group to severe (mixed and T. brucei brucei-infected groups testicular degenerations with reduction in number of spermatogenic cell layers, degenerated seminiferous tubules, congested interlobular spaces, loss of tissue architecture with significant (p<0.01 depletion, and loss of gonadal and epididymal sperm reserves in Groups I and III in comparison to Group II and the control Group IV. No observable clinical signs and histopathological lesions were found in those rams of the control Group IV. Conclusion: The study concluded

  19. Testicular pathology, gonadal and epididymal sperm reserves of Yankasa rams infected with experimental Trypanosoma brucei brucei and Trypanosoma evansi

    Science.gov (United States)

    Wada, Yunusa A.; Oniye, Sonnie J.; Rekwot, Peter I.; Okubanjo, Oluyinka O.

    2016-01-01

    Aim: The study was conducted to evaluate the pathological effects of trypanosomosis on the testes, gonadal, and epididymal sperm reserves of Yankasa rams for 98 days. Materials and Methods: A total of 16 Yankasa rams, aged between 24 and 30 months and weighed between 22 and 25 kg, were acclimatized for a period of 2-months in a clean fly proof house and were adequately fed and given water ad-libitum. Of the 16 rams, 12 that were clinically fit for the experiment at the end of the acclimatization period were randomly divided into four groups: Groups I, II, III, and IV, each having 3 rams. Groups I and II were each challenged singly with experimental Trypanosoma brucei brucei (Federer strain) and Trypanosoma evansi (Sokoto strain), respectively, while Group III was challenged with mixed T. brucei brucei and T. evansi parasites (50% of each species in the infective inoculum) and Group IV was left as an uninfected control. Each infected ram received 2 mL of the infected blood containing 2×106 trypomastigotes via the jugular vein, while the control group received 2 mL each, normal saline. Results: All the infected rams developed clinical signs typical of trypanosomosis at varying pre-patent periods. The gross lesions observed in the infected rams in Group II were moderate and more severe in those of Groups I and III. Histological sections of the testes of infected rams (Groups I, II, and III) showed moderate (T. evansi-infected group) to severe (mixed and T. brucei brucei-infected groups) testicular degenerations with reduction in number of spermatogenic cell layers, degenerated seminiferous tubules, congested interlobular spaces, loss of tissue architecture with significant (p<0.01) depletion, and loss of gonadal and epididymal sperm reserves in Groups I and III in comparison to Group II and the control Group IV. No observable clinical signs and histopathological lesions were found in those rams of the control Group IV. Conclusion: The study concluded that

  20. Control rod

    International Nuclear Information System (INIS)

    Purpose: To enable semi-permanent and safety use of a control rod in a water cooled type reactor operated under high temperature and high pressure conditions by using a blade in which hafnium materials at a nuclear reactor quality are covered with stainless steels or zirconium alloys. Constitution: A plate-like hafnium material is surrounded with a thin plate of stainless steels or zirconium alloys under vacuum and the joint portions of the thin plate is subjected to seam welding. Then a blade is prepared by welding the remaining joining portions at both ends in a conventional manner. The welding method usable herein includes electron beam welding, laser welding and the like. If it is required to increase the close bondability between the halfnium plate and the thin plate, the blade thus obtained is subjected as it is to extrusion fabrication thereby obtain a desired increased bondability. (Kawakami, Y.)

  1. Control rod operation device

    International Nuclear Information System (INIS)

    Purpose: To reduce operator's operation burdens in the low power state, while moderate his mental burdens upon high power state for the operation of control rod operation device. Constitution: Coordinate of main control rods to be operated, aimed insertion and withdrawal positions and velocity are calculated by the control rod operation sequence and the control rod worth table, to output a control rod selection signal and a control rod operation signal. The control rod operation device conducts extraction or insertion of control rods by these signals. In this way, the operator can automatically operate the control rods by merely manipulating the control rod operation device, by which the operator's operation burden can be reduced in low power state. Further, since the selection of the control rods, the operation speed, etc. are judged by an electronic computer also upon high reactor power state, operator's metal burdens can be moderated. (Kamimura, M.)

  2. Characterization of the mitochondrial inner membrane protein translocator Tim17 from Trypanosoma brucei

    OpenAIRE

    Singha, Ujjal K; PEPRAH, EMMANUEL; Williams, Shuntae; Walker, Robert; Saha, Lipi; Chaudhuri, Minu

    2008-01-01

    Mitochondrial protein translocation machinery in the kinetoplastid parasites, like Trypanosoma brucei, has been characterized poorly. In T. brucei genome data base, one homolog for a protein translocator of mitochondrial inner membrane (Tim) has been found, which is closely related to Tim17 from other species. The T. brucei Tim17 (TbTim17) has a molecular mass 16.2 kDa and it possesses four characteristic transmembrane domains. The protein is localized in the mitochondrial inner membrane. The...

  3. Trypanosoma brucei solanesyl-diphosphate synthase localizes to the mitochondrion

    Czech Academy of Sciences Publication Activity Database

    Lai, D.-H.; Bontempi, E. J.; Lukeš, Julius

    2012-01-01

    Roč. 183, č. 2 (2012), s. 189-192. ISSN 0166-6851 R&D Projects: GA ČR(CZ) GAP305/11/2179 Institutional support: RVO:60077344 Keywords : Trypanosoma brucei * Sleeping sickness * Ubiquinone * Solanesyl-diphosphate synthase * Digitonin permeabilization * In situ tagging Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.734, year: 2012 http://www.sciencedirect.com/science/article/pii/S0166685112000539

  4. Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes

    OpenAIRE

    Pusnik, Mascha; Small, Ian; Read, Laurie K.; Fabbro, Thomas; Schneider, André

    2008-01-01

    The pentatricopeptide repeat (PPR), a degenerate 35-amino-acid motif, defines a novel eukaryotic protein family. Plants have 400 to 500 distinct PPR proteins, whereas other eukaryotes generally have fewer than 5. The few PPR proteins that have been studied have roles in organellar gene expression, probably via direct interaction with RNA. Here we show that the parasitic protozoan Trypanosoma brucei encodes 28 distinct PPR proteins, an extraordinarily high number for a nonplant organism. A com...

  5. Changes in blood sugar levels of rats experimentally infected with Trypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    OpenAIRE

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu

    2016-01-01

    Objective: To determine the effect of Trypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected with T. brucei and treated with diminazene aceturate, and Group C was infected with T. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on ...

  6. Trypanosoma brucei mitochondrial respiratome: Composition and organization in procyclic form

    KAUST Repository

    Acestor, Nathalie

    2011-05-24

    The mitochondrial respiratory chain is comprised of four different protein complexes (I-IV), which are responsible for electron transport and generation of proton gradient in the mitochondrial intermembrane space. This proton gradient is then used by F oF 1-ATP synthase (complex V) to produce ATP by oxidative phosphorylation. In this study, the respiratory complexes I, II, and III were affinity purified from Trypanosoma brucei procyclic form cells and their composition was determined by mass spectrometry. The results along with those that we previously reported for complexes IV and V showed that the respiratome of Trypanosoma is divergent because many of its proteins are unique to this group of organisms. The studies also identified two mitochondrial subunit proteins of respiratory complex IV that are encoded by edited RNAs. Proteomics data from analyses of complexes purified using numerous tagged component proteins in each of the five complexes were used to generate the first predicted protein-protein interaction network of the Trypanosoma brucei respiratory chain. These results provide the first comprehensive insight into the unique composition of the respiratory complexes in Trypanosoma brucei, an early diverged eukaryotic pathogen. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Single molecule analysis of Trypanosoma brucei DNA replication dynamics.

    Science.gov (United States)

    Calderano, Simone Guedes; Drosopoulos, William C; Quaresma, Marina Mônaco; Marques, Catarina A; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L; Elias, Maria Carolina

    2015-03-11

    Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5' extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated. PMID:25690894

  8. Tracking autophagy during proliferation and differentiation of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    William R. Proto

    2014-01-01

    Full Text Available Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei.

  9. Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Graf, Fabrice E; Ludin, Philipp; Arquint, Christian; Schmidt, Remo S; Schaub, Nadia; Kunz Renggli, Christina; Munday, Jane C; Krezdorn, Jessica; Baker, Nicola; Horn, David; Balmer, Oliver; Caccone, Adalgisa; de Koning, Harry P; Mäser, Pascal

    2016-09-01

    Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol-pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu(131) in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine. PMID:26973180

  10. Infeção experimental por Trypanosoma brucei brucei em modelo murino e estudo da eficácia farmacológica do benznidazol

    OpenAIRE

    Pereira, João Luís Gomes

    2013-01-01

    ABSTRACT - TRYPANOSOMA BRUCEI BRUCEI MURINE EXPERIMENTAL MURINE INFECTION AND STUDIES ON PHARMACOLOCICAL EFFECTIVENESS OF BENZNIDAZOLE - African Trypanosomiasis (AT) is a parasitic disease caused by several species of Trypanosoma, transmitted by diptera of the Glossina genus, also known as the tsetse flies. This disease affects humans and animals, in humans takes the name of Sleeping Sickness, and in animals takes the name of Nagana. Diagnosis can be performed by parasite visualization...

  11. 1987 Sucker rod tables

    Energy Technology Data Exchange (ETDEWEB)

    1987-03-01

    This reference identifies manufacturers qualified to produce API sucker rods and related equipment, lists chemical and mechanical properties of the various types of rods and provides dimensional characteristics. In addition, similar information is given for non-API products such as fiberglass and hollow rods.

  12. Piston rod seal

    Energy Technology Data Exchange (ETDEWEB)

    Lindskoug, S.

    1984-06-05

    In a piston rod seal of the type comprising a gland through which the piston rod is passed the piston is provided with a sleeve surrounding the piston rod and extending axially so as to axially partly overlap the gland when the piston is in its bottom dead center position. 4 figs.

  13. Piston rod seal

    Energy Technology Data Exchange (ETDEWEB)

    Lindskoug, Stefan (Malmo, SE)

    1984-01-01

    In a piston rod seal of the type comprising a gland through which the piston rod is passed the piston is provided with a sleeve surrounding the piston rod and extending axially so as to axially partly overlap the gland when the piston is in its bottom dead center position.

  14. Tie rod insertion test

    CERN Multimedia

    B. LEVESY

    2002-01-01

    The superconducting coil is inserted in the outer vaccum tank and supported by a set of tie rods. These tie rods are made of titanium alloy. This test reproduce the final insertion of the tie rods inside the outer vacuum tank.

  15. Control rod drives

    International Nuclear Information System (INIS)

    Purpose: To prevent damages in control rod drives upon connection and disconnection with control rods by providing, to an extension rod, a closure and opening guide mechanism which is adapted to open and close depending upon connection and disconnection with the control rod. Constitution: In control rod drives having a driving section and a lower mechanism, the lower mechanism has a guide tube engaged into the upper cover of a reactor container and suspended therefrom into the reactor container. An opening and closure mechanism with guide blades capable of contacting the inner wall of the guide tube is secured to an extension rod for fastening the gripper which supports the control rod. Such a mechanism cap prevent damages in the control rod drives and the control rods due to the connection after disconnection of them by the buffering action between the extension rod and the control rod, as well as damages in both of them caused by rolling such as in earthquakes by the buffering action between the extension rod and the guide tube. (Moriyama, K.)

  16. Sucker rod construction

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.A.; Goodman, J.L.; Tickle, J.D.; Liskey, A.K.

    1987-03-31

    A sucker rod construction is described comprising: a connector member being formed to define a rod receptacle having a closed axially inner end and an open axially outer end, the rod receptacle having axially spaced, tapered annular surfaces, a cylindrical fiberglass rod having an end having an outer surface being received within the rod receptacle through the outer end and cooperating therewith to define an annular chamber between the outer surface of the end of the rod and the tapered annular surfaces, and a bonding means positioned in the annular chamber for bonding to the outer surface of the end of the rod to confront the tapered annular surfaces, each annular surface having an angle of taper with respect to the outer surface of the fiberglass rod, and each angle of taper being progressively and uniformly less toward the open end by an amount between one and one-half degrees and two degrees, inclusive, and a collet connected to the connector member adjacent the open axially outer end of the rod receptacle and having an axial bore therethrough retaining the end of the rod in coaxial position within the rod receptacle.

  17. Rab23 is a flagellar protein in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Field Mark C

    2011-06-01

    Full Text Available Abstract Background Rab small GTPases are important mediators of membrane transport, and orthologues frequently retain similar locations and functions, even between highly divergent taxa. In metazoan organisms Rab23 is an important negative regulator of Sonic hedgehog signaling and is crucial for correct development and differentiation of cellular lineages by virtue of an involvement in ciliary recycling. Previously, we reported that Trypanosoma brucei Rab23 localized to the nuclear envelope 1, which is clearly inconsistent with the mammalian location and function. As T. brucei is unicellular the potential that Rab23 has no role in cell signaling was possible. Here we sought to further investigate the role(s of Rab23 in T. brucei to determine if Rab23 was an example of a Rab protein with divergent function in distinct taxa. Methods/major findings The taxonomic distribution of Rab23 was examined and compared with the presence of flagella/cilia in representative taxa. Despite evidence for considerable secondary loss, we found a clear correlation between a conventional flagellar structure and the presence of a Rab23 orthologue in the genome. By epitope-tagging, Rab23 was localized and found to be present at the flagellum throughout the cell cycle. However, RNAi knockdown did not result in a flagellar defect, suggesting that Rab23 is not required for construction or maintenance of the flagellum. Conclusions The location of Rab23 at the flagellum is conserved between mammals and trypanosomes and the Rab23 gene is restricted to flagellated organisms. These data may suggest the presence of a Rab23-mediated signaling mechanism in trypanosomes.

  18. Sucker rod guide

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, B.J.; Starks, J.A.

    1989-08-22

    This patent describes a sucker rod guide for mounting on a sucker rod and spacing the sucker rod from the tubing in an oil well. The guide comprising a generally cylindrically-shaped, extruded, ultra-high density polyethylene body having a substantially smooth outside surface; a longitudinal bore provided centrally of the body. The bore having a smaller diameter than the diameter of the sucker rod; a plurality of grooves provided in circumferential relationship in the bore; and a tapered slot extending longitudinally through the body from the outside surface to the bore. The tapered slot further comprising a slot mouth located at the outside surface and a slot throat spaced from the slot mouth. The slot throat lying adjacent to the sucker rod bore and wherein the slot throat is wider than the slot mouth for mounting the sucker rod guide on the sucker rod.

  19. VSG gene expression site control in insect form Trypanosoma brucei.

    OpenAIRE

    Rudenko, G; Blundell, P A; Taylor, M. C.; Kieft, R.; Borst, P

    1994-01-01

    When the African trypanosome Trypanosoma brucei is taken up from mammals by a tse-tse fly, it replaces its variant surface glycoprotein (VSG) coat by a procyclin coat. Transcription of VSG genes stops in the fly, but transcription of sequences derived from the promoter area of the VSG expression site(s) remains high. Whether this is due to continuing high activity of one promoter or to low activity of many promoters was unclear. We have used the small differences between the sequences of diff...

  20. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jingyan

    2014-12-01

    Trypanosma brucei (T. Brucei) is an important pathogen agent of African trypanosomiasis. The flagellum is an essential and multifunctional organelle of T. Brucei, thus it is very important to recognize the flagellar proteins from T. Brucei proteins for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference of probability functions of flagella protein and the non-flagellar protein for the purpose of flagella protein recognition. We propose to learn a multi-kernel classification function to approximate this optimal decision function, by minimizing the information loss of such approximation which is measured by the Kull back-Leibler (KL) divergence. An iterative multi-kernel classifier learning algorithm is developed to minimize the KL divergence for the problem of T. Brucei flagella protein recognition, experiments show its advantage over other T. Brucei flagellar protein recognition and multi-kernel learning methods. © 2014 IEEE.

  1. Effects of DMSO on Diminazene Efficacy in Experimental Murine T. brucei Infection

    OpenAIRE

    K.I. Eghianruwa; Anika, S.M.

    2012-01-01

    This study evaluated the influence of dimethyl sulfoxide (DMSO) daily supplementation on diminazene treatment of trypanosomosis. Four groups of Trypanosoma brucei brucei infected rats received 7.0 mg/kg diminazene aceturate on day 7 post infection. Three of the four groups received different doses of DMSO (0.5, 1.0 and 2.0 g/kg, respectively) in addition to diminazene treatment. The changes in hematological parameters and the weights of liver, spleen and heart caused by T. brucei infection we...

  2. Fuel rod bowing

    International Nuclear Information System (INIS)

    The purpose of this investigation was to quantify the extent of fuel rod bowing in Westinghouse pressurized water reactors and to assess the effects of fuel rod bowing on plant safety and reliability. An empirical bow correlation was developed based on data from irradiated assemblies. Analyses conducted with these conservative empirical predictions show that: (1) generically identified DNBR margins are adequate to offset DNBR reductions due to rod bow, (2) the present design practice of increasing the highest calculated core peaking factor is sufficient to account for all deviations, including the effects of rod bow, and (3) fretting and corrosion of bowed rods are negligible. These conclusions indicate that fuel rod bowing results in no impact on plant safety or reliability

  3. Reactor control rod

    International Nuclear Information System (INIS)

    Object: To enable quick descent of a control rod body even when some relative phase deviation between upper drive means and wrapper tube is produced, while permitting a coolant to effectively flow into a protective tube irrespective of the position of the control rod body. Structure: In a control rod used for a nuclear reactor such as a fast breeder, an orifice which dispenses with a cylindrical guide tube and has a greater inner diameter than the outer diameter of the protective tube of the control rod body is provided on the inner side of a wrapper tube, thus permitting smooth operation of the control rod body and also permitting the coolant to effectively flow into the protective tube irrespective of the control rod body. (Horiuchi, T.)

  4. Status of rod consolidation

    International Nuclear Information System (INIS)

    Two of the factors that need to be taken into account with rod consolidation are (1) the effects on rods from their removal from the fuel assembly and (2) the effects on rods as a result of the consolidation process. Potential components of both factors are described in the report. Discussed under (1) are scratches on the fuel rod surfaces, rod breakage, crud, extended burnup, and possible cladding embrittlement due to hydrogen injection at BWRs. Discussed under (2) are the increased water temperature (less than 100C) because of closer packing of the rods, formation of crevices between rods in the close-packed mode, contact with dissimilar metals, and the potential for rapid heating of fuel rods following the loss of water from a spent fuel storage pool. Another factor that plays an important role in rod consolidation is the cost of disposal of the nonfuel-bearing components of the fuel assembly. Also, the dose rate from the components - especially Inconel spacer grids - can affect the handling procedures. Several licensing issues that exist are described. A list of recommendations is provided. 98 refs., 5 figs., 5 tabs

  5. Dynamic Rod Worth Measurement

    International Nuclear Information System (INIS)

    The dynamic rod worth measurement (DRWM) technique is a method of quickly validating the predicted bank worth of control rods and shutdown rods. The DRWM analytic method is based on three-dimensional, space-time kinetic simulations of the rapid rod movements. Its measurement data is processed with an advanced digital reactivity computer. DRWM has been used as the method of bank worth validation at numerous plant startups with excellent results. The process and methodology of DRWM are described, and the measurement results of using DRWM are presented

  6. Antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger on Trypanosoma brucei brucei-infected Wistar mice

    Directory of Open Access Journals (Sweden)

    P. I. Kobo

    2014-10-01

    Full Text Available Aim: The study was carried out to determine the in vivo antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger in Trypanosoma brucei brucei-infected mice. Materials and Methods: Twenty-five mice were randomly allocated into five groups of five animals each. Group I and II were given Tween 80 (1 ml/kg and diminazene aceturate (3.5 mg/kg to serve as untreated and treated controls, respectively. Groups III-V received the extract at 200, 400 and 800 mg/kg body weight, respectively. All treatments were given for 6 consecutive days and through the oral route. The mean body weight, mean survival period and daily level of parasitaemia were evaluated. Results: Acute toxicity showed the extract to be relatively safe. There was an insignificant increase in body weight and survival rate of mice treated with the extract. The level of parasitaemia in the extract treated groups was decreased. Conclusion: This study shows the in vivo potential of methanolic extract of Z. officinale in the treatment of trypanosomiasis.

  7. Hidden Markov Models for Gene Sequence Classification: Classifying the VSG genes in the Trypanosoma brucei Genome

    OpenAIRE

    Mesa, Andrea; Basterrech, Sebastián; Guerberoff, Gustavo; Alvarez-Valin, Fernando

    2015-01-01

    The article presents an application of Hidden Markov Models (HMMs) for pattern recognition on genome sequences. We apply HMM for identifying genes encoding the Variant Surface Glycoprotein (VSG) in the genomes of Trypanosoma brucei (T. brucei) and other African trypanosomes. These are parasitic protozoa causative agents of sleeping sickness and several diseases in domestic and wild animals. These parasites have a peculiar strategy to evade the host's immune system that consists in periodicall...

  8. The Phosphoproteome of Bloodstream Form Trypanosoma brucei, Causative Agent of African Sleeping Sickness

    OpenAIRE

    Nett, Isabelle R. E.; Martin, David M. A.; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D.; Mehlert, Angela; Ferguson, Michael A. J.

    2009-01-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of severa...

  9. Mechanism of Trypanosoma brucei gambiense (group 1) resistance to human trypanosome lytic factor.

    Science.gov (United States)

    Kieft, Rudo; Capewell, Paul; Turner, C Michael R; Veitch, Nicola J; MacLeod, Annette; Hajduk, Stephen

    2010-09-14

    Human innate immunity against most African trypanosomes, including Trypanosoma brucei brucei, is mediated by a minor subclass of toxic serum HDL, called trypanosome lytic factor-1 (TLF-1). This HDL contains two primate specific proteins, apolipoprotein L-1 and haptoglobin (Hp)-related protein, as well as apolipoprotein A-1. These assembled proteins provide a powerful defense against trypanosome infection. Trypanosoma brucei rhodesiense causes human African sleeping sickness because it has evolved an inhibitor of TLF-1, serum resistance-associated (SRA) protein. Trypanosoma brucei gambiense lacks the SRA gene, yet it infects humans. As transfection of T. b. gambiense (group 1) is not possible, we initially used in vitro-selected TLF-1-resistant T. b. brucei to examine SRA-independent mechanisms of TLF-1 resistance. Here we show that TLF-1 resistance in T. b. brucei is caused by reduced expression of the Hp/Hb receptor gene (TbbHpHbR). Importantly, T. b. gambiense (group 1) also showed a marked reduction in uptake of TLF-1 and a corresponding decrease in expression of T. b. gambiense Hp/Hb receptor (TbgHpHbR). Ectopic expression of TbbHpHbR in TLF-1-resistant T. b. brucei rescued TLF-1 uptake, demonstrating that decreased TbbHpHbR expression conferred TLF-1 resistance. Ectopic expression of TbgHpHbR in TLF-1-resistant T. b. brucei failed to rescue TLF-1 killing, suggesting that coding sequence changes altered Hp/Hb receptor binding affinity for TLF-1. We propose that the combination of coding sequence mutations and decreased expression of TbgHpHbR directly contribute to parasite evasion of human innate immunity and infectivity of group 1 T. b. gambiense. PMID:20805508

  10. Natively Inhibited Trypanosoma brucei Cathepsin B Structure Determined by Using an X-ray Laser

    OpenAIRE

    L. Redecke; Nass, K.; DePonte, D. P.; White, T A; Rehders, D.; Barty, A.; F. Stellato; Liang, M; Barends, T. R. M.; Boutet, S.; Williams, G J; Messerschmidt, M.; Seibert, M. M.; Aquila, A.; Arnlund, D.

    2012-01-01

    The Trypanosoma brucei cysteine protease cathepsin B (TbCatB), which is involved in host protein degradation, is a promising target to develop new treatments against sleeping sickness, a fatal disease caused by this protozoan parasite. The structure of the mature, active form of TbCatB has so far not provided sufficient information for the design of a safe and specific drug against T. brucei. By combining two recent innovations, in vivo crystallization and serial femtosecond crystallography, ...

  11. Rod drop measurement analysis

    International Nuclear Information System (INIS)

    In some cases control rod worth efficiencies evaluated by inverse point kinetics from out-core detector currents remarkable differ from direct calculations. Explanation of this effects is given and is supported by the analysis of some WWER-440 rod drop experiments. (Authors)

  12. The Molecular Dynamics of Trypanosoma brucei UDP-Galactose 4′-Epimerase: A Drug Target for African Sleeping Sickness

    OpenAIRE

    Friedman, Aaron J; Durrant, Jacob D.; Pierce, Levi C. T.; McCorvie, Thomas J; Timson, David J; McCammon, J. Andrew

    2012-01-01

    During the past century, several epidemics of human African trypanosomiasis, a deadly disease caused by the protist Trypanosoma brucei, have afflicted sub-Saharan Africa. Over 10 000 new victims are reported each year, with hundreds of thousands more at risk. As current drug treatments are either highly toxic or ineffective, novel trypanocides are urgently needed. The T. brucei galactose synthesis pathway is one potential therapeutic target. Although galactose is essential for T. brucei survi...

  13. Rod Photoreceptors Detect Rapid Flicker

    Science.gov (United States)

    Conner, J. D.; MacLeod, Donald I. A.

    1977-01-01

    Rod-isolation techniques show that light-adapted human rods detect flicker frequencies as high as 28 hertz, and that the function relating rod critical flicker frequency to stimulus intensity contains two distinct branches. (MLH)

  14. Trypanosoma brucei has a canonical mitochondrial processing peptidase.

    Science.gov (United States)

    Desy, Silvia; Schneider, André; Mani, Jan

    2012-10-01

    Most mitochondrial matrix and inner membrane proteins have N-terminal presequences which serve as import signals. After import these presequences are cleaved by the heterodimeric mitochondrial processing peptidase. In the parasitic protozoa Trypanosoma brucei mitochondrial protein import relies on presequences that are much shorter than in other eukaryotes. How they are processed is unknown. The trypansomal genome encodes four open reading frames that are annotated as mitochondrial processing peptidase. Here we show that RNAi-mediated ablation of two of these proteins leads to a growth arrest and a concomitant accumulation of mitochondrial precursor proteins inside mitochondria. Import experiments using isolated mitochondria from RNAi cell lines reveals that both proteins are required for efficient import and processing of the tested precursor protein. Reciprocal immunoprecipitation demonstrates that the proteins interact with each other. In summary these results show that we have identified the two subunits of the trypanosomal mitochondrial processing peptidase. PMID:22841752

  15. Control rod assembly

    International Nuclear Information System (INIS)

    In a control rod assembly comprising an extension rod extended upwardly from the upper end of a control rod main body disposed in a reactor core and an extension tube engaging a grip portion disposed to an upper portion of the extension rod for suspending the control rod main body, a shrinkable portion is disposed to a part of the extension tube or extension rod, or a grip portion shrinkable in the axial direction is disposed to the extension rod. Further, a spring is interposed to a portion of the extension tube and bellows are disposed to the inner side or the outer side of the spring. A double-cylindrical temperature sensing member is disposed surrounding the outer side of the bellows or the spring. Liquid metals are sealed in the temperature sensing member or the bellows. This can improve the response of the coolants to the temperature elevation and can suppress the change of the reactor core insertion amount relative to temperature change during usual operation. (T.M.)

  16. Flexible sucker rod unit

    Energy Technology Data Exchange (ETDEWEB)

    Allen, L.F.

    1987-02-03

    This patent describes a deep well having: a. an education tube with an inside diameter extending from the surface of the earth to far below the surface, b. a reciprocating pump housing attached to the bottom of the education tube, c. pump jack means at the surface for reciprocating the pump, d. a light sucker rod connected to the pump jack means and extending into the education tube, and e. a series of heavy sinker bars having a large cross sectional area in the education tube connecting the light sucker rod to the pump; f. an improved integral metal flexible rod unit interconnecting the sinker bars comprising in combination with the above: g. a coupling on each end of the integral metal flexible rod unit connecting the flexible rod unit to the contiguous sinker bar, h. a segment which is flexible as compared to the sinker bars connecting one of the couplings to i. an integral metal bearing adjacent to the other of the couplings, the bearing having j. a cylindrical surface with k. a diameter i. only slightly smaller than the inside diameter of the education tube thereby forming a sliding fit therewith, and ii. greater than the diameter of any other portion of the flexible rod unit and the sinker bar, and l. grooves in the cylindrical surface for the passage of fluid between in the education tube around the bearing.

  17. Control rod drives

    International Nuclear Information System (INIS)

    Purpose: To rapidly detect the position to which a control rod has been rapidly inserted into the reactor core upon scram in the control rod drives for use in LMFBR type reactors. Constitution: In control rod drives comprising an acceleration spring disposed to the outside of an extension pipe and an acceleration pipe for conducting the spring force to a control rod for rapidly dropping the rod into the reactor core, a magnet having a repulsive force is disposed to each acceleration pipe and guide pipe as decelerating and buffering means for the acceleration pipe. The position of the control rod is detected by the interaction between the magnet and the coils attached to the inside of the guide pipe or reactor lead switch. According to this invention, 85 % scram signal which has hitherto been difficult to be processed electrically can be obtained with a sufficient intensity and with no delay to thereby improve the entire safety of the reactor system. Then, the inserted position and the insertion time can accurately and rapidly be detected. (Horiuchi, T.)

  18. Control rod drives

    International Nuclear Information System (INIS)

    Purpose: To fix a magnetic rotor to a drive shaft and at the time of non-driving, to restrain the rotor by permanent magnets thereby to hold the position of the control rod safely and accurately. Constitution: A control rod position holding device is provided in a motor or a drive shaft of a control rod drive. This device consists of a rotor and a stator, the rotor being provided on its circumference with salient-poles arranged equidistantly, and the position of the rotor being determined depending upon the transfer distance of the control rod and the conversion ratio of the converter. On the other hand, the stator has salient-poles (any of them is a permanent magnet) having the number of poles and the positional relationship equivalent to those of the rotor, and provided in the inner periphery of a cylinder using the drive shaft as a central shaft and wound with a winding. When the control rod is not driven, the poles of the rotor are attracted by the magnetic force of the confronting poles of the stator, thereby to prevent the inverse rotation of the motor shaft due to the dead weight of the control rod. When a current is caused to flow through the winding, the magnetic force of the permanent magnet, and the stator release the rotor. (Yoshino, Y.)

  19. Control rod blocking device

    International Nuclear Information System (INIS)

    Purpose: To increase the degree of freedom for the reactor operation by control rod blocking by monitoring the critical power ratio (CPR) with real time. Constitution: There has been a problem that the withdrawal of control rods may occasionally be inhibited with all the margin in view of CPR. The present invention dissolves this problem. That is, the control rod withdrawal device periodically calculates CPR, and calculated CPR upon generation of a control rod withdrawing signal by conpensating the result of calculation with a LPRM signal and a reactor core flow rate signal. The CPR at real time is compared with a predetermined setting value to output a control rod withdrawing inhibition signal depending on the result of the comparison. In the device as described above, since CPR is monitored at real time, the control rod can be withdrawn without causing fuel damages, as well as the inhibition of withdrawal irrespective of the presence of margin in view of CPR can be avoided. Accordingly, degree of freedom in the reactor operation can be increased. (Kamimura, M.)

  20. Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, Andres [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Gupta, Shreedhara; Gualdron-Lopez, Melisa; Nguewa, Paul A. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Altabe, Silvia G. [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Deumer, Gladys; Wallemacq, Pierre [Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, LTAP, Universite Catholique de Louvain, Brussels (Belgium); Michels, Paul A.M. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Uttaro, Antonio D., E-mail: toniuttaro@yahoo.com.ar [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina)

    2011-08-26

    Highlights: {yields} Inhibiting {Delta}9 desaturase drastically changes T. brucei's fatty-acid composition. {yields} Isoxyl specifically inhibits the {Delta}9 desaturase causing a growth arrest. {yields} RNA interference of desaturase expression causes a similar effect. {yields} Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. {yields} 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC{sub 50}) of PCF was 1.0 {+-} 0.2 {mu}M for Isoxyl and 5 {+-} 2 {mu}M for 10-TS, whereas BSF appeared more susceptible with EC{sub 50} values 0.10 {+-} 0.03 {mu}M (Isoxyl) and 1.0 {+-} 0.6 {mu}M (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.

  1. Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

    International Nuclear Information System (INIS)

    Highlights: → Inhibiting Δ9 desaturase drastically changes T. brucei's fatty-acid composition. → Isoxyl specifically inhibits the Δ9 desaturase causing a growth arrest. → RNA interference of desaturase expression causes a similar effect. → Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. → 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC50) of PCF was 1.0 ± 0.2 μM for Isoxyl and 5 ± 2 μM for 10-TS, whereas BSF appeared more susceptible with EC50 values 0.10 0.03 μM (Isoxyl) and 1.0 ± 0.6 μM (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.

  2. Sucker rod centralizer

    Energy Technology Data Exchange (ETDEWEB)

    Rezewski, J.

    1988-01-26

    This patent describes an oil well sucker rod guide consisting of an elongated body having a number of radial slots. Each slot is disposed at equiangular spaced positions, and contains a roller rotatably supported upon an axle transverse to the slot, such that the roller projects outside the periphery of the body from only one end of the slot

  3. Piston for rod pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pastushenko, G.I.

    1965-06-22

    A piston, or plunger, for rod pumping, is made up of a cylindrical housing with labryinthal seals, a nose piece, and a scraper. In order to remove paraffin from the inside surface of the production pipe, the housing is made in telescopic form. The scraper consists of an arrangement of springs installed on the outer surface of the housing.

  4. Co-infection with Plasmodium berghei and Trypanosoma brucei increases severity of malaria and trypanosomiasis in mice.

    Science.gov (United States)

    Ademola, Isaiah Oluwafemi; Odeniran, Paul Olalekan

    2016-07-01

    Individuals in natural populations may be infected with multiple different parasites at a time. These parasites may interact with each other or act independently in the host, and this may result to varying outcomes on host health and survival. This study therefore aimed at investigating the health impact of co-infection of mice with Plasmodium berghei and Trypanosoma brucei. Forty Swiss albino mice (14-17g) were divided into four groups of ten. Mice in groups A and B received 10(6)P. berghei and groups B and C 10(5)T. brucei, while group D were uninfected. The co-infected mice had higher P. berghei and T. brucei parasitaemia, compared with the mono-infected mice. The co-infected mice had significantly (p<0.05) lower survival rate compared with the mono-infected mice. Co-infection of mice with P. berghei and T. brucei resulted in rapid P. berghei and T. brucei development and increased parasitaemia. The leukocyte numbers significantly (p<0.05) reduced on days 12 and 15 post infection among P. berghei infected mice, in the presence or absence of T. brucei. Anaemia and hypoglycaemia was more severe in the co-infected mice. Therefore, co-infection of mice with P. berghei and T. brucei may increase pathologic impact to the host by increasing parasitaemia. PMID:27021269

  5. Unfolded Protein Response Pathways in Bloodstream-Form Trypanosoma brucei?

    Science.gov (United States)

    Tiengwe, Calvin; Brown, Abigail E N A; Bangs, James D

    2015-11-01

    The unfolded protein response (UPR) is a stress mechanism to cope with misfolded proteins in the early secretory pathway, the hallmark being transcriptional upregulation of endoplasmic reticulum (ER) molecular chaperones such as BiP and protein disulfide isomerase. Despite the lack of transcriptional regulation and the absence of the classical UPR machinery, African trypanosomes apparently respond to persistent ER stress by a UPR-like response, including upregulation of BiP, and a related spliced leader silencing (SLS) response whereby SL RNA transcription is shut down. Initially observed by knockdown of the secretory protein translocation machinery, both responses are also induced by chemical agents known to elicit UPR in mammalian cells (H. Goldshmidt, D. Matas, A. Kabi, A. Carmi, R. Hope, S. Michaeli, PLoS Pathog 6:e1000731, 2010, http://dx.doi.org/10.1371/journal.ppat.1000731). As these findings were generated primarily in procyclic-stage trypanosomes, we have investigated both responses in pathogenic bloodstream-stage parasites. RNA interference (RNAi) silencing of the core translocon subunit Trypanosoma brucei Sec61α (TbSec61α) failed to induce either response. Interestingly, cell growth halted within 16 h of silencing, but sufficient TbSec61α remained to allow full competence for translocation of nascent secretory proteins for up to 24 h, indicating that replication is finely coupled with the capacity to synthesize and transport secretory cargo. Tunicamycin and thapsigargin at concentrations compatible with short-term (4 h) and long-term (24 h) viability also failed to induce any of the indicators of UPR-like or SLS responses. Dithiothreitol (DTT) was lethal at all concentrations tested. These results indicate that UPR-like and SLS responses to persistent ER stress do not occur in bloodstream-stage trypanosomes. PMID:26318397

  6. Control rod cluster with removable rods for nuclear fuel assembly

    International Nuclear Information System (INIS)

    For each removable control rod, the open end section of the sleeve has a certain length of reduced diameter with openings in its wall. The top end of the rod is joined to an extension tube that surrounds the shaft over part of its lenght. This extension tube fits over the reduced part of the sleeve when the shaft is screwed into the bore of the sleeve. Rotation of the rod in the sleeve is prevented by deforming the extension tube locally in the openings of the end part of the sleeve. The rod is dismantled by exerting a torque on it using a gripping area near the end of the rod

  7. Morphoelastic rods. Part I: A single growing elastic rod

    KAUST Repository

    Moulton, D.E.

    2013-02-01

    A theory for the dynamics and statics of growing elastic rods is presented. First, a single growing rod is considered and the formalism of three-dimensional multiplicative decomposition of morphoelasticity is used to describe the bulk growth of Kirchhoff elastic rods. Possible constitutive laws for growth are discussed and analysed. Second, a rod constrained or glued to a rigid substrate is considered, with the mismatch between the attachment site and the growing rod inducing stress. This stress can eventually lead to instability, bifurcation, and buckling. © 2012 Elsevier Ltd. All rights reserved.

  8. Method for making sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Rasi-Zade, A.T.O.; Kurbanov, N.G.O.; Sutovsky, P.M.; Shikhlinsky, T.M.O.; Kakhramanov, K.T.; Rabinovich, A.M.; Karaev, I.K.O.; Timofeev, V.I.; Ibragimov, O.I.O.

    1991-07-20

    A method for making sucker rods used in oil well pumping is provided, which has the objectives of cutting down the cost of producing sucker rods and of improving their reliability in arduous operating conditions found in wells containing corrosive fluids. The method is characterized in that a rod-body blank is first welded together with rod-end blanks which are made from different materials than the rod-body blank. A welded sucker-rod blank is thus obtained, on which end heads are upset from the blank. The length of the rod-end blank is selected so that weld joints are established, after the upsetting procedure, across the maximum cross-section of the end heads. The method of the invention provides for a weld joint having as much as 3.5 to 4 times the area compared to the rod body, within the zone of the minimum effective stresses acting upon the rod, hence possessing a safety margin of many times the maximum stress applied. This assures high operational reliability and durability of the rods produced according to the invention. The method of the invention does not require precision accuracy in welding the sucker-rod blanks, and minimizes the consumption of expensive alloyed steel, which is used only for making the part of the rod that is subjected to the greatest loads. 7 figs.

  9. Control rod calibration including the rod coupling effect

    International Nuclear Information System (INIS)

    In a reactor containing more than one control rod, which includes all reactors licensed in the United States, there will be a 'coupling' or 'shadowing' of control rod flux at the location of a control rod as a result of the flux depression caused by another control rod. It was decided to investigate this phenomenon further, and eventually to put calibration table data or formulae in a small computer in the control room, so once could insert the positions of the three control rods and receive the excess reactivity without referring to separate tables. For this to be accomplished, a 'three control- rod reactivity function' would be used which would include the flux coupling between the rods. The function is design and measured data was fitted into it to determine the calibration constants. The input data for fitting the trial functions consisted of 254 data points, each consisting of the position of the reg, shim, and transient rods, and the total excess reactivity. (About 200 of these points were 'critical balance points', that is the rod positions for which reactor was critical, and the remainder were determined by positive period measurements.) Although this may be unrealistic from a physical viewpoint, the function derived gave a very accurate recalculation of the input data, and thus would faithfully give the excess reactivity for any possible combination of the locations of the three control rods. The next step, incorporation of the three-rod function into the minicomputer, will be pursued in the summer and fall of 1984

  10. Telomere length affects the frequency and mechanism of antigenic variation in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Galadriel A Hovel-Miner

    Full Text Available Trypanosoma brucei is a master of antigenic variation and immune response evasion. Utilizing a genomic repertoire of more than 1000 Variant Surface Glycoprotein-encoding genes (VSGs, T. brucei can change its protein coat by "switching" from the expression of one VSG to another. Each active VSG is monoallelically expressed from only one of approximately 15 subtelomeric sites. Switching VSG expression occurs by three predominant mechanisms, arguably the most significant of which is the non-reciprocal exchange of VSG containing DNA by duplicative gene conversion (GC. How T. brucei orchestrates its complex switching mechanisms remains to be elucidated. Recent work has demonstrated that an exogenous DNA break in the active site could initiate a GC based switch, yet the source of the switch-initiating DNA lesion under natural conditions is still unknown. Here we investigated the hypothesis that telomere length directly affects VSG switching. We demonstrate that telomerase deficient strains with short telomeres switch more frequently than genetically identical strains with long telomeres and that, when the telomere is short, switching preferentially occurs by GC. Our data supports the hypothesis that a short telomere at the active VSG expression site results in an increase in subtelomeric DNA breaks, which can initiate GC based switching. In addition to their significance for T. brucei and telomere biology, the findings presented here have implications for the many diverse pathogens that organize their antigenic genes in subtelomeric regions.

  11. Biosynthesis of SUMOylated Proteins in Bacteria Using the Trypanosoma brucei Enzymatic System.

    Directory of Open Access Journals (Sweden)

    Paula Ana Iribarren

    Full Text Available Post-translational modification with the Small Ubiquitin-like Modifier (SUMO is conserved in eukaryotic organisms and plays important regulatory roles in proteins affecting diverse cellular processes. In Trypanosoma brucei, member of one of the earliest branches in eukaryotic evolution, SUMO is essential for normal cell cycle progression and is likely to be involved in the epigenetic control of genes crucial for parasite survival, such as those encoding the variant surface glycoproteins. Molecular pathways modulated by SUMO have started to be discovered by proteomic studies; however, characterization of functional consequences is limited to a reduced number of targets. Here we present a bacterial strain engineered to produce SUMOylated proteins, by transferring SUMO from T. brucei together with the enzymes essential for its activation and conjugation. Due to the lack of background in E. coli, this system is useful to express and identify SUMOylated proteins directly in cell lysates by immunoblotting, and SUMOylated targets can be eventually purified for biochemical or structural studies. We applied this strategy to describe the ability of TbSUMO to form chains in vitro and to detect SUMOylation of a model substrate, PCNA both from Saccharomyces cerevisiae and from T. brucei. To further validate targets, we applied an in vitro deconjugation assay using the T. brucei SUMO-specific protease capable to revert the pattern of modification. This system represents a valuable tool for target validation, mutant generation and functional studies of SUMOylated proteins in trypanosomatids.

  12. A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans

    DEFF Research Database (Denmark)

    Vanhollebeke, Benoit; De Muylder, Géraldine; Nielsen, Marianne J; Pays, Annette; Tebabi, Patricia; Dieu, Marc; Raes, Martine; Moestrup, Soren K; Pays, Etienne

    2008-01-01

    The protozoan parasite Trypanosoma brucei is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which bi...

  13. Control rod drive

    International Nuclear Information System (INIS)

    A control device for long time stopping is disposed for stopping by applying the same number of normal rotation and reverse rotation to a ball spindle at a predetermined time interval. Even in a case where a control rod is not operated for a long period of time, sticking between a sealing material and a ball spindle is prevented, rotational torque is not increased excessively, and the control rod can always be operated normally. Further, a stopping control device is disposed for applying rotation after the stop of the rotation of the ball spindle in the reverse direction within one turn. Lubricants and obstacles are introduced between the surfaces purified by the rotation, to prevent the direct contact of the purified surfaces to each other and correct the deformation of sealing members. Therefore, the rotational torque is not increased excessively. (N.H.)

  14. Sucker rod centralizer

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, O.; Newski, A.

    1989-10-03

    This patent describes a device for centralizing at least one sucker rod within a production pipe downhole in a well and for reducing frictional forces between the pipe and at least one sucker rod. It comprises an elongate, substantially cylindrical body member having a longitudinal axis, a plurality of slots within the member and a rotatable member mounted within each slot, each of the plurality of slots has its major dimension along a first axis parallel to the longitudinal axis of the body member and is oriented with respect to the other seats so as to form a helicoidal array for maximizing the total surface contact area between the rotatable members and the pipe and for decreasing the forces acting on each rotatable member.

  15. Fuel rod attachment system

    International Nuclear Information System (INIS)

    A reusable system for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member or vice versa. The locking cap has two opposing fingers and shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed. In an alternative embodiment, the cap is rigid and the strip is transversely resiliently compressible. (author)

  16. Control rod position detector

    International Nuclear Information System (INIS)

    The device of the present invention can save blowers for compulsory cooling. That is, the control rod position detector comprises (1) a control rod driving shaft made of a ferromagnetic material moving in a pressure vessel of a nuclear reactor and (2) detector coils arranged to the outside of the pressure vessel each at an identical distance over the moving stroke of the driving shaft for detecting the position of the driving shaft by the change of inductance. In addition, heat insulation materials are disposed between the detector coils and the reactor pressure vessel. Then, heat from the reactor pressure vessel can be insulated. Accordingly, temperature of the detector coils can be reduced by natural cooling. As a result, since it is no more necessary to dispose compulsory cooling fans as required in a conventional case, the entire device can be constituted economically, and the reliability of the device is improved. (I.S.)

  17. Segment fuel rods

    International Nuclear Information System (INIS)

    Purpose: To maintain the integrity of segment fuel rods without causing power spikes in adjacent fuel rods. Constitution: Power spikes are generated in the portions in adjacent with end plugs of segment fuel elements shielded welding zircaloy end plugs, because water/uranium ratio is locally increased due to the absence of pellets at the bonding end plugs to increase the neutron moderating effect thereby increasing the thermal neutron fluxes to rise the reactivity. This can be prevented most effectively by absorbing excess neutron absorbers. In view of the above, the purpose can be attained either by incorporating high neutron absorbing material at the bonding end plug, or constituting the bonding end plug itself with neutron absorbing material. (Kamimura, M.)

  18. Fuel rod fixing system

    International Nuclear Information System (INIS)

    This is a reusable system for fixing a nuclear reactor fuel rod to a support. An interlock cap is fixed to the fuel rod and an interlock strip is fixed to the support. The interlock cap has two opposed fingers, which are shaped so that a base is formed with a body part. The interlock strip has an extension, which is shaped so that this is rigidly fixed to the body part of the base. The fingers of the interlock cap are elastic in bending. To fix it, the interlock cap is pushed longitudinally on to the interlock strip, which causes the extension to bend the fingers open in order to engage with the body part of the base. To remove it, the procedure is reversed. (orig.)

  19. Sucker rod guide

    Energy Technology Data Exchange (ETDEWEB)

    White, R.C.

    1988-10-25

    This patent describes an improved guide for use in a string of sucker rods for reciprocation in a tubing string in a borehole, the sucker rods having threaded male ends, the guide comprising: an elongated upright cylindrical member of external diameter less than the internal diameter of tubing in which it is to be used, the member having sucker rod receiving female threaded openings at the upper and lower ends, the threaded openings being coaxial of the member cylindrical axis whereby the member may be positioned in a string of sucker rods, and including a plurality of spaced-apart parallel sided slots within the member, each slot being of semi-circular configuration and of depth greater than the radius and less than the diameter of the cylindrical member, the sidewalls of each slot being parallel to and equally spaced from a plane of the member cylindrical axis; the member having an axle bore therein for each of the slots, the axle bores being parallel and spaced apart from each other, a plane of the axis of each bore being perpendicular the member cylindrical axis and the axis of each bore being displaced away from the member cylindrical axis; an axle received in each axle bore; and a wheel received on each axle the diameter of each wheel being approximately the diameter of the cylindrical member, the periphery of each wheel extending beyond the member cylindrical wall whereby the wheels are positioned to engage and roll on the internal cylindrical surface of tubing, the planes of adjacent slots in the member being rotationally displaced from each other, a portion of each wheel extending beyond the cylindrical surface of the member, the opposed portion of each wheel being within the confines of the member cylindrical surface whereby each wheel can contact a tubing wall at only one point on its cylindrical surface.

  20. The phosphoproteome of bloodstream form Trypanosoma brucei, causative agent of African sleeping sickness.

    Science.gov (United States)

    Nett, Isabelle R E; Martin, David M A; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D; Mehlert, Angela; Ferguson, Michael A J

    2009-07-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of several T. brucei kinases, very few specific phosphorylation sites have been determined in this organism. Using a gel-free, phosphopeptide enrichment-based proteomics approach we performed the first large scale phosphorylation site analyses for T.brucei. Serine, threonine, and tyrosine phosphorylation sites were determined for a cytosolic protein fraction of the bloodstream form of the parasite, resulting in the identification of 491 phosphoproteins based on the identification of 852 unique phosphopeptides and 1204 phosphorylation sites. The phosphoproteins detected in this study are predicted from their genome annotations to participate in a wide variety of biological processes, including signal transduction, processing of DNA and RNA, protein synthesis, and degradation and to a minor extent in metabolic pathways. The analysis of phosphopeptides and phosphorylation sites was facilitated by in-house developed software, and this automated approach was validated by manual annotation of spectra of the kinase subset of proteins. Analysis of the cytosolic bloodstream form T. brucei kinome revealed the presence of 44 phosphorylated protein kinases in our data set that could be classified into the major eukaryotic protein kinase groups by applying a multilevel hidden Markov model library of the kinase catalytic domain. Identification of the kinase phosphorylation sites showed conserved phosphorylation sequence motifs in several kinase activation segments, supporting the view that

  1. Method for making sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Karaev, I.K.O.; Shikhlinsky, T.M.O.; Polikhronov, K.P.; Sutovsky, P.M.; Avakian, E.V.; Semkin, N.V.; Rabinovich, A.M.; Dzhabarov, R.D.

    1991-01-15

    A method for making sucker rods composed of a rod body and end heads is provided. The rod body end portions are subjected to an upsetting procedure which is carried out at a temperature that precludes softening of the rod body metal. A thickening is formed on each of the end portions, whose width in a direction square with the rod body axis is equal to or exceeds the head maximum diameter in the place of the weld joint, and whose length exceeds the width of the heat-affected zone involved in the welding process. A transition portion is shaped as a solid of revolution whose cross-section smoothly and continuously decreases from the thickening towards the rod body. The upsetting procedure is followed by pressure welding of each of the end heads together with the thickening on the rod body end portion and by turning the weld joint zone.

  2. Sucker rod coupling

    Energy Technology Data Exchange (ETDEWEB)

    Klyne, A.A.

    1986-11-11

    An anti-friction sucker rod coupling is described for connecting a pair of sucker rods and centralizing them in a tubing string, comprising: an elongate, rigid, substantially cylindrical body member, each end of the body member forming means for threadably connecting the body member with a sucker rod. The body member further forms a transversely extending, substantially diametric, generally vertical slot extending therethrough. The body member further forms a pin bore, such pin bore extending transversely through the body member so as to intersect the slot substantially perpendicularly; a wheel member positioned within the slot to rotate in a generally vertical plane. The wheel member has a portion thereof extending beyond the periphery of the body member to engage the inner surface of the tubing string and centralize the coupling; and a pin mounted in the pin bore and supporting member thereon, whereby the wheel member is rotatable within the slot; the wheel member having sufficient clearance between its side surfaces and the wall surfaces of the slot, when the wheel member is centered in the slot on the pin, whereby the wheel member may shift along the pin to assist in ejecting sand and oil from the slot.

  3. Control rod drive mechanisms

    International Nuclear Information System (INIS)

    Purpose: To accurately measure the loads generated upon scram and judge the absence or presence of deceleration in control rod drive mechanisms. Constitution: Control rod drive mechanisms for use in a BWR type reactor includes an index tube vertically movably, connected at the upper end to the control rod and having a drive piston at the lower end. A piezoelectric member for detecting the load generated upon uprise of the index tube is disposed and signals from the piezoelectric member is connected to a calculation processing device. A load exerted when the index tube uprises is measured by way of the piezoelectric member upon scram thereby judging the absence or presence of the decelerating operation. Therefore, the nuclear reactor can be shutdown only when it is required with no excess safety operation than required. As a result, the reactor availability can be improved and, in addition, it is also possible to mitigate the burden of in-service inspection and reduce the operators' exposure. (Kamimura, M.)

  4. Nuclear fuel rods

    International Nuclear Information System (INIS)

    Purpose: To enable a tight seal in fuel rods while keeping the sealing gas pressure at an exact predetermined pressure in fuel rods. Constitution: A vent aperture and a valve are provided to the upper end plug of a cladding tube. At first, the valve is opened to fill gas at a predetermined pressure in the fuel can. Then, a conical valve body is closely fitted to a valve seat by the rotation of a needle valve to eliminate the gap in the engaging thread portion and close the vent aperture. After conducting the reduced pressure test for the fuel rod in a water tank, welding joints are formed between the valve and the end plug through welding to completely seal the cladding tube. Since the welding is conducted after the can has been closed by the valve, the predetermined gas pressure can be maintained at an exact level with no efforts from welding heat and with effective gas leak prevention by the double sealing. (Kawakami, Y.)

  5. Trypanosoma brucei: Differential requirement of membrane potential for import of proteins into mitochondria in two developmental stages

    OpenAIRE

    Williams, Shuntae; Saha, Lipi; Singha, Ujjal K; Chaudhuri, Minu

    2007-01-01

    Trypanosome alternative oxidase (TAO) and the cytochrome oxidase (COX) are two developmentally regulated terminal oxidases of the mitochondrial electron transport chain in Trypanosoma brucei. Here, we have compared the import of TAO and cytochrome oxidase subunit IV (COIV), two stage specific nuclear encoded mitochondrial proteins, into the bloodstream and procyclic form mitochondria of T. brucei to understand the import processes in two different developmental stages. Under in vitro conditio...

  6. The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei

    OpenAIRE

    Hazel Xinyu Koh; Htay Mon Aye; Tan, Kevin S W; He, Cynthia Y.

    2015-01-01

    Background: Trypanosoma brucei is a blood-borne, protozoan parasite that causes African sleeping sickness in humans and nagana in animals. The current chemotherapy relies on only a handful of drugs that display undesirable toxicity, poor efficacy and drug-resistance. In this study, we explored the use of lysosomotropic drugs to induce bloodstream form T. brucei cell death via lysosome destabilization. Methods: We measured drug concentrations that inhibit cell proliferation by 50% (...

  7. The molecular dynamics of Trypanosoma brucei UDP-galactose 4'-epimerase:a drug target for African sleeping sickness

    OpenAIRE

    Friedman, Aaron J; Durrant, Jacob D.; Pierce, Levi C. T.; McCorvie, Thomas J; Timson, David J; McCammon, J. Andrew

    2012-01-01

    During the past century, several epidemics of human African trypanosomiasis, a deadly disease caused by the protist Trypanosoma brucei, have afflicted sub-Saharan Africa. Over 10 000 new victims are reported each year, with hundreds of thousands more at risk. As current drug treatments are either highly toxic or ineffective, novel trypanocides are urgently needed. The T. brucei galactose synthesis pathway is one potential therapeutic target. Although galactose is essential for T. brucei survi...

  8. Fiber optic laser rod

    Science.gov (United States)

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  9. Cone rod dystrophies

    Directory of Open Access Journals (Sweden)

    Hamel Christian P

    2007-02-01

    Full Text Available Abstract Cone rod dystrophies (CRDs (prevalence 1/40,000 are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP, also called the rod cone dystrophies (RCDs resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7. Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far. The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs, CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs, and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs. It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is

  10. Improved fuel rod support means

    International Nuclear Information System (INIS)

    A fuel bundle for a nuclear reactor having a plurality of fuel rods supported between spaced tie plates, wherein coolant flows through said tie plates and past said fuel rods, characterized by: an end plug disposed between an end of each fuel rod and the adjacent tie plate, and means defining a passage for the flow of coolant through the interface between said end plug and said tie plates to minimize crud buildup at said interface

  11. Piston and connecting rod assembly

    Science.gov (United States)

    Brogdon, James William (Inventor); Gill, David Keith (Inventor); Chatten, John K. (Inventor)

    2001-01-01

    A piston and connecting rod assembly includes a piston crown, a piston skirt, a connecting rod, and a bearing insert. The piston skirt is a component separate from the piston crown and is connected to the piston crown to provide a piston body. The bearing insert is a component separate from the piston crown and the piston skirt and is fixedly disposed within the piston body. A bearing surface of a connecting rod contacts the bearing insert to thereby movably associate the connecting rod and the piston body.

  12. Metrology of irradiated fuel rods

    International Nuclear Information System (INIS)

    A nuclear fuel rod has its diameter measured by back illumination from a lamp which casts a silhouette image of the rod on to a photo diode array. A radiation shielding wall exists between the rod and array with optical transmission through the wall. The output of the array is threshold voltage level sensed to generate a data pulse which envelops clock pulses digitally representing the rod diameter. The resolution is improved by interpolating between diode position in the array by means of an integrator. (author)

  13. Fuel rod plugs

    International Nuclear Information System (INIS)

    Purpose: To prevent the formation of voids to the inside of welded portion in fuel rod plugs. Constitution: A fuel rod is tightly sealed by welding end plugs at both ends of a fuel can charged with nuclear fuel material. For the welding of the end plug, laser welding has now been employed with the reason of increasing the welding efficiency and reducing the welding heat distortion. However, if the end plug is laser-welded to the end of the fuel can in the conventional form, there is a problem that voids are liable to be formed near the deepest penetration in the welding portion. That is, gases evolved near the deepest penetration remains in a key-hole like welded metal portion to result in voids there. Accordingly, grooves capable of passing the laser beam key hole therethrough are disposed along the circumferential direction of the pipe at the end plug welded portion in the fuel can. In this way, since gases generating near the deepest penetration are discharged into the grooves, the key hole-like welded metal is completely filled and voids are not formed. (Kamimura, M.)

  14. Control rod drive system

    International Nuclear Information System (INIS)

    The present invention concerns an electromotive driving-type control rod driving system of a BWR type reactor, for which sliding resistance (friction) test can be performed of a movable portion of the control rod driving mechanisms. Namely, a hydraulic pressure control unit has following constitutions in addition to a conventional constitution as a sliding resistance test performing function. (1) A restricting valve is disposed downstream of the scram valve of scram pipelines to control flow rate and pressure of pressurized water flown in the pipelines. (2) A pressure gauge detects a pressure between the scram valve and the restricting valve. (3) A flow meter detects the flow rate of pipelines controlled by the restricting valve. (4) A recording pressure detector detects the pressure at the downstream of the restricting valve. (5) The recording device is attached when the sliding resistant test is performed for tracing the pressure measured by the pressure detection device. Further, the scram valve sends electric signals to a central operation chamber when it is fully closed. The central operation chamber has a function of fully opening the restricting valve by way of the electric signals. (I.S.)

  15. Trypanosoma brucei Infection in asymptomatic greater Kudus (Tragelaphus strepsiceros) on a game ranch in Zambia.

    Science.gov (United States)

    Munang'andu, Hetron Mweemba; Siamudaala, Victor; Munyeme, Musso; Nambota, Andrew; Mutoloki, Stephen; Matandiko, Wigganson

    2010-03-01

    Trypomastogotes of Trypanosoma brucei were detected from 4 asymptomatic kudus (Tragelaphus strepsiceros) on a game ranch located approximately 45 km north east of Lusaka, Zambia. Blood smears examined from 14 wildlife species comprising of the impala (Aepyceros melampus), Kafue lechwe (kobus leche kafuensis), sable antelope (Hippotragus niger), tsessebe (Damaliscus lunatus), warthog (Phacochoerus aethiopicus), puku (Kobus vardoni), zebra (Equus burchelli), waterbuck (Kobus ellipsiprymnus), bushbuck (Tragelaphus scriptus), reedbuck (Redunca arundinum), wilderbeest (Connochaetes taurinus), hartebeest (Alcephelus lichtensteini), African buffalo (Syncerus caffer), and kudu (Tragelaphus strepsiceros) showed that only the kudu had T. brucei. Although game ranching has emerged to be a successful ex-situ conservation strategy aimed at saving the declining wildlife population in the National Parks, our findings suggest that it has the potential of aiding the re-distribution of animal diseases. Hence, there is a need for augmenting wildlife conservation with disease control strategies aimed at reducing the risk of disease transmission between wildlife and domestic animals. PMID:20333288

  16. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei

    Directory of Open Access Journals (Sweden)

    Michael Wink

    2008-10-01

    Full Text Available The potential induction of a programmed cell death (PCD in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, chelerythrine, emetine, sanguinarine, quinine, ajmalicine, ergotamine, harmine, vinblastine, vincristine, colchicine, chaconine, demissidine and veratridine induced programmed cell death, whereas quinolizidine, tropane, terpene and piperidine alkaloids were mostly inactive. Effective PCD induction (EC50 below 10 µM was caused in T. brucei by chelerythrine, emetine, sanguinarine, and chaconine. The active alkaloids can be characterized by their general property to inhibit protein biosynthesis, to intercalate DNA, to disturb membrane fluidity or to inhibit microtubule formation.

  17. Identification of Paralogous Life-Cycle Stage Specific Cytoskeletal Proteins in the Parasite Trypanosoma brucei

    OpenAIRE

    Neil Portman; Keith Gull

    2014-01-01

    The life cycle of the African trypanosome Trypanosoma brucei, is characterised by a transition between insect and mammalian hosts representing very different environments that present the parasite with very different challenges. These challenges are met by the expression of life-cycle stage-specific cohorts of proteins, which function in systems such as metabolism and immune evasion. These life-cycle transitions are also accompanied by morphological rearrangements orchestrated by microtubule ...

  18. Ribose 5-Phosphate Isomerase B Knockdown Compromises Trypanosoma brucei Bloodstream Form Infectivity

    OpenAIRE

    Inês Loureiro; Joana Faria; Christine Clayton; Sandra Macedo-Ribeiro; Nuno Santarém; Nilanjan Roy; Anabela Cordeiro-da-Siva; Joana Tavares

    2015-01-01

    Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive dru...

  19. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Science.gov (United States)

    de Macêdo, Juan P; Schumann Burkard, Gabriela; Niemann, Moritz; Barrett, Michael P; Vial, Henri; Mäser, Pascal; Roditi, Isabel; Schneider, André; Bütikofer, Peter

    2015-05-01

    Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug action or targeting. PMID

  20. Genetic validation of aminoacyl-tRNA synthetases as drug targets in Trypanosoma brucei.

    Science.gov (United States)

    Kalidas, Savitha; Cestari, Igor; Monnerat, Severine; Li, Qiong; Regmi, Sandesh; Hasle, Nicholas; Labaied, Mehdi; Parsons, Marilyn; Stuart, Kenneth; Phillips, Margaret A

    2014-04-01

    Human African trypanosomiasis (HAT) is an important public health threat in sub-Saharan Africa. Current drugs are unsatisfactory, and new drugs are being sought. Few validated enzyme targets are available to support drug discovery efforts, so our goal was to obtain essentiality data on genes with proven utility as drug targets. Aminoacyl-tRNA synthetases (aaRSs) are known drug targets for bacterial and fungal pathogens and are required for protein synthesis. Here we survey the essentiality of eight Trypanosoma brucei aaRSs by RNA interference (RNAi) gene expression knockdown, covering an enzyme from each major aaRS class: valyl-tRNA synthetase (ValRS) (class Ia), tryptophanyl-tRNA synthetase (TrpRS-1) (class Ib), arginyl-tRNA synthetase (ArgRS) (class Ic), glutamyl-tRNA synthetase (GluRS) (class 1c), threonyl-tRNA synthetase (ThrRS) (class IIa), asparaginyl-tRNA synthetase (AsnRS) (class IIb), and phenylalanyl-tRNA synthetase (α and β) (PheRS) (class IIc). Knockdown of mRNA encoding these enzymes in T. brucei mammalian stage parasites showed that all were essential for parasite growth and survival in vitro. The reduced expression resulted in growth, morphological, cell cycle, and DNA content abnormalities. ThrRS was characterized in greater detail, showing that the purified recombinant enzyme displayed ThrRS activity and that the protein localized to both the cytosol and mitochondrion. Borrelidin, a known inhibitor of ThrRS, was an inhibitor of T. brucei ThrRS and showed antitrypanosomal activity. The data show that aaRSs are essential for T. brucei survival and are likely to be excellent targets for drug discovery efforts. PMID:24562907

  1. The promoter for a variant surface glycoprotein gene expression site in Trypanosoma brucei.

    OpenAIRE

    Zomerdijk, J C; Ouellette, M; ten Asbroek, A L; Kieft, R.; Bommer, A M; Clayton, C E; Borst, P

    1990-01-01

    The variant-specific surface glycoprotein (VSG) gene 221 of Trypanosoma brucei is transcribed as part of a 60 kb expression site (ES). We have identified the promoter controlling this multigene transcription unit by the use of 221 chromosome-enriched DNA libraries and VSG gene 221 expression site specific transcripts. The start of transcription was determined by hybridization and RNase protection analysis of nascent RNA. The 5' ends of the major transcripts coming from the initiation region m...

  2. Reconstitution of a surface transferrin binding complex in insect form Trypanosoma brucei.

    OpenAIRE

    Ligtenberg, M.J.; Bitter, W.; Kieft, R.; Steverding, D; Janssen, H.; Calafat, J.; Borst, P

    1994-01-01

    In the bloodstream of the mammalian host, Trypanosoma brucei takes up host transferrin by means of a high-affinity uptake system, presumably a transferrin receptor. Transferrin-binding activity is seen in the flagellar pocket and is absent in insect form trypanosomes. By transfection we have reconstituted a transferrin-binding complex in insect form trypanosomes. Formation of this complex requires the products of two genes that are part of a variant surface glycoprotein expression site, expre...

  3. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Juan P de Macêdo

    2015-05-01

    Full Text Available Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug

  4. A Pre-clinical Animal Model of Trypanosoma brucei Infection Demonstrating Cardiac Dysfunction

    OpenAIRE

    McCarroll, Charlotte S; Rossor, Charlotte L.; Linda R Morrison; Morrison, Liam J.; Loughrey, Christopher M.

    2015-01-01

    Author Summary African trypanosomiasis (AT) is a disease caused by the single-celled protozoan parasite Trypanosoma brucei. In humans, AT causes neurological problems including sleep disturbances, which give the disease its colloquial name of “sleeping sickness”. Much of the focus of AT research has been on the neurological deficits, but other major organs are also affected, including the heart. Previous studies in humans and animals with AT have identified heart abnormalities such as contrac...

  5. Mitochondrial tRNA import in Trypanosoma brucei is independent of thiolation and the Rieske protein

    Czech Academy of Sciences Publication Activity Database

    Paris, Zdeněk; RUBIO, M. A. T.; Lukeš, Julius; Alfonzo, J. D.

    2009-01-01

    Roč. 15, č. 7 (2009), s. 1398-1406. ISSN 1355-8382 R&D Projects: GA ČR GA204/06/1558; GA MŠk LC07032; GA MŠk 2B06129 Institutional research plan: CEZ:AV0Z60220518 Keywords : T. brucei * tRNA import * 2-thiolation * RIC * Rieske * Fe-S cluster Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.198, year: 2009

  6. Proteins and lipids of glycosomal membranes from Leishmania tarentolae and Trypanosoma brucei

    OpenAIRE

    Claudia Colasante; Frank Voncken; Theresa Manful; Thomas Ruppert; Tielens, Aloysius G. M.; van Hellemond, Jaap J; Christine Clayton

    2013-01-01

    In kinetoplastid protists, several metabolic pathways, including glycolysis and purine salvage, are located in glycosomes, which are microbodies that are evolutionarily related to peroxisomes. With the exception of some potential transporters for fatty acids, and one member of the mitochondrial carrier protein family, proteins that transport metabolites across the glycosomal membrane have yet to be identified. We show here that the phosphatidylcholine species composition of Trypanosoma brucei...

  7. Molecular variation of Trypanosoma brucei subspecies as revealed by AFLP fingerprinting

    OpenAIRE

    Agbo, E.E.C.; Majiwa, P.A.O.; Claassen, H.J.H.M.; Pas, te, M.F.W.

    2002-01-01

    Genetic analysis of Trypanosoma spp. depends on the detection of variation between strains. We have used the amplified fragment length polymorphism (AFLP) technique to develop a convenient and reliable method for genetic characterization of Trypanosome (sub)species. AFLP accesses multiple independent sites within the genome and would allow a better definition of the relatedness of different Trypanosome (sub)species. Nine isolates (3 from each T. brucei subspecies) were tested with 40 AFLP pri...

  8. Wild fauna as a probable animal reservoir for Trypanosoma brucei gambiense in Cameroon

    OpenAIRE

    Njiokou, F.; Laveissière, Claude; Simo, G.; Nkinin, S.; Grébaut, Pascal; Cuny, Gérard; Herder, Stéphane

    2006-01-01

    In order to Study the existence of a wild animal reservoir for Trypanosoma brucei gambiense in South Cameroon, blood was collected from wild animals in three human African trypanosomiasis foci and from a nonendemic control area. The 1142 wild animals sampled belonged to 36 different species pertaining to eight orders (407 primates, 347 artiodactyls, 265 rodents, 54 pangolins, 53 carnivores, 11 Saurians and crocodilians, and five hyraxes). QBC (R) and KIVI tests detected trypanosomes on 1.7% (...

  9. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei)

    OpenAIRE

    Michael Wink; Vera Rosenkranz

    2008-01-01

    The potential induction of a programmed cell death (PCD) in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S) was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, c...

  10. Structure of a Trypanosoma brucei α/β-hydrolase fold protein with unknown function

    International Nuclear Information System (INIS)

    T. brucei gene Tb10.6k15.0140 codes for an α/β-hydrolase fold protein of unknown function. The 2.2 Å crystal structure shows that members of this sequence family retain a conserved Ser residue at the expected site of a catalytic nucleophile, but that trypanosomatid sequences lack structural homologs for the other expected residues of the catalytic triad. The structure of a structural genomics target protein, Tbru020260AAA from Trypanosoma brucei, has been determined to a resolution of 2.2 Å using multiple-wavelength anomalous diffraction at the Se K edge. This protein belongs to Pfam sequence family PF08538 and is only distantly related to previously studied members of the α/β-hydrolase fold family. Structural superposition onto representative α/β-hydrolase fold proteins of known function indicates that a possible catalytic nucleophile, Ser116 in the T. brucei protein, lies at the expected location. However, the present structure and by extension the other trypanosomatid members of this sequence family have neither sequence nor structural similarity at the location of other active-site residues typical for proteins with this fold. Together with the presence of an additional domain between strands β6 and β7 that is conserved in trypanosomatid genomes, this suggests that the function of these homologs has diverged from other members of the fold family

  11. Nuclear reactor with control rods

    International Nuclear Information System (INIS)

    The invention relates to liquid cooled nuclear reactors. In particular, it concerns reactors with mobile control rods in a straight line and guide tubes to guide these control rods through the internal upper components of the reactor vessel and in the aligned fuel assemblies of the core

  12. Tunable frequency 4-rod RFQ

    International Nuclear Information System (INIS)

    The frequency tunability of the 4-rod RFQ is investigated. By moving the shorting plate between the posts, which support the 4-rod electrodes, the resonant frequency can be varied almost twofold. Model studies and the calculation of the field uniformity, the variation of Q, and the shunt impedance are reported. (author)

  13. Sucker rod pump

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, J.R.

    1992-04-14

    This patent describes a subsurface well pump, it comprises: a working barrel; a plunger which reciprocates along the vertical axis within the working barrel between an upper and lower position; a rod connected to the plunger and extending to a means for providing reciprocating force; a well string extending from the top of the working barrel to the surface; an outlet check valve which permits flow to exit the working barrel into the well string and does not permit flow to exit the well string into the working barrel; and an inlet check valve which permits flow into the working barrel from outside of the subsurface pump, the inlet check valve being above the top position of the plunger, the inlet check valve having a cross sectional flow area about equal to or greater than the horizontal cross sectional area of the working barrel, and the inlet check valve being a hinged flapper valve.

  14. Fuel rod reprocessing plant

    International Nuclear Information System (INIS)

    A plant for the reprocessing of fuel rods for a nuclear reactor comprises a plurality of rectangular compartments desirably arranged on a rectangular grid. Signal lines, power lines, pipes, conduits for instrumentation, and other communication lines leave a compartment just below its top edges. A vehicle access zone permits overhead and/or mobile cranes to remove covers from compartments. The number of compartments is at least 25% greater than the number of compartments used in the initial design and operation of the plant. Vacant compartments are available in which replacement apparatus can be constructed. At the time of the replacement of a unit, the piping and conduits are altered to utilize the substitute equipment in the formerly vacant compartment, and it is put on stream prior to dismantling old equipment from the previous compartment. Thus the downtime for the reprocessing plant for such a changeover is less than in a traditional reprocessing plant

  15. Control rod drives

    International Nuclear Information System (INIS)

    Purpose: To improve the reliability of a device for driving an LMFBR type reactor control rod by providing a buffer unit having a stationary electromagnetic coil and a movable electromagnetic coil in the device to thereby avord impact stress at scram time and to simplify the structure of the buffer unit. Constitution: A non-contact type buffer unit is constructed with a stationary electromagnetic coil, a cable for the stationary coil, a movable electromagnetic coil, a spring cable for the movable coil, and a backup coil spring or the like. Force produced at scram time is delivered without impact by the attracting or repelling force between the stationary coil and the movable coil of the buffer unit. Accordingly, since the buffer unit is of a non-contact type, there is no mechanical impact and thus no large impact stress, and as it has simple configuration, the reliability is improved and the maintenance can be conducted more easily. (Yoshihara, H.)

  16. Nuclear fuel rod

    International Nuclear Information System (INIS)

    Purpose: To prevent eutectic reaction between coil spring material and end plug material at the welding work of fuel fabrication. Constitution: Close-contact windings are formed at the end of a coil spring, and base end of a stainless steel supporting member is screwed to the close-contact winding portion of the coil spring. The other end of the supporting member is formed in a conical shape whose apex is in contact with the center of the bottom surface of a zirconium alloy end plug of a cladding tube. In the fuel rod thus constructed, the heating temperature of the end contact portion of the supporting member, at the time of welding the end plug to the cladding tube, can be somewhat lower than the eutectic temperatures of iron, chromium, nickel (the main ingredients of the stainless steel) and zirconium (the main ingredient of the end plug), and accourdingly no eutectic reaction occurs. (Yoshihara, H.)

  17. Status of rod consolidation, 1988

    International Nuclear Information System (INIS)

    It is estimated that the spent fuel storage pools at some domestic light-water reactors will run out of space before 2003, the year that the US Department of Energy currently predicts it will have a repository available. Of the methods being studied to alleviate the problem, rod consolidation is one of the leading candidates for achieving more efficient use of existing space in spent fuel storage pools. Rod consolidation involves mechanically removing all the fuel rods from the fuel assembly hardware (i.e., the structural components) and placing the fuel rods in a close-packed array in a canister without space grids. A typical goal of rod consolidation systems is to insert the fuel rods from two fuel assemblies into a canister that has the same exterior dimensions as one standard fuel assembly (i.e., to achieve a consolidation or compaction ratio of 2:1) and to compact the nonfuel-bearing structural components from those two fuel assemblies by a factor of 10 to 20. This report provides an overview of the current status of rod consolidation in the United States and a small amount of information on related activities in other countries. 85 refs., 36 figs., 5 tabs

  18. Detection of fuel rod leakage

    International Nuclear Information System (INIS)

    Nuclear reactor fuel rod leakage is determined by measurement of vibrational characteristics of a resilient, flexible means sealed within the upper end caps of the fuel elements. The flexible means, which is preferably a metallic diaphragm, is set into motion by the impact of an internal metal rod which is operated by an external magnetic field, thereby permitting an indication of the pressure inside a fuel element without disturbing the welded assembly. The metal rod is activated and the vibration measurements are made through the use of a special tool which fits near the end cap of the fuel element to be tested

  19. Detection of fuel rod leakage

    International Nuclear Information System (INIS)

    Nuclear reactor fuel rod leakage is determined by measurement of vibrational characteristics of a resilient, flexible means sealed within the upper end caps of the fuel elements. The flexible means, which is preferably a metallic diaphragm, is set into motion by the impact of an internal metal rod which is operated by an external magnetic field, thereby permitting an indication of the pressure inside a fuel element without disturbing the welded assembly. The metal rod is activated and the vibration measurements are made through the use of a special tool which fits near the end cap of the fuel element to be tested. 5 claims, 8 figures

  20. Control rod drives

    International Nuclear Information System (INIS)

    Purpose: To enable fine positioning by using an induction motor of a simple structure as a driving source and thereby improve the reliability of control rod drives. Constitution: A step actuator is directly coupled with an induction motor, in which the induction motor is connected by way of a pulse driving control circuit to an AC power source, while the step actuator is connected to a DC power source. When a thyristor is turned ON, the motor outputs a positive torque and rotates and starts to rotate in the forward direction. When the other thyristor is turned ON, the motor is applied with braking by a reverse excitation in a manner equivalent to the change for the exciting phase sequence. When the speed is lowered to a predetermined value, braking is actuated by the torque of the step actuator and the motor stops at a zero position or balanced position. In this way, braking is actuated from the decelerating step to the stopping with no abrasion and a highly accurate positioning is possible due to the characteristics of the step actuator. (Horiuchi, T.)

  1. Nuclear fuel rod

    International Nuclear Information System (INIS)

    Purpose: To enable a wider range of output fluctuation by reducing the stress in the way of the connection between the lower end plug and the cladding tubes and thus increase the stress corrosion life. Constitution: Plurality of uranium dioxide pellets are filled in the zirconium alloy cladding tubes and the upper and lower ends are closed by zirconium alloy plugs to form nuclear fuel rods. The lower plug is provided with a hole from the inner side and in the axial direction of the plug. A structure of thermally conductive material, the conductivity of which is higher than that of the zirconium used for forming the plug, is provided in such a way that it has some clearance with the side of the said hole. By providing a hole on the lower plug and by installing a highly thermally conductive structure in it, the average temperature differential between the lower plug and the cladding tube is reduced thus reducing the thermal stress on the lower plug. (Yoshihara, Y.)

  2. Control rod drive

    International Nuclear Information System (INIS)

    Object: To provide a simple and compact construction of an apparatus for driving a drive shaft inside with a magnetic force from the outside of the primary system water side. Structure: The weight of a plunger provided with an attraction plate is supported by a plunger lift spring means so as to provide a buffer action at the time of momentary movement while also permitting the load on lift coil to be constituted solely by the load on the drive shaft. In addition, by arranging the attraction plate and lift coil so that they face each other with a small gap there-between, it is made possible to reduce the size and permit efficient utilization of the attracting force. Because of the small size, cooling can be simply carried out. Further, since there is no mechanical penetration portion, there is no possibility of leakage of the primary system water. Furthermore, concentration of load on a latch pin is prevented by arranging so that with a structure the load of the control rod to be directly beared through the scrum latch. (Kamimura, M.)

  3. LOFT nuclear fuel rod behavior

    International Nuclear Information System (INIS)

    An overview of the calculational models used to predict fuel rod response for Loss-of-Fluid Test (LOFT) data from the first LOFT nuclear test is presented and discussed and a comparison of predictions with experimental data is made

  4. Nuclear fuel rod supporting arrangement

    International Nuclear Information System (INIS)

    A grid structure for holding a number of nuclear fuel rods is described. The grid structure is of the type having walls including rigidly interconnected generally rectangular metal strips, forming passageways and adapted to support nuclear fuel rods within some of the passageways. The improvement provides elongated slots intermediate and normal to the longitudinal edges of each of the strips at each intersection of the strips. The slots form openings in each corner of each passageway

  5. Anti-trypanosomal Activity of Potential Inhibitors of Trypanosoma brucei Glycolytic Pathway Enzymes Selected by Docking Studies

    Directory of Open Access Journals (Sweden)

    Clarisse Musanabaganwa

    2014-12-01

    Full Text Available Human African trypanosomiasis (HAT, a potentially fatal protozoan infection caused by tsetse-fl mediated transmission of Trypanosoma brucei (T. Brucei, is largely recognized as a neglected disease. The repertoire of drugs that is effective against the infection is limited and all drugs have several drawbacks including high level of toxicity, diffiult administration regimens, and the resurgence of resistance. At present the biology of the parasite is well studied and a number of technologies are now available which can aid in the identifiation of potential drug targets. This review identifies putative inhibitors of trypanosomal glycolytic enzymes.

  6. Ethanolamine phosphoglycerol attachment to eEF1A is not essential for normal growth of Trypanosoma brucei

    OpenAIRE

    Eva Greganova; Peter Bütikofer

    2012-01-01

    Eukaryotic elongation factor 1A (eEF1A) is the only protein modified by ethanolamine phosphoglycerol (EPG). In mammals and plants, EPG is attached to conserved glutamate residues located in eEF1A domains II and III, whereas in the unicellular eukaryote, Trypanosoma brucei, a single EPG moiety is attached to domain III. A biosynthetic precursor of EPG and structural requirements for EPG attachment to T. brucei eEF1A have been reported, but the role of this unique protein modification in cellul...

  7. Mitochondrial tRNA import in the parasitic protozoon "Trypanosoma brucei" and its consequences on mitochondrial translation

    OpenAIRE

    Charrière, Fabien; Schneider, André; Linder, Patrick

    2007-01-01

    Le parasite protozoaire Trypanosoma brucei est l’agent pathogène responsable de la maladie du sommeil chez l’homme. En plus de son importance dans le domaine de la lutte contre les maladies tropicales, T. brucei est également un excellent modèle pour la recherche fondamentale car il présente beaucoup de caractéristiques qui lui sont propres. Par exemple, aucun ARN de transfert (ARNt) n’est codé dans le génome mitochondrial. Pour cette raison, les ARNts nécessaires au processus de traduction m...

  8. Phosphorylation-Dependent Protein Interaction with Trypanosoma brucei 14-3-3 Proteins that Display Atypical Target Recognition

    OpenAIRE

    Inoue, Masahiro; Yasuda, Kouichi; Uemura, Haruki; Yasaka, Natsumi; Inoue, Hiroshi; Sei, Yoshitatsu; Horikoshi, Nobuo; Fukuma, Toshihide

    2010-01-01

    Background The 14-3-3 proteins are structurally conserved throughout eukaryotes and participate in protein kinase signaling. All 14-3-3 proteins are known to bind to evolutionally conserved phosphoserine-containing motifs (modes 1 and/or 2) with high affinity. In Trypanosoma brucei, 14-3-3I and II play pivotal roles in motility, cytokinesis and the cell cycle. However, none of the T. brucei 14-3-3 binding proteins have previously been documented. Methodology/Principal Findings Initially we sh...

  9. Identification of the ISWI Chromatin Remodeling Complex of the Early Branching Eukaryote Trypanosoma brucei.

    Science.gov (United States)

    Stanne, Tara M; Narayanan, Mani Shankar; Ridewood, Sophie; Ling, Alexandra; Witmer, Kathrin; Kushwaha, Manish; Wiesler, Simone; Wickstead, Bill; Wood, Jennifer; Rudenko, Gloria

    2015-11-01

    ISWI chromatin remodelers are highly conserved in eukaryotes and are important for the assembly and spacing of nucleosomes, thereby controlling transcription initiation and elongation. ISWI is typically associated with different subunits, forming specialized complexes with discrete functions. In the unicellular parasite Trypanosoma brucei, which causes African sleeping sickness, TbISWI down-regulates RNA polymerase I (Pol I)-transcribed variant surface glycoprotein (VSG) gene expression sites (ESs), which are monoallelically expressed. Here, we use tandem affinity purification to determine the interacting partners of TbISWI. We identify three proteins that do not show significant homology with known ISWI-associated partners. Surprisingly, one of these is nucleoplasmin-like protein (NLP), which we had previously shown to play a role in ES control. In addition, we identify two novel ISWI partners, regulator of chromosome condensation 1-like protein (RCCP) and phenylalanine/tyrosine-rich protein (FYRP), both containing protein motifs typically found on chromatin proteins. Knockdown of RCCP or FYRP in bloodstream form T. brucei results in derepression of silent variant surface glycoprotein ESs, as had previously been shown for TbISWI and NLP. All four proteins are expressed and interact with each other in both major life cycle stages and show similar distributions at Pol I-transcribed loci. They are also found at Pol II strand switch regions as determined with ChIP. ISWI, NLP, RCCP, and FYRP therefore appear to form a single major ISWI complex in T. brucei (TbIC). This reduced complexity of ISWI regulation and the presence of novel ISWI partners highlights the early divergence of trypanosomes in evolution. PMID:26378228

  10. Trypanosoma brucei modifies the tsetse salivary composition, altering the fly feeding behavior that favors parasite transmission.

    Directory of Open Access Journals (Sweden)

    Jan Van Den Abbeele

    Full Text Available Tsetse flies are the notorious transmitters of African trypanosomiasis, a disease caused by the Trypanosoma parasite that affects humans and livestock on the African continent. Metacyclic infection rates in natural tsetse populations with Trypanosoma brucei, including the two human-pathogenic subspecies, are very low, even in epidemic situations. Therefore, the infected fly/host contact frequency is a key determinant of the transmission dynamics. As an obligate blood feeder, tsetse flies rely on their complex salivary potion to inhibit host haemostatic reactions ensuring an efficient feeding. The results of this experimental study suggest that the parasite might promote its transmission through manipulation of the tsetse feeding behavior by modifying the saliva composition. Indeed, salivary gland Trypanosoma brucei-infected flies display a significantly prolonged feeding time, thereby enhancing the likelihood of infecting multiple hosts during the process of a single blood meal cycle. Comparison of the two major anti-haemostatic activities i.e. anti-platelet aggregation and anti-coagulation activity in these flies versus non-infected tsetse flies demonstrates a significant suppression of these activities as a result of the trypanosome-infection status. This effect was mainly related to the parasite-induced reduction in salivary gland gene transcription, resulting in a strong decrease in protein content and related biological activities. Additionally, the anti-thrombin activity and inhibition of thrombin-induced coagulation was even more severely hampered as a result of the trypanosome infection. Indeed, while naive tsetse saliva strongly inhibited human thrombin activity and thrombin-induced blood coagulation, saliva from T. brucei-infected flies showed a significantly enhanced thrombinase activity resulting in a far less potent anti-coagulation activity. These data clearly provide evidence for a trypanosome-mediated modification of the tsetse

  11. Evidence for a degradosome-like complex in the mitochondria of Trypanosoma brucei

    OpenAIRE

    Mattiacio, Jonelle L.; Read, Laurie K.

    2009-01-01

    Mitochondrial RNA turnover in yeast involves the degradosome, composed of DSS-1 exoribonuclease and SUV3 RNA helicase. Here, we describe a degradosome-like complex, containing SUV3 and DSS-1 homologues, in the early branching protozoan, Trypanosoma brucei. TbSUV3 is mitochondrially localized and co-sediments with TbDSS-1 on glycerol gradients. Co-immunoprecipitation demonstrates that TbSUV3 and TbDSS-1 associate in a stable complex, which differs from the yeast degradosome in that it is not s...

  12. Antitrypanosomal alkaloids from Polyalthia suaveolens (Annonaceae): their effects on three selected glycolytic enzymes of Trypanosoma brucei.

    Science.gov (United States)

    Ngantchou, Igor; Nyasse, Barthélemy; Denier, Colette; Blonski, Casimir; Hannaert, Véronique; Schneider, Bernd

    2010-06-15

    In continuation of our study on medicinal plants of Cameroon, stem barks of Polyalthia suaveolens were phytochemically studied. This investigation yielded a new indolosesquiterpene alkaloid, named polysin (1) and four hitherto known alkaloids (2-5). Polysin (1) appeared as a competitive reversible inhibitor (K(i)=10 microM) of phosphofructo kinase (PFK) of Trypanosoma brucei with respect to fructose-6-phosphate (K(i)/K(M)=0.05) and could be used in the design of new trypanocidal drugs. The other isolated compounds (2-5) also exhibited interesting inhibitory effects on selected glycolytic enzymes (PFK, glyceraldehyde-3-phosphate dehydrogenase and aldolase). PMID:20529682

  13. A Gateway® compatible vector for gene silencing in bloodstream form Trypanosoma brucei

    OpenAIRE

    Kalidas, Savitha; Li, Qiong; Margaret A Phillips

    2011-01-01

    RNA interference is the most rapid method for generation of conditional knockdown mutants in Trypanosoma brucei. The dual T7 promoter (pZJM) and the stem-loop vectors have been widely used to generate stable inducible RNAi cell lines with the latter providing tighter regulatory control. However, the steps for cloning stem-loop constructs are cumbersome requiring either multiple cloning steps or multi-fragment ligation reactions. We report the development of a vector (pTrypRNAiGate) derived fr...

  14. Development of Simplified Heterocyclic Acetogenin Analogues as Potent and Selective Trypanosoma brucei Inhibitors.

    Science.gov (United States)

    Florence, Gordon J; Fraser, Andrew L; Gould, Eoin R; King, Elizabeth F; Menzies, Stefanie K; Morris, Joanne C; Thomson, Marie I; Tulloch, Lindsay B; Zacharova, Marija K; Smith, Terry K

    2016-07-19

    Neglected tropical diseases caused by parasitic infections are an ongoing and increasing concern. They are a burden to human and animal health, having the most devastating effect on the world's poorest countries. Building upon our previously reported triazole analogues, in this study we describe the synthesis and biological testing of other novel heterocyclic acetogenin-inspired derivatives, namely 3,5-isoxazoles, furoxans, and furazans. Several of these compounds maintain low-micromolar levels of inhibition against Trypanosoma brucei, whilst having no observable inhibitory effect on mammalian cells, leading to the possibility of novel lead compounds for selective treatment. PMID:27283448

  15. Simulation of leaking fuel rods

    International Nuclear Information System (INIS)

    The behaviour of failed fuel rods includes several complex phenomena. The cladding failure initiates the release of fission product from the fuel and in case of large defect even urania grains can be released into the coolant. In steady state conditions an equilibrium - diffusion type - release is expected. During transients the release is driven by a convective type leaching mechanism. There are very few experimental data on leaking WWER fuel rods. For this reason the activity measurements at the nuclear power plants provide very important information. The evaluation of measured data can help in the estimation of failed fuel rod characteristics and the prediction of transient release dynamics in power plant transients. The paper deals with the simulation of leaking fuel rods under steady state and transient conditions and describes the following new results: 1) A new algorithm has been developed for the simulation of leaking fuel rods under steady state conditions and the specific parameters of the model for the Paks NPP has been determined; 2) The steady state model has been applied to calculation of leaking fuel characteristics using iodine and noble gas activity measurement data; 3) A new computational method has been developed for the simulation of leaking fuel rods under transient conditions and the specific parameters for the Paks NPP has been determined; 4) The transient model has been applied to the simulation of shutdown process at the Paks NPP and for the prediction of the time and magnitude of 123I activity peak; 5) Using Paks NPP data a conservative value has been determined for the upper limit of the 123I release from failed fuel rods during transients

  16. Radioactive lightning rods waste treatment

    International Nuclear Information System (INIS)

    Full text: In this paper, we present alternative processes that could be adopted for the management of radioactive waste that arises from the replacement of lightning rods with attached Americium-241 sources. Lightning protectors, with Americium-241 sources attached to the air terminals, were manufactured in Brazil until 1989, when the regulatory authority overthrew the license for fabrication, commerce, and installation of radioactive lightning rods. It is estimated that, during the license period, about 75,000 such devices were set up in public, commercial and industrial buildings, including houses and schools. However, the policy of CNEN in regard to the replacement of the installed radioactive rods, has been to leave the decision to municipal governments under local building regulations, requiring only that the replaced rods be sent immediately to one of its research institutes to be treated as radioactive waste. As a consequence, the program of replacement proceeds in a low pace and until now only about twenty thousand rods have reached the waste treatment facilities The process of management that was adopted is based primarily on the assumption that the Am-241 sources will be disposed of as radioactive sealed sources, probably in a deep borehole repository. The process can be described broadly by the following steps: a) Receive and put the lightning rods in initial storage; b) Disassemble the rods and pull out the sources; c) Decontaminate and release the metal parts to metal recycling; d) Store the sources in intermediate storage; e) Package the sources in final disposal packages; and f) Send the sources for final disposal. Up to now, the disassembled devices gave rise to about 90,000 sources which are kept in storage while the design of the final disposal package is in progress. (author)

  17. Modelling of sucker rod string

    Energy Technology Data Exchange (ETDEWEB)

    Hojjati, M.H. [Mazandaran Univ., (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Lukasiewicz, S.A. [Calgary Univ., AB (Canada). Dept. of Mechanical and Manufacturing Engineering

    2005-12-01

    Rod pumping is used extensively in the oil well industry as a method of artificial lift. In order to analyze the performance of oil wells, the force and displacement at the polished rod are measured using a dynamometer. The data is applied to the boundary conditions when calculating the forces and displacement at the bottom of the rod string that defines the conditions of the pump, pumping effectiveness and production rate. This study proposed a transfer matrix method to model the dynamic behavior of the sucker string rod. The main reason for developing the method was to simplify the currently used mathematical method with a simple matrix operation in which the bottom-hole force-displacement values are obtained as a product of data vectors at the polished rod end by a transfer matrix. The problem was solved using D'Alembert's systems solution equation and the adaptive filter matrix method. The proposed method reduces calculation time because a more efficient matrix operation is used without losing accuracy. This study showed that it is possible to use the transfer matrix to calculate load-displacement relations a hundred or more times in one stroke, which is beneficial when developing tools to control oil wells, such as wellhead controllers. 9 refs., 3 tabs., 8 figs.

  18. The Third ATLAS ROD Workshop

    CERN Multimedia

    Poggioli, L.

    A new-style Workshop After two successful ATLAS ROD Workshops dedicated to the ROD hardware and held at the Geneva University in 1998 and in 2000, a new style Workshop took place at LAPP in Annecy on November 14-15, 2002. This time the Workshop was fully dedicated to the ROD-TDAQ integration and software in view of the near future integration activities of the final RODs for the detector assembly and commissioning. More precisely, the aim of this workshop was to get from the sub-detectors the parameters needed for T-DAQ, as well as status and plans from ROD builders. On the other hand, what was decided and assumed had to be stated (like EB decisions and URDs), and also support plans. The Workshop gathered about 70 participants from all ATLAS sub-detectors and the T-DAQ community. The quite dense agenda allowed nevertheless for many lively discussions, and for a dinner in the old town of Annecy. The Sessions The Workshop was organized in five main sessions: Assumptions and recommendations Sub-de...

  19. Refabricated and instrumented fuel rods

    International Nuclear Information System (INIS)

    Nuclear Fuel for power reactors capabilities evaluation is strongly based on the intimate knowledge of its behaviour under irradiation. This knowledge can be acquired from refabricated and instrumented fuel rods irradiated at different levels in commercial reactors. This paper presents the development and qualification of a new technique called RECTO related to a double-instrumented rod re-fabrication process developed by CEA/LECA hot laboratory facility at CADARACHE. The technique development includes manufacturing of the properly dimensioned cavity in the fuel pellet stack to house the thermocouple and the use of a newly designed pressure transducer. An analytic irradiation of such a double-instrumented fuel rod will be performed in OSIRIS test reactor starting October 2004. (Author)

  20. Advanced gray rod control assembly

    Science.gov (United States)

    Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

    2013-09-17

    An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

  1. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 2 discusses the following topics: Fuel Rod Extraction System Test Results and Analysis Reports and Clamping Table Test Results and Analysis Reports

  2. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    The objective of Phase III of the Prototypical Rod Consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod Consolidation System as described in the NUS Phase II Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase III effort the system was tested on a component, subsystem, and system level. Volume IV provides the Operating and Maintenance Manual for the Prototypical Rod Consolidation System that was installed at the Cold Test Facility. This document, Book 5 of Volume IV, discusses: Corrective maintenance procedures; Calibration procedures; Surveillance procedures; Equipment changeover procedures; Decontamination procedures; Recovery procedures; and Cable schedule

  3. Mitochondrial translation factors of Trypanosoma brucei: elongation factor-Tu has a unique subdomain that is essential for its function

    Czech Academy of Sciences Publication Activity Database

    Cristodero, M.; Mani, J.; Oeljeklaus, S.; Aeberhard, L.; Hashimi, Hassan; Ramrath, D.J.F.; Lukeš, Julius; Warscheid, B.; Schneider, A.

    2013-01-01

    Roč. 90, č. 4 (2013), s. 744-755. ISSN 0950-382X R&D Projects: GA ČR GAP305/12/2261 Institutional support: RVO:60077344 Keywords : mitochondrial translation * Trypanosoma brucei * EF-Tu Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.026, year: 2013

  4. KREX2 is not essential for either procyclic or bloodstream form Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Jason Carnes

    Full Text Available BACKGROUND: Most mitochondrial mRNAs in Trypanosoma brucei require RNA editing for maturation and translation. The edited RNAs primarily encode proteins of the oxidative phosphorylation system. These parasites undergo extensive changes in energy metabolism between the insect and bloodstream stages which are mirrored by alterations in RNA editing. Two U-specific exonucleases, KREX1 and KREX2, are both present in protein complexes (editosomes that catalyze RNA editing but the relative roles of each protein are not known. METHODOLOGY/PRINCIPAL FINDINGS: The requirement for KREX2 for RNA editing in vivo was assessed in both procyclic (insect and bloodstream form parasites by methods that use homologous recombination for gene elimination. These studies resulted in null mutant cells in which both alleles were eliminated. The viability of these cells demonstrates that KREX2 is not essential in either life cycle stage, despite certain defects in RNA editing in vivo. Furthermore, editosomes isolated from KREX2 null cells require KREX1 for in vitro U-specific exonuclease activity. CONCLUSIONS: KREX2 is a U-specific exonuclease that is dispensable for RNA editing in vivo in T. brucei BFs and PFs. This result suggests that the U deletion activity, which is required for RNA editing, is primarily mediated in vivo by KREX1 which is normally found associated with only one type of editosome. The retention of the KREX2 gene implies a non-essential role or a role that is essential in other life cycle stages or conditions.

  5. The TgsGP gene is essential for resistance to human serum in Trypanosoma brucei gambiense.

    Science.gov (United States)

    Capewell, Paul; Clucas, Caroline; DeJesus, Eric; Kieft, Rudo; Hajduk, Stephen; Veitch, Nicola; Steketee, Pieter C; Cooper, Anneli; Weir, William; MacLeod, Annette

    2013-01-01

    Trypanosoma brucei gambiense causes 97% of all cases of African sleeping sickness, a fatal disease of sub-Saharan Africa. Most species of trypanosome, such as T. b. brucei, are unable to infect humans due to the trypanolytic serum protein apolipoprotein-L1 (APOL1) delivered via two trypanosome lytic factors (TLF-1 and TLF-2). Understanding how T. b. gambiense overcomes these factors and infects humans is of major importance in the fight against this disease. Previous work indicated that a failure to take up TLF-1 in T. b. gambiense contributes to resistance to TLF-1, although another mechanism is required to overcome TLF-2. Here, we have examined a T. b. gambiense specific gene, TgsGP, which had previously been suggested, but not shown, to be involved in serum resistance. We show that TgsGP is essential for resistance to lysis as deletion of TgsGP in T. b. gambiense renders the parasites sensitive to human serum and recombinant APOL1. Deletion of TgsGP in T. b. gambiense modified to uptake TLF-1 showed sensitivity to TLF-1, APOL1 and human serum. Reintroducing TgsGP into knockout parasite lines restored resistance. We conclude that TgsGP is essential for human serum resistance in T. b. gambiense. PMID:24098129

  6. The TgsGP gene is essential for resistance to human serum in Trypanosoma brucei gambiense.

    Directory of Open Access Journals (Sweden)

    Paul Capewell

    Full Text Available Trypanosoma brucei gambiense causes 97% of all cases of African sleeping sickness, a fatal disease of sub-Saharan Africa. Most species of trypanosome, such as T. b. brucei, are unable to infect humans due to the trypanolytic serum protein apolipoprotein-L1 (APOL1 delivered via two trypanosome lytic factors (TLF-1 and TLF-2. Understanding how T. b. gambiense overcomes these factors and infects humans is of major importance in the fight against this disease. Previous work indicated that a failure to take up TLF-1 in T. b. gambiense contributes to resistance to TLF-1, although another mechanism is required to overcome TLF-2. Here, we have examined a T. b. gambiense specific gene, TgsGP, which had previously been suggested, but not shown, to be involved in serum resistance. We show that TgsGP is essential for resistance to lysis as deletion of TgsGP in T. b. gambiense renders the parasites sensitive to human serum and recombinant APOL1. Deletion of TgsGP in T. b. gambiense modified to uptake TLF-1 showed sensitivity to TLF-1, APOL1 and human serum. Reintroducing TgsGP into knockout parasite lines restored resistance. We conclude that TgsGP is essential for human serum resistance in T. b. gambiense.

  7. Transcription of the procyclic acidic repetitive protein genes of Trypanosoma brucei

    International Nuclear Information System (INIS)

    The procyclic acidic repetitive protein (parp) genes of Trypanosoma brucei encode a small family of abundant surface proteins whose expression is restricted to the procyclic form of the parasite. They are found at two unlinked loci, parpA and parpB; transcription of both loci is developmentally regulated. The region of homology upstream of the A and B parp genes is only 640 base pairs long and may contain sequences responsible for transcriptional initiation and regulation. Transcription upstream of this putative promoter region is not developmentally regulated and is much less active than that of the parp genes; the polymerase responsible is inhibited by alpha-amanitin, whereas that transcribing the parp genes is not. Transcription of the parp genes is strongly stimulated by low levels of UV irradiation. The putative parp promoter, when placed upstream of the chloramphenicol acetyltransferase gene, is sufficient to cause production of chloramphenicol acetyltransferase in a T. brucei DNA transformation assay. Taken together, these results suggest that a promoter for an alpha-amanitin-resistant RNA polymerase lies less than 600 nucleotides upstream of the parp genes

  8. Action of trypanosomal lipolytic enzymes on the membrane-form variant surface glycoprotein of trypanosoma brucei

    International Nuclear Information System (INIS)

    The membrane-form variant surface glycoprotein (mfVSG) of Trypanosoma brucei is anchored in the plasma membrane by myristoyl residues ester-linked to glycerophosphoethanolamine. The authors have extracted [myristoyl-3H]-mfVSG from trypanosomes incubated with [3H]-myristate and have isolated the protein by reverse phase HPLC. The extraction solvent, 20% acetonitrile in 0.1% trifluoroacetic acid, prevents lipolysis of the mfVSG during isolation. The mfVSG was shown to be homogeneous by SDS-PAGE, with an apparent molecular mass ratio of 66,000. No other proteins were labelled with [3H]-myristate. The major lipolytic enzyme of T. brucei, phospholipase A1, did not release myristate from mfVSG to any significant extent, though the enzyme readily hydrolyzes ester linkages of myristoyl phospholipids and p-nitrophenylmyristate. Trypanosomal membranes contain a phosphodiesterase which releases [3H]-1,2-diglyceride from [3H]-myristoyl-mfVSG. The phospholipase A1 can be separated from the myristoyl-releasing activity (phosphodiesterase) by centrifugation, affinity chromatography and anion-exchange chromatography

  9. Action of trypanosomal lipolytic enzymes on the membrane-form variant surface glycoprotein of trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, A.; Forsberg, C.M.; Hambrey, P.N.

    1986-05-01

    The membrane-form variant surface glycoprotein (mfVSG) of Trypanosoma brucei is anchored in the plasma membrane by myristoyl residues ester-linked to glycerophosphoethanolamine. The authors have extracted (myristoyl-/sup 3/H)-mfVSG from trypanosomes incubated with (/sup 3/H)-myristate and have isolated the protein by reverse phase HPLC. The extraction solvent, 20% acetonitrile in 0.1% trifluoroacetic acid, prevents lipolysis of the mfVSG during isolation. The mfVSG was shown to be homogeneous by SDS-PAGE, with an apparent molecular mass ratio of 66,000. No other proteins were labelled with (/sup 3/H)-myristate. The major lipolytic enzyme of T. brucei, phospholipase A/sub 1/, did not release myristate from mfVSG to any significant extent, though the enzyme readily hydrolyzes ester linkages of myristoyl phospholipids and p-nitrophenylmyristate. Trypanosomal membranes contain a phosphodiesterase which releases (/sup 3/H)-1,2-diglyceride from (/sup 3/H)-myristoyl-mfVSG. The phospholipase A/sub 1/ can be separated from the myristoyl-releasing activity (phosphodiesterase) by centrifugation, affinity chromatography and anion-exchange chromatography.

  10. Analysis of reciprocating compressor piston rod failures

    Energy Technology Data Exchange (ETDEWEB)

    Tripp, H.A.; Drosjack, M.J.

    1984-02-01

    This report presents the analysis of five piston rod failures which occurred on reciprocating compressors. Calculations are shown for rod stress which includes nominal rod loading sources as well as additional loads due to unusual pressure losses in the compressor valves, flexure of the rods due to misalignment, and manufacturing errors. The additional loads were incorporated on the basis of field measurements. The stress values are used with Baquin's equation to produce fatigue life curves for the rods. Based on the calculations, recommendations for modified rods were made. The calculation procedures are described in a manner which will permit their application to other reciprocating compressors.

  11. A Gene of the β3-Glycosyltransferase Family Encodes N-Acetylglucosaminyltransferase II Function in Trypanosoma brucei.

    Science.gov (United States)

    Damerow, Manuela; Graalfs, Frauke; Güther, M Lucia S; Mehlert, Angela; Izquierdo, Luis; Ferguson, Michael A J

    2016-06-24

    The bloodstream form of the human pathogen Trypanosoma brucei expresses oligomannose, paucimannose, and complex N-linked glycans, including some exceptionally large poly-N-acetyllactosamine-containing structures. Despite the presence of complex N-glycans in this organism, no homologues of the canonical N-acetylglucosaminyltransferase I or II genes can be found in the T. brucei genome. These genes encode the activities that initiate the elaboration of the Manα1-3 and Manα1-6 arms, respectively, of the conserved trimannosyl-N-acetylchitobiosyl core of N-linked glycans. Previously, we identified a highly divergent T. brucei N-acetylglucosaminyltransferase I (TbGnTI) among a set of putative T. brucei glycosyltransferase genes belonging to the β3-glycosyltransferase superfamily (Damerow, M., Rodrigues, J. A., Wu, D., Güther, M. L., Mehlert, A., and Ferguson, M. A. (2014) J. Biol. Chem. 289, 9328-9339). Here, we demonstrate that TbGT15, another member of the same β3-glycosyltransferase family, encodes an equally divergent N-acetylglucosaminyltransferase II (TbGnTII) activity. In contrast to multicellular organisms, where GnTII activity is essential, TbGnTII null mutants of T. brucei grow in culture and are still infectious to animals. Characterization of the large poly-N-acetyllactosamine containing N-glycans of the TbGnTII null mutants by methylation linkage analysis suggests that, in wild-type parasites, the Manα1-6 arm of the conserved trimannosyl core may carry predominantly linear poly-N-acetyllactosamine chains, whereas the Manα1-3 arm may carry predominantly branched poly-N-acetyllactosamine chains. These results provide further detail on the structure and biosynthesis of complex N-glycans in an important human pathogen and provide a second example of the adaptation by trypanosomes of β3-glycosyltransferase family members to catalyze β1-2 glycosidic linkages. PMID:27189951

  12. Flaw detecting device for control rod cluster

    International Nuclear Information System (INIS)

    The device of the present invention measures the reduction of a wall thickness of each cladding tube of control rod caused by abrasion or flaws at a high accuracy in a short period of time in a control rod cluster for a PWR type reactor. Namely, a control rod cluster for a PWR type reactor is formed by bundling a plurality of control rods at one end. The reduction of the wall thickness of the control rod cladding tubes is measured by a flaw detecting method using eddy current. A group of flaw detecting probes is moved in the axial direction relative to the control rod cluster to scan all the control rods in the axial direction of the cladding tubes. The group of the flaw detecting probes has circular flaw detecting probes at least by the total number of the control rods corresponding to the position of each of the arranged control rods of the control rod cluster. Each of the circular flaw detecting probes has a measuring hole through which one control rod can pass. Accordingly, all of the control rods are scanned from one end to the other end for the control rod cluster thereby capable of measuring the entire surface simultaneously. (I.S.)

  13. Application of fiberglass sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, S.G. (Nabla Corporation (US))

    1991-05-01

    Fiberglass sucker rods are assuming a place in artificial-lift technology. This paper briefly describes the manufacturing process and gives some design and operational hints for practical applications. It also describes some mathematical modeling modifications needed for fiberglass wave-equation design programs.

  14. Application of fiberglass sucker rods

    International Nuclear Information System (INIS)

    Fiberglass sucker rods are assuming a place in artificial-lift technology. This paper briefly describes the manufacturing process and gives some design and operational hints for practical applications. It also describes some mathematical modeling modifications needed for fiberglass wave-equation design programs

  15. Turbodrill rod angular velocity indicator

    Energy Technology Data Exchange (ETDEWEB)

    Rogachev, O.K.; Belozerova, L.P.; Konenkov, A.K.

    1984-01-01

    This paper outlines shortcomings of existing types of telemetry systems which resulted in production of the IChT-1 unit. Unit is intended for control of angular velocity of serially produced turbodrill rods, during drilling of wells up to 5000 m deep, and bottomhole temperatures to 100C. The paper provides a detailed description and diagrams for installing this unit.

  16. Flow resistance in rod assemblies

    International Nuclear Information System (INIS)

    The general form of relation between the resistance force and the velocity vector, resistance tensor structure and possible types of anisotropy in the flow thorough such structures as rod or tube assemblies are under discussion. Some questions of experimental determination of volumetric resistance force tensor are also under consideration. (author)

  17. Control rods in LMFBRs: a physics assessment

    International Nuclear Information System (INIS)

    This physics assessment is based on roughly 300 control rod worth measurements in ZPPR from 1972 to 1981. All ZPPR assemblies simulated mixed-oxide LMFBRs, representing sizes of 350, 700, and 900 MWe. Control rod worth measurements included single rods, various combinations of rods, and Ta and Eu rods. Additional measurements studied variations in B4C enrichment, rod interaction effects, variations in rod geometry, neutron streaming in sodium-filled channels, and axial worth profiles. Analyses were done with design-equivalent methods, using ENDF/B Version IV data. Some computations for the sensitivities to approximations in the methods have been included. Comparisons of these analyses with the experiments have allowed the status of control rod physics in the US to be clearly defined

  18. Control rods in LMFBRs: a physics assessment

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, H.F.; Collins, P.J.

    1982-08-01

    This physics assessment is based on roughly 300 control rod worth measurements in ZPPR from 1972 to 1981. All ZPPR assemblies simulated mixed-oxide LMFBRs, representing sizes of 350, 700, and 900 MWe. Control rod worth measurements included single rods, various combinations of rods, and Ta and Eu rods. Additional measurements studied variations in B/sub 4/C enrichment, rod interaction effects, variations in rod geometry, neutron streaming in sodium-filled channels, and axial worth profiles. Analyses were done with design-equivalent methods, using ENDF/B Version IV data. Some computations for the sensitivities to approximations in the methods have been included. Comparisons of these analyses with the experiments have allowed the status of control rod physics in the US to be clearly defined.

  19. Digitization on control rod position indication system

    International Nuclear Information System (INIS)

    This paper introduces the design mechanism, system structure of Control Rod Position Indication System and the application of Programmable Logic Controller (PLC) on Control Rod Position Indication System. (authors)

  20. Design, Mathematical Modelling, Construction and Testing of Synthetic Gene Network Oscillators to Establish Roseobacter Clade Bacteria and the Protozoan Trypanosoma brucei as Synthetic Biology Chassis.

    OpenAIRE

    Borg, Y.

    2015-01-01

    The aim of this project is to establish Roseobacter marine bacteria and Trypanosoma brucei (T. brucei) protozoa as synthetic biology chassis. This work addresses the gap within synthetic biology resulting from the limited choice of host cells available for use in practice. This was done by developing synthetic bacterial and trypanosomal genetic regulatory networks (GRNs) which function as an oscillator as well as by developing the necessary protocols and set-ups to allow for the analysis of G...

  1. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    OpenAIRE

    Nwoha Rosemary Ijeoma Ogechi; Anene Boniface Maduka

    2015-01-01

    Objective: To determine the effect of Ancylostoma caninum (A. caninum) and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods: Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense), and GPIV was infected with Trypanosoma brucei (T. brucei)/A. caninum. The dogs w...

  2. Solitary waves on nonlinear elastic rods. II

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.;

    1987-01-01

    In continuation of an earlier study of propagation of solitary waves on nonlinear elastic rods, numerical investigations of blowup, reflection, and fission at continuous and discontinuous variation of the cross section for the rod and reflection at the end of the rod are presented. The results...

  3. Fuel followed control rod installation at AFRRI

    International Nuclear Information System (INIS)

    Fuel Followed Control Rods (FFCRs) were installed at the Armed Forces Radiobiology Research Institute's 1 MW TRIGA Reactor. The procedures for obtaining, shipping, and installing the FFCRs is described. As part of the FFCR installation, the transient rod drive was relocated. Core performance due to the addition of the fuel followed control rods is discussed. (author)

  4. Process and apparatus for controlling control rods

    International Nuclear Information System (INIS)

    This process and apparatus is characterized by 2 methods, for examination of cluster of nuclear control rods. Foucault current analyzer which examines fraction by fraction all the control rods. This examination is made by rotation of the cluster. Doubtful rods are then analysed by ultrasonic probe

  5. Leaf spring puller for nuclear fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Fogg, J.L.

    1981-11-03

    A fuel rod puller in the form of a collet for pulling fuel rods from a storage area into grids of a nuclear reactor fuel assembly. The rod puller moves longitudinally through the grids to a storage area where projections on the end of leaf springs grasp onto an end plug in a fuel rod. Drive apparatus then pulls the rod puller and connected fuel rod from the storage area into the fuel assembly grids. The rod puller includes an outer tube having leaf springs on one end thereof in one modification, mounted within the outer tube is a movable plunger which acts to urge the leaf springs outwardly to a position to permit passing or with the end of a end plug. Upon withdrawal of the plunger, the leaf springs move into a groove formed in the end of a fuel rod end plug, and the fuel rod subsequently is pulled into the fuel assembly grids. In another modification, the leaf springs on the outer rod are biased in an outward direction and a longitudinally movable tube on the outer rod is moved in a direction to contract the leaf springs into a position where the projections thereof engage the groove formed in a fuel rod end plug.

  6. Rod and lamellar growth of eutectic

    OpenAIRE

    M. Trepczyńska - Łent

    2010-01-01

    The paper presents adaptation problem of lamellar growth of eutectic. The formation of rod eutectic microstructure was investigated systematically. A new rod eutectic configuration was observed in which the rods form with elliptical cylindrical shape. A new interpretation of the eutectic growth theory was proposed.

  7. Rod and lamellar growth of eutectic

    Directory of Open Access Journals (Sweden)

    M. Trepczyńska-Łent

    2010-04-01

    Full Text Available The paper presents adaptation problem of lamellar growth of eutectic. The formation of rod eutectic microstructure was investigated systematically. A new rod eutectic configuration was observed in which the rods form with elliptical cylindrical shape. A new interpretation of the eutectic growth theory was proposed.

  8. Detecting small flaws in fuel rods with sophisticated Eddy Current testing and single rod sipping

    International Nuclear Information System (INIS)

    AREVA has profound experience in efficient methods for finding defective irradiated fuel rods: - Eddy Current (EC) testing of single fuel rods - Sipping of fuel assemblies. In order to further improve the efficiency, AREVA developed new techniques: A. New sophisticated EC for detecting Small Defects in Irradiated Fuel Rod Claddings (SDIRC-EC) B. Single rod sipping (orig.)

  9. Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells.

    Science.gov (United States)

    Worku, Netsanet; Mossie, Andualem; Stich, August; Daugschies, Arwid; Trettner, Susanne; Hemdan, Nasr Y A; Birkenmeier, Gerd

    2013-01-01

    The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behaviour of T. brucei by cell counting and light microscopy. CEF was the most efficient growth inhibitor in comparison to AMR and RMA. Nevertheless, in LNCaP and THP-1 cells, all extracts significantly inhibited tumor growth at 3 μg/mL. All extracts inhibited proliferation of T. brucei cells in a concentration-dependent manner. Microscopic analysis revealed that 95% of the T. brucei cells died when exposed to 33 μg/mL CEF for 3 hrs. Similar results were obtained using 33 μg/mL AMR for 6 hrs. In case of RMA, however, higher concentrations were necessary to obtain similar effects on T. brucei. This demonstrates the antitumor efficacy of these extracts as well as their ability to dampen viability and proliferation of T. brucei, suggesting a common mechanism of action on highly proliferative cells, most probably by targeting cell metabolism. PMID:25937964

  10. Effects of Trypanosoma brucei tryptophanyl-tRNA synthetases silencing by RNA interference

    Directory of Open Access Journals (Sweden)

    Liliana Torcoroma García

    2007-09-01

    Full Text Available The kinetoplast genetic code deviates from the universal code in that 90% of mitochondrial tryptophans are specified by UGA instead of UGG codons. A single nucleus-encoded tRNA Trp(CCA is used by both nuclear and mitochondria genes, since all kinetoplast tRNAs are imported into the mitochondria from the cytoplasm. To allow decoding of the mitochondrial UGA codons as tryptophan, the tRNA Trp(CCA anticodon is changed to UCA by an editing event. Two tryptophanyl tRNA synthetases (TrpRSs have been identified in Trypanosoma brucei: TbTrpRS1 and TbTrpRS2 which localize to the cytoplasm and mitochondria respectively. We used inducible RNA interference (RNAi to assess the role of TbTrpRSs. Our data validates previous observations of TrpRS as potential drug design targets and investigates the RNAi effect on the mitochondria of the parasite.

  11. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia.

    Science.gov (United States)

    Szempruch, Anthony J; Sykes, Steven E; Kieft, Rudo; Dennison, Lauren; Becker, Allison C; Gartrell, Anzio; Martin, William J; Nakayasu, Ernesto S; Almeida, Igor C; Hajduk, Stephen L; Harrington, John M

    2016-01-14

    Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia. PMID:26771494

  12. Trypanosoma brucei: Enrichment by UV of intergenic transcripts from the variable surface glycoprotein gene expression site

    International Nuclear Information System (INIS)

    The expression site for the variable surface glycoprotein (VSG) gene AnTat 1.3A of Trypanosoma brucei is 45 kilobases long and encompasses seven expression site-associated genes (ESAGs). After UV irradiation, several large transcripts from the putative promoter region were strongly enriched. We report that one such major transcript starts near the poly(A) addition site of the first gene (ESAG 7), spans the intergenic region, and extends to the poly(A) addition site of the second gene (ESAG 6), thus bypassing the normal 3' splice site of the ESAG 6 mRNA. Since this transcript is spliced, we conclude that UV irradiation does not inhibit splicing but stabilizes unstable processing products. This demonstrates that at least some intergenic regions of the VSG gene expression site are continuously transcribed in accordance with a polycistronic transcription model

  13. Delay stroke piston and rod for engine

    Energy Technology Data Exchange (ETDEWEB)

    Booher, B.V.

    1995-03-09

    A reciprocating piston internal combustion engine comprises a cylinder having opposed ends, a piston reciprocably mounted in the cylinder, a connecting rod having a crank journal end and a piston journal end, the connecting rod connected to the piston at the piston journal end by means for first and second wrist pins spaced longitudinally along the rod, the first wrist pin journaled in a bore in the piston and in a slot in the piston rod, and the second wrist pin journaled in a bore in the piston rod and a longitudinal slot in the piston. (author)

  14. Snubber assembly for a control rod drive

    International Nuclear Information System (INIS)

    A snubber cartridge assembly is mounted to the nozzle of a control rod drive mechanism to insure that the snubber assembly will be located within the liquid filled section of a nuclear reactor vessel whenever the control rod drive is assembled thereto. The snubber assembly includes a piston mounted proximate to the control rod connecting end of the control rod drive leadscrew to allow the piston to travel within the liquid filled snubber cartridge and controllably exhaust liquid therefrom during a ''scram'' condition. The snubber cartridge provides three separate areas of increasing resistance to piston travel to insure a speedy but safe ''scram'' of the control rod into the reactor

  15. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    Science.gov (United States)

    Young, J.N.

    1958-04-22

    An electromagnetic apparatus for moving a rod-like member in small steps in either direction is described. The invention has particular application in the reactor field where the reactor control rods must be moved only a small distance and where the use of mechanical couplings is impractical due to the high- pressure seals required. A neutron-absorbing rod is mounted in a housing with gripping uaits that engage the rod, and coils for magnetizing the gripping units to make them grip, shift, and release the rod are located outside the housing.

  16. Analysis of Fly Fishing Rod Casting Dynamics

    OpenAIRE

    Gang Wang; Norman Wereley

    2011-01-01

    An analysis of fly fishing rod casting dynamics was developed comprising of a nonlinear finite element representation of the composite fly rod and a lumped parameter model for the fly line. A nonlinear finite element model was used to analyze the transient response of the fly rod, in which fly rod responses were simulated for a forward casting stroke. The lumped parameter method was used to discretize the fly line system. Fly line motions were simulated during a cast based on fly rod tip resp...

  17. Guide for rotating sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Harrel, R.D.

    1986-11-04

    This patent describes an improved guide for use in a string of sucker rods rotated in a tubing string in a borehole, the sucker rods having threaded male ends, the guide comprising: an elongated upright solid cylindrical coupling body of external diameter less than the internal diameter of tubing in which it is to be used; a pair of spaced apart axle holders positioned in three recess; an axle received in each recess in the coupling body, the axis of each axle being parallel and spaced from the body longitudinal axis; a roller rotatably received on each axle, the periphery of each roller extending exteriorly of the external cylindrical surface of the coupling body; and means to retain each of the holders in the coupling body recess.

  18. Nuclear reactor fuel rod spacer

    International Nuclear Information System (INIS)

    A spacer for positioning at least the four corner fuel rods in a tubular flow channel of a nuclear reactor is disclosed. The spacer comprises a support member having four side bands interconnected by four corner bands to form a unitary structure. Each of the side bands has a L-shaped lobe adjacent to each of its ends with one leg of each lobe extending to the adjacent end of its side band. Each of the corner bands is narrower than the side bands and is offset so as to be spaced from the lobe. One leg of each lobe is positioned to engage the tubular flow channel to maintain proper spacing between the flow channel and the adjacent corner fuel rod and to improve the thermal-hydraulic performance of the spacer

  19. Prototypical Rod Construction Demonstration Project

    International Nuclear Information System (INIS)

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 3 discusses the following topics: Downender Test Results and Analysis Report; NFBC Canister Upender Test Results and Analysis Report; Fuel Assembly Handling Fixture Test Results and Analysis Report; and Fuel Canister Upender Test Results and Analysis Report

  20. Method of withdrawing fuel rods

    International Nuclear Information System (INIS)

    Purpose: To facilitate the withdrawal of fuel rods from a fuel bundle by heating a lower tie plate. Constitution: A lower tie plate for a fuel bundle is disposed within a heating coil. Magnetic fluxes and eddy currents passing through the lower tie plate are induced by applying an alternating current to the heating coil to generate eddy current loss and hysteresis loss in the lower tie plate thereby generating heat to the inside of the lower tie plate per se with no external heating. The lower tie plate is heated in this way. Since the lower tie plate has a greater linear expansion coefficient than that of the lower end plug, a gap is resulted at the engaging portion between the lower tie plate and the lower end plug, by which the fastening of the lower end plug is released to facilitate the withdrawal of the fuel rod. (Yoshino, Y.)

  1. Cooled water rod (loca conditions)

    International Nuclear Information System (INIS)

    A process is described for providing a radiation heat sink for fuel bundles having a large water moderator tube in the event of a loss of coolant accident the fuel bundles having an upper tie plate, a lower tie plate, a channel surrounding and connecting the tie plate, a plurality of fuel rods supported between the tie plates and within the channels in side by side upstanding relation; a large water moderator tube having at least twice the diameter of the fuel rods. The process consists of: spraying core cooling spray in an evenly divided flow over the upper tie plate; collecting core cooling spray at an uper end of the large water moderator tube; and distributing the core cooling spray circumferentially along the inner surfaces of the large water moderator tube in a downward flow separating the flow of the core cooling spray from the flow of steam resulting from the flashing of water to steam within the moderator tube

  2. KINIK, Absorber Rod Calibration Kinetics

    International Nuclear Information System (INIS)

    1 - Description of program or function: KINIK is an inverse kinetic code that solves the inverse form of the point kinetic equations using the Runge-Kutta method. An optimization procedure is involved to control the time step and to reduce the running time. Up to 24 delayed neutron groups of different types (in case of heavy water as moderator or beryllium as reflector) are considered. KINIK is commonly applied to determine reactivity worths and to calibrate absorber rods. Following a rod drop, neutron flux or power is recorded as a function of time and used as input. 2 - Method of solution: The inverse point kinetic equations are numerically solved for each time step using the Runge-Kutta method. The input data resulting from measurements are first approximated by polynomials of maximum degree 10 using a least-squares approach

  3. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 1 discusses the following topics: the background of the project; test program description; summary of tests and test results; problem evaluation; functional requirements confirmation; recommendations; and completed test documentation for tests performed in Phase 3

  4. Exploiting rod technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1990-06-01

    ROD development was proceeding apace until recent budgetary decisions caused funding support for ROD development to be drastically reduced. The funding which was originally provided by DARPA and the Balanced Technology Initiative (BTI) Office has been cut back to zero from $800K. To determine the aeroballistic coefficients of a candidate dart, ARDEC is currently supporting development out of its own 6.2 funds at about $100K. ARDEC has made slow progress toward achieving this end because of failures in the original dart during testing. It appears that the next dart design to be tested will diverge from the original concept visualized by DARPA and Science and Technology Associates (STA). STA, the design engineer, takes exception to these changes on the basis of inappropriate test conditions and insufficient testing. At this time, the full resolution of this issue will be difficult because of the current management structure, which separates the developer (ARDEC) from the designer (STA).

  5. Protein functional links in Trypanosoma brucei, identified by gene fusion analysis

    Directory of Open Access Journals (Sweden)

    Trimpalis Philip

    2011-07-01

    Full Text Available Abstract Background Domain or gene fusion analysis is a bioinformatics method for detecting gene fusions in one organism by comparing its genome to that of other organisms. The occurrence of gene fusions suggests that the two original genes that participated in the fusion are functionally linked, i.e. their gene products interact either as part of a multi-subunit protein complex, or in a metabolic pathway. Gene fusion analysis has been used to identify protein functional links in prokaryotes as well as in eukaryotic model organisms, such as yeast and Drosophila. Results In this study we have extended this approach to include a number of recently sequenced protists, four of which are pathogenic, to identify fusion linked proteins in Trypanosoma brucei, the causative agent of African sleeping sickness. We have also examined the evolution of the gene fusion events identified, to determine whether they can be attributed to fusion or fission, by looking at the conservation of the fused genes and of the individual component genes across the major eukaryotic and prokaryotic lineages. We find relatively limited occurrence of gene fusions/fissions within the protist lineages examined. Our results point to two trypanosome-specific gene fissions, which have recently been experimentally confirmed, one fusion involving proteins involved in the same metabolic pathway, as well as two novel putative functional links between fusion-linked protein pairs. Conclusions This is the first study of protein functional links in T. brucei identified by gene fusion analysis. We have used strict thresholds and only discuss results which are highly likely to be genuine and which either have already been or can be experimentally verified. We discuss the possible impact of the identification of these novel putative protein-protein interactions, to the development of new trypanosome therapeutic drugs.

  6. Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrón-López, Melisa [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium); Michels, Paul A.M., E-mail: paul.michels@uclouvain.be [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)

    2013-02-01

    Highlights: ► Most eukaryotic cells have a single gene for the peroxin PEX5. ► PEX5 is sensitive to in vitro proteolysis in distantly related organisms. ► TbPEX5 undergoes N-terminal truncation in vitro and possibly in vivo. ► Truncated TbPEX5 is still capable of binding PTS1-containing proteins. ► PEX5 truncation is physiologically relevant or an evolutionary conserved artifact. -- Abstract: Glycolysis in kinetoplastid protists such as Trypanosoma brucei is compartmentalized in peroxisome-like organelles called glycosomes. Glycosomal matrix-protein import involves a cytosolic receptor, PEX5, which recognizes the peroxisomal-targeting signal type 1 (PTS1) present at the C-terminus of the majority of matrix proteins. PEX5 appears generally susceptible to in vitro proteolytic processing. On western blots of T. brucei, two PEX5 forms are detected with apparent M{sub r} of 100 kDa and 72 kDa. 5′-RACE-PCR showed that TbPEX5 is encoded by a unique transcript that can be translated into a protein of maximally 72 kDa. However, recombinant PEX5 migrates aberrantly in SDS–PAGE with an apparent M{sub r} of 100 kDa, similarly as observed for the native peroxin. In vitro protease susceptibility analysis of native and {sup 35}S-labelled PEX5 showed truncation of the 100 kDa form at the N-terminal side by unknown parasite proteases, giving rise to the 72 kDa form which remains functional for PTS1 binding. The relevance of these observations is discussed.

  7. Secondary Metabolites from Vietnamese Marine Invertebrates with Activity against Trypanosoma brucei and T. cruzi

    Directory of Open Access Journals (Sweden)

    Nguyen Phuong Thao

    2014-06-01

    Full Text Available Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50 < 5.0 μg/mL. Among the compounds isolated from these extracts, laevigatol B (1 from Lobophytum crassum and L. laevigatum, (24S-ergost-4-ene-3-one (2 from Sinularia dissecta, astropectenol A (3 from Astropecten polyacanthus, and cholest-8-ene-3β,5α,6β,7α-tetraol (4 from Diadema savignyi showed inhibitory activity against T. brucei with EC50 values ranging from 1.57 ± 0.14 to 14.6 ± 1.36 μM, relative to the positive control, pentamidine (EC50 = 0.015 ± 0.003 μM. Laevigatol B (1 and 5α-cholest-8(14-ene-3β,7α-diol (5 exhibited also significant inhibitory effects on T. cruzi. The cytotoxic activity of the pure compounds on mammalian cells was also assessed and found to be insignificant in all cases. This is the first report on the inhibitory effects of marine organisms collected in Vietnamese seas against Trypanosoma species responsible for neglected tropical diseases.

  8. Population genetics of Trypanosoma brucei rhodesiense: clonality and diversity within and between foci.

    Directory of Open Access Journals (Sweden)

    Craig W Duffy

    2013-11-01

    Full Text Available African trypanosomes are unusual among pathogenic protozoa in that they can undergo their complete morphological life cycle in the tsetse fly vector with mating as a non-obligatory part of this development. Trypanosoma brucei rhodesiense, which infects humans and livestock in East and Southern Africa, has classically been described as a host-range variant of the non-human infective Trypanosoma brucei that occurs as stable clonal lineages. We have examined T. b. rhodesiense populations from East (Uganda and Southern (Malawi Africa using a panel of microsatellite markers, incorporating both spatial and temporal analyses. Our data demonstrate that Ugandan T. b. rhodesiense existed as clonal populations, with a small number of highly related genotypes and substantial linkage disequilibrium between pairs of loci. However, these populations were not stable as the dominant genotypes changed and the genetic diversity also reduced over time. Thus these populations do not conform to one of the criteria for strict clonality, namely stability of predominant genotypes over time, and our results show that, in a period in the mid 1990s, the previously predominant genotypes were not detected but were replaced by a novel clonal population with limited genetic relationship to the original population present between 1970 and 1990. In contrast, the Malawi T. b. rhodesiense population demonstrated significantly greater diversity and evidence for frequent genetic exchange. Therefore, the population genetics of T. b. rhodesiense is more complex than previously described. This has important implications for the spread of the single copy T. b. rhodesiense gene that allows human infectivity, and therefore the epidemiology of the human disease, as well as suggesting that these parasites represent an important organism to study the influence of optional recombination upon population genetic dynamics.

  9. Trypanocidal action of bisphosphonium salts through a mitochondrial target in bloodstream form Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Abdulsalam A.M. Alkhaldi

    2016-04-01

    Full Text Available Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1 was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei, bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial FoF1 ATPase.

  10. Tribe kills fuel rod proposal

    International Nuclear Information System (INIS)

    This article is a review of nuclear utilities' efforts to find a repository of spent fuel rods. The rejection by the Mescalero Apaches of plans to build a waste repository on tribal lands has left a number of utilities scrambling to find interim solutions. Prairie Island will have to close before the end of the year unless a solution is found, and the Hope Creek/Salem units, exhausting there storage capacity within ten years, are considering dry-cask storage

  11. Tests pinpoint sucker-rod failures

    Energy Technology Data Exchange (ETDEWEB)

    Elshawesh, F.; Elhoud, A.; Elagdel, E. [Petroleum Research Center, Tripoli (Libyan Arab Jamahiriya)

    1997-05-26

    A detailed metallurgical examination of a 7/8-inch and a 1-inch sucker rod revealed corrosion fatigue had caused their failure. The 7 to 8-inch rod had failed after a few months of service while the 1-inch rod failed after 1 year. Both rods had been used in a sweet-oil environment. Both rods failed by corrosion fatigue because of repeated loads during operations. Pitting because of the presence of chloride ions and carbon dioxide was initiated on the rod surface, which in turn acted as a crack origin from which the fatigue crack initiated and propagated during operations. The pitting was on the external surface. These pits were large and penetrated through the rod cross-section. Fatigue cracking is initiated at the bottom of the pit where high stress concentration is expected and propagated because the rods were subjected to the alternating stresses during operation. The extent of the fatigue crack varied in the two examined rods because of the difference in the rod heat treatment and microstructure. The paper discusses fatigue failure, the visual examination, macroscopic and microscopic examinations, rod properties, and future operations.

  12. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 4 discusses the following topics: Rod Compaction/Loading System Test Results and Analysis Report; Waste Collection System Test Results and Analysis Report; Waste Container Transfer Fixture Test Results and Analysis Report; Staging and Cutting Table Test Results and Analysis Report; and Upper Cutting System Test Results and Analysis Report

  13. Inhibitors of the mitochondrial cytochrome b-c1 complex inhibit the cyanide-insensitive respiration of Trypanosoma brucei.

    Science.gov (United States)

    Turrens, J F; Bickar, D; Lehninger, A L

    1986-06-01

    The cyanide-insensitive respiration of bloodstream trypomastigote forms of Trypanosoma brucei (75 +/- 8 nmol O2 min-1(mg protein)-1) is completely inhibited by the mitochondrial ubiquinone-like inhibitors 2-hydroxy-3-undecyl-1,4-naphthoquinone (UHNQ) and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT). The Ki values for UHDBT (30 nM) and UHNQ (2 microM) are much lower than the reported Ki for salicylhydroxamic acid (SHAM) (5 microM), a widely used inhibitor of the cyanide-insensitive oxidase. UHNQ also stimulated the glycerol-3-phosphate-dependent reduction of phenazine methosulfate, demonstrating that the site of UHNQ inhibition is on the terminal oxidase of the cyanide-insensitive respiration of T. brucei. These results suggest that a ubiquinone-like compound may act as an electron carrier between the two enzymatic components of the cyanide-insensitive glycerol-3-phosphate oxidase. PMID:3016533

  14. Catalytic properties, localization, and in vivo role of Px IV, a novel tryparedoxin peroxidase of Trypanosoma brucei.

    Science.gov (United States)

    Liu, Ilon; Bogacz, Marta; Schaffroth, Corinna; Dirdjaja, Natalie; Krauth-Siegel, R Luise

    2016-06-01

    Px IV is a distant relative of the known glutathione peroxidase-type enzymes of African trypanosomes. Immunofluorescence microscopy of bloodstream cells expressing C-terminally Myc6-tagged Px IV revealed a mitochondrial localization. Recombinant Px IV possesses very low activity as glutathione peroxidase but catalyzes the trypanothione/tryparedoxin-dependent reduction of hydrogen peroxide and, even more efficiently, of arachidonic acid hydroperoxide. Neither overexpression in bloodstream cells nor the deletion of both alleles in bloodstream or procyclic parasites affected the in vitro proliferation. Trypanosoma brucei Px IV shares 58% of all residues with TcGPXII. The orthologous enzymes have in common their substrate preference for fatty acid hydroperoxides. However, the T. cruzi protein has been reported to be localized in the endoplasmic reticulum and to be specific for glutathione as reducing agent. Taken together, our data show that Px IV is a low abundant tryparedoxin peroxidase of T. brucei that is not essential, at least under culture conditions. PMID:27262262

  15. In vitro investigation of Brazilian Cerrado plant extract activity against Plasmodium falciparum, Trypanosoma cruzi and T. brucei gambiense.

    Science.gov (United States)

    Charneau, Sébastien; de Mesquita, Mariana Laundry; Bastos, Izabela Marques Dourado; Santana, Jaime Martins; de Paula, José Elias; Grellier, Philippe; Espindola, Laila Salmen

    2016-06-01

    The threatened Brazilian Cerrado biome is an important biodiversity hotspot but still few explored that constitutes a potential reservoir of molecules to treat infectious diseases. We selected eight Cerrado plant species for screening against the erythrocytic stages of Plasmodium falciparum, human intracellular stages of Trypanosoma cruzi and bloodstream forms of T. brucei gambiense, and for their cytotoxicity upon the rat L6-myoblast cell line. Bioassays were performed with 37 hexane, ethyl acetate and ethanol extracts prepared from different plant organs. Activities against parasites were observed for 24 extracts: 9 with anti-P. falciparum, 4 with anti-T. cruzi and 11 with anti-T. brucei gambiense activities. High anti-protozoal activity (IC50 values knowledge essential for Cerrado conservation and sustainable development. PMID:26222897

  16. High-resolution complex of papain with remnants of a cysteine protease inhibitor derived from Trypanosoma brucei

    OpenAIRE

    Alphey, Magnus S.; Hunter, William N.

    2006-01-01

    Attempts to cocrystallize the cysteine protease papain derived from the latex of Carica papaya with an inhibitor of cysteine proteases (ICP) from Trypanosoma brucei were unsuccessful. However, crystals of papain that diffracted to higher resolution, 1.5 Å, than other crystals of this archetypal cysteine protease were obtained, so the analysis was continued. Surprisingly, the substrate-binding cleft was occupied by two short peptide fragments which have been assigned as remnants of ICP. Compar...

  17. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Sharlow

    Full Text Available BACKGROUND: The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK, an enzyme essential to the parasite that transfers the gamma-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay. METHODOLOGY/PRINCIPAL FINDINGS: Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were approximately 20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics. CONCLUSIONS/SIGNIFICANCE: The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

  18. Dynamics of Mitochondrial RNA-Binding Protein Complex in Trypanosoma brucei and Its Petite Mutant under Optimized Immobilization Conditions

    Czech Academy of Sciences Publication Activity Database

    Huang, Zhenqiu; Kaltenbrunner, S.; Šimková, Eva; Staněk, David; Lukeš, Julius; Hashimi, Hassan

    2014-01-01

    Roč. 13, č. 9 (2014), s. 1232-1240. ISSN 1535-9778 R&D Projects: GA ČR GAP305/12/2261; GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 ; RVO:68378050 Keywords : mitochondrion * Trypanosoma brucei * YFP Subject RIV: EB - Genetics ; Molecular Biology; EB - Genetics ; Molecular Biology (UMG-J) Impact factor: 2.820, year: 2014

  19. A structural domain mediates attachment of ethanolamine phosphoglycerol to eukaryotic elongation factor 1A in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Eva Greganova

    Full Text Available Ethanolamine phosphoglycerol (EPG represents a protein modification that so far has only been found in eukaryotic elongation factor 1A (eEF1A. In mammals and plants, EPG is covalently attached to two conserved glutamate residues located in domains II and III of eEF1A. In contrast, Trypanosoma brucei eEF1A contains a single EPG attached to Glu362 in domain III. The sequence and/or structural requirements for covalent linkage of EPG to eEF1A have not been determined for any organism. Using a combination of biosynthetic labelling of parasites with tritiated ethanolamine and mass spectrometry analyses, we demonstrate that replacement of Glu362 in T. brucei eEF1A by site-directed mutagenesis prevents EPG attachment, whereas single or multiple amino acid substitutions around the attachment site are not critical. In addition, by expressing a series of eEF1A deletion mutants in T. brucei procyclic forms, we demonstrate that a peptide consisting of 80 amino acids of domain III of eEF1A is sufficient for EPG attachment to occur. Furthermore, EPG addition also occurs if domain III of eEF1A is fused to a soluble reporter protein. To our knowledge, this is the first report addressing amino acid sequence, or structure, requirements for EPG modification of eEF1A in any organism. Using T. brucei as a model organism, we show that amino acid substitutions around the modification site are not critical for EPG attachment and that a truncated version of domain III of eEF1A is sufficient to mediate EPG addition.

  20. Diagnosis of human trypanosomiasis, due to Trypanosoma brucei gambiense in central Africa, by the polymerase chain reaction

    OpenAIRE

    Penchenier, Laurent; Simo, G.; Grébaut, Pascal; Nkinin, S.; Laveissière, Claude; Herder, Stéphane

    2000-01-01

    During a mass screening of sleeping sickness conducted in 1998 and 1999, and involving 27,932 persons in Cameroon and the Central African Republic, we tested the polymerase chain reaction (PCR) on whole blood for the diagnosis of human African trypanosomiasis due to #Trypanosoma brucei gambiense$. The 1858 samples obtained were from 4 groups : 155 infected patients, 1432 serological suspects detected by the card agglutination test for trypanosomiasis (CATT), 222 negative controls living in th...

  1. Trypanosoma brucei 29-13 strain is inducible in but not permissive for the tsetse fly vector

    Czech Academy of Sciences Publication Activity Database

    Herder, S.; Votýpka, Jan; Jirků, Milan; Rádrová, J.; Janzen, C. J.; Lukeš, Julius

    2007-01-01

    Roč. 117, č. 1 (2007), s. 111-114. ISSN 0014-4894 R&D Projects: GA MŠk(CZ) LC06009; GA MŠk 2B06129 Grant ostatní: MŠk(CZ) Barrande 2-06-28 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trypanosoma brucei * tsetse * Glossina * GFP * Transmission * midgut infection * tetracycline Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.597, year: 2007

  2. Functional dissection of T. brucei Protein Tyrosine Phosphatase 1 and investigation of its development as a therapeutic target

    OpenAIRE

    Ruberto, Irene

    2011-01-01

    Trypanosoma brucei undergoes developmentally regulated morphological and biochemical changes during its life cycle, being transmitted between the mammalian host and the tsetse fly. It is generally recognized that cellular responses to environmental changes are mediated through signalling pathways, but our understanding of trypanosome signal transduction during differentiation is limited. Protein Tyrosine Phosphatase 1 (TbPTP1) is the one of the few factors identified to b...

  3. Vibrational characteristics and wear of fuel rods

    International Nuclear Information System (INIS)

    Fuel rod wear, due to vibration, is a continuing concern in the design of liquid-cooled reactors. In my report, the methodology and models that are used to predict fuel rod vibrational response and vibratory wear, in a light water reactor environment, are discussed. This methodology is being followed at present in the design of Westinghouse Nuclear Fuel. Fuel rod vibrations are expressed as the normal bending modes, and sources of rod vibration are examined with special emphasis on flow-induced mechanisms in the stable flow region. In a typical Westinghouse PWR fuel assembly design, each fuel rod is supported at multiple locations along the rod axis by a square-shaped 'grid cell'. For a fuel rod /grid support system, the development of small oscillatory motions, due to fluid flow at the rod/grid interface, results in material wear. A theoretical wear mode is developed using the Archard Theory of Adhesive Wear as the basis. Without question certainty, fretting wear becomes a serious problem if it progresses to the stage where the fuel cladding is penetrated and fuel is exposed to the coolant. Westinghouse fuel is designed to minimize fretting wear by limiting the relative motion between the fuel rod and its supports. The wear producing motion between the fuel rod and its supports occurs when the vibration amplitude exceeds the slippage threshold amplitude

  4. Ab initio identification of novel regulatory elements in the genome of Trypanosoma brucei by Bayesian inference on sequence segmentation.

    Directory of Open Access Journals (Sweden)

    Steven Kelly

    Full Text Available BACKGROUND: The rapid increase in the availability of genome information has created considerable demand for both comparative and ab initio predictive bioinformatic analyses. The biology laid bare in the genomes of many organisms is often novel, presenting new challenges for bioinformatic interrogation. A paradigm for this is the collected genomes of the kinetoplastid parasites, a group which includes Trypanosoma brucei the causative agent of human African trypanosomiasis. These genomes, though outwardly simple in organisation and gene content, have historically challenged many theories for gene expression regulation in eukaryotes. METHODOLOGY/PRINCIPLE FINDINGS: Here we utilise a Bayesian approach to identify local changes in nucleotide composition in the genome of T. brucei. We show that there are several elements which are found at the starts and ends of multicopy gene arrays and that there are compositional elements that are common to all intergenic regions. We also show that there is a composition-inversion element that occurs at the position of the trans-splice site. CONCLUSIONS/SIGNIFICANCE: The nature of the elements discovered reinforces the hypothesis that context dependant RNA secondary structure has an important influence on gene expression regulation in Trypanosoma brucei.

  5. Evidence for loss of a partial flagellar glycolytic pathway during trypanosomatid evolution.

    Directory of Open Access Journals (Sweden)

    Robert W B Brown

    Full Text Available Classically viewed as a cytosolic pathway, glycolysis is increasingly recognized as a metabolic pathway exhibiting surprisingly wide-ranging variations in compartmentalization within eukaryotic cells. Trypanosomatid parasites provide an extreme view of glycolytic enzyme compartmentalization as several glycolytic enzymes are found exclusively in peroxisomes. Here, we characterize Trypanosoma brucei flagellar proteins resembling glyceraldehyde-3-phosphate dehydrogenase (GAPDH and phosphoglycerate kinase (PGK: we show the latter associates with the axoneme and the former is a novel paraflagellar rod component. The paraflagellar rod is an essential extra-axonemal structure in trypanosomes and related protists, providing a platform into which metabolic activities can be built. Yet, bioinformatics interrogation and structural modelling indicate neither the trypanosome PGK-like nor the GAPDH-like protein is catalytically active. Orthologs are present in a free-living ancestor of the trypanosomatids, Bodo saltans: the PGK-like protein from B. saltans also lacks key catalytic residues, but its GAPDH-like protein is predicted to be catalytically competent. We discuss the likelihood that the trypanosome GAPDH-like and PGK-like proteins constitute molecular evidence for evolutionary loss of a flagellar glycolytic pathway, either as a consequence of niche adaptation or the re-localization of glycolytic enzymes to peroxisomes and the extensive changes to glycolytic flux regulation that accompanied this re-localization. Evidence indicating loss of localized ATP provision via glycolytic enzymes therefore provides a novel contribution to an emerging theme of hidden diversity with respect to compartmentalization of the ubiquitous glycolytic pathway in eukaryotes. A possibility that trypanosome GAPDH-like protein additionally represents a degenerate example of a moonlighting protein is also discussed.

  6. Control rod studies for enigma configurations

    International Nuclear Information System (INIS)

    Collaboration is underway between Argonne and the CEA-Cadarache on the preparation of experiments for the ENIGMA program dedicated to the reactor physics experiments supporting the development of gas-cooled fast reactors. Specifications have been defined for the study of control rods in the central void zone of ENIGMA configurations. Deterministic calculations of the rodded configurations have been performed using the ERANOS code system. The various core criticality states for the different phases of the control rod experiments have been determined by specifying the number of additional fuel assemblies required to restore criticality. Control rod worths, flux distributions, and reactions rate distributions for a few nuclides have been analyzed. The study revealed the significant impact of spatial heterogeneity in the rod configurations used for the experiments, indicating flexibility for the control rod experiments

  7. Hybrid composite rods for concrete reinforcement

    OpenAIRE

    Fangueiro, Raúl; Pereira, Cristiana Gonilho; Jalali, Said; Araújo, Mário Duarte de; Marques, P.

    2010-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement.Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. ...

  8. Tensile properties of braided composite rods

    OpenAIRE

    Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Araújo, Mário Duarte de; Marques, P

    2008-01-01

    The current work is concerning the development of braided reinforced composite rods for civil engineering applications, namely for concrete internal reinforcement. The research study aims to understand the mechanical behaviour of braided reinforced composite rods produced from an innovative technique. Seven types of braided reinforced composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided fabric. E-glass, carbon, HT polyethylene fibres ...

  9. Nuclear reactor fuel rod attachment system

    International Nuclear Information System (INIS)

    The invention involves a technique to quickly, inexpensively and rigidly attach a nuclear reactor fuel rod to a support member. The invention also allows for the repeated non-destructive removal and replacement of the fuel rod. The proposed fuel rod and support member attachment and removal system consists of a locking cap fastened to the fuel rod and a locking strip fastened to the support member or vice versa. The locking cap has two or more opposing fingers shaped to form a socket. The fingers spring back when moved apart and released. The locking strip has an extension shaped to rigidly attach to the socket's body portion

  10. Absorber rod for pebble-bed reactor

    International Nuclear Information System (INIS)

    The absorber rod that can be moved into the pebble bed from the top reflector is enclosed by a cladding tube which, if it is completely moved down, ends above the pebble bed and is open at the bottom. Through the cladding tube the absorber rod is cooled with gas. The cladding tube consists of e.g. boron steel. If the absorber rod is drawn it takes along the cladding tube which is moved into the guide tube like a telescope. The rigidity of that part of the absorber rod projecting from the pebble bed is thus guaranteed. (DG)

  11. Growth and Morphology of Rod Eutectics

    Energy Technology Data Exchange (ETDEWEB)

    Jing Teng; Shan Liu; R. Trivedi

    2008-03-17

    The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than the other one.

  12. Heat transfer in rod bundle subchannels with varying rod-wall proximity

    International Nuclear Information System (INIS)

    Heat transfer characteristics have been measured around an outer rod of a 37-rod bundle model, in which localized heat was provided by a narrow heated strip. The rod was traversed perpendicularly to its axis and rotated about itself, thus permitting measurement of the local heat transfer coefficient around its perimeter for various rod-wall proximities, including cases with narrow rod-wall gaps, rod-wall contact and rod-rod-wall contact. The measurements show that the heat transfer coefficient was minimum near narrow gaps and maximum in open-flow but its variation became substantial only when the gap diminished below a certain value. In-flow mean temperature and temperature fluctuation measurements were also conducted in the subchannel adjacent to the heater. Asymmetries of the mean temperature and the temperature fluctuation contours were observed with the heater near the gap as well as facing the subchannel centre. (orig.)

  13. High-yield production of hydrophobins RodA and RodB from Aspergillus fumigatus in Pichia pastoris

    DEFF Research Database (Denmark)

    Pedersen, Mona Højgaard; Borodina, Irina; Moresco, Jacob Lange;

    2011-01-01

    -PAGE. Recombinant RodA as well as rRodB were able to convert a glass surface from hydrophilic to hydrophobic similar to native RodA, but only rRodB was able to decrease the hydrophobicity of a Teflon-like surface to the same extent as native RodA, while rRodA showed this ability to a lesser extent. Recombinant Rod...

  14. Changes in blood sugar levels of rats experimentally infected withTrypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu

    2016-01-01

    Objective:To determine the effect ofTrypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected withT. brucei and treated with diminazene aceturate, and Group C was infected withT. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on Days 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 for the assessment of change in blood sugar levels. The blood sugar levels were determined with a glucometer (Accu-chek active serialNo.GN:10023338). Results: By 4 to 5 days post infection, there was a significant increase (P 0.05) was observed in the groups when compared with the control group till Day 12 of the experiment. Conclusions:T. brucei caused a significant increase in blood sugar of infected rats.

  15. A Host-Pathogen Interaction Reduced to First Principles: Antigenic Variation in T. brucei.

    Science.gov (United States)

    Hovel-Miner, Galadriel; Mugnier, Monica; Papavasiliou, F Nina; Pinger, Jason; Schulz, Danae

    2015-01-01

    Antigenic variation is a common microbial survival strategy, powered by diversity in expressed surface antigens across the pathogen population over the course of infection. Even so, among pathogens, African trypanosomes have the most comprehensive system of antigenic variation described. African trypanosomes (Trypanosoma brucei spp.) are unicellular parasites native to sub-Saharan Africa, and the causative agents of sleeping sickness in humans and of n'agana in livestock. They cycle between two habitats: a specific species of fly (Glossina spp. or, colloquially, the tsetse) and the bloodstream of their mammalian hosts, by assuming a succession of proliferative and quiescent developmental forms, which vary widely in cell architecture and function. Key to each of the developmental forms that arise during these transitions is the composition of the surface coat that covers the plasma membrane. The trypanosome surface coat is extremely dense, covered by millions of repeats of developmentally specified proteins: procyclin gene products cover the organism while it resides in the tsetse and metacyclic gene products cover it while in the fly salivary glands, ready to make the transition to the mammalian bloodstream. But by far the most interesting coat is the Variant Surface Glycoprotein (VSG) coat that covers the organism in its infectious form (during which it must survive free living in the mammalian bloodstream). This coat is highly antigenic and elicits robust VSG-specific antibodies that mediate efficient opsonization and complement mediated lysis of the parasites carrying the coat against which the response was made. Meanwhile, a small proportion of the parasite population switches coats, which stimulates a new antibody response to the prevalent (new) VSG species and this process repeats until immune system failure. The disease is fatal unless treated, and treatment at the later stages is extremely toxic. Because the organism is free living in the blood, the VSG

  16. Self-assembly of rod-coil-rod ABA-type triblock copolymers.

    Science.gov (United States)

    Chen, Ji-Zhong; Sun, Zhao-Yan; Zhang, Cheng-Xiang; An, Li-Jia; Tong, Zhen

    2008-02-21

    Self-assembled behavior of symmetric ABA rod-coil-rod triblock copolymer melts is studied by applying self-consistent-field lattice techniques in three-dimensional space. The phase diagram is constructed to understand the effects of the chain architecture on the self-assembled behavior. Four stable structures are observed for the ABA rod-coil-rod triblock, i.e., spherelike, lamellar, gyroidlike, and cylindrical structures. Different from AB rod-coil diblock and BAB coil-rod-coil triblock copolymers, the lamellar structure observed in ABA rod-coil-rod triblock copolymer melts is not stable for high volume fraction of the rod component (f(rod)=0.8), which is attributed to the intramolecular interactions between the two rod blocks of the polymer chain. When 0.3blocks of the polymer chain are decrease, which results in the occurrence of some interesting metastable mixed structures. These structures have not been observed in polymers containing only one rod block, such as a lamellar-alt-lamellar structure. The results are expected to provide guidance for the design of microstructures in experiments. PMID:18298171

  17. Reduced Mitochondrial Membrane Potential Is a Late Adaptation of Trypanosoma brucei brucei to Isometamidium Preceded by Mutations in the γ Subunit of the F1Fo-ATPase

    Science.gov (United States)

    Munday, Jane C.; Tagoe, Daniel N. A.; Stelmanis, Valters; Schnaufer, Achim

    2016-01-01

    Background Isometamidium is the main prophylactic drug used to prevent the infection of livestock with trypanosomes that cause Animal African Trypanosomiasis. As well as the animal infective trypanosome species, livestock can also harbor the closely related human infective subspecies T. b. gambiense and T. b. rhodesiense. Resistance to isometamidium is a growing concern, as is cross-resistance to the diamidine drugs diminazene and pentamidine. Methodology/Principal Findings Two isometamidium resistant Trypanosoma brucei clones were generated (ISMR1 and ISMR15), being 7270- and 16,000-fold resistant to isometamidium, respectively, which retained their ability to grow in vitro and establish an infection in mice. Considerable cross-resistance was shown to ethidium bromide and diminazene, with minor cross-resistance to pentamidine. The mitochondrial membrane potentials of both resistant cell lines were significantly reduced compared to the wild type. The net uptake rate of isometamidium was reduced 2-3-fold but isometamidium efflux was similar in wild-type and resistant lines. Fluorescence microscopy and PCR analysis revealed that ISMR1 and ISMR15 had completely lost their kinetoplast DNA (kDNA) and both lines carried a mutation in the nuclearly encoded γ subunit gene of F1 ATPase, truncating the protein by 22 amino acids. The mutation compensated for the loss of the kinetoplast in bloodstream forms, allowing near-normal growth, and conferred considerable resistance to isometamidium and ethidium as well as significant resistance to diminazene and pentamidine, when expressed in wild type trypanosomes. Subsequent exposure to either isometamidium or ethidium led to rapid loss of kDNA and a further increase in isometamidium resistance. Conclusions/Significance Sub-lethal exposure to isometamidium gives rise to viable but highly resistant trypanosomes that, depending on sub-species, are infective to humans and cross-resistant to at least some diamidine drugs. The crucial

  18. Hollow sucker rod for PCP systems

    Energy Technology Data Exchange (ETDEWEB)

    Villasante, J.A.; Ernst, H.A. [Tenaris Research and Development, Campana (Argentina)

    2008-07-01

    This paper described a new hollow sucker rod technology designed for use with progressive cavity pumps (PCPs). The technology provided a high torque load to yielding ratio, as well as high backspin resistance and pumping rates. The technology was also designed to allow for the injection of other fluids such as corrosion inhibitors or diluents via its hollow sucker rod. Torsion, axial, and bending load stress analyses were conducted to determine critical zones in a top hollow rod connection at the well head and a bottom hollow rod connection at the well bottom. The study showed that the ratio between the equivalent stress and ultimate tensile stress was a function of torsional load. Backspin analyses were conducted to determine the release of energy accumulated in the hollow rod and traditional pumping system. The evaluation showed that the elastic torsional deformation was lower in the hollow rod system, while backspin resistance was higher. Multiple make and break operations were conducted to determine torsional load values. Results from the study were used to optimize the hollow rod technology. It was concluded that the hollow sucker rod system is now being used in various configurations at sites around the world. 8 tabs., 14 figs.

  19. 49 CFR 236.793 - Rod, lock.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rod, lock. 236.793 Section 236.793 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.793 Rod, lock. A...

  20. Control rod guide tube assembly

    International Nuclear Information System (INIS)

    An improved fuel assembly is described as consisting of a sleeve that engages one end of a control rod guide tube essentially fixing the guide tube to one of the fuel assembly end structures. The end of the sleeve protrudes above the surface of the end fitting. The outer surface of the sleeve has a peripheral groove that engages the resilient sides of a cellular grid or lattice shaped lock. This lock fixes the sleeve in position between the various elements that comprise the end fitting, thereby eliminating a profusion of costly and potentially troublesome nuts, threaded studs and the like that are frequently employed in the fuel assemblies that are presently in use

  1. Flux Analysis of the Trypanosoma brucei Glycolysis Based on a Multiobjective-Criteria Bioinformatic Approach

    Directory of Open Access Journals (Sweden)

    Amine Ghozlane

    2012-01-01

    Full Text Available Trypanosoma brucei is a protozoan parasite of major of interest in discovering new genes for drug targets. This parasite alternates its life cycle between the mammal host(s (bloodstream form and the insect vector (procyclic form, with two divergent glucose metabolism amenable to in vitro culture. While the metabolic network of the bloodstream forms has been well characterized, the flux distribution between the different branches of the glucose metabolic network in the procyclic form has not been addressed so far. We present a computational analysis (called Metaboflux that exploits the metabolic topology of the procyclic form, and allows the incorporation of multipurpose experimental data to increase the biological relevance of the model. The alternatives resulting from the structural complexity of networks are formulated as an optimization problem solved by a metaheuristic where experimental data are modeled in a multiobjective function. Our results show that the current metabolic model is in agreement with experimental data and confirms the observed high metabolic flexibility of glucose metabolism. In addition, Metaboflux offers a rational explanation for the high flexibility in the ratio between final products from glucose metabolism, thsat is, flux redistribution through the malic enzyme steps.

  2. Synchronous expression of individual metacyclic variant surface glycoprotein genes in Trypanosoma brucei.

    Science.gov (United States)

    Ramey-Butler, Kiantra; Ullu, Elisabetta; Kolev, Nikolay G; Tschudi, Christian

    2015-01-01

    One distinctive feature of the Trypanosoma brucei life cycle is the presence of two discrete populations that are based on differential expression of variant surface glycoproteins (VSGs). Both are adapted to the environmental pressures they face and more importantly, both contribute directly to transmission. Metacyclics in the tsetse fly enable transmission to a new mammalian host, whereas bloodstream trypanosomes must avoid immune destruction to the extent that sufficient numbers are available for transmission, when the insect vector takes a blood meal. At present, there are few investigations on the molecular aspects of parasite biology in the tsetse vector and specifically about the activation of metacyclic VSG gene expression. Here we used an established in vitro differentiation system based on the overexpression of the RNA-binding protein 6 (RBP6), to monitor two metacyclic VSGs (VSG 397 and VSG 653) during development from procyclics to infectious metacyclic forms. We observed that activation of these two mVSGs was simultaneous both at the transcript and protein level, and manifested by the appearance of only one of the mVSGs in individual cells. PMID:25896436

  3. Familial aggregation of Trypanosoma brucei gambiense trypanosomiasis in a very high incidence community in Zaire.

    Science.gov (United States)

    Khonde, N; Pépin, J; Niyonsenga, T; De Wals, P

    1997-01-01

    Familial aggregation of Trypanosoma brucei gambiense human African trypanosomiasis (HAT) was investigated in 3 adjacent villages of central Zaire where 318/1431 inhabitants had previously suffered from HAT. Neither spatial nor familial aggregation was detected when analysing the distribution of cases in the whole community using Poisson, negative binomial and pairwise odds ratio models. However, clustering of cases was observed when specific familial relationships were examined. The risk of HAT for a child was significantly increased if the mother had also had HAT, but it was not influenced by a past history of HAT in the father. Sisters and brothers of cases of HAT had a higher risk of HAT than siblings of individuals who had never had HAT, but no such association was documented for half-sisters and half-brothers. Among married couples, a past history of HAT in one spouse had no impact on the other spouse's risk of HAT. Indirect arguments suggested that familial clustering was a consequence of shared exposure, either sequential or simultaneous, rather than of genetic susceptibility. The existence of familial clustering should be kept in mind when implementing passive or active case-finding activities. PMID:9463655

  4. Immune Evasion Strategies of Trypanosoma brucei within the Mammalian Host: Progression to Pathogenicity

    Science.gov (United States)

    Stijlemans, Benoît; Caljon, Guy; Van Den Abbeele, Jan; Van Ginderachter, Jo A.; Magez, Stefan; De Trez, Carl

    2016-01-01

    The diseases caused by African trypanosomes (AT) are of both medical and veterinary importance and have adversely influenced the economic development of sub-Saharan Africa. Moreover, so far not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. These strictly extracellular protozoan parasites are confronted with different arms of the host’s immune response (cellular as well as humoral) and via an elaborate and efficient (vector)–parasite–host interplay they have evolved efficient immune escape mechanisms to evade/manipulate the entire host immune response. This is of importance, since these parasites need to survive sufficiently long in their mammalian/vector host in order to complete their life cycle/transmission. Here, we will give an overview of the different mechanisms AT (i.e. T. brucei as a model organism) employ, comprising both tsetse fly saliva and parasite-derived components to modulate host innate immune responses thereby sculpturing an environment that allows survival and development within the mammalian host.

  5. Latent Trypanosoma brucei gambiense foci in Uganda: a silent epidemic in children and adults?

    Science.gov (United States)

    Wastling, S L; Picozzi, K; Wamboga, C; VON Wissmann, B; Amongi-Accup, C; Wardrop, N A; Stothard, J R; Kakembo, A; Welburn, S C

    2011-10-01

    Trypanosoma brucei gambiense sleeping sickness follows a long asymptomatic phase and persists in ancient foci from which epidemic clinical disease arises. A putative focus of T. b. gambiense infections has been identified, initially in mothers and young children, on the Lake Albert shoreline of Western Uganda leading to mass screening of 6207 individuals in September 2008. T. b. gambiense infections were identified by Card Agglutination Test for Trypanosomiasis (CATT) and sub-species-specific PCR although parasitological methods failed to confirm any patent trypanosome infections. In April 2009, CATT positives were re-visited; diagnosis of individuals by CATT and PCR was unstable over the two time points and parasites remained undetected, even using mini Anion Exchange Centrifugation Technique (mAECT). These observations suggest the possibility of a silent focus of disease, where all infected individuals are in a latent stage, and highlight our limited understanding of the local natural history and disease progression of T. b. gambiense in children and adults. PMID:21554841

  6. Dynamic modelling under uncertainty: the case of Trypanosoma brucei energy metabolism.

    Directory of Open Access Journals (Sweden)

    Fiona Achcar

    2012-01-01

    Full Text Available Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabolic model, but so far it has been studied with a fixed set of parameters only. Here we evaluate the effect of parameter uncertainty. In order to define probability distributions for each parameter, information about the experimental sources and confidence intervals for all parameters were collected. We created a wiki-based website dedicated to the detailed documentation of this information: the SilicoTryp wiki (http://silicotryp.ibls.gla.ac.uk/wiki/Glycolysis. Using information collected in the wiki, we then assigned probability distributions to all parameters of the model. This allowed us to sample sets of alternative models, accurately representing our degree of uncertainty. Some properties of the model, such as the repartition of the glycolytic flux between the glycerol and pyruvate producing branches, are robust to these uncertainties. However, our analysis also allowed us to identify fragilities of the model leading to the accumulation of 3-phosphoglycerate and/or pyruvate. The analysis of the control coefficients revealed the importance of taking into account the uncertainties about the parameters, as the ranking of the reactions can be greatly affected. This work will now form the basis for a comprehensive Bayesian analysis and extension of the model considering alternative topologies.

  7. Spliced leader trapping reveals widespread alternative splicing patterns in the highly dynamic transcriptome of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Daniel Nilsson

    Full Text Available Trans-splicing of leader sequences onto the 5'ends of mRNAs is a widespread phenomenon in protozoa, nematodes and some chordates. Using parallel sequencing we have developed a method to simultaneously map 5'splice sites and analyze the corresponding gene expression profile, that we term spliced leader trapping (SLT. The method can be applied to any organism with a sequenced genome and trans-splicing of a conserved leader sequence. We analyzed the expression profiles and splicing patterns of bloodstream and insect forms of the parasite Trypanosoma brucei. We detected the 5' splice sites of 85% of the annotated protein-coding genes and, contrary to previous reports, found up to 40% of transcripts to be differentially expressed. Furthermore, we discovered more than 2500 alternative splicing events, many of which appear to be stage-regulated. Based on our findings we hypothesize that alternatively spliced transcripts present a new means of regulating gene expression and could potentially contribute to protein diversity in the parasite. The entire dataset can be accessed online at TriTrypDB or through: http://splicer.unibe.ch/.

  8. Isothermal microcalorimetry, a new tool to monitor drug action against Trypanosoma brucei and Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Tanja Wenzler

    Full Text Available Isothermal microcalorimetry is an established tool to measure heat flow of physical, chemical or biological processes. The metabolism of viable cells produces heat, and if sufficient cells are present, their heat production can be assessed by this method. In this study, we investigated the heat flow of two medically important protozoans, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Heat flow signals obtained for these pathogens allowed us to monitor parasite growth on a real-time basis as the signals correlated with the number of viable cells. To showcase the potential of microcalorimetry for measuring drug action on pathogenic organisms, we tested the method with three antitrypanosomal drugs, melarsoprol, suramin and pentamidine and three antiplasmodial drugs, chloroquine, artemether and dihydroartemisinin, each at two concentrations on the respective parasite. With the real time measurement, inhibition was observed immediately by a reduced heat flow compared to that in untreated control samples. The onset of drug action, the degree of inhibition and the time to death of the parasite culture could conveniently be monitored over several days. Microcalorimetry is a valuable element to be added to the toolbox for drug discovery for protozoal diseases such as human African trypanosomiasis and malaria. The method could probably be adapted to other protozoan parasites, especially those growing extracellularly.

  9. Immune mechanisms in trypanosomiasis: Studies in mice using 75Se-labelled Trypanosoma brucei

    International Nuclear Information System (INIS)

    Using trypanosomes labelled in vivo with 75Se-methionine, the ability of normal and immunized mice to remove radiolabelled parasites from their circulation was investigated. It was found that immune animals had the capacity to clear parasites rapidly from their blood essentially as a result of hepatic uptake, whereas normal mice did not have this ability and the parasites remained in the circulation. A series of experiments in actively and passively immunized mice showed that hepatic uptake was closely related to antibody levels and was not markedly influenced by macrophage activation or blockade. In subsequent studies in infected animals it was found that, in contrast to mice with chronic infections, those with acute fulminating parasitaemias were unable to remove radiolabelled trypanosomes from their circulation. It was found that this was not due to impaired macrophage function, but was apparently caused by rapid parasite replication outpacing antibody production so that effective opsonization of the trypanosomes did not occur. A comparison of replication rates of the acute strain of T. brucei with that of a strain which causes a more chronic infection showed that, while their initial rates were similar after day 5 the 'chronic' strain changed to a much slower replication rate and this allowed antibody to rise to effective levels. In contrast to the findings of other workers, there was no evidence that the parasite caused any significant suppression of antibody responses in these acute infections. (author)

  10. A new generation of T7 RNA polymerase-independent inducible expression plasmids for Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Jack Sunter

    Full Text Available Expression of transgenes is central to forward and reverse genetic analysis in Trypanosoma brucei. The inducible expression of transgenes in trypanosomes is based on the tetracycline repressor binding to a tetracycline operator to prevent transcription in the absence of tetracycline. The same inducible system is used to produce double-stranded RNA for RNAi knockdown of target genes. This study describes a new plasmid pSPR2.1 that drives consistent high-level expression of tetracycline repressor in procyclic form trypanosomes. A complementary expression plasmid, p3227, was constructed. The major difference between this and current plasmids is the separation of the inducible transgene and selectable marker promoters by the plasmid backbone. The plasmid p3227 was able to support inducible expression in cell lines containing pSPR2.1 as well as the established Lister 427 29-13 cell line. p3666, a derivative of p3227, was made for inducible expression of stem loop RNAi constructs and was effective for knockdown of DRBD3, which had proved problematic using existing RNAi plasmids with head-to-head promoters. The plasmid system was also able to support inducible transgene expression and DRBD3 RNAi knockdown in bloodstream form cells expressing tetracycline repressor from an integrated copy of the plasmid pHD1313.

  11. Identification of paralogous life-cycle stage specific cytoskeletal proteins in the parasite Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Neil Portman

    Full Text Available The life cycle of the African trypanosome Trypanosoma brucei, is characterised by a transition between insect and mammalian hosts representing very different environments that present the parasite with very different challenges. These challenges are met by the expression of life-cycle stage-specific cohorts of proteins, which function in systems such as metabolism and immune evasion. These life-cycle transitions are also accompanied by morphological rearrangements orchestrated by microtubule dynamics and associated proteins of the subpellicular microtubule array. Here we employed a gel-based comparative proteomic technique, Difference Gel Electrophoresis, to identify cytoskeletal proteins that are expressed differentially in mammalian infective and insect form trypanosomes. From this analysis we identified a pair of novel, paralogous proteins, one of which is expressed in the procyclic form and the other in the bloodstream form. We show that these proteins, CAP51 and CAP51V, localise to the subpellicular corset of microtubules and are essential for correct organisation of the cytoskeleton and successful cytokinesis in their respective life cycle stages. We demonstrate for the first time redundancy of function between life-cycle stage specific paralogous sets in the cytoskeleton and reveal modification of cytoskeletal components in situ prior to their removal during differentiation from the bloodstream form to the insect form. These specific results emphasise a more generic concept that the trypanosome genome encodes a cohort of cytoskeletal components that are present in at least two forms with life-cycle stage-specific expression.

  12. The isolation and partial characterization of the plasma membrane from Trypanosoma brucei.

    Science.gov (United States)

    Voorheis, H P; Gale, J S; Owen, M J; Edwards, W

    1979-04-15

    Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase. PMID:486094

  13. Identification of the mitochondrially encoded subunit 6 of F1FO ATPase in Trypanosoma brucei.

    Science.gov (United States)

    Škodová-Sveráková, Ingrid; Horváth, Anton; Maslov, Dmitri A

    2015-06-01

    Kinetoplast maxicircle DNA of trypanosomatids encodes eighteen proteins. RNA editing is required to confer translatability to mRNA for twelve of these. Sequence conservation of the predicted hydrophobic polypeptides indicates that they represent functional components of the respiratory chain. Yet, so far only two of those, cytochrome c oxidase subunit I and apocytochrome b of cytochrome c reductase, have been identified with biochemical methods. Here we report on identification of A6 subunit of F1FO ATPase encoded by a pan-edited mRNA in Trypanosoma brucei. The polypeptide was present among the (35)S-labeled mitochondrial translation products characterized by anomalous migration in denaturing 2D gels. It was identified as an ATPase subunit by co-migration with this complex in Blue Native 2D gels. A partial N-terminal sequence of the corresponding polypeptide present in the gel-purified ATPase complex from Leishmania tarentolae was consistent with the predicted A6 sequence. PMID:26276057

  14. Thermal behavior simulation of a nuclear fuel rod through an eletrically heated rod

    International Nuclear Information System (INIS)

    In thermalhydraulic loops the nuclear industry often uses electrically heated rods to simulate power transients, which occur in nuclear fuel rods. The development and design of a electrically heated rod, by supplying the dimensions and materials which should be used in order to yeld the same temperature and heat flux at the surfaces of the nuclear rod and the electrically heated rod are presented. To a given nuclear transient this equality was obtained by fitting the linear power through the lumped parameters technique. (Author)

  15. Attachment for sucker rod depth adjustment

    Energy Technology Data Exchange (ETDEWEB)

    Collins, N.D.

    1992-04-07

    This patent describes a surface unit of an oil well pumping system, having a walking beam, a suspended carrier bar and an interconnected sucker rod assembly for stroking a reciprocating down-hole pump. It comprises a cross bar having a centrally located passage therein for the sucker rod assembly and adapted to be transversely supported by the carrier bar; a depth adjusting bar, having a centrally located passage therein for the sucker rod assembly, positioned at a selected fixed dimension above and parallel to the cross bar and adapted to operatively support the sucker rod assembly; clamping means for fixing the sucker rod relative to the depth adjusting bar; and hydraulically extendable means supportively connecting the depth adjusting bar to the cross bar on at least each side of the carrier bar for adjusting the selected fixed dimension and maintaining the adjustment during operation.

  16. Film cooling of vertical fuel rods

    International Nuclear Information System (INIS)

    Spray cooling of vertical rods has been studied at low heat fluxes appropriate to the removal of fission product heating following a reactor shut down. A series of tests have been made at atmospheric pressure using electrically heated rods, both singly and in a seven rod cluster, cooled by a falling film of water. Four modes of film breakdown were observed; progressive evaporation of the film; dry-patch formation due to surface tension effects at high inlet subcooling; stripping of the film by the flooding action of counterflow steam; and the disruption of the film on a hot rod caused by sputtering. Each of these phenomena is described in relation to the application of film cooling to long vertical fuel rod clusters. (author)

  17. Numerical investigation on flow and heat transfer of peripheral rods in PWR rod bundle assembly

    International Nuclear Information System (INIS)

    A numerical investigation of peripheral rods in PWR rod bundle assemblies was performed to better understand the impact on flow patterns and rod heat transfer downstream of spacer grids in the peripheral rod region. Computational Fluid Dynamic (CFD) models were prepared for the peripheral rod region of typical spacer grids with and without mixing vanes to understand how grid design may have an impact on peripheral rod heat transfer. The results of the CFD analysis indicate a large degradation in heat transfer on the outer face of the peripheral rods due to increased hydraulic resistance of the grid perimeter strip and tabs for the grid without mixing vanes. With mixing vanes on the interior region of the spacer grid more flow is redistributed to the outer region of the peripheral rods so there is improved peripheral rod heat transfer. The degradation in heat transfer on the outer face of the peripheral rods for grids without mixing vanes may be a contributing factor in increasing local hotspots and boiling to increase corrosion thickness and crud deposition. To verify the improvement in peripheral rod heat transfer due to the addition of mixing vanes, corrosion data is presented from in-reactor oxide measurements for fuel with and without mixing vanes in symmetric core positions. (author)

  18. Fabrication Of Control Rod System Of The RSG-GAS

    International Nuclear Information System (INIS)

    Eight units of control rod mechanical system of RSG-GAS has been fabricated. The control rod mechanical system of RSG-GAS consist of guide tube and lifting rod. Complete construction of the control rod mechanical system of RSG-GAS are guide tube, lifting rod, absorber, and absorber casing. The eight units of the control rod mechanical system of RSG-GAS has been fabricated according to the mechanical engineering design

  19. Guiding system for a control rod

    International Nuclear Information System (INIS)

    This invention concerns a system for guiding and maintaining in a vertical position a control rod for a fast neutron nuclear reactor cooled by a liquid metal. These rods are fitted to slide in fixed sleeves, located at given places in the reactor core, and taking the shape of boxes with a regular polygonal straight cross section, open at their upper end and fitted with a positioning foot at their lower end. Efficient cooling of the absorbing part of the rod is assured through a proper flow of the liquid metal (sodium) cooling the core and flowing inside the control rod sleeve from the bottom upwards as from the bottom foot to the open top end. Most of this flow is forced to pass inside the rod itself and not between the rod and the sleeve in which it slides. The system, whilst ensuring that the rod slides in its sleeve without any risk of jamming, leaves the upper part of the sleeve free

  20. TVO'S Experiences with Fuel and Control Rods

    International Nuclear Information System (INIS)

    The Finnish regulatory guides require that the nuclear power plants must maintain a supervision programme for the fuel and the control rods. The aim of the supervision is to evaluate whether the performance is in accordance with the design bases and the expectation. At each unit at least 8 fuel assemblies and fuel channels are annually inspected visually. Many dimensional measurements and oxide thickness measurements have also been performed. During the 1980's TVO reused fuel channels. The dimensions of the channels were measured before reuse, which means that TVO has measured the dimension of more than 1000 fuel channels. The rate of fission gas release from the fuel pellets to the free volume of the rods has been determined, based on the Kr-85 activity of the plenum gas, on 22 fuel assemblies. Eddy current inspection has been applied to find leakers. During shutdowns the high exposure control rods of control cells are rather exchanged than inspected and reinserted, the inspection of these control rods is made later. Some medium exposure control rods are selected for inspection during the shut down. Normally only visual inspection is performed. However, some rods exhibiting cracks in the visual inspection have been neutron radiographed. A summary of the inspection results is given in this paper. The future development foreseen for the design and operation strategy is also presented, concerning fuel assemblies, control rods, operating strategies and power up-rating

  1. More on the penetration of yawed rods

    Science.gov (United States)

    Rosenberg, Z.; Dekel, E.; Ashuach, Y.

    2006-08-01

    One of the most complex processes, in the field of terminal ballistics, is that of yawed impact of long rods. In spite of many experimental observations, and some analytical modeling, a clear picture of this issue is still lacking. In order to gain some insight into the operating mechanisms, we developed a simple engineering model which considers the yawed rod as a series of small disks. We then define the effective length and diameter of the rod by considering those disks which are going to hit the initial crater which is opened by the impact. We also performed a series of 3D numerical simulations with various L/D tungsten alloy rods impacting a steel target, at yaws in the full range of 0-90^circ. We analyzed the results of these simulations in terms of the normalized penetration (P/D), where D is the rod diameter, and looked for systematic trends in the results for the various rods. The agreement between our model predictions and both experimental data and simulation results is quite good. Based on this agreement we can highlight some new features of the penetration process of yawed rods.

  2. Granular materials interacting with thin flexible rods

    Science.gov (United States)

    Neto, Alfredo Gay; Campello, Eduardo M. B.

    2016-01-01

    In this work, we develop a computational model for the simulation of problems wherein granular materials interact with thin flexible rods. We treat granular materials as a collection of spherical particles following a discrete element method (DEM) approach, while flexible rods are described by a large deformation finite element (FEM) rod formulation. Grain-to-grain, grain-to-rod, and rod-to-rod contacts are fully permitted and resolved. A simple and efficient strategy is proposed for coupling the motion of the two types (discrete and continuum) of materials within an iterative time-stepping solution scheme. Implementation details are shown and discussed. Validity and applicability of the model are assessed by means of a few numerical examples. We believe that robust, efficiently coupled DEM-FEM schemes can be a useful tool to the simulation of problems wherein granular materials interact with thin flexible rods, such as (but not limited to) bombardment of grains on beam structures, flow of granular materials over surfaces covered by threads of hair in many biological processes, flow of grains through filters and strainers in various industrial segregation processes, and many others.

  3. Estimation of irradiated control rod worth

    Energy Technology Data Exchange (ETDEWEB)

    Varvayanni, M., E-mail: melina@ipta.demokritos.g [NCSR ' DEMOKRITOS' , PO Box 60228, 15310 Aghia Paraskevi (Greece); Catsaros, N. [NCSR ' DEMOKRITOS' , PO Box 60228, 15310 Aghia Paraskevi (Greece); Antonopoulos-Domis, M. [School of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece)

    2009-11-15

    When depleted control rods are planned to be used in new core configurations, their worth has to be accurately predicted in order to deduce key design and safety parameters such as the available shutdown margin. In this work a methodology is suggested for the derivation of the distributed absorbing capacity of a depleted rod, useful in the case that the level of detail that is known about the irradiation history of the control rod does not allow an accurate calculation of the absorber's burnup. The suggested methodology is based on measurements of the rod's worth carried out in the former core configuration and on corresponding calculations based on the original (before first irradiation) absorber concentration. The methodology is formulated for the general case of the multi-group theory; it is successfully tested for the one-group approximation, for a depleted control rod of the Greek Research Reactor, containing five neutron absorbers. The computations reproduce satisfactorily the irradiated rod worth measurements, practically eliminating the discrepancy of the total rod worth, compared to the computations based on the nominal absorber densities.

  4. Control Rod Malfunction at the NRAD Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L. Maddock

    2010-05-01

    The neutron Radiography Reactor (NRAD) is a training, research, and isotope (TRIGA) reactor located at the INL. The reactor is normally shut down by the insertion of three control rods that drop into the core when power is removed from electromagnets. During a routine shutdown, indicator lights on the console showed that one of the control rods was not inserted. It was initially thought that the indicator lights were in error because of a limit switch that was out of adjustment. Through further testing, it was determined that the control rod did not drop when the scram switch was initially pressed. The control rod anomaly led to a six month shutdown of the reactor and an in depth investigation of the reactor protective system. The investigation looked into: scram switch operation, console modifications, and control rod drive mechanisms. A number of latent issues were discovered and corrected during the investigation. The cause of the control rod malfunction was found to be a buildup of corrosion in the control rod drive mechanism. The investigation resulted in modifications to equipment, changes to both operation and maintenance procedures, and additional training. No reoccurrences of the problem have been observed since corrective actions were implemented.

  5. French LMFBR's control rods experience and development

    International Nuclear Information System (INIS)

    Since the last ten years, the French program has been, first of all, directed to the setting up, and then the development of, at once, the Phenix control rods, and next, the Super-Phenix ones. The vented pin design, with porous plug and sodium bonding, which allows the choices of large diameters, has been taken, since the Rapsodie experience was decisive. The absorber material is sintered, 10B enriched, boron carbide. The can is made of 316 type stainless steel, stabilised, or not, with titanium. The experience gained in Phenix up to now is important, and deals with about six loads of control rods. Results confirm the validity of the design of the absorber pins. Some difficulties has been encountered for the guiding devices, due to the swelling of the steel. They have required design and material improvements. Such difficulties are discarded by a new design of the bearing, for the Super-Phenix control rods. The other parts of these rods, from the Primary Shut-Down System, are strictly derived from Phenix. The design of the rods from the Secondary Shut-Down System is rather different, but it's not the case for the design of the absorber pins: in many a way, they are derived from Phenix pins and from Rapsodie control rods. Both types of rods irradiation tests are in progress in Phenix

  6. Nuclear-encoded mitochondrial tRNAs of Trypanosoma brucei have a modified cytidine in the anticodon loop.

    OpenAIRE

    Schneider, A.; McNally, K P; Agabian, N

    1994-01-01

    The mitochondrial genome of Trypanosoma brucei does not appear to encode any tRNA genes. Isolated organellar tRNAs hybridize to nuclear DNA, suggesting that they are synthesized in the nucleus and subsequently imported into the mitochondrion. Most imported tRNAs have cytosolic counterparts, showing identical mobility on two-dimensional polyacrylamide gels. We have compared three nuclear-encoded mitochondrial tRNAs (tRNA(Lys), tRNA(Leu), tRNA(Tyr)) with their cytosolic isoforms by direct enzym...

  7. THE MULTIPLE ROLES OF CYCLIN E1 IN CONTROLLING CELL CYCLE PROGRESSION AND CELLULAR MORPHOLOGY OF TRYPANOSOMA BRUCEI

    OpenAIRE

    Gourguechon, Stéphane; Savich, Jason M.; Ching C Wang

    2007-01-01

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi ...

  8. Control rod housing alignment and repair method

    International Nuclear Information System (INIS)

    This patent describes a method for underwater welding of a control rod drive housing inserted through a stub tube to maintain requisite alignment and elevation of the top of the control rod drive housing to an overlying and corresponding aperture in a core plate as measured by an alignment device which determines the relative elevation and angularity with respect to the aperture. It comprises providing a welding cylinder dependent from the alignment device such that the elevation of the top of the welding cylinder is in a fixed relationship to the alignment device and is gas-proof; pressurizing the welding cylinder with inert welding gas sufficient to maintain the interior of the welding cylinder dry; lowering the welding cylinder through the aperture in the core plate by depending the cylinder with respect to the alignment device, the lowering including lowering through and adjusting the elevation relationship of the welding cylinder to the alignment device such that when the alignment device is in position to measure the elevation and angularity of the new control rod drive housing, the lower distal end of the welding cylinder extends below the upper periphery of the stub where welding is to occur; inserting a new control rod drive housing through the stub tube and positioning the control rod drive housing to a predetermined relationship to the anticipated final position of the control rod drive housing; providing welding implements transversely rotatably mounted interior of the welding cylinder relative to the alignment device such that the welding implements may be accurately positioned for dispensing weldment around the periphery of the top of the stub tube and at the side of the control rod drive housing; measuring the elevation and angularity of the control rod drive housing; and dispensing weldment along the top of the stub tube and at the side of the control rod drive housing

  9. Apparatus for handling control rod drives

    International Nuclear Information System (INIS)

    An apparatus for handling control rod drives (CRD's) attached by detachable fixing means to housings mounted in a reactor pressure vessel and each coupled to one of control rods inserted in the reactor pressure vessel is described. The apparatus for handling the CRD's comprise cylindrical housing means, uncoupling means mounted in the housing means for uncoupling each of the control rods from the respective CRD, means mounted on the housing means for effecting attaching and detaching of the fixing means, means for supporting the housing means, and means for moving the support means longitudinally of the CRD

  10. Fuel rod welding (LWBR development program)

    International Nuclear Information System (INIS)

    Procedures were developed to weld both ends of approximately 25,000 fuel rods for the Light Water Breeder Reactor (LWBR) core. The rods were welded using the gas tungsten arc (GTA) method in high-purity helium at 1 atmosphere. Welding parameters, including weld current, arc gap, and speed of rotation, were established to control the size of the weld. Electrode and chill positioning with respect to the endclosure/tube joint controlled the location of the weld. Weld quality of the fuel rods was ensured by 100-percent nondestructive testing by ultrasonic and radiographic inspection and the destructive evaluation of process control samples in each weld lot

  11. Dry rod consolidation technology development

    International Nuclear Information System (INIS)

    The Department of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is funding a program to consolidate commercial spent fuel for testing in dry storage casks and to develop technology that will be fed into other OCRWM programs, e.g., Prototypical Consolidation Demonstration Program (PCDP). The program is being conducted at the Idaho National Engineering Laboratory (INEL) by the INEL Operating Contractor EG and G Idaho, Inc. Hardware and software have been designed and fabricated for installation in a hot cell adjacent to the Test Area North (TAN) Hot Shop Facility. This equipment is used to perform dry consolidation of commercial spent fuel from the Virginia Power (VP) Cooperative Agreement Spent Fuel Storage Cask (SFSC) Demonstration Program and assemblies that had previously been stored at the Engine Maintenance and Disassembly (EMAD) facility in Nevada. Consolidation is accomplished by individual, horizontal rod pulling. A computerized semiautomatic control system with operator involvement is utilized to conduct consolidation operations. During consolidation operations, data is taken to characterize this technology. Still photo, video tape, and other documentation will be generated to make developed information available to interested parties. Cold checkout of the hardware and software was completed in September of 1986. Following installation in the hot cell, consolidation operations begins in May 1987. Resulting consolidated fuel will be utilized in the VP Cooperative Agreement SFSC Program

  12. A monoclonal antibody marker for the exclusion-zone filaments of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Decossas Marion

    2008-07-01

    Full Text Available Abstract Background Trypanosoma brucei is a haemoflagellate pathogen of man, wild animals and domesticated livestock in central and southern Africa. In all life cycle stages this parasite has a single mitochondrion that contains a uniquely organised genome that is condensed into a flat disk-like structure called the kinetoplast. The kinetoplast is essential for insect form procyclic cells and therefore is a potential drug target. The kinetoplast is unique in nature because it consists of novel structural proteins and thousands of circular, interlocking, DNA molecules (kDNA. Secondly, kDNA replication is critically timed to coincide with nuclear S phase and new flagellum biogenesis. Thirdly, the kinetoplast is physically attached to the flagellum basal bodies via a structure called the tripartite attachment complex (TAC. The TAC consists of unilateral filaments (within the mitochondrion matrix, differentiated mitochondrial membranes and exclusion-zone filaments that extend from the distal end of the basal bodies. To date only one protein, p166, has been identified to be a component of the TAC. Results In the work presented here we provide data based on a novel EM technique developed to label and characterise cytoskeleton structures in permeabilised cells without extraction of mitochondrion membranes. We use this protocol to provide data on a new monoclonal antibody reagent (Mab 22 and illustrate the precise localisation of basal body-mitochondrial linker proteins. Mab 22 binds to these linker proteins (exclusion-zone filaments and provides a new tool for the characterisation of cytoskeleton mediated kinetoplast segregation. Conclusion The antigen(s recognised by Mab 22 are cytoskeletal, insensitive to extraction by high concentrations of non-ionic detergent, extend from the proximal region of basal bodies and bind to the outer mitochondrial membrane. This protein(s is the first component of the TAC exclusion-zone fibres to be identified. Mab 22

  13. Trypanosoma brucei TIF2 and TRF Suppress VSG Switching Using Overlapping and Independent Mechanisms

    Science.gov (United States)

    Jehi, Sanaa E.; Nanavaty, Vishal; Li, Bibo

    2016-01-01

    Trypanosoma brucei causes debilitating human African trypanosomiasis and evades the host’s immune response by regularly switching its major surface antigen, VSG, which is expressed exclusively from subtelomeric loci. We previously showed that two interacting telomere proteins, TbTRF and TbTIF2, are essential for cell proliferation and suppress VSG switching by inhibiting DNA recombination events involving the whole active VSG expression site. We now find that TbTIF2 stabilizes TbTRF protein levels by inhibiting their degradation by the 26S proteasome, indicating that decreased TbTRF protein levels in TbTIF2-depleted cells contribute to more frequent VSG switching and eventual cell growth arrest. Surprisingly, although TbTIF2 depletion leads to more subtelomeric DNA double strand breaks (DSBs) that are both potent VSG switching inducers and detrimental to cell viability, TbTRF depletion does not increase the amount of DSBs inside subtelomeric VSG expression sites. Furthermore, expressing an ectopic allele of F2H-TbTRF in TbTIF2 RNAi cells allowed cells to maintain normal TbTRF protein levels for a longer frame of time. This resulted in a mildly better cell growth and partially suppressed the phenotype of increased VSG switching frequency but did not suppress the phenotype of more subtelomeric DSBs in TbTIF2-depleted cells. Therefore, TbTIF2 depletion has two parallel effects: decreased TbTRF protein levels and increased subtelomeric DSBs, both resulting in an acute increased VSG switching frequency and eventual cell growth arrest. PMID:27258069

  14. Widespread variation in transcript abundance within and across developmental stages of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Kifer Charles T

    2009-10-01

    Full Text Available Abstract Background Trypanosoma brucei, the causative agent of African sleeping sickness, undergoes a complex developmental cycle that takes place in mammalian and insect hosts and is accompanied by changes in metabolism and cellular morphology. While differences in mRNA expression have been described for many genes, genome-wide expression analyses have been largely lacking. Trypanosomatids represent a unique case in eukaryotes in that they transcribe protein-coding genes as large polycistronic units, and rarely regulate gene expression at the level of transcription initiation. Results Here we present a comprehensive analysis of mRNA expression in several stages of parasite development. Utilizing microarrays that have multiple copies of multiple probes for each gene, we were able to demonstrate with a high degree of statistical confidence that approximately one-fourth of genes show differences in mRNA expression levels in the stages examined. These include complex patterns of gene expression within gene families, including the large family of variant surface glycoproteins (VSGs and their relatives, where we have identified a number of constitutively expressed family members. Furthermore, we were able to assess the relative abundance of all transcripts in each stage, identifying the genes that are either weakly or highly expressed. Very few genes show no evidence of expression. Conclusion Despite the lack of gene regulation at the level of transcription initiation, our results reveal extensive regulation of mRNA abundance associated with different life cycle and growth stages. In addition, analysis of variant surface glycoprotein gene expression reveals a more complex picture than previously thought. These data provide a valuable resource to the community of researchers studying this lethal agent.

  15. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction.

    Directory of Open Access Journals (Sweden)

    Johanna L Höög

    2016-01-01

    Full Text Available Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility.We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum.The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life cycle of this human parasite.

  16. Simulating the complex cell design of Trypanosoma brucei and its motility.

    Directory of Open Access Journals (Sweden)

    Davod Alizadehrad

    2015-01-01

    Full Text Available The flagellate Trypanosoma brucei, which causes the sleeping sickness when infecting a mammalian host, goes through an intricate life cycle. It has a rather complex propulsion mechanism and swims in diverse microenvironments. These continuously exert selective pressure, to which the trypanosome adjusts with its architecture and behavior. As a result, the trypanosome assumes a diversity of complex morphotypes during its life cycle. However, although cell biology has detailed form and function of most of them, experimental data on the dynamic behavior and development of most morphotypes is lacking. Here we show that simulation science can predict intermediate cell designs by conducting specific and controlled modifications of an accurate, nature-inspired cell model, which we developed using information from live cell analyses. The cell models account for several important characteristics of the real trypanosomal morphotypes, such as the geometry and elastic properties of the cell body, and their swimming mechanism using an eukaryotic flagellum. We introduce an elastic network model for the cell body, including bending rigidity and simulate swimming in a fluid environment, using the mesoscale simulation technique called multi-particle collision dynamics. The in silico trypanosome of the bloodstream form displays the characteristic in vivo rotational and translational motility pattern that is crucial for survival and virulence in the vertebrate host. Moreover, our model accurately simulates the trypanosome's tumbling and backward motion. We show that the distinctive course of the attached flagellum around the cell body is one important aspect to produce the observed swimming behavior in a viscous fluid, and also required to reach the maximal swimming velocity. Changing details of the flagellar attachment generates less efficient swimmers. We also simulate different morphotypes that occur during the parasite's development in the tsetse fly, and

  17. Rod phantom dimensions - Does size matter?

    International Nuclear Information System (INIS)

    The international standard ISO 4037-3:1999 recommends a cylindrical polymethyl methacrylate rod phantom of 300 mm length and 19 mm diameter for the calibration of extremity dosemeters worn on the finger. No tolerances are stated. This paper investigates the influence of the actual rod phantom dimensions on the calibration results of finger dosemeters. For this purpose, thermoluminescence detectors were attached to rod phantoms of different size and irradiated at the PTB reference X-ray fields. Rod phantoms with a diameter of (19 ± 1) mm and a length of at least 100 mm can be considered to be equivalent for the calibration of finger dosemeters, since the variation in the calibration results is below the significance level of 1%. The decrease in the response towards the edge of the phantom is negligible as long as the distance from the nearest edge exceeds 10 mm. (authors)

  18. Probabilistic assessment for nuclear fuel rods behavior

    International Nuclear Information System (INIS)

    BACO is a code for the simulation of the thermo-mechanical and fission gas behavior of a cylindrical fuel rod under operation conditions. Input parameters and, therefore, output ones may include statistical dispersion. In this paper, experimental CANDU fuel rods irradiated at the NRX reactor together with experimental MOX fuel rods and the IAEA'CRP FUMEX cases are used in order to determine the sensitivity of BACO code predictions. We analyze the CARA and CAREM fuel rods relation between predicted performance and statistical dispersion in order of enhanced their original designs. These exercises show the sensitivity of the predictions concerning such parameters and the extended features of the BACO code for a probability study. (author)

  19. Turbulent flow through two asymmetric rod bundles

    International Nuclear Information System (INIS)

    Measurements of the mean velocity, of the wall shear stresses, and of the turbulence have been performed in four wall subchannels of rod bundles of four parallel rods enclosed in a rectangular channel. The pitch-to-diameter ratio was P/D=1.148 and the wall-to-diameter ratios ranged from 1.045 to 1.252. The full Reynolds stress tensor has been determined by hot-wire technique. The results of the turbulences intensities show that the flow through rod bundles differs widely from flow through circular tubes. More sophisticated analytical tools than presently available are required to predict turbulent flow through rod bundles with sufficient accuracy

  20. Control rod for a nuclear reactor

    International Nuclear Information System (INIS)

    A control rod assembly for a nuclear reactor is disclosed having a remotely disengageable coupling between the control rod and the control rod drive shaft. The coupling is actuated by first lowering then raising the drive shaft. The described motion causes axial repositioning of a pin in a grooved rotatable cylinder, each being attached to different parts of the drive shaft which are axially movable relative to each other. In one embodiment, the relative axial motion of the parts of the drive shaft is used either to couple or to uncouple the connection by forcing resilient members attached to the drive shaft into or out of shouldered engagement, respectively, with an indentation formed in the control rod

  1. Rod worth measurement innovation at Westinghouse

    International Nuclear Information System (INIS)

    Bank worth measurement of control rods and shut-down rods is required for every cycle startup of a nuclear power plant for design validation. For Pressurized Water Reactors (PWR), the bank worth measurement is part of the Low Power Physics Tests (LPPT) program. In almost all instances, this program is on critical path during ascension to power. There is a strong incentive for the utility industry to have a fast and reliable method of measuring the bank worth. Over the past decade, Westinghouse has been developing new advanced rod worth measurement methods to provide faster, safer, more accurate and easier to use products. The advancement of 3D core simulation codes has made it possible to make revolutionary developments for a new generation of rod worth measurement methods

  2. Rod bundle burnout data and correlation comparisons

    International Nuclear Information System (INIS)

    Rod bundle burnout data from 30 steady-state and 3 transient tests were obtained from experiments performed in the Thermal Hydraulic Test Facility at the Oak Ridge National Laboratory. The tests covered a parameter range relevant to intact core reactor accidents ranging from large break to small break loss-ofcoolant conditions. Instrumentation within the 64-rod test section indicated that burnout occurred over an axial range within the bundle. The distance from the point where the first dry rod was detected to the point where all rods were dry was up to 60 cm in some of the tests. The burnout data should prove useful in developing new correlations for use in reactor thermalhydraulic codes. Evaluation of several existing critical heat flux correlations using the data show that three correlations, the Barnett, Bowring, and Katto correlations, perform similarly and correlate the data better than the Biasi correlation

  3. Control rod drive of nuclear reactor

    International Nuclear Information System (INIS)

    This invention relates to nuclear reactors and, more particularly, to a drive of a control rod of a nuclear reactor and allows power control, excess reactivity compensation, and emergency shut-down of a reactor. (author)

  4. Thermal and stress analysis of control rod

    International Nuclear Information System (INIS)

    In order to survey the mechanical integrity of a control rod in the high temperature core of the VHTR, thermal analysis and thermal stress analysis were carried out by means of calculus of finite differentials and finite element methods for the plant under the normal operating condition as well as under several abnormal conditions. The results of the analyses have been applied to refine the mechanical design of the control rod

  5. High Power Performance of Rod Fiber Amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Michieletto, Mattia; Kristensen, Torben;

    2015-01-01

    An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W.......An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W....

  6. Self-diagnosing braided composite rod

    OpenAIRE

    Fangueiro, Raúl; Zdraveva, E.; Pereira, Cristiana Gonilho; Ferreira, A.; Lanceros-Méndez, S.

    2010-01-01

    This paper presents the development of a braided reinforced composite rod (BCR) able to both reinforce and monitor the stress state of concrete structures. Carbon fibers have been used as sensing and reinforcing materials along with glass fiber. Various composites rods have been produced using an author patented technique based on a modified conventional braiding machine. The materials investigated were prepared with different carbon fiber content as follows: BCR2 (77% glass/23...

  7. Rod-cone interaction in flicker perimetry.

    OpenAIRE

    Alexander, K. R.; Fishman, G. A.

    1984-01-01

    We have assessed the influence of the rod system on cone flicker sensitivity during flicker perimetry. For temporal frequencies above 18 Hz extrafoveal cone-mediated flicker thresholds for a white test stimulus are as much as 1.5 log units lower when measured against a large background light that saturates the rods than when measured in darkness. Following a Ganzfeld bleach extrafoveal cone flicker thresholds are at their minimum once the cones have recovered their sensitivity, but then thres...

  8. The 2’-O-ribose methyltransferase for cap 1 of spliced leader RNA and U1 small nuclear RNA in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Zamudio, J. R.; Mittra, B.; Foldynová-Trantírková, Silvie; Zeiner, G. M.; Lukeš, Julius; Bujnicki, J. M.; Sturm, N. R.; Campbell, D. A.

    2007-01-01

    Roč. 27, č. 17 (2007), s. 6084-6092. ISSN 0270-7306 R&D Projects: GA MŠk 2B06129; GA MŠk LC07032 Institutional research plan: CEZ:AV0Z60220518 Keywords : methylation * Trypanosoma brucei * methyltransferase * RNA interference Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.420, year: 2007

  9. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

    Directory of Open Access Journals (Sweden)

    Fabian C. Herrmann

    2015-09-01

    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  10. A novel high-throughput activity assay for the Trypanosoma brucei editosome enzyme REL1 and other RNA ligases

    Science.gov (United States)

    Zimmermann, Stephan; Hall, Laurence; Riley, Sean; Sørensen, Jesper; Amaro, Rommie E.; Schnaufer, Achim

    2016-01-01

    The protist parasite Trypanosoma brucei causes Human African trypanosomiasis (HAT), which threatens millions of people in sub-Saharan Africa. Without treatment the infection is almost always lethal. Current drugs for HAT are difficult to administer and have severe side effects. Together with increasing drug resistance this results in urgent need for new treatments. T. brucei and other trypanosomatid pathogens require a distinct form of post-transcriptional mRNA modification for mitochondrial gene expression. A multi-protein complex called the editosome cleaves mitochondrial mRNA, inserts or deletes uridine nucleotides at specific positions and re-ligates the mRNA. RNA editing ligase 1 (REL1) is essential for the re-ligation step and has no close homolog in the mammalian host, making it a promising target for drug discovery. However, traditional assays for RELs use radioactive substrates coupled with gel analysis and are not suitable for high-throughput screening of compound libraries. Here we describe a fluorescence-based REL activity assay. This assay is compatible with a 384-well microplate format and sensitive, satisfies statistical criteria for high-throughput methods and is readily adaptable for other polynucleotide ligases. We validated the assay by determining kinetic properties of REL1 and by identifying REL1 inhibitors in a library of small, pharmacologically active compounds. PMID:26400159

  11. Tracking the Biogenesis and Inheritance of Subpellicular Microtubule in Trypanosoma brucei with Inducible YFP-α-Tubulin

    Directory of Open Access Journals (Sweden)

    Omar Sheriff

    2014-01-01

    Full Text Available The microtubule cytoskeleton forms the most prominent structural system in Trypanosoma brucei, undergoing extensive modifications during the cell cycle. Visualization of tyrosinated microtubules leads to a semiconservative mode of inheritance, whereas recent studies employing microtubule plus end tracking proteins have hinted at an asymmetric pattern of cytoskeletal inheritance. To further the knowledge of microtubule synthesis and inheritance during T. brucei cell cycle, the dynamics of the microtubule cytoskeleton was visualized by inducible YFP-α-tubulin expression. During new flagellum/flagellum attachment zone (FAZ biogenesis and cell growth, YFP-α-tubulin was incorporated mainly between the old and new flagellum/FAZ complexes. Cytoskeletal modifications at the posterior end of the cells were observed with EB1, a microtubule plus end binding protein, particularly during mitosis. Additionally, the newly formed microtubules segregated asymmetrically, with the daughter cell inheriting the new flagellum/FAZ complex retaining most of the new microtubules. Together, our results suggest an intimate connection between new microtubule formation and new FAZ assembly, consequently leading to asymmetric microtubule inheritance and cell division.

  12. Genome-wide Analysis Reveals Extensive Functional Interaction between DNA Replication Initiation and Transcription in the Genome of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Calvin Tiengwe

    2012-07-01

    Full Text Available Identification of replication initiation sites, termed origins, is a crucial step in understanding genome transmission in any organism. Transcription of the Trypanosoma brucei genome is highly unusual, with each chromosome comprising a few discrete transcription units. To understand how DNA replication occurs in the context of such organization, we have performed genome-wide mapping of the binding sites of the replication initiator ORC1/CDC6 and have identified replication origins, revealing that both localize to the boundaries of the transcription units. A remarkably small number of active origins is seen, whose spacing is greater than in any other eukaryote. We show that replication and transcription in T. brucei have a profound functional overlap, as reducing ORC1/CDC6 levels leads to genome-wide increases in mRNA levels arising from the boundaries of the transcription units. In addition, ORC1/CDC6 loss causes derepression of silent Variant Surface Glycoprotein genes, which are critical for host immune evasion.

  13. Synthesis of novel amide and urea derivatives of thiazol-2-ethylamines and their activity against Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Patrick, Donald A; Wenzler, Tanja; Yang, Sihyung; Weiser, Patrick T; Wang, Michael Zhuo; Brun, Reto; Tidwell, Richard R

    2016-06-01

    2-(2-Benzamido)ethyl-4-phenylthiazole (1) was one of 1035 molecules (grouped into 115 distinct scaffolds) found to be inhibitory to Trypanosoma brucei, the pathogen causing human African trypanosomiasis, at concentrations below 3.6μM and non-toxic to mammalian (Huh7) cells in a phenotypic high-throughput screen of a 700,000 compound library performed by the Genomics Institute of the Novartis Research Foundation (GNF). Compound 1 and 72 analogues were synthesized in this lab by one of two general pathways. These plus 10 commercially available analogues were tested against T. brucei rhodesiense STIB900 and L6 rat myoblast cells (for cytotoxicity) in vitro. Forty-four derivatives were more potent than 1, including eight with IC50 values below 100nM. The most potent and most selective for the parasite was the urea analogue 2-(2-piperidin-1-ylamido)ethyl-4-(3-fluorophenyl)thiazole (70, IC50=9nM, SI>18,000). None of 33 compounds tested were able to cure mice infected with the parasite; however, seven compounds caused temporary reductions of parasitemia (⩾97%) but with subsequent relapses. The lack of in vivo efficacy was at least partially due to their poor metabolic stability, as demonstrated by the short half-lives of 15 analogues against mouse and human liver microsomes. PMID:27102161

  14. TbPIF5 is a Trypanosoma brucei mitochondrial DNA helicase involved in processing of minicircle Okazaki fragments.

    Directory of Open Access Journals (Sweden)

    Beiyu Liu

    2009-09-01

    Full Text Available Trypanosoma brucei's mitochondrial genome, kinetoplast DNA (kDNA, is a giant network of catenated DNA rings. The network consists of a few thousand 1 kb minicircles and several dozen 23 kb maxicircles. Here we report that TbPIF5, one of T. brucei's six mitochondrial proteins related to Saccharomyces cerevisiae mitochondrial DNA helicase ScPIF1, is involved in minicircle lagging strand synthesis. Like its yeast homolog, TbPIF5 is a 5' to 3' DNA helicase. Together with other enzymes thought to be involved in Okazaki fragment processing, TbPIF5 localizes in vivo to the antipodal sites flanking the kDNA. Minicircles in wild type cells replicate unidirectionally as theta-structures and are unusual in that Okazaki fragments are not joined until after the progeny minicircles have segregated. We now report that overexpression of TbPIF5 causes premature removal of RNA primers and joining of Okazaki fragments on theta structures. Further elongation of the lagging strand is blocked, but the leading strand is completed and the minicircle progeny, one with a truncated H strand (ranging from 0.1 to 1 kb, are segregated. The minicircles with a truncated H strand electrophorese on an agarose gel as a smear. This replication defect is associated with kinetoplast shrinkage and eventual slowing of cell growth. We propose that TbPIF5 unwinds RNA primers after lagging strand synthesis, thus facilitating processing of Okazaki fragments.

  15. Independent analysis of the flagellum surface and matrix proteomes provides insight into flagellum signaling in mammalian-infectious Trypanosoma brucei.

    Science.gov (United States)

    Oberholzer, Michael; Langousis, Gerasimos; Nguyen, HoangKim T; Saada, Edwin A; Shimogawa, Michelle M; Jonsson, Zophonias O; Nguyen, Steven M; Wohlschlegel, James A; Hill, Kent L

    2011-10-01

    The flagellum of African trypanosomes is an essential and multifunctional organelle that functions in motility, cell morphogenesis, and host-parasite interaction. Previous studies of the trypanosome flagellum have been limited by the inability to purify flagella without first removing the flagellar membrane. This limitation is particularly relevant in the context of studying flagellum signaling, as signaling requires surface-exposed proteins in the flagellar membrane and soluble signaling proteins in the flagellar matrix. Here we employ a combination of genetic and mechanical approaches to purify intact flagella from the African trypanosome, Trypanosoma brucei, in its mammalian-infectious stage. We combined flagellum purification with affinity-purification of surface-exposed proteins to conduct independent proteomic analyses of the flagellum surface and matrix fractions. The proteins identified encompass a broad range of molecular functionalities, including many predicted to function in signaling. Immunofluorescence and RNA interference studies demonstrate flagellum localization and function for proteins identified and provide insight into mechanisms of flagellum attachment and motility. The flagellum surface proteome includes many T. brucei-specific proteins and is enriched for proteins up-regulated in the mammalian-infectious stage of the parasite life-cycle. The combined results indicate that the flagellum surface presents a diverse and dynamic host-parasite interface that is well-suited for host-parasite signaling. PMID:21685506

  16. Close packing of rods on spherical surfaces

    Science.gov (United States)

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-01

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets.

  17. Topological optimisation of rod-stirring devices

    CERN Document Server

    Finn, Matthew D

    2011-01-01

    There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently given by the topological entropy of the rod motion. We discuss the problem of optimising such rod devices from a topological viewpoint. We express rod motions in terms of generators of the braid group, and assign a cost based on the minimum number of generators needed to write the braid. We show that for one cost function -- the topological entropy per generator -- the optimal growth rate is the logarithm of the golden ratio. For a more realistic cost function,involving the topological entropy per operation where rods are allowed to move together, the optimal growth rate is the logarithm of the silver ratio, $1+\\sqrt{2}$. We show how to construct devices that realise th...

  18. Annular burnout data from rod bundle experiments

    International Nuclear Information System (INIS)

    Burnout data for annular flow in a rod bundle are presented for both transient and steady-state conditions. Tests were performed at the Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF), a pressurized-water loop containing an electrically heated 64-rod bundle. The bundle configuration is typical of later generation pressurized-water reactors with 17 x 17 fuel arrays. Both axial and radial power profiles are flat. All experiments were carried out in upflow with subcooled inlet conditions, insuring accurate flow measurement. Conditions within the bundle were typical of those which could be encountered during a nuclear reactor loss-of-coolant accident. Level average fluid conditions within the test section were calculated using steady-state mass and energy conservation considerations for the steady-state tests and a transient, homogeneous, equilibrium computer code for the transient tests. Unlike tube dryout, burnout within a rod bundle does not necessarily occur at one distinct axial level. The location of individual rod dryout was determined by scanning rods axially and locating the position where rod superheat increased from approx. =0 to 30 K or greater. Thermocouple instrumentation within the bundle allows the location of dryout to be determined to within approximately +.5 cm for many of the tests

  19. Close packing of rods on spherical surfaces.

    Science.gov (United States)

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-28

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets. PMID:27131565

  20. Mechanical performance of fiberglass sucker-rod strings

    Energy Technology Data Exchange (ETDEWEB)

    Tripp, H.A.

    1988-08-01

    The natural frequencies of fiberglass sucker-rod strings can be calculated by treating the rod strings as modified spring/mass vibration systems. The ratio of the pumping-unit operating speed to the rod-string natural frequency can then be used as a basis for understanding fiberglass-rod performance and for predicting downhole pump stroke lengths.

  1. 49 CFR 230.93 - Pistons and piston rods.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Pistons and piston rods. 230.93 Section 230.93... Tenders Driving Gear § 230.93 Pistons and piston rods. (a) Maintenance and testing. Pistons and piston rods shall be maintained in safe and suitable condition for service. Piston rods shall be inspected...

  2. Increased fuel column height for boiling water reactor fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Matzner, B.

    1993-06-15

    Rods to maintain said fuel rods upstanding and permitting the exit of water and generated steam is described; a fuel bundle channel extending from said lower tie plate to the vicinity of said upper tie plate, and surrounding said fuel rods therebetween for producing an isolated flow region through said matrix of upstanding fuel rods for the generation of steam by nuclear reaction within said fuel rods; a first plurality of said fuel rods being full length fuel rods for extending fully between said upper and lower tie plates; and, a second plurality of said fuel rods being part length fuel rods for extending part way from a supported disposition on said lower tie plate to a point of fuel rod termination below said upper tie plate whereby a vacated vertical interval is defined between the upper end of said part length fuel rod and said upper tie plate; the improvement to said first plurality of full length fuel rods comprising in combination: said full length fuel rods including a first lower region having a first and smaller diameter containing said pellets of fissionable material; and, at least some of said full length fuel rods including an upper region containing said plenum which is devoid of fuel pellets having a second and larger diameter for providing to said plenum an expanded volume whereby the flow area overlying said part length fuel rods defines additional outflow area adjacent said plenums and the active length of fissionable pellets within said full length fuel rods can be increased.

  3. Increased fuel column height for boiling water reactor fuel rods

    International Nuclear Information System (INIS)

    Rods to maintain said fuel rods upstanding and permitting the exit of water and generated steam is described; a fuel bundle channel extending from said lower tie plate to the vicinity of said upper tie plate, and surrounding said fuel rods therebetween for producing an isolated flow region through said matrix of upstanding fuel rods for the generation of steam by nuclear reaction within said fuel rods; a first plurality of said fuel rods being full length fuel rods for extending fully between said upper and lower tie plates; and, a second plurality of said fuel rods being part length fuel rods for extending part way from a supported disposition on said lower tie plate to a point of fuel rod termination below said upper tie plate whereby a vacated vertical interval is defined between the upper end of said part length fuel rod and said upper tie plate; the improvement to said first plurality of full length fuel rods comprising in combination: said full length fuel rods including a first lower region having a first and smaller diameter containing said pellets of fissionable material; and, at least some of said full length fuel rods including an upper region containing said plenum which is devoid of fuel pellets having a second and larger diameter for providing to said plenum an expanded volume whereby the flow area overlying said part length fuel rods defines additional outflow area adjacent said plenums and the active length of fissionable pellets within said full length fuel rods can be increased

  4. International symposium on fuel rod simulators: development and application

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, R.W. (comp.)

    1981-05-01

    Separate abstracts are included for each of the papers presented concerning fuel rod simulator operation and performance; simulator design and evaluation; clad heated fuel rod simulators and fuel rod simulators for cladding investigations; fuel rod simulator components and inspection; and simulator analytical modeling. Ten papers have previously been input to the Energy Data Base.

  5. Displacer rod for use in a mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    A displacer rod for use in a mechanical spectral shift pressurized water nuclear reactor comprises a sectioned substantially hollow low neutron absorbing metal rod capable of displacing reactor coolant without absorbing a high amount of neutrons. The tubular sections preferably consist of stainless steel and Zircaloy tubing interconnected by a solid Zircaloy metal rod and may contain pellets for weighting the displacer rod. (author)

  6. Nuclear reactor remote disconnect control rod coupling indicator

    International Nuclear Information System (INIS)

    A coupling indicator for use with nuclear reactor control rod assemblies which have remotely disengageable couplings between the control rod and the control rod drive shaft is described. The coupling indicator indicates whether the control rod and the control rod drive shaft are engaged or disengaged. A resistive network, utilizing magnetic reed switches, senses the position of the control rod drive mechanism lead screw and the control rod position indicating tube, and the relative position of these two elements with respect to each other is compared to determine whether the coupling is engaged or disengaged

  7. Development of a statistical fuel rod design methodology

    International Nuclear Information System (INIS)

    A statistical fuel rod design methodology, which uses the response surface method and Monte Carlo calculation, has been developed to reduce conservatism included in the rod internal gas pressure calculation by replacing the worst case data by data with statistically known conservatism. 95% value of rod internal gas pressure estimated by the statistical fuel rod design methodology is much smaller than rod internal gas pressure obtained by the worst case data

  8. Development of a statistical procedure for rod internal pressure calculation

    International Nuclear Information System (INIS)

    A statistical procedure which checks rod internal pressure criterion is developed. Variations in fuel fabrication and model parameters are considered statistically to obtain rod internal pressure. A sample calculation is presented using the numerical values for 17x17 rod array fuel assemblies. The results indicate that the statistical procedure predicts much smaller value of rod internal pressure(RIP) than the deterministic procedure which uses the worst combination of fuel fabrication and model parameters in the sense of rod internal pressure

  9. Regulatory perspective on incomplete control rod insertions

    Energy Technology Data Exchange (ETDEWEB)

    Chatterton, M.

    1997-01-01

    The incomplete control rod insertions experienced at South Texas Unit 1 and Wolf Creek are of safety concern to the NRC staff because they represent potential precursors to loss of shutdown margin. Even before it was determined if these events were caused by the control rods or by the fuel there was an apparent correlation of the problem with high burnup fuel. It was determined that there was also a correlation between high burnup and high drag forces as well as with rod drop time histories and lack of rod recoil. The NRC staff initial actions were aimed at getting a perspective on the magnitude of the problem as far as the number of plants and the amount of fuel that could be involved, as well as the safety significance in terms of shutdown margin. As tests have been performed and data has been analyzed the focus has shifted more toward understanding the problem and the ways to eliminate it. At this time the staff`s understanding of the phenomena is that it was a combination of factors including burnup, power history and temperature. The problem appears to be very sensitive to these factors, the interaction of which is not clearly understood. The model developed by Westinghouse provides a possible explanation but there is not sufficient data to establish confidence levels and sensitivity studies involving the key parameters have not been done. While several fixes to the problem have been discussed, no definitive fixes have been proposed. Without complete understanding of the phenomena, or fixes that clearly eliminate the problem the safety concern remains. The safety significance depends on the amount of shutdown margin lost due to incomplete insertion of the control rods. Were the control rods to stick high in the core, the reactor could not be shutdown by the control rods and other means such as emergency boration would be required.

  10. Influence of trypanocidal therapy on the haematology of vervet monkeys experimentally infected with Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Ngotho, Maina; Kagira, John M; Kariuki, Christopher; Maina, Naomi; Thuita, John K; Mwangangi, David M; Farah, Idle O; Hau, Jann

    2011-07-01

    The aim of this study was to characterise the sequential haematological changes in vervet monkeys infected with Trypanosoma brucei rhodesiense and subsequently treated with sub-curative diminazene aceturate (DA) and curative melarsoprol (MelB) trypanocidal drugs. Fourteen vervet monkeys, on a serial timed-kill pathogenesis study, were infected intravenously with 10(4) trypanosomes of a stabilate T. b. rhodesiense KETRI 2537. They were treated with DA at 28 days post infection (dpi) and with MelB following relapse of infection at 140 dpi. Blood samples were obtained from the monkeys weekly, and haematology conducted using a haematological analyser. All the monkeys developed a disease associated with macrocytic hypochromic anaemia characterised by a reduction in erythrocytes (RBC), haemoglobin (HB), haematocrit (HCT), mean cell volume (MCV), platelet count (PLT), and an increase in the red cell distribution width (RDW) and mean platelet volume (MPV). The clinical disease was characteristic of human African trypanosomiasis (HAT) with a pre-patent period of 3 days. Treatment with DA cleared trypanosomes from both the blood and cerebrospinal fluid (CSF). The parasites relapsed first in the CSF and later in the blood. This treatment normalised the RBC, HCT, HB, PLT, MCV, and MPV achieving the pre-infection values within two weeks while RDW took up to 6 weeks to attain pre-infection levels after treatment. Most of the parameters were later characterised by fluctuations, and declined at one to two weeks before relapse of trypanosomes in the haemolymphatic circulation. Following MelB treatment at 140 dpi, most values recovered within two weeks and stabilised at pre-infection levels, during the 223 days post treatment monitoring period. It is concluded that DA and MelB treatments cause similar normalising changes in the haematological profiles of monkeys infected with T. b. rhodesiense, indicating the efficacy of the drugs. The infection related changes in haematology

  11. Fuel rod mechanical deformation during the PBF/LOFT lead rod loss-of-coolant experiments

    International Nuclear Information System (INIS)

    Results of four PBF/LOFT Lead Rod (LLR) sequential blowdown tests conducted in the Power Burst Facility (PBF) are presented. Each test employed four separately shrouded fuel rods. The primary objective of the test series was to evaluate the extent of mechanical deformation that would be expected to occur to low pressure (0.1 MPa), light water reactor design fuel rods when subjected to a series of double ended cold leg break loss-of-coolant accident (LOCA) tests, and to determine whether subjecting these deformed fuel rods to subsequent testing would result in rod failure. The extent of mechanical deformation (buckling, collapse, or waisting of the cladding) was evaluated by comparison of cladding temperature and system pressure measurements with out-of-pile experimental data, and by posttest visual examinations and cladding diametral measurements

  12. End fitting for oil well sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, C.P.

    1984-02-07

    An end fitting for a sucker rod for oil wells is described with the end fitting having a chamber portion extending inwardly from one end thereof and an externally threaded portion at its other end. The chamber portion is defined by a plurality of spaced-apart annular ridges which define frusto-conical shaped cavities therebetween. The end fitting also has a bore extending inwardly thereinto from its other end which communicates with the inner end of the chamber portion. A valve is mounted in the end fitting and has a valve stem positioned in the bore and a valve head positioned at the inner end of the chamber portion. The chamber portion is adapted to receive a glass reinforced resin bonded cylindrical rod which is maintained therein by a two-part epoxy resin which surrounds the rod and is received in the cavities to form epoxy wedges bonded to the rod. The outer end of the bore is provided with internal threads which threadably receive a screw therein which engages the end of the valve stem so that longitudinal force may be applied to the valve thereby transmitting longitudinal force to the end of the rod.

  13. Control rod drives for HTGR type reactor

    International Nuclear Information System (INIS)

    The device of the present invention has a feature of having stable braking characteristics upon scram operation of control rods. That is, control rod drives are moved upon and down by a dram which rotates the control rod suspended from to a wire rope, and the dram is disconnected from the driving mechanism by a crutch mechanism upon scram, to rapidly insert the control rod in the reactor by its own weight. An electric generator is used as a braking mechanism for controlling the scram speed of the control rod. A plurality of resistors disposed outside of the reactor coolants boundary are connected in parallel between input/output terminals of the electric generator. With such a constitution, braking characteristics are determined by the intensity of the permanent magnet, number of the coil windings and values of the resistors constituting the power generator. Accordingly, the braking characteristics are less changed relative to the working circumstantial conditions, the history of use and the state of mounting. As a result, stable braking characteristics can always be obtained. Further, braking characteristics can easily be controlled by varying the resistance value. (I.S.)

  14. Radiological characterization of spent control rod assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Lepel, E.A.; Robertson, D.E.; Thomas, C.W.; Pratt, S.L.; Haggard, D.L. [Pacific Northwest Lab., Richland, WA (United States)

    1995-10-01

    This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 for the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.

  15. Clad buffer rod sensors for liquid metals

    International Nuclear Information System (INIS)

    Clad buffer rods, consisting of a core and a cladding, have been developed for ultrasonic monitoring of liquid metal processing. The cores of these rods are made of low ultrasonic-loss materials and the claddings are fabricated by thermal spray techniques. The clad geometry ensures proper ultrasonic guidance. The lengths of these rods ranges from tens of centimeters to 1m. On-line ultrasonic level measurements in liquid metals such as magnesium at 700 deg C and aluminum at 960 deg C are presented to demonstrate their operation at high temperature and their high ultrasonic performance. A spherical concave lens is machined at the rod end for improving the spatial resolution. High quality ultrasonic images have been obtained in the liquid zinc at 600 deg C. High spatial resolution is needed for the detection of inclusions in liquid metals during processing. We also show that the elastic properties such as density, longitudinal and shear wave velocities of liquid metals can be measured using a transducer which generates and receives both longitudinal and shear waves and is mounted at the end of a clad buffer rod. (author)

  16. Rod consolidation at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab

  17. System analysis for sucker-rod pumping

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Z.; Doty, D.R.

    1989-05-01

    Pumping free gas in an oil well can significantly decrease the efficiency of a sucker-rod-pumping installation. Pump placement depth and use of a downhole gas/liquid separator (gas anchor) were found to be significant variables in improving the overall efficiency. A procedure is presented that shows when and to what degree the use of a gas anchor improves the efficiency of a sucker-rod pumping system. It was found that at lower pump intake pressures, the gas anchor usually improves efficiency, but at higher pump intake pressures, use of a gas anchor produces no positive effect. Also, elevating the pump to the highest position that still allows proper pump loading was found to reduce the operating costs of a sucker-rod-pumping installation significantly. Finally, a procedure is presented to calculate directly the pump volumetric efficiency and required volumetric pump displacement rate.

  18. Interpretation of calculated forces on sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Lea, J.F.; Pattillo, P.D. (Amoco Production Research co., Tulsa, OK (United States)); Studenmund, W.R. (Stanford Univ., CA (United States))

    1995-02-01

    The analysis of working loads in a sucker rod string during a pumping cycle has received substantial coverage in the petroleum literature. These load predictions have tended to focus on mechanical design considerations such as excess load and fatigue prediction. In contrast, the current study addresses the issues of buckling associated with working axial/pressure loads in an attempt to clarify the means of both predicting buckling and minimizing its effects. The study begins with a review of the static loads acting near the pump, and proceeds to a discussion of how these loads relate to the tendency of a rod string to buckle on the downstroke. Critical to this discussion is the concept of effective tension. Definition of the effective tension leads to the application of this concept to sinker bar design as a means of mitigating the buckling tendency of a rod string. Key points are reinforced by illustrative examples.

  19. Elliptical cross section fuel rod study II

    International Nuclear Information System (INIS)

    In this paper it is continued the behavior analysis and comparison between cylindrical fuel rods of circular and elliptical cross sections. Taking into account the accepted models in the literature, the fission gas swelling and release were studied. An analytical comparison between both kinds of rod reveals a sensible gas release reduction in the elliptical case, a 50% swelling reduction due to intragranular bubble coalescence mechanism and an important swelling increase due to migration bubble mechanism. From the safety operation point of view, for the same linear power, an elliptical cross section rod is favored by lower central temperatures, lower gas release rates, greater gas store in ceramic matrix and lower stored energy rates. (author). 6 refs., 8 figs., 1 tab

  20. The turbulent flow in rod bundles

    International Nuclear Information System (INIS)

    Experimental studies have shown that the axial and azimuthal turbulence intensities in the gap regions of rod bundles increase strongly with decreasing rod spacing; the fluctuating velocities in the axial and azimuthal directions have a quasi-periodic behaviour. To determine the origin of this phenomenon, an its characteristics as a function of the geometry and the Reynolds number, an experimental investigation was performed on the turbulent in several rod bundles with different aspect ratios (P/D, W/D). Hot-wires and microsphones were used for the measurements of velocity and wall pressure fluctuations. The data were evaluated to obtain spectra as well as auto and cross correlations. Based on the results, a phenomenological model is presented to explain this phenomenon. By means of the model, the mass exchange between neighbouring subchannels is explained

  1. Fragmentation of an axially impacted slender rod

    Science.gov (United States)

    Ji, W.; Waas, A. M.

    2010-02-01

    Motivated by experimental results on the dynamic buckling and fragmentation of a vertical column impacted by a falling mass, results from an analytical model for dynamic buckling which considers the dynamic interaction between the axial column deformation and the out-of-plane buckling displacements are used to interpret the fragmentation process and the resulting fragment lengths. It is shown that a critical time exists for the rod to undergo fragmentation. At this critical time, the rod deforms in a modulated pattern of waves, setting up the stage for the ensuing fragmentation as a result of induced large curvatures that exceed the critical bending strain of the rod material. The resulting fragment length distributions, which show two characteristics peaks at \\frac{\\lambda}{2} and \\frac{\\lambda}{4} , where λ is a characteristic half-wavelength, are found to compare favorably with the experimental results.

  2. Upper end plug of fuel rod

    International Nuclear Information System (INIS)

    The present invention concerns a seal-welding of an upper end plug of a fuel rod for nuclear fuels conducted in a final stage of molding fabrication of the fuel rod in a pressurized helium gas. A welding protrusion is formed at the periphery of a vent hole on the upper surface of the upper end plug, and the welding protrusion is melted by irradiation of laser beams. The melted protrusion intrudes into the end portion of the bent hole by capillary to close the vent hole. The upper end plug can be closed by an extremely simple operation of irradiating the laser beams to the protrusion. Control for electrode gap on every fuel rods and exchange for the electrodes as in TIG welding can be saved, thereby enabling to speed up and simplify the sealing operation for the upper end plug. (N.H.)

  3. Self-Propelled Rods near Surfaces

    CERN Document Server

    Elgeti, Jens

    2009-01-01

    We study the behavior of self-propelled nano- and micro-rods in three dimensions, confined between two parallel walls, by simulations and scaling arguments. Our simulations include thermal fluctuations and hydrodynamic interactions, which are both relevant for the dynamical behavior at nano- to micrometer length scales. In order to investigate the importance hydrodynamic interactions, we also perform Brownian-dynamics-like simulations. In both cases, we find that self-propelled rods display a strong surface excess in confined geometries. An analogy with semi-flexible polymers is employed to derive scaling laws for the dependence on the wall distance, the rod length, and the propulsive force. The simulation data confirm the scaling predictions.

  4. Control rod driving device for nuclear reactor

    International Nuclear Information System (INIS)

    In a magnetic jack type control rod drives, superconducting wires having current limiting effect are connected to a line for supplying current to coils. Ceramics type superconducting material is used as the superconducting wires. If abnormality should occur in the control rod drives, superconducting wire reaches a critical temperature due to the temperature elevation of the coolants. Then, the superconducting wires are instantaneously changed from the superconducting material to insulating material which is the inherent nature of the ceramic material to rapidly interrupt the current flowing through the coils. Thus, scram can be conducted simply. (S.T.)

  5. Method for making nuclear fuel rods

    International Nuclear Information System (INIS)

    A method of manufacturing a nuclear rod is described. It comprises only partially filling a mold cavity with nuclear fuel particles, closing the mold cavity and reducing the volume thereof such that the fuel particles substantially fill the mold cavity, injecting a fluid solidifiable binder into the particle-filled mold cavity to fill the interstices between the fuel particles. The volume of particle-filled mold cavity is reduced by applying pressure to the contents thereof via a movable portion of mold cavity, and solidifying binder in cavity to form a fuel rod

  6. Study of Fluidized-Bed Control Rods

    International Nuclear Information System (INIS)

    Control of nuclear reactors with fluidized-bed control rods (FBCR) has been previously proposed; but, despite some apparent advantages over electromechanical systems, such rods have not received widespread attention. With the FBCR concept, the reactor control system becomes a flow-regulating system using either variable-speed pumps or motor-driven control valves in the main coolant. Alternatively, in-core by-pass piping similar to control systems now being developed for fluidized-bed reactors may be utilized. Some of the possible advantages of the FBCR concept are as follows: (1) Most pressure-vessel head penetrations are eliminated, and refueling is simplified; (2) Automatic scram results from a loss-of-flow accident; (3) Axial power can be shaped by the use of contoured channels or variable-sized particles; (4). Water-gap flux peaking can be reduced for the partially withdrawn control rod; (5) The temperature reactivity allowance may be reduced if the fluidized control rods have a negative temperature coefficient; and (6) Fabrication costs are much lower than for electromechanical systems. An evaluation of the FBCR concept, including construction of prototype models and testing of the hydraulic and nuclear characteristics, has been performed. Two types of rods were studied: transmission rods (thickness ≦ 2 mean-free-paths) and reflection rods (thickness ≦ 4 mean-free-paths). Acceptable hydraulic and nuclear characteristics are possible with both types. The feasibility of controlling low-power reactors by either transmission- or reflection-type fluidized.-bed control rods has been established. Furthermore, it was shown that the FBCR concept has good control properties which may be calculated by standard theoretical methods. For high-power, high-temperature applications, additional information on particle material characteristics is needed. A great advantage offered by the FBCR is the possibility of shaping the axial flux either by the use of particles of

  7. Environmental report for rod storage. Volume V

    International Nuclear Information System (INIS)

    Volume V of this report examines the environmental impact of the rod consolidation program. The postulated, nonsite-specific, differential impacts are primarily additional occupational exposures due to the rod storage operations. Other potential radiological and nonradiological impacts that are identified and addressed are negligible. There are no increases in population exposures except those associated with transportation of spent fuel and waste material. The increased utilization of existing spent fuel storage space could result in a decrease in the nonrecoverable material resources lost to new permanent spent fuel storage

  8. Abrasion measuring method for rod of control rod assembly of reactor

    International Nuclear Information System (INIS)

    The present invention provides a method of easily measuring abrasion caused on the outer surface of control rods of a control assembly to be used in a PWR type reactor. Namely, the control rod assembly comprise a plurality of control rods assembled in a cluster-like manner. Light is irradiated to a control rod to be measured from an optical measuring device for measuring the extent of abrasion on the surface of the control rods. The distance is measured by receiving the reflected light. The depth of abrasion is determined by comparing the thus measured distance to the abraded portion and the distance to an integral portion. Then, the depth of the abrasion is adjusted based on the control rod position and the angle to determine final depth of abrasion. The abrasion of control rods can be measured by remote control using one kind of light sensor. The device can be reduced in the size and the time for the measuring operation can also be shortened. (I.S.)

  9. Quivers For Special Fuel Rods-Disposal Of Special Fuel Rods In CASTOR V Casks

    Energy Technology Data Exchange (ETDEWEB)

    Bannani, Amin; Cebula, Wojciech; Buchmuller, Olga; Huggenberg, Roland [GNS, Essen (Germany); Helmut Kuhl [WTI, Julich (Germany)

    2015-05-15

    While GNS casks of the CASTOR family are a suitable means to transfer fuel assemblies (FA) from the NPP to an interim dry storage site, Germanys phase-out of nuclear energy has triggered the demand for an additional solution to dispose of special fuel rods (SFR), normally remaining in the fuel pond until the final shutdown of the NPP. SFR are fuel rods that had to be removed from fuel assemblies mainly due to their special condition, e. g. damages in the cladding of the fuel rods which may have occurred during reactor operations. SFR are usually stored in the spent fuel pond after they are removed from the FA. The quiver for special fuel rods features a robust yet simple design, with a high mechanical stability, a reliable leak-tightness and large safety margins for future requirements on safety analysis. The quiver for special fuel rods can be easily adapted to a large variety of different damaged fuel rods and tailored to the specific need of the customer. The quiver for special fuel rods is adaptable e.g. in length and diameter for use in other types of transport and storage casks and is applicable in other countries as well. The overall concept presented here is a first of its kind solution for the disposal of SFRs via Castor V-casks. This provides an important precondition in achieving the status 'free from nuclear fuel' of the shut down German NPPs.

  10. JBP2, a SWI2/SNF2-like protein, regulates de novo telomeric DNA glycosylation in bloodstream form Trypanosoma brucei.

    Science.gov (United States)

    Kieft, Rudo; Brand, Verena; Ekanayake, Dilrukshi K; Sweeney, Kate; DiPaolo, Courtney; Reznikoff, William S; Sabatini, Robert

    2007-11-01

    Synthesis of the modified thymine base, beta-d-glucosyl-hydroxymethyluracil or J, within telomeric DNA of Trypanosoma brucei correlates with the bloodstream form specific epigenetic silencing of telomeric variant surface glycoprotein genes involved in antigenic variation. In order to analyze the function of base J in the regulation of antigenic variation, we are characterizing the regulatory mechanism of J biosynthesis. We have recently proposed a model in which chromatin remodeling by a SWI2/SNF2-like protein (JBP2) regulates the developmental and de novo site-specific localization of J synthesis within bloodstream form trypanosome DNA. Consistent with this model, we now show that JBP2 (-/-) bloodstream form trypanosomes contain five-fold less base J and are unable to stimulate de novo J synthesis in newly generated telomeric arrays. PMID:17706299

  11. Differential expression of glycosomal and mitochondrial proteins in the two major life-cycle stages of Trypanosoma brucei.

    Science.gov (United States)

    Vertommen, Didier; Van Roy, Joris; Szikora, Jean-Pierre; Rider, Mark H; Michels, Paul A M; Opperdoes, Fred R

    2008-04-01

    Label-free semi-quantitative differential three-dimensional liquid chromatography coupled to mass spectrometry (3D-LC-MS/MS) was used to compare the glycosomal and mitochondrial proteomes of the bloodstream- and insect-form of Trypanosoma brucei. The abundance of glycosomal marker proteins identified in the two life-cycle stages corresponded well with the relative importance of biochemical pathways present in the glycosomes of the two stages and the peptide spectral count ratios of selected enzymes were in good agreement with published data about their enzymatic specific activities. This approach proved extremely useful for the generation of large scale proteomics data for the comparison of different life-cycle stages. Several proteins involved in oxidative stress protection, sugar-nucleotide synthesis, purine salvage, nucleotide-monophosphate formation and purine-nucleotide cycle were identified as glycosomal proteins. PMID:18242729

  12. Synthesis of novel guttiferone A derivatives: in-vitro evaluation toward Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani.

    Science.gov (United States)

    Fromentin, Yann; Gaboriaud-Kolar, Nicolas; Lenta, Bruno Ndjakou; Wansi, Jean Duplex; Buisson, Didier; Mouray, Elisabeth; Grellier, Philippe; Loiseau, Philippe M; Lallemand, Marie-Christine; Michel, Sylvie

    2013-07-01

    The catechol pharmacomodulation of the natural product guttiferone A, isolated from the Symphonia globulifera tree, led to the semisynthesis of a collection of twenty derivatives. The ester and ether derivatives of guttiferone A were evaluated for their anti-plasmodial, trypanocidal and anti-leishmanial activities. Some compounds described below have shown potent antiparasitic activity against Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani in a range from 1 to 5 μM. The evaluation of guttiferone A derivatives against VERO cells highlighted catechol modulations as an interesting tool to decrease the toxicity and keep the activity of this natural compound. The current study revealed new molecules as promising new antiparasitic drug candidates. PMID:23727538

  13. Crystal Structures of TbCatB and rhodesain, potential chemotherapeutic targets and major cysteine proteases of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Iain D Kerr

    Full Text Available BACKGROUND: Trypanosoma brucei is the etiological agent of Human African Trypanosomiasis, an endemic parasitic disease of sub-Saharan Africa. TbCatB and rhodesain are the sole Clan CA papain-like cysteine proteases produced by the parasite during infection of the mammalian host and are implicated in the progression of disease. Of considerable interest is the exploration of these two enzymes as targets for cysteine protease inhibitors that are effective against T. brucei. METHODS AND FINDINGS: We have determined, by X-ray crystallography, the first reported structure of TbCatB in complex with the cathepsin B selective inhibitor CA074. In addition we report the structure of rhodesain in complex with the vinyl-sulfone K11002. CONCLUSIONS: The mature domain of our TbCat*CA074 structure contains unique features for a cathepsin B-like enzyme including an elongated N-terminus extending 16 residues past the predicted maturation cleavage site. N-terminal Edman sequencing reveals an even longer extension than is observed amongst the ordered portions of the crystal structure. The TbCat*CA074 structure confirms that the occluding loop, which is an essential part of the substrate-binding site, creates a larger prime side pocket in the active site cleft than is found in mammalian cathepsin B-small molecule structures. Our data further highlight enhanced flexibility in the occluding loop main chain and structural deviations from mammalian cathepsin B enzymes that may affect activity and inhibitor design. Comparisons with the rhodesain*K11002 structure highlight key differences that may impact the design of cysteine protease inhibitors as anti-trypanosomal drugs.

  14. The orthologue of Sjogren's syndrome nuclear autoantigen 1 (SSNA1 in Trypanosoma brucei is an immunogenic self-assembling molecule.

    Directory of Open Access Journals (Sweden)

    Helen P Price

    Full Text Available Primary Sjögren's Syndrome (PSS is a highly prevalent autoimmune disease, typically manifesting as lymphocytic infiltration of the exocrine glands leading to chronically impaired lacrimal and salivary secretion. Sjögren's Syndrome nuclear autoantigen 1 (SSNA1 or NA14 is a major specific target for autoantibodies in PSS but the precise function and clinical relevance of this protein are largely unknown. Orthologues of the gene are absent from many of the commonly used model organisms but are present in Chlamyodomonas reinhardtii (in which it has been termed DIP13 and most protozoa. We report the functional characterisation of the orthologue of SSNA1 in the kinetoplastid parasite, Trypanosoma brucei. Both TbDIP13 and human SSNA1 are small coiled-coil proteins which are predicted to be remote homologues of the actin-binding protein tropomyosin. We use comparative proteomic methods to identify potential interacting partners of TbDIP13. We also show evidence that TbDIP13 is able to self-assemble into fibril-like structures both in vitro and in vivo, a property which may contribute to its immunogenicity. Endogenous TbDIP13 partially co-localises with acetylated α-tubulin in the insect procyclic stage of the parasite. However, deletion of the DIP13 gene in cultured bloodstream and procyclic stages of T. brucei has little effect on parasite growth or morphology, indicating either a degree of functional redundancy or a function in an alternative stage of the parasite life cycle.

  15. Structural characterization of CYP51 from Trypanosoma cruzi and Trypanosoma brucei bound to the antifungal drugs posaconazole and fluconazole.

    Directory of Open Access Journals (Sweden)

    Chiung-Kuang Chen

    Full Text Available BACKGROUND: Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14alpha-demethylase (CYP51, which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 A and 2.27 A, and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A, co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180 degrees depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. CONCLUSIONS/SIGNIFICANCE: The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and

  16. The spliceosomal snRNP core complex of Trypanosoma brucei: Cloning and functional analysis reveals seven Sm protein constituents

    Science.gov (United States)

    Palfi, Zsofia; Lücke, Stephan; Lahm, Hans-Werner; Lane, William S.; Kruft, Volker; Bragado-Nilsson, Elisabeth; Séraphin, Bertrand; Bindereif, Albrecht

    2000-01-01

    Each of the trypanosome small nuclear ribonucleoproteins (snRNPs) U2, U4/U6, and U5, as well as the spliced leader (SL) RNP, contains a core of common proteins, which we have previously identified. This core is unusual because it is not recognized by anti-Sm Abs and it associates with an Sm-related sequence in the trypanosome small nuclear RNAs (snRNAs). Using peptide sequences derived from affinity-purified U2 snRNP proteins, we have cloned cDNAs for five common proteins of 8.5, 10, 12.5, 14, and 15 kDa of Trypanosoma brucei and identified them as Sm proteins SmF (8.5 kDa), -E (10 kDa), -D1 (12.5 kDa), -G (14 kDa), and -D2 (15 kDa), respectively. Furthermore, we found the trypanosome SmB (T. brucei) and SmD3 (Trypanosoma cruzi) homologues through database searches, thus completing a set of seven canonical Sm proteins. Sequence comparisons of the trypanosome proteins revealed several deviations in highly conserved positions from the Sm consensus motif. We have identified a network of specific heterodimeric and -trimeric Sm protein interactions in vitro. These results are summarized in a model of the trypanosome Sm core, which argues for a strong conservation of the Sm particle structure. The conservation extends also to the functional level, because at least one trypanosome Sm protein, SmG, was able to specifically complement a corresponding mutation in yeast. PMID:10900267

  17. The multiple roles of cyclin E1 in controlling cell cycle progression and cellular morphology of Trypanosoma brucei.

    Science.gov (United States)

    Gourguechon, Stéphane; Savich, Jason M; Wang, Ching C

    2007-05-11

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi assays, we used the yeast two-hybrid system and an in vitro glutathione-S-transferase pulldown assay and observed interactions between cyclin E1 and CRK1, CRK2 and CRK3. Cyclins E1-E4 are homologues of yeast Pho80 cyclin. But yeast complementation assays indicated that none of them possesses a Pho80-like function. Analysis of cyclin E1+CRK1 and cyclin E1+CRK2 double knockdowns in the procyclic form of T. brucei indicated that the cells were arrested more extensively in the G1 phase beyond the cumulative effect of individual knockdowns. But BrdU incorporation was impaired significantly only in cyclin E1+CRK1-depleted cells, whereas a higher percentage of cyclin E1+CRK2 knockdown cells assumed a grossly elongated posterior end morphology. A double knockdown of cyclin E1 and CRK3 arrested cells in G2/M much more efficiently than if only CRK3 was depleted. Taken together, these data suggest multiple functions of cyclin E1: it forms a complex with CRK1 in promoting G1/S phase transition; it forms a complex with CRK2 in controlling the posterior morphogenesis during G1/S transition; and it forms a complex with CRK3 in promoting passage across the G2/M checkpoint in the trypanosome. PMID:17376478

  18. Modeling and simulation performance of sucker rod beam pump

    Energy Technology Data Exchange (ETDEWEB)

    Aditsania, Annisa, E-mail: annisaaditsania@gmail.com [Department of Computational Sciences, Institut Teknologi Bandung (Indonesia); Rahmawati, Silvy Dewi, E-mail: silvyarahmawati@gmail.com; Sukarno, Pudjo, E-mail: psukarno@gmail.com [Department of Petroleum Engineering, Institut Teknologi Bandung (Indonesia); Soewono, Edy, E-mail: esoewono@math.itb.ac.id [Department of Mathematics, Institut Teknologi Bandung (Indonesia)

    2015-09-30

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  19. Modeling and simulation performance of sucker rod beam pump

    International Nuclear Information System (INIS)

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research

  20. Modeling and simulation performance of sucker rod beam pump

    Science.gov (United States)

    Aditsania, Annisa; Rahmawati, Silvy Dewi; Sukarno, Pudjo; Soewono, Edy

    2015-09-01

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  1. Nuclear fuel rod straightness measuring system and method

    International Nuclear Information System (INIS)

    A method is described for measuring the straightness of a rod, comprising the following steps: (a) supporting the rod so that if the rod were straight, the rod would remain straight without transverse translational movement while supported and if rotated about its longitudinal axis, and so that if the rod were cambered, the rod would remain so cambered while supported and if rotated; (b) rotating the supported the rod so that if the rod were straight, the rod would be rotated about its longitudinal axis; (c) measuring the distances during the rotation between the supported and rotating the rod and rigidly-mounted, spaced-apart range finders, the range finders disposed apart from and directed towards the supported and rotating the rod and disposed so that if the rod were straight, the range finders would each be directed transverse to the longitudinal axis; and (d) calculating for each of the range finders the difference between the maximum and minimum of the distance measurements, the differences indicating the degree of straightness of the rod

  2. RodPilot{sup R} - The Innovative and Cost-Effective Digital Control Rod Drive Control System for PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Baron, Clemens [AREVA NP GmbH, NLEE-G, Postfach 1199, 91001 Erlangen (Germany)

    2008-07-01

    With RodPilot, AREVA NP offers an innovative and cost-effective system for controlling control rods in Pressurized Water Reactors. RodPilot controls the three operating coils of the control rod drive mechanism (lift, moveable gripper and stationary gripper coil). The rods are inserted into or withdrawn from the core as required by the Reactor Control System. The system combines modern components, state-of-the-art logic and a proven electronic control rod drive control principle to provide enhanced reliability and lower maintenance costs. (author)

  3. RodPilotR - The Innovative and Cost-Effective Digital Control Rod Drive Control System for PWRs

    International Nuclear Information System (INIS)

    With RodPilot, AREVA NP offers an innovative and cost-effective system for controlling control rods in Pressurized Water Reactors. RodPilot controls the three operating coils of the control rod drive mechanism (lift, moveable gripper and stationary gripper coil). The rods are inserted into or withdrawn from the core as required by the Reactor Control System. The system combines modern components, state-of-the-art logic and a proven electronic control rod drive control principle to provide enhanced reliability and lower maintenance costs. (author)

  4. Analysis of sucker rod and sinkerbar failures

    Energy Technology Data Exchange (ETDEWEB)

    Waggoner, J.R.; Buchheit, R.G.

    1993-03-01

    This report presents results of a study of performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, finite element analysis, and failure data collection. Metallography showed that the microstructure of the steel bar stock needs to be considered to improve the fatigue resistance of the sucker rod strings. The current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding, and tensile strength is not always a good measure of fatigue resistance. Finite element analysis of the threaded connection quantitatively assesses the coupling designs under various loading conditions. Subcritical fractures in metallography are also suggested by calculated stress distribution in threaded coupling. Failure data illustrates both magnitude and frequency of failures, as well as categorizing the suspected cause of failure. Application of the results in each of these project areas is expected to yield improved choice of metal bar stock, thread design, and make-up practices which can significantly reduce the frequency of sucker rod failures. Sucker rod failures today are not inherent in the process, but can be minimized through the application of new technology and observation of common-sense practices.

  5. Program optimizes sucker-rod pumping mode

    International Nuclear Information System (INIS)

    Direct energy costs for sucker-rod pumping can be optimized by selecting the right pump size, stroke length, and pumping speed for the required liquid production rate. Calculation procedures for a computer program are developed for optimizing the design of conventional pumping units

  6. Wear simulation of sucker rod couplings

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, W.J. (Armco, Inc., Middletown, OH (United States))

    1991-09-01

    This paper reports that sucker rod strings are devices used to actuate pumps located at the bottom of oil wells. The individual rods are connected together by threaded couplings. Since the couplings have a larger diameter than the rods, they sometimes contact the inside diameter of the tubing during the up and down pumping cycle. Usually, this is not problem unless buckling occurs in the downstroke; however, this can lead to accelerated wear of the coupling and tubing. In nonvertical wells (offset, deviated, or slanted), the contact is more severe and rapid wear takes place. Couplings are more easily replaced during shutdowns; it is very important to minimize wear to tubing since it is virtually impossible to replace. TRIBONIC 20, an iron-based alloy containing approximately 13% Mn, 5% Si, 5.5% Cr, and 5% Ni, was laboratory evaluated to determine whether or not it could solve the sucker rod coupling-production tubing wear problem. The alloy demonstrated outstanding wear resistance both to itself and in protecting type 1019 steel.

  7. Program optimizes sucker-rod pumping mode

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, G. (Technical Univ. of Miskolc, Miskolc (HU))

    1990-10-01

    Direct energy costs for sucker-rod pumping can be optimized by selecting the right pump size, stroke length, and pumping speed for the required liquid production rate. Calculation procedures for a computer program are developed for optimizing the design of conventional pumping units.

  8. Sucker rod scraper method and device

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, A.E.

    1988-05-03

    A plurality of sucker rod scrapers are securely attached in space apart relationship to a length of sucker rod for scraping paraffin deposits from the interior of a tubing string. This is done to vitiate obstruction to the flow of oil by maintaining a satisfactory effective flow area within the tubing string. The scrapers each have a spiraled scraping surface wound helically about the sucker rod and attached at each opposed end by the provision of a clamping member which includes a U-band and a heat shield. The U-band has confronting marginal edge portions which overlap the edge portions of the heat shield. The heat shield has a slot formed centrally therein for receiving a tab located at either of the opposed ends of the spiraled scraper. The confronting edges of the U-band are welded to one of the marginal opposed ends of the scraper, while the heat shield prevents the metal of the sucker rod being elevated to a temperature which changes its characteristics.

  9. Piston rod seal for a Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, W.

    1984-01-31

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal. 3 figs.

  10. Piston rod seal for a Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, Wilbur (Schenectady, NY)

    1984-01-01

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

  11. Technological improvements in wire rod mills

    Energy Technology Data Exchange (ETDEWEB)

    Lestani, M.

    1996-07-01

    The paper deals with the latest rolling technologies and hi-tech equipment developed by Danieli-mogardshammar to ensure top performance of modern wire rod mills. In particular, a high reduction sizing mill, a twin module fast finishing block and a high speed cropping shear are presented. (authors)

  12. Image analysis for measuring rod network properties

    Science.gov (United States)

    Kim, Dongjae; Choi, Jungkyu; Nam, Jaewook

    2015-12-01

    In recent years, metallic nanowires have been attracting significant attention as next-generation flexible transparent conductive films. The performance of films depends on the network structure created by nanowires. Gaining an understanding of their structure, such as connectivity, coverage, and alignment of nanowires, requires the knowledge of individual nanowires inside the microscopic images taken from the film. Although nanowires are flexible up to a certain extent, they are usually depicted as rigid rods in many analysis and computational studies. Herein, we propose a simple and straightforward algorithm based on the filtering in the frequency domain for detecting the rod-shape objects inside binary images. The proposed algorithm uses a specially designed filter in the frequency domain to detect image segments, namely, the connected components aligned in a certain direction. Those components are post-processed to be combined under a given merging rule in a single rod object. In this study, the microscopic properties of the rod networks relevant to the analysis of nanowire networks were measured for investigating the opto-electric performance of transparent conductive films and their alignment distribution, length distribution, and area fraction. To verify and find the optimum parameters for the proposed algorithm, numerical experiments were performed on synthetic images with predefined properties. By selecting proper parameters, the algorithm was used to investigate silver nanowire transparent conductive films fabricated by the dip coating method.

  13. Genetics Home Reference: cone-rod dystrophy

    Science.gov (United States)

    ... common cause of autosomal recessive cone-rod dystrophy , accounting for 30 to 60 percent of cases. At ... 1 ClinicalTrials.gov (1 link) ClinicalTrials.gov Scientific articles on PubMed (1 link) PubMed OMIM (21 links) ...

  14. Solitary waves on nonlinear elastic rods. I

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.

    1984-01-01

    Acoustic waves on elastic rods with circular cross section are governed by improved Boussinesq equations when transverse motion and nonlinearity in the elastic medium are taken into account. Solitary wave solutions to these equations have been found. The present paper treats the interaction between...

  15. Improved designs reduce sucker-rod pumping costs

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, G. [Univ. of Miskolc (Hungary)

    1996-10-07

    Pumping mode selection, optimum counterbalance determination, and rod string design are factors that can reduce operational costs and improve sucker-rod pumping operations. To maximize profits from sucker-rod pumped wells, designs must aim at technically and economically optimum conditions. Assessment of surface and downhole energy losses are basic considerations for improving system efficiency. It is important to properly select the pumping mode, such as the combination of plunger size, pumping speed, stroke length, and rod taper design. The best pumping mode maximizes lifting efficiency and, at the same time, reduces prime-mover power requirements and electrical costs. Surface equipment operational efficiency can be improved with optimum counterbalancing of the pumping unit, and top achieve an ideal sucker-rod pumping system, a tapered rod string must have a proper mechanical design. The paper discusses rod pumping, downhole energy losses, surface losses, optimum efficiency, mode selection, counterbalancing, minimizing the cyclic load factor, and rod string design.

  16. Validation Test of CARR Safety Rod Driving Mechanism

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>CARR safety Rods are driven by hydraulic force. The safety rod driving mechanism is designed by Tsinghua University and manufactured by Shenyang LIMING factory. Two sets of the mechanism are used for the validation test.

  17. Analysis of buffering process of control rod hydraulic absorber

    International Nuclear Information System (INIS)

    Control Rod Hydraulic Drive Mechanism(CRHDM) is a newly invented build-in control rod drive mechanism. Hydraulic absorber is the key part of this mechanism, and is used to cushion the control rod when the rod scrams. Thus, it prevents the control rod from being deformed and damaged. In this paper dynamics program ANSYS CFX is used to calculate all kinds of flow conditions in hydraulic absorber to obtain its hydraulic characteristics. Based on the flow resistance coefficients obtained from the simulation results, fluid mass and momentum equations were developed to get the trend of pressure change in the hydraulic cylinder and the displacement of the piston rod during the buffering process of the control rod. The results obtained in this paper indicate that the hydraulic absorber meets the design requirement. The work in this paper will be helpful for the design and optimization of the control rod hydraulic absorber. (author)

  18. Longitudinal Vibrations of Rheological Rod With Variable Cross Section

    Institute of Scientific and Technical Information of China (English)

    Katica(Stevanovic)HEDRIH; AleksandarFILIPOVSKI

    1999-01-01

    Longitudinal vibrations of rheological rod with variable cross section are examined.Particular solutions and eigenfunction are accomplished for natural vibrations of the rod with hereditary material of standard hereditary body.Some examples are given.

  19. Digitization of the rod control and rod position systems at Qinshan NPP

    International Nuclear Information System (INIS)

    The rod control and rod position systems in No.1 reactor of Qinshan nuclear power plant have been remodeled into digitized systems. The digital systems were achieved by PLC logic control functions, and a human-machine interface was used for online monitoring of system status and parameter changes. Redundant configuration was adopted for PLC controller to improve the system flexibility and reliability. The original analog circuits were modified into double-hold circuits against failures. Redundant communication between the rod control and rod position system was used to reduce the numbers of field cable. A data collection cabinet was designed to sample the coil waveform data on the drive mechanism for real-time data acquisition and facilitate post-accident analysis. (authors)

  20. CHF and flow instability in rod bundles

    International Nuclear Information System (INIS)

    Data for two very different rod bundles have been analyzed using a new CHF correlation and a crude, but simple, subchannel analysis. The CHF correlation was developed for round uniform tubes and has been shown to accurately predict CHF in nonuniform tubes. The first set of data was for a KWU rod bundle (37 rods) with a heated length of 3.00 m and an O.D. (outside diameter) of 12.9 mm over a range of pressure 70 to 150 bar in upflow. The second set of data was for a 5 x 5 TRIGA rod bundle with a heated length of 0.559 m and 13.75 mm O.D. over a range of pressure of 0.945 to 1.372 bar in downflow. In contrast to the KWU data, the correlation greatly over estimates the CHF values for the TRIGA data. The TRIGA CHF data correlate very well with the variable qsat assuming no mixing, qc,exp = 0.955qsat (stdev = 9.87%). This result strongly suggests that these instabilities, which resulted immediately in CHF, are triggered by the Onset of Flow Instability (OFI) rather than CHF. The wide spread in rod power factors, the low pressure, and the downflow condition all contribute to promoting this type of instability (Ledinegg). The crude subchannel analysis has been compared with calculations of exit conditions of the hot channel using COBRA code. The agreement is fair when the homogeneous equilibrium model is used in the COBRA code. This is expected since the exit of the hot channel is always subcooled. Using Zuber's, along with other, void fraction relations in COBRA yields much lower exit velocities and high positive exit qualities, and, in some cases, convergence difficulties arise. The facts indicate that the bundle has already past the OFI point: which is possible since no CHF calculation was made in these COBRA analyses. (J.P.N)

  1. Composite models for combined rod and fluid dynamics in sucker-rod pumping well systems

    Energy Technology Data Exchange (ETDEWEB)

    Lekia, S.D.L.

    1989-01-01

    This study presents the derivation and the numerical solution of composite models in which both the rod string and the fluid dynamics are coupled so as to accurately account for the effects of viscous friction in sucker-rod pumped wells. A viscous damped hyperbolic first order partial differential equation is coupled to the time derivative of Hooke's law to model the rod string motion and Navier Stokes equations are used to model the fluid dynamics in the rod-tubing annulus. A set of four equations comprise the composite model from which four sub-models for different flow scenarios are considered. The equations are solved numerically by a shock capturing algorithm known as the MacCormack Explicit Scheme which is a two-step predictor-corrector scheme and is second order accuracy in time and space. Five example problems covering various pump setting depths, fluid properties and surface pumping unit kinematics are presented to study the effects of certain important variables. From the analyses of the results of these example problems it is concluded that (1) while the effects of fluid dynamics may appear masked in shallow to medium depth sucker-rod pumped wells, they can not be ignored in deeper wells where large discrepancies occur in the prediction of system parameters, (2) the load range decreases moderately as viscosity increases and the predicted polished rod horsepower does not change significantly over the range of viscosities studied in shallow to medium depth sucker-rod pumped wells, (3) the presence of small quantities of the gas phase in the fluid column reduces system peak torque and precipitate the need for smaller counterbalance weights and (4) the influence of two-phase gas-liquid flow in the rod-tubing annulus on system design parameters declines with increasing pump setting depth. The results are compared against other design models appearing in the literature.

  2. Nuclear fuel rod frame with fuel rods positioned by moveable member

    International Nuclear Information System (INIS)

    Described is a grid structure for holding a plurality of nuclear fuel rods. The grid structure is of the type having wall means, including rigidly interconnected generally rectangular metal strips, forming a plurality of passageways and adapted to support nuclear fuel rods within some of the passageways. The improvement comprises providing elongated slots intermediate and normal to the longitudinal edges of each of the strips at each intersection of the strips whereby the slots form openings in each corner of each passageway

  3. Distributed Mode Filtering Rod Fiber Amplifier With Improved Mode Stability

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas Tanggaard; Broeng, Jes;

    2012-01-01

    We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime.......We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime....

  4. Sucker rod string design of the pumping systems

    Directory of Open Access Journals (Sweden)

    Chun Hua Liu

    2015-08-01

    Full Text Available The existing design of sucker rod string mainly focuses on the simplifying assumptions that rod string was exposed to simple tension loading. And its goal was to have equal modified stress at the top of each taper. The improved rod design was to have the same degree of safety at each section, and it used a dynamic force distribution that was proportional along the whole string. However, the available procedures did not provide the desired accuracy of its pertinent analysis, and the operators could not identify the specific phenomena that occur in CBM wells. In this paper, the mathematical models of rod loads and string length were developed based on the cyclic nature of rod string loading; the fatigue endurance method is used to design the single rod string; and the tapered rod string is designed to have an equal equivalent stress at the top of each section. Its application characteristics are demonstrated by the example of CBM wells in Ordos Basin. The interpretations of results show that the previous design gave the single rods a larger diameter and the top rods in the string a greater percent than the proposed method. The calculation should concern about inertial, vibration and friction forces to illustrate the elastic force waves travelling in the rod material with the speed of sound. The single string should be designed using fatigue endurance ratings due to asymmetric pulsating tension of rod loading; and the tapered string should involve a balanced design by setting the fatigue endurance at each section equal. A shorter stroke length gives a greater rod taper percentage and an increased load capacity results to an enhanced rod diameter. The rod diameter increases with the pump size and load capacity for the single string, and the rod taper percentage of the top rod strings increases with plunger diameter for the tapered string. The proposed research improves efficiency of the pumping system, assures good operating conditions, and reduces

  5. Dependence of control rod worth on fuel burnup

    Energy Technology Data Exchange (ETDEWEB)

    Savva, P., E-mail: savvapan@ipta.demokritos.g [NCSR ' DEMOKRITOS' , PoB 60228, 15310 Aghia Paraskevi (Greece); Varvayanni, M., E-mail: melina@ipta.demokritos.g [NCSR ' DEMOKRITOS' , PoB 60228, 15310 Aghia Paraskevi (Greece); Catsaros, N., E-mail: nicos@ipta.demokritos.g [NCSR ' DEMOKRITOS' , PoB 60228, 15310 Aghia Paraskevi (Greece)

    2011-02-15

    Research highlights: Diffusion and MC calculations for rod worth dependence on burnup and Xe in reactors. One-step rod withdrawal/insertion are used for rod worth estimation. The study showed that when Xe is present the rods worth is significantly reduced. Rod worth variation with burnup depends on rod position in core. Rod worth obtained with MC code is higher than that obtained from deterministic. - Abstract: One important parameter in the design and the analysis of a nuclear reactor core is the reactivity worth of the control rods, i.e. their efficiency to absorb excess reactivity. The control rod worth is affected by parameters such as the fuel burnup in the rod vicinity, the Xe concentration in the core, the operational time of the rod and its position in the core. In the present work, two different computational approaches, a deterministic and a stochastic one, were used for the determination of the rods worth dependence on the fuel burnup level and the Xe concentration level in a conceptual, symmetric reactor core, based on the MTR fuel assemblies used in the Greek Research Reactor (GRR-1). For the deterministic approach the neutronics code system composed by the SCALE modules NITAWL and XSDRN and the diffusion code CITATION was used, while for the stochastic one the Monte Carlo code TRIPOLI was applied. The study showed that when Xe is present in the core, the rods worth is significantly reduced, while the rod worth variation with increasing burnup depends on the rods position in the core grid. The rod worth obtained with the use of the Monte Carlo code is higher than the one obtained from the deterministic code.

  6. Fluorescent colloidal silica rods - synthesis and phase behavior

    OpenAIRE

    Kuijk, A.

    2012-01-01

    Although the experimental study of spherical colloids has been extensive, similar studies on rod-like particles are rare because suitable model systems are scarce. To fulfill this need, we present the synthesis of monodisperse rod-like silica colloids with tunable dimensions. Rods were produced with diameters of 200 nm and larger and lengths up to 10 µm, which resulted in aspect ratios ranging from 1 to 25. The growth mechanism of these rods involves emulsion droplets of water in pentanol, in...

  7. Population genetics of Trypanosoma brucei circulating in Glossina palpalis palpalis and domestic animals of the Fontem sleeping sickness focus of Cameroon

    OpenAIRE

    Simo, Gustave; Njitchouang, Guy Roger; Melachio, Tresor Tito Tanekou; Njiokou, Flobert; Cuny, Gerard; Tazoacha, Asonganyi

    2014-01-01

    Background: Human African Trypanosomiasis is still a public health threat in Cameroon. To assess Trypanosoma brucei strains circulating in the Fontem sleeping sickness focus, we conducted a genetic structure study using microsatellites to assess genotypes circulating in both tsetse flies and domestic animals. Method: For this study, pyramidal traps were set up and 2695 tsetse flies were collected and 1535 (57%) living flies were dissected and their mid- guts collected. Furthermore, blood samp...

  8. Characterization of a novel trans-sialidase of Trypanosoma brucei procyclic trypomastigotes and identification of procyclin as the main sialic acid acceptor

    OpenAIRE

    1993-01-01

    Here we report the presence of a trans-sialidase on the surface of Trypanosoma brucei culture-derived procyclic trypomastigotes. The enzyme is not detected in lysates of bloodstream trypomastigotes enriched for either stumpy or slender forms. The trans-sialidase catalyzes the transfer of alpha(2-3)-linked sialic acid residues to lactose. beta-galactopyranosyl residues are at least 100 times better acceptors for sialic acid than alpha-galactopyranosyl residues. In the absence of efficient acce...

  9. A Four-Point Screening Method for Assessing Molecular Mechanism of Action (MMOA) Identifies Tideglusib as a Time-Dependent Inhibitor of Trypanosoma brucei GSK3β

    OpenAIRE

    Swinney, Zachary T.; Haubrich, Brad A.; Xia, Shuangluo; Ramesha, Chakk; Gomez, Stephen R.; Guyett, Paul; Mensa-Wilmot, Kojo; Swinney, David C.

    2016-01-01

    Background New therapeutics are needed for neglected tropical diseases including Human African trypanosomiasis (HAT), a progressive and fatal disease caused by the protozoan parasites Trypanosoma brucei gambiense and T. b. rhodesiense. There is a need for simple, efficient, cost effective methods to identify new molecules with unique molecular mechanisms of action (MMOAs). The mechanistic features of a binding mode, such as competition with endogenous substrates and time-dependence can affect...

  10. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Anene Boniface Maduka

    2015-01-01

    Objective:To determine the effect of Ancylostoma caninum (A. caninum) and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods:Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense), and GPIV was infected with Trypanosoma brucei (T. brucei)/A. caninum. The dogs were first vaccinated with antirabies vaccine before infecting GPII, GPIII and GPIV with A. caninum which were done 4 weeks after vaccination. By 2-week post-vaccination, trypanosome parasites were superimposed on both GPIII and GPIV. A secondary vaccination was given to GPI, GPII, GPIII, and GPIV by Week 12 of the experiment (4 weeks post treatment). Results:The prepatent period was (3.00 ± 1.40) days, in the conjunct infection of T. brucei/A. caninum. It was (9.00 ± 1.10) days, in conjunct T. congolense/A. caninum. The prepatent period of A. caninum was (14.0 ± 2.0) days in the single A. caninum group and (13.0 ± 1.0) days in the conjunct trypanosome/A. caninum. At the 1st week after vaccination, the antibody titer in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (P Conclusions:It was therefore concluded that A. caninum, T. brucei and T. congolense induced immunosuppression in antirabies vaccination in dogs.

  11. Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells

    OpenAIRE

    Netsanet Worku; Andualem Mossie; August Stich; Arwid Daugschies; Susanne Trettner; Hemdan, Nasr Y. A.; Gerd Birkenmeier

    2013-01-01

    The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behav...

  12. The de novo and salvage pathways of GDP-mannose biosynthesis are both sufficient for the growth of bloodstream-form Trypanosoma brucei

    OpenAIRE

    Kuettel, Sabine; Wadum, Majken C T; Güther, Maria Lucia S; Mariño, Karina; Riemer, Carolin; Ferguson, Michael A. J.

    2012-01-01

    Summary The sugar nucleotide GDP-mannose is essential for Trypanosoma brucei. Phosphomannose isomerase occupies a key position on the de novo pathway to GDP-mannose from glucose, just before intersection with the salvage pathway from free mannose. We identified the parasite phosphomannose isomerase gene, confirmed that it encodes phosphomannose isomerase activity and localized the endogenous enzyme to the glycosome. We also created a bloodstream-form conditional null mutant of phosphomannose ...

  13. Investigation of control rod worth and nuclear end of life of BWR control rods

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, Per

    2008-01-15

    This work has investigated the Control Rod Worth (CRW) and Nuclear End of Life (NEOL) values for BWR control rods. A study of how different parameters affect NEOL was performed with the transport code PHOENIX4. It was found that NEOL, expressed in terms of {sup 10}B depletion, can be generalized beyond the conditions for which the rod is depleted, such as different power densities and void fractions, the corresponding variation in the NEOL will be about 0.2-0.4% {sup 10}B. It was also found that NEOL results for different fuel types and different fuel enrichments have a variation of about 2-3% in {sup 10}B depletion. A comparative study on NHOL and CRW was made between PHOENIX4 and the stochastic Monte Carlo code MCNP. It was found that there is a significant difference, both due to differences in the codes and to limitations in the geometrical modeling in PHOENIX4. Since MCNP is considered more physically correct, a methodology was developed to calculate the nuclear end of life of BWR control rods with MCNP. The advantages of the methodology are that it does not require other codes to perform the depletion of the absorber material, it can describe control rods of any design and it can deplete the control rod absorber material without burning the fuel. The disadvantage of the method is that is it time-consuming.

  14. Investigation of control rod worth and nuclear end of life of BWR control rods

    International Nuclear Information System (INIS)

    This work has investigated the Control Rod Worth (CRW) and Nuclear End of Life (NEOL) values for BWR control rods. A study of how different parameters affect NEOL was performed with the transport code PHOENIX4. It was found that NEOL, expressed in terms of 10B depletion, can be generalized beyond the conditions for which the rod is depleted, such as different power densities and void fractions, the corresponding variation in the NEOL will be about 0.2-0.4% 10B. It was also found that NEOL results for different fuel types and different fuel enrichments have a variation of about 2-3% in 10B depletion. A comparative study on NHOL and CRW was made between PHOENIX4 and the stochastic Monte Carlo code MCNP. It was found that there is a significant difference, both due to differences in the codes and to limitations in the geometrical modeling in PHOENIX4. Since MCNP is considered more physically correct, a methodology was developed to calculate the nuclear end of life of BWR control rods with MCNP. The advantages of the methodology are that it does not require other codes to perform the depletion of the absorber material, it can describe control rods of any design and it can deplete the control rod absorber material without burning the fuel. The disadvantage of the method is that is it time-consuming

  15. Shield mining frame piston rod. Schildausbaugestell-Kolbenstange

    Energy Technology Data Exchange (ETDEWEB)

    Schuett, F.

    1981-05-02

    A piston rod for a shield mining frame for coal mining is described. This has radial outward connecting openings at the free end for hydraulic pipes. The plug-in connections are pushed in here and held with clamps. The piston rod part, in which these openings are situated, is made as a bar. The piston rod and bar form one part.

  16. Fluorescent colloidal silica rods - synthesis and phase behavior

    NARCIS (Netherlands)

    Kuijk, A.

    2012-01-01

    Although the experimental study of spherical colloids has been extensive, similar studies on rod-like particles are rare because suitable model systems are scarce. To fulfill this need, we present the synthesis of monodisperse rod-like silica colloids with tunable dimensions. Rods were produced with

  17. Low fluid level in pulse rod shock absorber

    International Nuclear Information System (INIS)

    On various occasions during pulse mode operation the shim and regulating control rods would drop when the pulse rod was withdrawn. Subsequent investigation traced the problem to the pulse rod shock absorber which was found to be low in hydraulic fluid. The results of the investigation, the corrective action taken, and a method for measuring the shock absorber fluid level are presented. (author)

  18. Preliminary nuclear design for test MOX Fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Hyung Kook; Kim, Taek Kyum; Jeong, Hyung Guk; Noh, Jae Man; Cho, Jin Young; Kim, Young Il; Kim, Young Jin; Sohn, Dong Seong

    1997-10-01

    As a part of activity for future fuel development project, test MOX fuel rods are going to be loaded and irradiated in Halden reactor core as a KAERI`s joint international program with Paul Scherrer Institute (PSI). PSI will fabricate test MOX rods with attrition mill device which was developed by KAERI. The test fuel assembly rig contains three MOX rods and three inert matrix rods. One of three MOX rods will be fabricated by BNFL, the other two MOX fuel rods will be manufacturing jointly by KAERI and PSI. Three inert matrix fuel rods will be fabricated with Zr-Y-Er-Pu oxide. Neutronic evaluation was preliminarily performed for test fuel assembly suggested by PSI. The power distribution of test fuel rod in test fuel assembly was analyzed for various fuel rods position in assembly and the depletion characteristic curve for test fuel was also determined. The fuel rods position in test fuel assembly does not effect the rod power distribution, and the proposal for test fuel rods suggested by PSI is proved to be feasible. (author). 2 refs., 13 tabs., 16 figs.

  19. [Serological evidence of the existence of a wild reservoir of Trypanosoma brucei gambiense in the Pendjari biosphere reservation in the Republic of Benin].

    Science.gov (United States)

    Guedegbe, B; Verhulst, A; Van Meirvenne, N; Pandey, V S; Doko, A

    1992-06-01

    In the national park of Pendjari, situated in the North-West of Benin, 91 wild animals, belonging to seven species, were darted. Thick and thin blood smears were examined for trypanosomes and plasma for trypanolytic antibodies against 6 antigenic variants of Trypanosoma brucei gambiense. Parasites were found in 13.92% and trypanolytic antibodies in 20.88% of the samples. A total of 28.57% of animals were positive by at least one of the two test systems used. Morphologically Trypanosoma congolense, T. vivax and T. brucei were identified. Overall prevalence was 40% in Adenota kob (n: 50), 13.63% in Alcelaphus buselaphus (n: 22), 10% in Hippotragus equinus (n: 10), 33% in Kobus defassa (n: 3), 0% in Phacochoerus aethiopicus (n: 3) and in Syncerus caffer (n: 2). The only lion (Panthera leo) examined was serologically positive. The results indicate that the wild animals are reservoirs of animal trypanosomes and suggest that among them Adenota kob and Panthera leo are carriers of T. brucei gambiense, one of the etiological aspects of human trypanosomiasis. PMID:1417158

  20. Transient rod failure in a pulsing TRIGA Mark I reactor

    International Nuclear Information System (INIS)

    Full text: On July 7, 1970 the University of Texas at Austin TRIGA Mark I Pulsing Reactor experienced a failure of the transient control rod. Although no danger to personnel or damage to the reactor other than the pulse rod occurred, the failure was promptly reported to the USAEC regional compliance office. The first indication of an abnormal situation was unusual multiplication behavior during the first start-up of the day. As usual for steady state operation, the operator removed the transient rod and began to withdraw the shim and regulating rods. After partial withdrawal, he noticed that the count rate was not increasing as rapidly as was customary. While remaining at the console,the operator had a technician make a visual inspection of the core. The technician observed the transient drive rod was swinging freely in the pool and the poison section was detached. It was concluded, based on the indications of the.reactor instrumentation and visual inspection, that the transient control rod had broken off and remained in position in the core. The regulating and shim rods were inserted and the transient rod was manually cranked to the down position. The manual manipulation of the transient rod, instead of dropping the rod by gravity, was used so that the connecting rod could be reinserted in the control rod guide tube. The reactor core was then partially unloaded so that a critical mass was not present. The transient rod drive and connecting rod were removed from the pool. The poison section was retrieved from its position in the core by welding a tap to a long rod and tapping into the top of the poison section. Visual inspection of the poison section showed that the weld joining the male threads on the poison section to the main body of the control rod had failed. The threads remained screwed in the control rod drive shaft upon separation and the poison section remained fully inserted in the core. A new control rod was fabricated by Gulf General Atomic and shipped

  1. Test Research on Special Sucker Rod for Screw Pump

    Institute of Scientific and Technical Information of China (English)

    Zhang Mingyi; Chen Mingzhan; Li Zhi

    2006-01-01

    @@ According to the statistics of straight thread sucker rods' application in screw pump in Daqing Oilfield before2000, the proportion of sucker rods' yearly breakaway reached to 41.6%, taking up 70% of the total wells that were checked. Thus it can be seen that the rods breakaway problem was becoming the main barrier restricting screw pump large-scale population and application. Since then,the development work on the special sucker rods for screw pump had been carried on. Through the analysis on the failure position and failure form of the sucker rods',the following conclusions arepresented:

  2. Sealing system for piston rod of hot gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Lundholm, S.G.; Ringqvist, S.A.

    1980-11-25

    An improvement to a sealing system for restricting fluid flow around a piston rod between a piston cylinder and crankshaft space in a hot gas engine where a seal element is secured around the piston rod in an intermediate chamber, the improvement including a link in the crankshaft space connecting, and permitting relative radial motion between, the piston rod and the crosshead and an o-ring having a diameter substantially greater than that of the piston rod and being secured between a lower ring securing the seal element in place around the piston rod and a wall of the intermediate chamber for frictionally restricting radial movement of the lower ring.

  3. Method and means of packaging nuclear fuel rods for handling

    International Nuclear Information System (INIS)

    Nuclear fuel rods, especially spent nuclear fuel rods that may show physical distortion, are encased within a metallic enclosing structure by forming a tube about the fuel pod. The tube has previously been rolled to form and overlapping tubular structure and then unrolled and coiled about an axis perpendicular to the tube. The fuel rod is inserted into the tube as the rolled tube is removed from a coiled strip and allowed to reassume its tubular shape about the fuel rod. Rollers support the coiled strip in an open position as the coiled strip is uncoiled and allowed to roll about the fuel rod

  4. Whole-rod testing of intact and defective LWR rods under expected dry-storage conditions

    International Nuclear Information System (INIS)

    The objective of this project is to provide the Nuclear Regulatory Commission with information to confirm or establish spent fuel dry storage licensing positions relative to: (1) the long-term, low-temperature (less than 2500C) behavior of spent fuel rods in dry storage; and (2) the radioactive contamination potential of crud from cladding in dry storage. The basic need for this data is to: confirm long-term, low temperature (less than 2500C) spent fuel dry storage performance predictions based on theoretical analyses and on results from high-temperature, short-term laboratory tests; determine the nature and behavior of crud layers as a function of dry storage time; and determine the potential radioactive crud contamination (e.g., spalling characteristics) for dry storage. An eight-rod test matrix of PWR and BWR rods was chosen which consisted of all combinations of intact or breached cladding in an oxidizing or inert atmosphere. The PWR rods (30.5 GWD/MTU) were discharged from H.B. Robinson in May 1974, and the BWR rods (12.9 GWD/MTU) were discharged from Peach Bottom in March 1976. The eight test rods were visually inspected for crud and defects with the results recorded on video tape. Cladding penetration was confirmed. All the rods were put in test capsules with the appropriate atmosphere and leak checked. The test capsules were loaded into a test train and the train was placed in the furnace cavity. The test was started on September 15, 1982 and is presently at 2300C. After the first 10-month run is completed, an interim examination, consisting of visual inspection, gamma scanning, and crud sampling, will be conducted

  5. Fluid Dynamics in Sucker Rod Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, R.P.; Mansure, A.J.

    1999-01-14

    Sucker rod pumps are installed in approximately 90% of all oil wells in the U.S. Although they have been widely used for decades, there are many issues regarding the fluid dynamics of the pump that have not been fully investigated. A project was conducted at Sandia National Laboratories to develop unimproved understanding of the fluid dynamics inside a sucker rod pump. A mathematical flow model was developed to predict pressures in any pump component or an entire pump under single-phase fluid and pumping conditions. Laboratory flow tests were conducted on instrumented individual pump components and on a complete pump to verify and refine the model. The mathematical model was then converted to a Visual Basic program to allow easy input of fluid, geometry and pump parameters and to generate output plots. Examples of issues affecting pump performance investigated with the model include the effects of viscosity, surface roughness, valve design details, plunger and valve pressure differentials, and pumping rate.

  6. Absorber rod drive for nuclear reactors

    International Nuclear Information System (INIS)

    The invention concerns an absorber rod drive for Boiling Water Reactors, in which a mechanical drive is combined with a hydraulic drive working separately from it, so that both drives are situated concentric within an overall length. The driving torque of a motor is transmitted to a threaded spindle, which moves a free adjacent hollow piston vertically via a fixed nut. The same means are used for the hydraulic liquid which is used as coolant or moderator and there are nozzles, annular gaps and/or bores between the hydraulic system and the reactor pressure vessel for the purpose of pressure compensation. All the components of the absorber rod drive except the sealing housing and the setting drive are situated in one casing tube taking the differential pressure. (orig./HP)

  7. Replacement means for control rod drive mechanism

    International Nuclear Information System (INIS)

    Object: To permit assembling and removal operation of a control rod drive mechanism to be carried out speedily and properly irrespective of the degree of skill of the operating personnel. Structure: When removing a control rod drive mechanism (CRD) a service platform and a frame body are operated for bringing a CRD lift guide frame to a position below the CRD to be removed. Then, a CRD receptacle is placed at the lower end of the CRD, and water is drained from the CRD. Subsequently, a chain is driven by a drive means in a direction which lowers the receptacle, and only the CRD is lowered along the CRD lift guide frame. Thereafter, the CRD is secured at its upper portion by a support means, and the CRD lift guide frame is lowered by a lift jack to thereby permit revolution of the CRD, The CRD lift frame after revolution is lifted and then removed to the outside. (Kamimura, M.)

  8. The lifetime of the control rod drives

    International Nuclear Information System (INIS)

    The lifetime of the control rod drives is studied. Their function is to take out or to pull in the control rods. The drive and the experiments carried out, are described. The analysis of the behaviour under operation, the drive inspections and surveyance, are also considered. The results are obtained from: the investigations performed on the fatigue strength of the 900 MW and 1300 MW drives, which allowed to deduce a low of wear and to identify the important aspects to be studied, the measurements of the dynamical stresses of mobile elements and a dynamical calculation model. The study leads to the conclusion that a probabilistic approach is needed for the fatigue damage analysis of some elements. Moreover, a systematic examination is also needed, to verify the agreement betwem the drives calculated aging values and the measured ones

  9. Photonic mesophases from cut rod rotators

    Energy Technology Data Exchange (ETDEWEB)

    Stelson, Angela C.; Liddell Watson, Chekesha M., E-mail: cml66@cornell.edu [Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Avendano, Carlos [Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2016-01-14

    The photonic band properties of random rotator mesophases are calculated using supercell methods applied to cut rods on a hexagonal lattice. Inspired by the thermodynamic mesophase for anisotropic building blocks, we vary the shape factor of cut fraction for the randomly oriented basis. We find large, stable bandgaps with high gap isotropy in the inverted and direct structures as a function of cut fraction, dielectric contrast, and filling fraction. Bandgap sizes up to 34.5% are maximized at high dielectric contrast for rods separated in a matrix. The bandgaps open at dielectric contrasts as low as 2.0 for the transverse magnetic polarization and 2.25 for the transverse electric polarization. Additionally, the type of scattering that promotes the bandgap is correlated with the effect of disorder on bandgap size. Slow light properties are investigated in waveguide geometry and slowdown factors up to 5 × 10{sup 4} are found.

  10. Composites reinforcement by rods: a SAS study

    International Nuclear Information System (INIS)

    The mechanical properties of composites are governed by size, shape and dispersion degree of so-called reinforcing particles. Polymeric fillers based on thermodynamically driven microphase separation of block copolymers offer the opportunity to study a model system of controlled rod-like filler particles. We chose a triblock copolymer (PBPSPB) and carried out SAS measurements with both X-rays and neutrons, in order to characterize separately the hard phase and the cross-linked PB matrix. The properties of the material depend strongly on the way that stress is carried and transferred between the soft matrix and the hard fibers. The failure of the strain-amplification concept and the change of topological contributions to the free energy and scattering factor have to be addressed. In this respect the composite shows a similarity to a two-network system, i.e. interpenetrating rubber and rod-like filler networks. (orig.)

  11. Hollow Sucker Rod Applied in Production Engineering

    Institute of Scientific and Technical Information of China (English)

    Wang Tongbin; Liu Liandong; Hu Daoming; Jia Yanshan

    1997-01-01

    @@ Working Principle A positive cycle system or a working channel can be formed by means of hollow sucker rod and its mating parts in the oil tube ofa well, through which heat carriers (such as hot water,hot oil and steam), chemicals and heating cable can be pumped or put into the well so as to lower the viscosity of crude, dissolve the paraffin building-up and open the conduit, thus leading to the smooth oil flow out of well.

  12. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  13. Analysis of Double-encapsulated Fuel Rods

    Energy Technology Data Exchange (ETDEWEB)

    Hales, Jason Dean [Idaho National Laboratory; Medvedev, Pavel G [Idaho National Laboratory; Novascone, Stephen Rhead [Idaho National Laboratory; Perez, Danielle Marie [Idaho National Laboratory; Williamson, Richard L [Idaho National Laboratory

    2014-09-01

    In an LWR fuel rod, the cladding encapsulates the fuel, contains fission products, and transfers heat directly to the water coolant. In some situations, it may be advantageous to separate the cladding from the coolant through use of a secondary cladding or capsule. This may be done to increase confidence that the fuel or fission products will not mix with the coolant, to provide a mechanism for controlling the rod temperature, or to place multiple experimental rodlets within a single housing. With an axisymmetric assumption, it is possible to derive closed-form expressions for the temperature profile in a fuel rod using radially-constant thermal conductivity in the fuel. This is true for both a traditional fuel-cladding rod and a double-encapsulated fuel (fuel, cladding, capsule) configuration. Likewise, it is possible to employ a fuel performance code to analyse both a traditional and a double-encapsulated fuel. In the case of the latter, two sets of gap heat transfer conditions must be imposed. In this work, we review the equations associated with radial heat transfer in a cylindrical system, present analytic and computational results for a postulated power and gas mixture history for IFA-744, and describe the analysis of the AFC-2A, 2B metallic fuel alloy experiments at the Advanced Test Reactor, including the effect of a release of fission products into the cladding-capsule gap. The computational results for these two cases were obtained using BISON, a fuel performance code under development at Idaho National Laboratory.

  14. Control rod drive mechanisms seismic analysis

    International Nuclear Information System (INIS)

    In the Taishan joint-design, in order to finish Control Rod Drive Mechanism (CRDM) seismic analysis, a response spectrum analysis in combination with quasi-static analysis and a time history analysis are performed according to the different design stages and inputs. The simulated and simplified model of nonlinear structure is studied in the basic design stage; the translation of seismic input data and the use of nonlinear elements are studied in the detailed design stage. (authors)

  15. Rod-Cone convergence in the retina.

    OpenAIRE

    Muchungi, Kendi

    2015-01-01

    Vision enables visual perception of one's environs, as well as self-navigation within space. Objects within our environs are visible by virtue of the fact that they re ect light. To see or have visual perception, this light needs to be converted into an electrical signal. This process is referred to as visual transduction and takes place in the retina. Recently, it has become apparent that the convergence of rod and cone systems in transduction is crucial to enable retina fu...

  16. Nuclear thermionic converter. [tungsten-thorium oxide rods

    Science.gov (United States)

    Phillips, W. M.; Mondt, J. F. (Inventor)

    1977-01-01

    Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability.

  17. Description and characterization of HBWR Series H-1 test rods

    Energy Technology Data Exchange (ETDEWEB)

    Wagoner, S.R.; Barner, J.O.; Welty, R.K.

    1979-06-01

    The as-built characterization results are presented for the HBWR Series H-1 test rods to be irradiated as part of the Fuel Performance Improvement Program (FPIP). The irradiation of these rods is to be conducted in the Halden Boiling Water Reactor (HBWR). Series H-1 consists of twelve rods for irradiation and six spares. Rod design types include (1) a reference dished pellet design, (2) an annular pellet design, (3) an annular pellet design combined with graphite-coated cladding, and (4) a packed-particle (vipac) design. The report, which describes the fabrication and detailed characterization results for the rods, is divided into four major sections: (1) experiment description, (2) process development required to fabricate the test rods, (3) methods and procedures used to fabricate and characterize the rods, and (4) a summary of the characterization results.

  18. PIE of a failed rod from IFA 597.2

    International Nuclear Information System (INIS)

    Two rods in IFA 597.2 were refabricated from fuel rod 33-25065 irradiated in Ringhals 1. The irradiation of the father rod in Ringhals was prolonged to 'two lives' to reach high burnup. The objective of the test at Halden was to study the thermal behaviour and the fission gas release of high burnup commercial BWR-LWR fuel. The rods in the test were instrumented with fuel centreline thermocouples and bellows pressure transducers. Fuel rod 5 in IFA 597.2 failed during the test at Halden. The failed rod was transported to Studsvik for post irradiation examination. The main purpose of the examination was a study of the failure. The examination of the failed rod, described in this paper, was financed by the Swedish Nuclear Power Inspectorate (author) (ml)

  19. Control rod for PWR type reactor

    International Nuclear Information System (INIS)

    Since a silver-indium-cadmium alloy has been used as the absorber for control rods, swelling due to neutron absorption has been caused. On the other hand, a stainless steel cladding tube for the absorber gradually reduces its outer diameter by the pressure of reactor coolants and neutron irradiation and causes contact during working life to often bring about cracking in the cladding tube. Then, the control rod is divided into two independent portions and joined by an intermediate end plug into a single rod, in which the upper portion is made free from pressure and the lower portion is pressurized. Further, a large gap is formed between the lower absorber and the lower cladding tube. Further, chromium or chromium carbide is coated to the outer surface of the upper cladding tube for improving the abrasion resistance. Thus, the cladding tube is made abrasion resistant and it is possible to prevent cracking in the cladding tube due to interaction between the tube and the absorber, inner presurization at the lower portion, reduced diameter for the absorber and the gap of the tube. (N.H.)

  20. Powder Forging of a Motorcycle Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch was divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. Powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the alloy powder. Through testing and metallographic observation the physical and mechanical properties of the connecting rod produced by the P/M hot forging were found to be superior to those manufactured by the traditional method.

  1. Control rod ejection analysis during a depressurization accident and the development of a rod-ejection-preventing device

    International Nuclear Information System (INIS)

    The control rods used for the experimental VHTR are suspended in the core by means of flexible steel cables and it is conceivable that an accidental rod ejection could occur due to a depressurization accident. The computer code AFLADE was developed in order to analyze the possibility of accidental rod ejection, and several studies were performed. The parametric study results showed that the adopted design condition for the VHTR core will not cause a rod ejection accident. In parallel with these accident analyses, a rod-ejection-preventing device was developed in preparation for a hypothetical accident, and its function was verified by the component tests

  2. Spherical Joint Piston and Connecting Rod Developed

    Science.gov (United States)

    1996-01-01

    Under an interagency agreement with the Department of Energy, the NASA Lewis Research Center manages a Heavy-Duty Diesel Engine Technology (HDET) research program. The overall program objectives are to reduce fuel consumption through increased engine efficiency, reduce engine exhaust emissions, and provide options for the use of alternative fuels. The program is administered with a balance of research contracts, university research grants, and focused in-house research. The Cummins Engine Company participates in the HDET program under a cost-sharing research contract. Cummins is researching and developing in-cylinder component technologies for heavy-duty diesel engines. An objective of the Cummins research is to develop technologies for a low-emissions, 55-percent thermal efficiency (LE-55) engine. The best current-production engines in this class achieve about 46-percent thermal efficiency. Federal emissions regulations are driving this technology. Regulations for heavy duty diesel engines were tightened in 1994, more demanding emissions regulations are scheduled for 1998, and another step is planned for 2002. The LE-55 engine emissions goal is set at half of the 1998 regulation level and is consistent with plans for 2002 emissions regulations. LE-55 engine design requirements to meet the efficiency target dictate a need to operate at higher peak cylinder pressures. A key technology being developed and evaluated under the Cummins Engine Company LE-55 engine concept is the spherical joint piston and connecting rod. Unlike conventional piston and connecting rod arrangements which are joined by a pin forming a hinged joint, the spherical joint piston and connecting rod use a ball-and-socket joint. The ball-and-socket arrangement enables the piston to have an axisymmetric design allowing rotation within the cylinder. The potential benefits of piston symmetry and rotation are reduced scuffing, improved piston ring sealing, improved lubrication, mechanical and thermal

  3. Between a Map and a Data Rod

    Science.gov (United States)

    Teng, W. L.; Rui, H.; Strub, R. F.; Vollmer, B.

    2015-12-01

    A "Digital Divide" has long stood between how NASA and other satellite-derived data are typically archived (time-step arrays or "maps") and how hydrology and other point-time series oriented communities prefer to access those data. In essence, the desired method of data access is orthogonal to the way the data are archived. Our approach to bridging the Divide is part of a larger NASA-supported "data rods" project to enhance access to and use of NASA and other data by the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS) and the larger hydrology community. Our main objective was to determine a way to reorganize data that is optimal for these communities. Two related objectives were to optimally reorganize data in a way that (1) is operational and fits in and leverages the existing Goddard Earth Sciences Data and Information Services Center (GES DISC) operational environment and (2) addresses the scaling up of data sets available as time series from those archived at the GES DISC to potentially include those from other Earth Observing System Data and Information System (EOSDIS) data archives. Through several prototype efforts and lessons learned, we arrived at a non-database solution that satisfied our objectives/constraints. We describe, in this presentation, how we implemented the operational production of pre-generated data rods and, considering the tradeoffs between length of time series (or number of time steps), resources needed, and performance, how we implemented the operational production of on-the-fly ("virtual") data rods. For the virtual data rods, we leveraged a number of existing resources, including the NASA Giovanni Cache and NetCDF Operators (NCO) and used data cubes processed in parallel. Our current benchmark performance for virtual generation of data rods is about a year's worth of time series for hourly data (~9,000 time steps) in ~90 seconds. Our approach is a specific

  4. Flagellum ontogeny in trypanosomes studied via an inherited and regulated RNA interference system.

    Science.gov (United States)

    Bastin, P; Ellis, K; Kohl, L; Gull, K

    2000-09-01

    The African trypanosome, Trypanosoma brucei possesses a large and unique intraflagellar structure called the paraflagellar rod (PFR). The PFR is composed of 2 major proteins, PFRA and PFRC. We have generated an inducible mutant trypanosome cell line (snl-2) that expresses linked inverted copies of a PFRA gene, capable of forming a PFRA double-stranded (ds) RNA. When expression of this dsRNA was induced, new PFRA RNA and PFRA protein quickly disappeared and PFR construction was affected, resulting in cell paralysis. This inducible RNA interference (RNAi) effect was fast-acting, heritable and reversible. It allowed us to demonstrate that PFR proteins are able to enter both mature and growing flagella but appear to concentrate differentially in new flagella because of the construction process. The PFR is constructed by a polar assembly process at the distal end of the flagellum resulting in a stable cytoskeletal structure with low turn-over. The inducible RNAi approach will have widespread applicability in studies of gene function and cellular processes in parasites. PMID:10954429

  5. A model for fuel rod and tie rod elongations in boiling water reactor fuel bundles

    International Nuclear Information System (INIS)

    A structural model is developed to determine the relative axial displacements of the spring held fuel rods to the tie rods in Boiling Water Reactor fuel bundles. An irradiation dependent relaxation model, which considers a two stage relaxation process dependent upon the fast fluence is used for the compression springs. The changes in spring compression resulting from the change in the length of the zircaloy fuel cladding due to irradiation enhanced anisotropic creep and growth is also considered in determining the time dependent variation of the spring forces. The time dependence of the average linear heat generation rates and their axial distributions is taken into account in determining the fuel cladding temperatures and fast fluxes for the various fuel rod locations within each of the BWR fuel bundles whose relative displacements were measured and used in this verification study. (orig.)

  6. The ATLAS tile calorimeter ROD injector and multiplexer board

    International Nuclear Information System (INIS)

    The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented.

  7. Sucker-rod pumping handbook production engineering fundamentals and long-stroke rod pumping

    CERN Document Server

    Takacs, Gabor

    2015-01-01

    Sucker-Rod Pumping Handbook presents the latest information on the most common form of production enhancement in today's oil industry, making up roughly two-thirds of the producing oilwell operations in the world. The book begins with an introduction to the main features of sucker rod pumping and an explanation and comparison of lift methods. It goes on to provide the technical and practical knowledge needed to introduce the new and practicing production engineer and operator to the equipment, technology, and applications required to maintain optimum operating conditions.

  8. Probing the metabolic network in bloodstream-form Trypanosoma brucei using untargeted metabolomics with stable isotope labelled glucose.

    Directory of Open Access Journals (Sweden)

    Darren J Creek

    2015-03-01

    Full Text Available Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate.

  9. GMP synthase is essential for viability and infectivity of Trypanosoma brucei despite a redundant purine salvage pathway.

    Science.gov (United States)

    Li, Qiong; Leija, Christopher; Rijo-Ferreira, Filipa; Chen, Jun; Cestari, Igor; Stuart, Kenneth; Tu, Benjamin P; Phillips, Margaret A

    2015-09-01

    The causative agent of human African trypanosomiasis, Trypanosoma brucei, lacks de novo purine biosynthesis and depends on purine salvage from the host. The purine salvage pathway is redundant and contains two routes to guanosine-5'-monophosphate (GMP) formation: conversion from xanthosine-5'-monophosphate (XMP) by GMP synthase (GMPS) or direct salvage of guanine by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). We show recombinant T. brucei GMPS efficiently catalyzes GMP formation. Genetic knockout of GMPS in bloodstream parasites led to depletion of guanine nucleotide pools and was lethal. Growth of gmps null cells was only rescued by supraphysiological guanine concentrations (100 μM) or by expression of an extrachromosomal copy of GMPS. Hypoxanthine was a competitive inhibitor of guanine rescue, consistent with a common uptake/metabolic conversion mechanism. In mice, gmps null parasites were unable to establish an infection demonstrating that GMPS is essential for virulence and that plasma guanine is insufficient to support parasite purine requirements. These data validate GMPS as a potential therapeutic target for treatment of human African trypanosomiasis. The ability to strategically inhibit key metabolic enzymes in the purine pathway unexpectedly bypasses its functional redundancy by exploiting both the nature of pathway flux and the limited nutrient environment of the parasite's extracellular niche. PMID:26043892

  10. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

    Directory of Open Access Journals (Sweden)

    E DeJesus

    Full Text Available Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1. This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT, escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens.

  11. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

    Science.gov (United States)

    DeJesus, E; Kieft, R; Albright, B; Stephens, N A; Hajduk, S L

    2013-01-01

    Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1). This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR) on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT), escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR) mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens. PMID:23637606

  12. Molecular Evidence of a Trypanosoma brucei gambiense Sylvatic Cycle in the Human African Trypanosomiasis Foci of Equatorial Guinea

    Directory of Open Access Journals (Sweden)

    Carlos eCordon-Obras

    2015-07-01

    Full Text Available Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of Gambiense trypanosomiasis.

  13. A pseudouridylation switch in rRNA is implicated in ribosome function during the life cycle of Trypanosoma brucei.

    Science.gov (United States)

    Chikne, Vaibhav; Doniger, Tirza; Rajan, K Shanmugha; Bartok, Osnat; Eliaz, Dror; Cohen-Chalamish, Smadar; Tschudi, Christian; Unger, Ron; Hashem, Yaser; Kadener, Sebastian; Michaeli, Shulamit

    2016-01-01

    The protozoan parasite Trypanosoma brucei, which causes devastating diseases in humans and animals in sub-Saharan Africa, undergoes a complex life cycle between the mammalian host and the blood-feeding tsetse fly vector. However, little is known about how the parasite performs most molecular functions in such different environments. Here, we provide evidence for the intriguing possibility that pseudouridylation of rRNA plays an important role in the capacity of the parasite to transit between the insect midgut and the mammalian bloodstream. Briefly, we mapped pseudouridines (Ψ) on rRNA by Ψ-seq in procyclic form (PCF) and bloodstream form (BSF) trypanosomes. We detected 68 Ψs on rRNA, which are guided by H/ACA small nucleolar RNAs (snoRNA). The small RNome of both life cycle stages was determined by HiSeq and 83 H/ACAs were identified. We observed an elevation of 21 Ψs modifications in BSF as a result of increased levels of the guiding snoRNAs. Overexpression of snoRNAs guiding modification on H69 provided a slight growth advantage to PCF parasites at 30 °C. Interestingly, these modifications are predicted to significantly alter the secondary structure of the large subunit (LSU) rRNA suggesting that hypermodified positions may contribute to the adaption of ribosome function during cycling between the two hosts. PMID:27142987

  14. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

    Directory of Open Access Journals (Sweden)

    Susan T Mashiyama

    Full Text Available We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups ("M32" and "C51" that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html.

  15. Numerical simulations of square arrayed rod bundles

    International Nuclear Information System (INIS)

    Highlights: ► CFD simulations with square arrayed rod bundles. ► Mesh dependency and turbulence model study by comparison with experiments. ► Gibson and Launder Reynolds stress model shows good agreement with experiments. ► Effect of pitch to diameter ratio and Reynolds number is correctly captured. - Abstract: Computational fluid dynamics (CFD) simulations were performed with square arrayed rod bundles featuring pitch to diameter (P/D) ratio of 1.194 and 1.326 in order to find an optimal mesh and turbulence model for simulations with more complex geometries in the future. With the tighter lattice a mesh sensitivity and turbulence model study were accomplished and the post processed turbulence quantities, velocity field and wall shear stress were compared with experimental data ( Developed single phase turbulent flow through a square-pitch rod cluster. Nuclear Engineering and Design 60, 365–379.). The comparisons show that Reynolds-Averaged Navier–Stokes method with the Reynolds stress model of Gibson and Launder in conjunction with an appropriate mesh can provide reasonable agreement with the experiment for this lattice. For pure bundle simulations the body fitted structured meshes are suggested, since slightly better agreement can be captured considering all quantities with the same number of cells. Based on the drawn conclusions the procession was repeated for P/D = 1.326, where, due to lack of experiment, just the correct tendencies of the turbulence quantities and velocity field were established. The results show Reynolds number independency correctly and the increase of P/D issues in more similar flow to axisymmetric pipe flow.

  16. Simulation of nuclear fuel rods by using process computer-controlled power for indirect electrically heated rods

    International Nuclear Information System (INIS)

    An investigation was carried out to determine how the simulation of nuclear fuel rods with indirect electrically heated rods could be improved by use of a computer to control the electrical power during a loss-of-coolant accident (LOCA). To aid in the experiment, a new version of the HETRAP code was developed which simulates a LOCA with heater rod power controlled by a computer that adjusts rod power during a blowdown to minimize the difference in heat flux of the fuel and heater rods. Results show that without computer control of heater rod power, only the part of a blowdown up to the time when the heat transfer mode changes from nucleate boiling to transition or film boiling can be simulated well and then only for short times. With computer control, the surface heat flux and temperature of an electrically heated rod can be made nearly identical to that of a reactor fuel rod with the same cooling conditions during much of the LOCA. A small process control computer can be used to achieve close simulation of a nuclear fuel rod with an indirect electrically heated rod

  17. Lubrication Oil Flow Simulation in Connecting Rod

    OpenAIRE

    Alendal, Ivar Audun Lothe

    2015-01-01

    Lubrication oil-flow in the crank system of an medium size diesel engine running at 750 RPM was modeled and analyzed. The model was built up by combining models from several studies in both engine lubrication systems and pipe flow modal analysis. The model is first used to analyze a system where the oil supply lines are fully open during the complete engine cycle. The result showed that these designs need a very high oil supply pressure to maintain a positive pressure in the connecting rod at...

  18. Thermographic imaging of nuclear fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Oldberg, S. Jr. (Electric Power Research Inst., Palo Alto, CA); Honey, R.C.; Falconer, D.G.; Zebroski, E.L.

    1977-04-01

    A method has been demonstrated for imaging details of the fuel-cladding gap region in nuclear fuel rods. The method exploits the geometry-sensitive variation in fuel-cladding gap conductance. After rapid electric resistance heating of the cladding tube by discharge of a capacitor bank, those regions of cladding cool first that have narrow fuel-cladding gaps. The cladding surface temperature is recorded by an infrared camera with a cathode ray tube display. Potential is seen for the measurement technique as a research tool and as a receiving inspection method.

  19. Rod Ellis, Gary Barkhuizen, Analysing Learner Language

    OpenAIRE

    Narcy-Combes, Marie-Françoise

    2014-01-01

    Ce livre vient à point nommé pour compléter les outils à la disposition des jeunes chercheurs en linguistique appliquée et didactique des langues, comme des praticiens de terrain désireux de conduire une recherche-action. Comme souvent en ce qui concerne les ouvrages de Rod Ellis, il s’agit d’une somme : une étude diachronique des outils utilisés depuis les années soixante par les chercheurs en acquisition des langues pour l’analyse des productions écrites et orales des apprenants de langue. ...

  20. Scram release for a control rod

    International Nuclear Information System (INIS)

    A double-sided rack and pinion control element drive mechanism for a nuclear reactor is disclosed wherein scram release is accomplished by the dual action of withdrawing the pinion from its engagement with the rack while at the same time rotating the pinion in a direction consistent with the movement of the rack and the control rod in their downward travel. The pinion is withdrawn from engagement with the rack while remaining in engagement with its stationary driving means. The continuing engagement with the stationary driving means causes the pinion to rotate when the pinion is caused to move away from the rack during disengagement. 10 claims, 7 drawing figures

  1. Experimental design for HTGR fuel rods

    International Nuclear Information System (INIS)

    Fuel rods for the high temperature gas cooled reactor are composed of pyrolytic carbon coated fuel particles bounded by a carbonaceous matrix. Because of differential shrinkage between coated particles and the carbonaceous matrix, breakage of the pyrolytic coating has been observed with certain combinations of coated particles and matrix compositions. The pyrolytic coating is intended to be the primary containment for fission products. Therefore, an experiment is desired to determine the breakage characteristics of different strength coated particles combined with different matrix compositions during irradiation

  2. Uspon silovatelja: etnicitet, rod i nasilje

    OpenAIRE

    Mežnarić, Silva

    1993-01-01

    Članak raspravlja o uporabi silovanja kao politike u slučajevima kada se, do tragičnih posljedica, ukrštaju nasilje, rod i etnicitet. Prvo se ispituje kampanja srbijanskih medija 1990. na Kosovu protiv Albanaca kao silovatelja; zatim se analizira upotreba silovanja u prinudnom etničkom čišćenju prilikom srpske agresije na Bosnu, 1992-1993. Pokazuje se da je kampanja na Kosovu bila predigra stvarnom silovanju u Bosni. U oba je slučaja silovanje poslužilo u ograđivanju teritorija i definiranju ...

  3. Minimization of PWR reactor control rods wear

    International Nuclear Information System (INIS)

    The Rod Cluster Control Assemblies (RCCA's) of Pressurized Water Reactors (PWR's) have experienced a continuously wall cladding wear when Reactor Coolant Pumps (RCP's) are running. Fretting wear is a result of vibrational contact between RCCA rodlets and the guide cards which provide lateral support for the rodlets when RCCA's are withdrawn from the core. A procedure is developed to minimize the rodlets wear, by the shuffling and axial reposition of RCCA's every operating cycle. These shuffling and repositions are based on measurement of the rodlet cladding thickness of all RCCA's. (author). 3 refs, 2 figs, 2 tabs

  4. Nondestructive assay of green HTGR fuel rods

    International Nuclear Information System (INIS)

    This report describes the nondestructive (NDA) work done at Los Alamos during 1979 and 1980 as part of the New Brunswick Laboratory-sponsored evaluation of NDA of the uranium content of fabricated fuel rods for high-temperature gas-cooled reactors (HTGR). The methods used (delayed neutron and passive gamma ray) are concisely described, and the results are summarized and compared in graphical and tabular form. The results indicate that, with the use of proper physical standards, accuracies within about 1 percent should be achievable by NDA procedures

  5. Wideband Circularly Polarized Dielectric Rod Antenna

    OpenAIRE

    Min Guo; Ji-Jun Yan; Shun-Shi Zhong; Zhu Sun

    2012-01-01

    A new dielectric rod antenna (DRA) is introduced to produce circular polarization (CP) over a wide frequency band without a complex feed network. Along with the simulated results, measured results of the antenna prototype are presented, showing a 3 dB axial ratio (AR) CP bandwidth of 17.7%. The radiation characteristics of the fabricated antenna are also demonstrated showing the measured gain of better than 6.2 dBi. Moreover, the measured impedance bandwidth (VSWR ≤2) reaches 20.1%, from 8.75...

  6. 4-rod RFQ linac for ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Hiroshi; Hamamoto, Nariaki; Inouchi, Yutaka [Nisshin Electric Co. Ltd., Kyoto (Japan)

    1997-03-01

    A 34 MHz 4-rod RFQ linac system has been upgraded in both its rf power efficiency and beam intensity. The linac is able to accelerate in cw operation 0.83 mA of a B{sup +} ion beam from 0.03 to 0.91 MeV with transmission of 61 %. The rf power fed to the RFQ is 29 kW. The unloaded Q-value of the RFQ has been improved approximately 61 % to 5400 by copper-plating stainless steel cooling pipes in the RFQ cavity. (author)

  7. Nonelastomeric Rod Seals for Advanced Hydraulic Systems

    Science.gov (United States)

    Hady, W. F.; Waterman, A. W.

    1976-01-01

    Advanced high temperature hydraulic system rod sealing requirements can be met by using seals made of nonelastomeric (plastic) materials in applications where elastomers do not have adequate life. Exploratory seal designs were optimized for advanced applications using machinable polyimide materials. These seals demonstrated equivalent flight hour lives of 12,500 at 350 F and 9,875 at 400 F in advanced hydraulic system simulation. Successful operation was also attained under simulated space shuttle applications; 96 reentry thermal cycles and 1,438 hours of vacuum storage. Tests of less expensive molded plastic seals indicated a need for improved materials to provide equivalent performance to the machined seals.

  8. Gas Interference in Sucker Rod Pump

    Science.gov (United States)

    Samad, Abdus

    2010-10-01

    Commonly used artificial lift or dewatering system is sucker rod pump and gas interference of the pump is the biggest issue in the oil and gas industry. Gas lock or fluid pound problems occur due to the gas interference when the pump has partially or completely unfilled plunger barrel. There are several techniques available in the form of patents to solve these problems but those techniques have positive as well as negative aspects. Some of the designs rely on the leakage and some of the designs rely on the mechanical arrangements etc to break the gas lock. The present article compares the existing gas interference handling techniques.

  9. Development of the Rod-Drop Technique

    International Nuclear Information System (INIS)

    The integral count technique is generalized, and then applied to a perturbation formula to estimate the influence of finite dropping times. In a second version of the integral method a weight factor t is introduced to suppress errors near the starting point. It enhances the influence of the medium times after the rod-drop which proved advantageous in the evaluation. This weighting method is still more generalized and applied to set up a system of equations to determine an arbitrary number of parameters in the negative reactivity if the time dependence of the power is known

  10. SEFLEX fuel rod simulator effects in flooding experiments. Pt. 1

    International Nuclear Information System (INIS)

    The aim of the SEFLEX program has been to quantify the influence of the design and the physical properties of different fuel rod simulators on heat transfer and quench front progression in unblocked and blocked rod bundles during the reflood phase of a LOCA in a PWR. Fuel rod simulators with Zy claddings and a gas-filled gap between claddings and pellets exhibit lower peak cladding temperatures and shorter quench times than gapless heater rods with stainless steel claddings. Grid spacers cause significant cooling enhancement downstream during the time span at which maximum cladding temperatures occur. Ballooned Zy claddings, forming e.g. a 90 percent blockage, are quenched substantially earlier than thickwall stainless steel blockage sleeves attached to the rods, and even earlier than undeformed rod claddings. A comparison of test data with results of the 'Best Estimate' computer program COBRA-TF shows a good agreement with unblocked bundle data including grid spacer effects. (orig./HP)

  11. Control Rods in high-Flux Swimming-Pool Reactors

    International Nuclear Information System (INIS)

    Control-rod problems in open swimming-pool high-flux and high specific power research reactors are examined in the light of the calibrations and experiments made during the construction of the SILOE reactor. Control-rod operating experience for this reactor at 13 MW is also described. 2. The following are considered in turn: (a) Reactivity balances and reactivity values for the different types of rod tested (cadmium, B4C , rare earths and combinations of these different elements). (b) Flux peaks set up in the core by the presence of the control rods, their incidence on the specific power, the fast fluxes that can be obtained and means of increasing them. (c ) The technological problems involved in constructing the rods. (d) In-pile cooling, vibration, deformation and scram-time problems. 3. In conclusion, current studies on control rods in open swimming-pool reactors operating in the 10 - 30 1W range are briefly summarized. (author)

  12. The integration of control rod calculation and VSOP

    International Nuclear Information System (INIS)

    Accurate calculation of the control rod outside the active zone in pebble bed HTR requires special treatment, integration of this detailed control rod calculation with whole core calculation like VSOP package requires more efforts, which is not realized before. Accurate calculation of control rod is proposed to use the discontinuity factor-corrected diffusion method accompanied with transport calculation in advance. Appropriate coupling between the control rod calculation and whole core calculation must be developed to take into account of the buckling feedback, spectrum change, data transform and so on. In this paper, internal spectrum calculation module inside VSOP is used to model the control rod region, and the neutron leakage obtained from the whole core calculation is used as the boundary condition of the control rod region. The numerical calculation demonstrated the feasibility and accuracy of this coupling and integration method. (author)

  13. Optimization and Cost Reduction by Finite Element Analysis of Connecting Rod Using Aluminum Composite

    OpenAIRE

    Naveen Lohan*,; Sandeep Nandal2

    2014-01-01

    In an engine the connecting rod connects the piston to the crankshaft. Connecting rods may also convert rotating motion into reciprocating motion. Generally connecting rod are manufactured using C70 steel. This Paper mainly focuses to reduce weight and manufacturing cost of the connecting rod by replacing existing steel material Connecting rod to Aluminium composite material connecting rod. The connecting rod is investigated with composite material that comprises aluminum as m...

  14. Sucker rod string design of the pumping systems

    OpenAIRE

    Chun Hua Liu

    2015-01-01

    The existing design of sucker rod string mainly focuses on the simplifying assumptions that rod string was exposed to simple tension loading. And its goal was to have equal modified stress at the top of each taper. The improved rod design was to have the same degree of safety at each section, and it used a dynamic force distribution that was proportional along the whole string. However, the available procedures did not provide the desired accuracy of its pertinent analysis, and the operators ...

  15. FEA ANALYSIS OF GEOMETRIC PARAMETERS OF CONNECTING ROD BIG END

    OpenAIRE

    SURENDRA PRASAD BARATAM; SANJAY B CHIKALTHANKAR; V. M. Nandedkar

    2012-01-01

    The automobile engine connecting rod is a high volume production, critical component. It connects reciprocating piston to rotating crankshaft, transmitting the thrust of the piston to the crankshaft. In order to carry out successfully the function, it is needed to grasp the rotating crankshaft and also to keep the good stiffness of the big-end of the connecting rod in acceptable ranges during engine operation. When the stiffness of the Connecting rod is needed to be reinforced, in general, so...

  16. Finite Element Analysis of Connecting Rod of IC Engine

    OpenAIRE

    Samal Prasanta Kumar; Murali B; Abhilash; Pasha Tajmul

    2015-01-01

    A connecting rod of IC engine is subjected to complex dynamic loading conditions. Therefore it is a critical machine element which attracts researchers’ attention. This paper aims at development of simple 3D model, finite element analyses and the optimization by intuition of the connecting rod for robust design. In this study the detailed load analysis under in-service loading conditions was performed for a typical connecting rod. The CAD model was prepared taking the detailed dimensions from...

  17. COMPUTER MODEL OF TEMPERATURE DISTRIBUTION IN OPTICALLY PUMPED LASER RODS

    Science.gov (United States)

    Farrukh, U. O.

    1994-01-01

    Managing the thermal energy that accumulates within a solid-state laser material under active pumping is of critical importance in the design of laser systems. Earlier models that calculated the temperature distribution in laser rods were single dimensional and assumed laser rods of infinite length. This program presents a new model which solves the temperature distribution problem for finite dimensional laser rods and calculates both the radial and axial components of temperature distribution in these rods. The modeled rod is either side-pumped or end-pumped by a continuous or a single pulse pump beam. (At the present time, the model cannot handle a multiple pulsed pump source.) The optical axis is assumed to be along the axis of the rod. The program also assumes that it is possible to cool different surfaces of the rod at different rates. The user defines the laser rod material characteristics, determines the types of cooling and pumping to be modeled, and selects the time frame desired via the input file. The program contains several self checking schemes to prevent overwriting memory blocks and to provide simple tracing of information in case of trouble. Output for the program consists of 1) an echo of the input file, 2) diffusion properties, radius and length, and time for each data block, 3) the radial increments from the center of the laser rod to the outer edge of the laser rod, and 4) the axial increments from the front of the laser rod to the other end of the rod. This program was written in Microsoft FORTRAN77 and implemented on a Tandon AT with a 287 math coprocessor. The program can also run on a VAX 750 mini-computer. It has a memory requirement of about 147 KB and was developed in 1989.

  18. Determination of reactor parameters by single fuel rod experiments

    International Nuclear Information System (INIS)

    Reactor parameters were measured by measuring neutron flux distribution in the vicinity of single fuel rod and it was shown that it can be applied for testing fuel elements. Four types of fuel elements were used, natural uranium rod, 2% enriched fuel element, and fuel clusters with 19 and 27 fuel rods. Neutron flux distribution was measured by irradiating Au and Dy foils. results were compared to results obtained by two-group and three-group neutron diffusion theory

  19. Age-Related Deterioration of Rod Vision in Mice

    OpenAIRE

    Kolesnikov, Alexander V.; Fan, Jie; Crouch, Rosalie K.; Kefalov, Vladimir J.

    2010-01-01

    Even in healthy individuals, aging leads to deterioration in visual acuity, contrast sensitivity, visual field, and dark adaptation. Little is known about the neural mechanisms that drive the age-related changes of the retina and more specifically of photoreceptors. According to one hypothesis, the age-related deterioration in rod function is due to the limited availability of 11-cis-retinal for rod pigment formation. To determine how aging affects rod photoreceptors and to test the retinoid ...

  20. Two compartment water rod for boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matzner, B.; Wolters, B.A.

    1993-07-27

    In a fuel bundle for boiling water nuclear reactor, said fuel bundle is described including a matrix of upstanding fuel rods for undergoing nuclear reaction and generating steam, a lower tie plate for supporting the matrix of fuel rods and admitting liquid water moderator to the fuel bundle from the lower portion of said fuel bundle, an upper tie plate for fastening to at least some of the fuel rods and permitting the outflow of liquid and vapor water moderator from the upper portion of said fuel bundle, a channel surrounding said upper and lower tie plates and said fuel rods therebetween for confining moderator flow between said tie plates and around said fuel rods, and a plurality of vertically spaced apart fuel rod spacers, each said spacer surrounding each said fuel rod at the particular elevation of said spacer for maintaining said fuel rods in side-by-side relation, and a water rod for installation to said fuel bundle for supplying liquid moderator to the upper two phase region of said fuel bundle, the improvement to said water rod comprising: said water rod having a first upper compartment, and a second lower compartment, said upper compartment isolated from said lower compartment; said first upper compartment defining an open, upwardly exposed end for receiving and maintaining water in said upper water rod compartment during the power generating operation of said fuel bundle will fill with liquid by gravity flow from above; means communicated to the bottom portion of said lower compartment for receiving water from said lower portion of said fuel bundle; and, means communicated to the upper portion of said lower compartment for discharging water to the interior of said fuel bundle below the upper most spacer of said fuel bundle whereby discharge to said fuel bundle occurs in said upper two phase region of said bundle.

  1. Two compartment water rod for boiling water reactors

    International Nuclear Information System (INIS)

    In a fuel bundle for boiling water nuclear reactor, said fuel bundle is described including a matrix of upstanding fuel rods for undergoing nuclear reaction and generating steam, a lower tie plate for supporting the matrix of fuel rods and admitting liquid water moderator to the fuel bundle from the lower portion of said fuel bundle, an upper tie plate for fastening to at least some of the fuel rods and permitting the outflow of liquid and vapor water moderator from the upper portion of said fuel bundle, a channel surrounding said upper and lower tie plates and said fuel rods therebetween for confining moderator flow between said tie plates and around said fuel rods, and a plurality of vertically spaced apart fuel rod spacers, each said spacer surrounding each said fuel rod at the particular elevation of said spacer for maintaining said fuel rods in side-by-side relation, and a water rod for installation to said fuel bundle for supplying liquid moderator to the upper two phase region of said fuel bundle, the improvement to said water rod comprising: said water rod having a first upper compartment, and a second lower compartment, said upper compartment isolated from said lower compartment; said first upper compartment defining an open, upwardly exposed end for receiving and maintaining water in said upper water rod compartment during the power generating operation of said fuel bundle will fill with liquid by gravity flow from above; means communicated to the bottom portion of said lower compartment for receiving water from said lower portion of said fuel bundle; and, means communicated to the upper portion of said lower compartment for discharging water to the interior of said fuel bundle below the upper most spacer of said fuel bundle whereby discharge to said fuel bundle occurs in said upper two phase region of said bundle

  2. Control rod for a pebble bed nuclear reactor

    International Nuclear Information System (INIS)

    In order to leave the density of the pebble bed unchanged when the control rod is driven in and out, the tip of the control rod is provided with moving parts in the form of conical hemispheres or spoons. These parts move close to the control rod when it is driven in and spread out due to the effect of gravity when it is driven out. This loosens the heap of pebble shaped operating elements again. (DG)

  3. Vitreous fluorophotometry in patients with cone-rod dystrophy.

    OpenAIRE

    Miyake, Y; Goto, S.; Ota, I; Ichikawa, H.

    1984-01-01

    Eight patients with cone-rod dystrophy were examined by means of vitreous fluorophotometry. The data in three patients with an early stage of retinitis pigmentosa (rod-cone dystrophy) served for comparison. In contrast with the abnormal findings on vitreous fluorophotometry in patients with an early stage of retinitis pigmentosa the value of vitreous fluorophotometry in cone-rod dystrophy was within the normal range in all patients except the two with advanced stages of this disease. Our resu...

  4. Tensile performance of braided composite rods for concrete reinforcement

    OpenAIRE

    Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Araújo, Mário Duarte de; Marques, P.

    2008-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. Eglass, car...

  5. Braided composite rods to reinforce concrete subjected to aggressive environments

    OpenAIRE

    Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Marques, P.; Araújo, Mário Duarte de

    2008-01-01

    The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. E-glass, ca...

  6. Rod-cone interaction in patients with fundus flavimaculatus.

    OpenAIRE

    Schneider, T.; Zrenner, E.

    1987-01-01

    Dark adaptation and the rise of cone flicker threshold (25 Hz) during dark adaptation were measured psychophysically in three patients with fundus flavimaculatus. The dark adaptation curve showed a delayed rod-cone break but a normal final rod threshold in all these patients. However, the rise of cone flicker threshold during dark adaptation was not delayed and also reached a normal final value. This indicates that the delay in rod dark adaptation does not influence the rise of cone flicker t...

  7. Lateral suppression of mesopic rod and cone flicker detection

    OpenAIRE

    Cao, Dingcai; Lu, Yolanda H.

    2012-01-01

    This study investigated the mechanisms of flicker detection suppression by measuring mesopic rod and cone critical flicker frequencies (CFFs) at different center and surround illuminance levels. Stimuli were generated with a four-primary photostimulator that provided independent control of rod and cone excitations. The results showed that dim surrounds ≤0.2 Td suppressed cone-mediated CFFs at ≥20 Td but not rod-mediated CFFs. These results can be understood in terms of peak amplitudes of phot...

  8. Three-phase coexistence in colloidal rod-plate mixtures

    OpenAIRE

    Woolston, Phillip; Van Duijneveldt, Jeroen S

    2015-01-01

    Aqueous suspensions of clay particles, such as montmorillonite (MMT) platelets and sepiolite (Sep) rods, tend to form gels at concentrations around 1 vol %. For Sep rods, adsorbing sodium polyacrylate to the surface allows for an isotropic-nematic phase separation to be seen instead. Here, MMT is added to such Sep suspensions, resulting in a complex phase behavior. Across a range of clay concentrations, separation into three phases is observed: a lower, nematic phase dominated by Sep rods, a ...

  9. Nuclear reactor internals construction and failed fuel rod detection system

    International Nuclear Information System (INIS)

    A system is provided for determining during operation of a nuclear reactor having fluid pressure operated control rod mechanisms the exact location of a fuel assembly with a defective fuel rod. The construction of the reactor internals is simplified in a manner to facilitate the testing for defective fuel rods and the reduce the cost of producing the upper internals of the reactor. 13 claims, 10 drawing figures

  10. The analytic method for calculating the control rod worth

    International Nuclear Information System (INIS)

    We calculated the control rod worth in this paper. To avoid complexity, we did not consider burnable poisons and soluble boron. The system was localized within one assembly. The control rod was treated as not an absorber but an another boundary. Thus all of the group constants were unchanged before and after control rod insertion. And we discussed the method for calculation of the reactivity of the whole core

  11. Process device for measuring the absorber rod position

    International Nuclear Information System (INIS)

    In gas-cooled high temperature reactors, the absorber rods can move in their longitudinal direction between two end positions. The position measurement is done indirectly by evaluating the movement of the mechanical elements of the rod drive. The translatory lifting movement of the absorber rod is converted into a rotation movement for measurement purposes and is transferred to at least two pulse transmitters per end position. (orig./HP)

  12. Immunocytochemical Evidence that Monkey Rod Bipolar Cells Use GABA

    OpenAIRE

    Lassová, Luisa; Fina, Marie; Sulaiman, Pyroja; Vard, Noga

    2010-01-01

    Certain bipolar cells in most species immunostain for GABA or its synthesizing enzyme, GAD. However it is unknown whether they actually release GABA, and if so, from which cellular compartment, and by what release mechanism. We investigated these questions in monkey retina where rod bipolar cells immunostain for GABA. We found that rod bipolar cells immunostain for one isoform of GAD, GAD65, in their somas, dendrites, and axon terminals. Near the fovea, the somatic stain of rod bipolar cells ...

  13. Numerical simulation of the sucker-rod pumping system

    OpenAIRE

    Oldrich Joel Romero; Paula Almeida

    2014-01-01

    The sucker rod pump is an artificial lift method frequently applied in onshore petroleum wells. This system can be described using a numerical simulation based on the behavior of a rod string. In the past, the elastic behavior of the rod string made it difficult to model the system. However, since the 1960s and with the advent of digital computers, it has been modeled numerically. The rod string be-haves like a slender bar, and thus, the propagation of elastic waves along the bar can be repre...

  14. Biophysical mechanism of transient retinal phototropism in rod photoreceptors

    Science.gov (United States)

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

    2016-03-01

    Oblique light stimulation evoked transient retinal phototropism (TRP) has been recently detected in frog and mouse retinas. High resolution microscopy of freshly isolated retinas indicated that the TRP is predominated by rod photoreceptors. Comparative confocal microscopy and optical coherence tomography (OCT) revealed that the TRP predominantly occurred from the photoreceptor outer segment (OS). However, biophysical mechanism of rod OS change is still unknown. In this study, frog retinal slices, which open a cross section of retinal photoreceptor and other functional layers, were used to test the effect of light stimulation on rod OS. Near infrared light microscopy was employed to monitor photoreceptor changes in retinal slices stimulated by a rectangular-shaped visible light flash. Rapid rod OS length change was observed after the stimulation delivery. The magnitude and direction of the rod OS change varied with the position of the rods within the stimulated area. In the center of stimulated region the length of the rod OS shrunk, while in the peripheral region the rod OS tip swung towards center region in the plane perpendicular to the incident stimulus light. Our experimental result and theoretical analysis suggest that the observed TRP may reflect unbalanced disc-shape change due to localized pigment bleaching. Further investigation is required to understand biochemical mechanism of the observed rod OS kinetics. Better study of the TRP may provide a noninvasive biomarker to enable early detection of age-related macular degeneration (AMD) and other diseases that are known to produce retinal photoreceptor dysfunctions.

  15. SEFLEX fuel rod simulator effects in flooding experiments. Pt. 3

    International Nuclear Information System (INIS)

    This report presents typical data and a limited heat transfer analysis from blocked bundle reflood tests of an experimental thermal-hydraulic program. Full-length bundles of 5x5 fuel rod simulators having a gas-filled gap between the Zy cladding and the alumina pellets were tested in the test rig designed for the earlier Flooding Experiments with Blocked Arrays (FEBA-program). The 5x5 FEBA rod bundle tests were performed with gapless heater rods. These rods have a close thermal contact between the stainless steel cladding and the electric insulation material. A comparison of the SEFLEX data with the reference data of FEBA obtained under identical initial and reflood conditions shows the influence of different fuel rod simulators on the thermal-hydraulic behavior during forced feed bottom reflooding of unblocked and blocked arrays. Compared to bundles of gapless rods, bundles of rods with Zy claddings and a gas filled gap between claddings and pellets, which more closely represent the features that exist in an actual fuel rod geometry, produced higher quench front velocities, enhanced removal of stored heat in the rods, reduced peak cladding temperatures, increased grid spacer effects and absolutely unproblematic coolability of 90 percent blockages with bypass. The data offer the opportunity for further validation of computer codes to make realistic predictions of safety margins during a LOCA in a PWR. (orig./HP)

  16. Detection of defects in control rods by eddy current examination

    International Nuclear Information System (INIS)

    To detect the defects of control rods in a reactor, a standard specimen including external defects, internal defects, and through-hole defects is fabricated. The eddy current signals of these defects are stored, analyzed on a PC by a program developed to acquire data of eddy currents. The optimum frequency for detecting defects of the control rods is 200 kHz. The defect location, and defect shape of the cladding in the control rods are detected by analyzing the impedance phase of the eddy current. It is confirmed that the defects in hafnium of control rods can be detected. (author)

  17. Process for tightly sealing nuclear reactor fuel rods

    International Nuclear Information System (INIS)

    This invention refers to a process for pressurising and tightly sealing fuel rods used in nuclear reactors. The fuel rods utilised in commercial nuclear reactors are usually composed of a zircaloy tubular cladding of around 15 mm in diameter and up to 5 m long, filled with fuel pellets maintained in place by end plugs sealed on each end of the cladding. The main purpose of the invention is to promote a process using laser beam welding equipment to seal the end plugs on the fuel rods, drill a pressurising hole in one of the end plugs and hermetically seal the hole after the fuel rod has been placed under pressure

  18. Customer benefits due to cycle specific fuel rod design analysis

    International Nuclear Information System (INIS)

    Plant operating conditions vary from cycle to cycle and are influenced by the core loading pattern, as well as by the plant operation itself. The goal of a fuel rod design analysis is the verification of a safe operation of the fuel rods with an optimized core design and plant operation, assessed by the fulfillment of all fuel rod design criteria. In the following, it is shown how the cycle by cycle thermo1mechanical fuel rod design analysis, based on full core information, supports this goal. The fuel rod loads during normal operation are influenced mainly by the fuel rod power histories (linear heat generation rate versus time). Therefore, the focus in the following chapters will be on the consequences of such loads (e.g. rod internal pressure, long term interaction between fuel and cladding, cladding corrosion). Other loads and possible design goals must also be considered (e.g. initial conditions for dry storage, RIA risk assessment) or evaluations of fuel rod load related to specific operational conditions. Other full core cycle by cycle evaluations are related to the verification of conservative bounds of the hot rod analysis and the extent of damage analysis. A detailed analysis of the whole core, cycle by cycle, is especially important and useful, if non1technical bounding conditions lead to untypical loading patterns like fuel tax or limited life time of plants. (orig.)

  19. Evaluation of fission gas release in Oskarshamn 2 fuel rods

    International Nuclear Information System (INIS)

    Data on fission gas release from 30 Oskarshamn 2 fuel rods is presented and analyzed. These rods were selected by gamma scanning screening measurements performed on 65 fuel rods. The rods experienced peak power levels 25-34 kW/m in the burnup range of 18.5 to 41 MWd/kg U, higher power and burnups than the previous experimental programs, the Oskarshamn 1 and Barsebeck 1 rods. As a result, a larger fraction of rods fall into the high fission gas release group. The STAV5 code is used for the analysis of fission gas release data. The code is capable in most instances to capture the experimental points. It takes as an input the fuel rod design dimensions data and power histories calculated by other ASEA-ATOM codes. With STAV5, one is enabled to treat each rod individually on the bases of its detailed power histories and its UO2 stability properties. The report includes manufacturing data, PIE data, and the description of the models used in STAV5 for gas release prediction. The results of STAV5 calculations for a number of rods are reported and several remarks for improvements have been proposed. (author)

  20. Nuclear fuel rods along the sand dunes?

    International Nuclear Information System (INIS)

    Just north of the small town of Covert, Michigan, Consumers Power Co. officials and environmental activists are locked in a battle that marks a new phase in the nation's long-running struggle over nuclear power. The company's Palisades power plant reactor needs refueling. But the utility has no more room for the spent fuel rods it must place in its water-filled storage pool. So Consumers is taking advantage of a 1990 Nuclear Regulatory Commission rule that lets utilities store waste above ground without agency review. Palisades officials plan to transfer older radioactive fuel rods from its storage pool into concrete and steel silo-like casks on a site overlooking Lake Michigan. Over the next decade, nearly half of the nation's 109 operating nuclear plants will run out of space in water-filled storage pools and be forced to consider aboveground storage. The Palisades plant is causing a stir because it is the first to exploit the 1990 NRC rule, which doesn't require utilities to seek approval for waste-storage sites as long as the waste is stored in an approved container. Before 1990, five other utilities had received the agency O.K. for above-ground storage - but only after a lengthy and exhaustive analysis of each site

  1. Fluid Dynamics in Sucker Rod Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, Robert P.; Mansure, Arthur J.

    1999-06-01

    Sucker rod pumps are installed in approximately 90% of all oil wells in the U.S. Although they have been widely used for decades, there are many issues regarding the fluid dynamics of the pump that have not been filly investigated. A project was conducted at Sandia National Laboratories to develop an improved understanding of the fluid dynamics inside a sucker rod pump. A mathematical flow model was developed to predict pressures in any pump component or an entire pump under single-phase fluid and pumping conditions. Laboratory flow tests were conducted on instrumented individual pump components and on a complete pump to verifi and refine the model. The mathematical model was then converted to a Visual Basic program to allow easy input of fluid, geometry and pump parameters and to generate output plots. Examples of issues affecting pump performance investigated with the model include the effects of viscosity, surface roughness, valve design details, plunger and valve pressure differentials, and pumping rate.

  2. Analysis of sucker rod and sinkerbar failures

    Energy Technology Data Exchange (ETDEWEB)

    Waggoner, J.R.; Buchheit, R.G.

    1992-01-01

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  3. Sucker rod coupling with protective coating

    Energy Technology Data Exchange (ETDEWEB)

    Gray, K.W.

    1990-03-06

    This patent describes a coupling adapted to be used in a string of oil well sucker rods. It comprises: a cylindrical metallic cuff having a radial face at each end and internal threads for its entire length, having a resinous coating about 0.040 inches thick bonded over all of the external surfaces, the resinous coating is fused onto the metal. This patent describes a second coupling adapted to be used in a string of oil well sucker rods. It comprises: a cylindrical metallic cuff having a radial face at each end and internal threads for its entire length, having a resinous coating bonded over all of the external surfaces, the resinous coating is fused onto the metal, a distal plug within one end of the cuff, the distal plug snugly fitting the threads of one end and covering all internal surfaces, and an eyelet plug on the other end. The eyelet plug extending within the other end and covering the threads of that end and all internal surfaces.

  4. Analysis of sucker rod and sinkerbar failures

    Energy Technology Data Exchange (ETDEWEB)

    Waggoner, J.R.; Buchheit, R.G.

    1992-12-31

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  5. Thermal phenomenae in nuclear fuel rods

    International Nuclear Information System (INIS)

    Thermal phenomenae occurring in a nuclear fuel rod under irradiation are studied. The most important parameters of either steady or transient thermal states are determined. The validity of applying the Fourier's approximation equations to these problems is also studied. A computer program TRANS is developed in order to study the transient cases. This program solves a system of coupled, non-linear partial differential equations, of parabolic type, in cylindrical coordinates with various boundary conditions. The benchmarking of the TRANS program is done by comparing its predictions with the analytical solution of some simplified transient cases. Complex transient cases such as those corresponding to characteristic reactor accidents are studied, in particular for typical pressurized heavy water reactor (PHWR) fuel rods, such as those of Atucha I. The Stefan problem emerging in the case of melting of the fuel element is solved. Qualitative differences between the classical Stefan problem, without inner sources, and that one, which includes sources are discussed. The MSA program, for solving the Stefan problem with inner sources is presented; and furthermore, it serves to predict thermal evolution, when the fuel element melts. Finally a model for fuel phase change under irradiation is developed. The model is based on the dimensional invariants of the percolation theory when applied to the connectivity of liquid spires nucleated around each fission fragment track. Suggestions for future research into the subject are also presented. (autor)

  6. Laser decontamination of the radioactive lightning rods

    International Nuclear Information System (INIS)

    Between 1970 and 1980 Brazil experienced a significant market for radioactive lightning rods (RLR). The device consists of an air terminal with one or more sources of americium-241 attached to it. The sources were used to ionize the air around them and to increase the attraction of atmospheric discharges. Because of their ineffectiveness, the nuclear regulatory authority in Brazil suspended the license for manufacturing, commerce and installation of RLR in 1989, and determined that the replaced RLR were to be collected to a centralized radioactive waste management facility for treatment. The first step for RLR treatment is to remove the radioactive sources. Though they can be easily removed, some contaminations are found all over the remaining metal scrap that must decontaminated for release, otherwise it must be treated as radioactive waste. Decontamination using various chemicals has proven to be inefficient and generates large amounts of secondary wastes. This work shows the preliminary results of the decontamination of 241Am-contaminated metal scrap generated in the treatment of radioactive lightning rods applying laser ablation. A Nd:YAG nanoseconds laser was used with 300 mJ energy leaving only a small amount of secondary waste to be treated. - Highlights: • The process generates minimal additional secondary waste. • The effectiveness of this technique may allow certain materials to be recycled reducing radioactive waste volumes. • The process allows reuse of decontaminated metals

  7. Plastic Guidance Fins for Long Rod Projectiles .

    Directory of Open Access Journals (Sweden)

    Mark L. Bundy

    1997-10-01

    Full Text Available Projectile tail fins on long rod kinetic energy (KE penetrators serve the same purpose as fletchings (feathers on an arrow, namely, they help align the projectile axis with its velocity vector. This reduces the projectile's yaw and hence reduces its aerodynamic drag. In addition, a low yaw angle at target impact helps to maximise the projectile's target penetration. It is typical for projectiles to exit the gun muzzle and enter free flight at some ndn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create a stabilising torque about the projectile's centre of gravity (CG. This torque can be increased by making the fin material lighter. Most conventional long rod penetrators fired from high performance guns have tail fins made from aluminium. However, aluminium can undergo catastrophic oxidation (rapid burning in-bore. Coating aluminium with Al/sub 2/O/sub 3/ {hardcoat prevents ignition of the substrate, provided solid propellant grain impacts do not chip the brittle hardcoat off the surface. Plastic is lighter than aluminium and less exothermic when oxidized. Therefore, other factors aside, it is conceivable that plastic fins could increase projectile stability while incurring less thermal erosion than aluminium. However, thermal loads are not the only concern when considering plastic as an alternative tail fin material. The mechanical strength of plastic is also a critical factor. This paper discusses some of the successes and failures of plastic fins, at least relatively thin fins, for use as KE stabilisers.

  8. Laser decontamination of the radioactive lightning rods

    Science.gov (United States)

    Potiens, A. J.; Dellamano, J. C.; Vicente, R.; Raele, M. P.; Wetter, N. U.; Landulfo, E.

    2014-02-01

    Between 1970 and 1980 Brazil experienced a significant market for radioactive lightning rods (RLR). The device consists of an air terminal with one or more sources of americium-241 attached to it. The sources were used to ionize the air around them and to increase the attraction of atmospheric discharges. Because of their ineffectiveness, the nuclear regulatory authority in Brazil suspended the license for manufacturing, commerce and installation of RLR in 1989, and determined that the replaced RLR were to be collected to a centralized radioactive waste management facility for treatment. The first step for RLR treatment is to remove the radioactive sources. Though they can be easily removed, some contaminations are found all over the remaining metal scrap that must decontaminated for release, otherwise it must be treated as radioactive waste. Decontamination using various chemicals has proven to be inefficient and generates large amounts of secondary wastes. This work shows the preliminary results of the decontamination of 241Am-contaminated metal scrap generated in the treatment of radioactive lightning rods applying laser ablation. A Nd:YAG nanoseconds laser was used with 300 mJ energy leaving only a small amount of secondary waste to be treated.

  9. Safety analysis of control rod drive computers

    International Nuclear Information System (INIS)

    The analysis of the most significant user programmes revealed no errors in these programmes. The evaluation of approximately 82 cumulated years of operation demonstrated that the operating system of the control rod positioning processor has a reliability that is sufficiently good for the tasks this computer has to fulfil. Computers can be used for safety relevant tasks. The experience gained with the control rod positioning processor confirms that computers are not less reliable than conventional instrumentation and control system for comparable tasks. The examination and evaluation of computers for safety relevant tasks can be done with programme analysis or statistical evaluation of the operating experience. Programme analysis is recommended for seldom used and well structured programmes. For programmes with a long, cumulated operating time a statistical evaluation is more advisable. The effort for examination and evaluation is not greater than the corresponding effort for conventional instrumentation and control systems. This project has also revealed that, where it is technologically sensible, process controlling computers or microprocessors can be qualified for safety relevant tasks without undue effort. (orig./HP)

  10. Rolls-Royce digital Rod Control System

    International Nuclear Information System (INIS)

    Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar

  11. Rolls-Royce digital Rod Control System

    Energy Technology Data Exchange (ETDEWEB)

    Pouillot, M. [Rolls-Royce Civil Nuclear SAS (France)

    2010-07-01

    Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar

  12. Process for charging a container with reactor fuel rods or absorber rods, and device for implementation of the process

    International Nuclear Information System (INIS)

    For the optimum utilisation of the vessel volume, a vessel is charged with fuel rods whose longitudinal axes are parallel to one another by first loading the vessel with imitation rods adapted in size to the real ones packed together closely in the same way as the real ones. The imitation rods are replaced by the real ones when the latter are inserted into the planned closely-packed arrangement in an axial direction. (orig./HP)

  13. Characterization of control rod worths and fuel rod power peaking factors in the university of Utah TRIGA Mark I reactor

    OpenAIRE

    Alroumi Fawaz; Kim Donghoon; Schow Ryan; Jevremovic Tatjana

    2016-01-01

    Control rod reactivity (worths) for the three control rods and fuel rod power peaking factors in the University of Utah research reactor (100 kW TRIGA Mark I) are characterized using the AGENT code system and the results described in this paper. These values are compared to the MCNP6 and existing experimental measurements. In addition, the eigenvalue, neutron spatial flux distributions and reaction rates are analyzed and discussed. The AGENT code system is ...

  14. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    Directory of Open Access Journals (Sweden)

    Nwoha Rosemary Ijeoma Ogechi

    2015-06-01

    Full Text Available Objective: To determine the effect of Ancylostoma caninum (A. caninum and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods: Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense, and GPIV was infected with Trypanosoma brucei (T. brucei/A. caninum. The dogs were first vaccinated with antirabies vaccine before infecting GPII, GPIII and GPIV with A. caninum which were done 4 weeks after vaccination. By 2-week post-vaccination, trypanosome parasites were superimposed on both GPIII and GPIV. A secondary vaccination was given to GPI, GPII, GPIII, and GPIV by Week 12 of the experiment (4 weeks post treatment. Results: The prepatent period was (3.00 ± 1.40 days, in the conjunct infection of T. brucei/ A. caninum. It was (9.00 ± 1.10 days, in conjunct T. congolense/A. caninum. The prepatent period of A. caninum was (14.0 ± 2.0 days in the single A. caninum group and (13.0 ± 1.0 days in the conjunct trypanosome/A. caninum. At the 1st week after vaccination, the antibody titer in all the vaccinated groups (GPI, GPII, GPIII, and GPIV significantly increased (P < 0.05 and peaked at the 3rd week after vaccination. Following infections, there were marked significant decreases (P < 0.05 in the antibody production against rabies in GPII, GPIII and GPIV. The significant decrease (P < 0.05 in antibody titer was highest in the conjunct groups (GPIII and GPIV compared to the single infection (GPII. Treatment with diminazene aceturate and mebendazole did not significantly improve antibody response in the dogs. A secondary vaccination administered at the 12th week after the primary vaccination significantly increased (P < 0.05 the antibody titer with a peak at the 3rd week after the secondary vaccination. Conclusions: It was therefore concluded

  15. Development of fission gas sampling system for PWR spent nuclear fuel rods and test evaluation using dummy nuclear fuel rods

    International Nuclear Information System (INIS)

    Fission gas sampling system for measuring the fission gas quantity and internal pressure of PWR spent nuclear fuel rods was developed in KAERI. This system has the advantages of reducing the time required in equilibrium pressure by using as positive pressure in the chamber when the fission gas is expanded from the fuel rod to the puncturing and standard chamber, also improving the accuracy in measuring the fuel rod internal pressure. As a results of performance evaluation test using several dummy fuel rods in the inactive region, the accuracy of measuring system appeared to be good agreement within ±5% error range

  16. Measurements of Burnout Conditions for Flow of Boiling Water in Vertical 3-Rod and 7-Rod Clusters

    International Nuclear Information System (INIS)

    The present report deals with measurements of burnout conditions for flow of boiling water in vertical 3-rod and 7-rod clusters. Data were obtained,in respect of heating the rods only, as well as for simultaneous uniform and non-uniform heating of the rods and the shroud. Totally, 520 runs were performed. In the case of equal heat fluxes on all surfaces of the channels, burnout always occurred on the rods, and the data were low by a factor of about 1.3 compared with round duct data. When only the rods were heated, the data showed very low burnout values in comparison with the results for total uniform heating and round ducts. This disagreement was explained by considering the climbing film flow model and the fact that only a fraction of the channel perimeter was heated. For simultaneous and non-uniform heating of the rods and the shroud it was found that the shroud could be overloaded up to 50 per cent without reducing the margin of safety in respect of burnout for the rod cluster. Finally, a correlation for predicting burnout conditions in round ducts, annuli and rod clusters has been presented. This correlation predicts the burnout heat fluxes for the present measurements and previously obtained annuli measurements within ± 5 per cent

  17. Calculations of control rods interference for tajoura research reactor

    International Nuclear Information System (INIS)

    Measurement or experimental determination of the total reactivity worth of the safety and all shim control rods of any research reactor is very essential for the safe operation of the reactor. Integral worth curves are usually used to pre-estimate the criticality positions of the reactor before carrying out any new experiment. These integral worth curves themselves depend very much on the criticality state at which they have been determined. In this paper the computer code CITVAP is used to investigate the shadowing or control rods interference by analytically calibrating the safety, regulating, and shim rods of the Tajoura research reactor. Because experimental integral reactivity curves are usually obtained with control rods positions corresponding to a critical state of the reactor. In our calculations the values of three cases are compared. The case at which the position of the control rods correspond to a critical or close to critical state is taken as a reference case, the values in this case are very close to the experimental values. The obtained results show that shadowing effect is very significant in research reactors, which have small cores with control rods placed close to each other and they also show that for each rod there is an upper limit value and a lower limit value for each rod integral worth and this is very important for the safe operation of the reactor. For the regulating rod which has a small integral reactivity worth, less than 0.5 in our reactor, the upper and lower limits are 0.54 βeff and 0.27 βeff respectively. For a central shim rod they are 4.4 βeff and 3.6 βeff for the other rods the values are tabulated among the results. Due to shadowing effect, the total worth calculated for all the rods together, that is the change in reactivity between the case where all rods are fully raised and the case when they are fully inserted, is higher than the sum of the worth of the individual rods each is being calibrated with the other rods are

  18. Investigation of axial power gradients near a control rod tip

    International Nuclear Information System (INIS)

    Highlights: → Pin power gradients near BWR control rod tips have been investigated. → A control rod tip is modeled in MCNP and compared to simplified 2D/3D geometry. → Small nodes increases pin power gradients; standard nodes underestimates gradients. → The MCNP results are validated against axial gamma scan of a controlled fuel pin. - Abstract: Control rod withdrawal in BWRs induces large power steps in the adjacent fuel assemblies. This paper investigates how well a 2D/3D method, e.g., CASMO5/SIMULATE5 computes axial pin power gradients adjacent to an asymmetrical control-rod tip in a BWR. The ability to predict pin power gradients accurately is important for safety considerations whereas large powers steps induced by control rod withdrawal can cause Pellet Cladding Interaction. The computation of axial pin power gradients axially around a control rod tip is a challenging task for any nodal code. On top of that, asymmetrical control rod handles are present in some BWR designs. The lattice code CASMO requires diagonal symmetry of all control rod parts. This introduces an error in computed pin power gradients that has been evaluated by Monte Carlo calculations. The results show that CASMO5/SIMULATE5, despite the asymmetrical control rod handle, is able to predict the axial pin power gradient within 1%/cm for axial nodal sizes of 15-3.68 cm. However, a nodal size of 3.68 cm still causes underestimations of pin power gradients compared with 1 cm nodes. Furthermore, if conventional node sizes are used, ∼15 cm, pin power gradients can be underestimated by over 50% compared with 1 cm nodes. The detailed axial pin power profiles from MCNP are corroborated by measured gamma scan data on fuel rods irradiated adjacent to control rods.

  19. Trypanosoma brucei gambiense Infections in Mice Lead to Tropism to the Reproductive Organs, and Horizontal and Vertical Transmission.

    Science.gov (United States)

    Biteau, Nicolas; Asencio, Corinne; Izotte, Julien; Rousseau, Benoit; Fèvre, Muriel; Pillay, Davita; Baltz, Théo

    2016-01-01

    Trypanosoma brucei gambiense, transmitted by the tsetse fly, is the main causative agent of Human African trypanosomosis in West Africa and poses a significant health risk to 70 million people. Disease progression varies depending on host immunity, but usually begins with a haemo-lymphatic phase, followed by parasite invasion of the central nervous system. In the current study, the tropism of T. b. gambiense 1135, causing a low level chronic 'silent' infection, was monitored in a murine model using bioluminescence imaging and PCR. A tropism to the reproductive organs, in addition to the central nervous system, after 12-18 months of infection was observed. Bioluminescent analysis of healthy females crossed with infected males showed that 50%, 62.5% and 37.5% of the female mice were subsequently positive for parasites in their ovaries, uteri and brain respectively. Although PCR confirmed the presence of parasites in the uterus of one of these mice, the blood of all mice was negative by PCR and LAMP. Subsequently, bioluminescent imaging of the offspring of infected female mice crossed with healthy males indicated parasites were present in the reproductive organs of both male (80%) and female (60%) offspring. These findings imply that transmission of T. b. gambiense 1135 occurs horizontally, most probably via sexual contact, and vertically in a murine model, which raises the possibility of a similar transmission in humans. This has wide reaching implications. Firstly, the observations made in this study are likely to be valid for wild animals acting as a reservoir for T. b. gambiense. Also, the reproductive organs may act as a refuge for parasites during drug treatment in a similar manner to the central nervous system. This could leave patients at risk of a relapse, ultimately allowing them to act as a reservoir for subsequent transmission by tsetse and possibly, horizontally and vertically. PMID:26735855

  20. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    Energy Technology Data Exchange (ETDEWEB)

    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R. (ULdB); (Vanderbilt); (TTU); (Toronto); (NWU); (Meharry)

    2010-01-25

    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  1. Functional and structural insights revealed by molecular dynamics simulations of an essential RNA editing ligase in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Rommie E Amaro

    Full Text Available RNA editing ligase 1 (TbREL1 is required for the survival of both the insect and bloodstream forms of Trypanosoma brucei, the parasite responsible for the devastating tropical disease African sleeping sickness. The type of RNA editing that TbREL1 is involved in is unique to the trypanosomes, and no close human homolog is known to exist. In addition, the high-resolution crystal structure revealed several unique features of the active site, making this enzyme a promising target for structure-based drug design. In this work, two 20 ns atomistic molecular dynamics (MD simulations are employed to investigate the dynamics of TbREL1, both with and without the ATP substrate present. The flexibility of the active site, dynamics of conserved residues and crystallized water molecules, and the interactions between TbREL1 and the ATP substrate are investigated and discussed in the context of TbREL1's function. Differences in local and global motion upon ATP binding suggest that two peripheral loops, unique to the trypanosomes, may be involved in interdomain signaling events. Notably, a significant structural rearrangement of the enzyme's active site occurs during the apo simulations, opening an additional cavity adjacent to the ATP binding site that could be exploited in the development of effective inhibitors directed against this protozoan parasite. Finally, ensemble averaged electrostatics calculations over the MD simulations reveal a novel putative RNA binding site, a discovery that has previously eluded scientists. Ultimately, we use the insights gained through the MD simulations to make several predictions and recommendations, which we anticipate will help direct future experimental studies and structure-based drug discovery efforts against this vital enzyme.

  2. Designing a sucker-rod pumping system for maximum efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Gault, R.H.

    1987-11-01

    Consideration of the energy requirements in the design of a sucker-rod pumping system is very important. Examples are given that detail how the use of the largest possible pump with the lightest, strongest rod string and special-geometry units can provide a substantial energy reduction.

  3. Gripping device for a cluster of nuclear fuel rods

    International Nuclear Information System (INIS)

    This device is made by a central rectangular aperture subdivided into sections by parralel partitions. Mobile spacers in these sections push each rod against the spacers. With this device it is possible to dismantle, with only one manipulation, a cluster of nuclear fuel rods

  4. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the...

  5. Control rod drive for high temperature gas cooled reactor

    Institute of Scientific and Technical Information of China (English)

    DengJun-Xian; XuJi-Ming; 等

    1998-01-01

    This control rod drive is developed for HTR-10 high temperature gas cooled test reactor.The stepmotor is prefered to improve positioning of the control rod and the scram behavior.The preliminary test in 1600170 ambient temperature shows that the selected stepmotor and transmission system can meet the main operation function requirements of HTR-10.

  6. Apparatus for consolidation of spent nuclear fuel rods

    International Nuclear Information System (INIS)

    This patent describes apparatus for the consolidation of nuclear fuel rods and compaction of their structural member within a storage pool. It comprises: a multi-axis computer controlled robot mounted above the pool, the robot having an operating arm adapted to be swung over the pool, the arm having a distal end to which is mounted a depending shaft, the shaft having a distal end to which is mounted coupling means, a frame member extending vertically within the pool below the robot, an apertured work table mounted to the frame member within the pool, the work table having vertically extending holders mounted in the apertures thereof, at least a first one of the holders being a fuel assembly holder, and a second one of the holders being adapted to hold a fuel rod canister therein, means for tilting the second one of the holders at an angle to the vertical, rod guiding means for guiding fuel rods into a fuel rod canister within the second one of the holders, long reach tools mounted adjacent the frame, at lease one of the tools having first and second ends and having coupling means adapted to couple to the coupling means on the shaft mounted on the first end and fuel rod grasping means adapted to grasp a fuel rod at the second end, tool guide means for guiding the second end to a location directly over a fuel rod in the fuel assembly

  7. Probabilistic thermo-chemical analysis of a pultruded composite rod

    DEFF Research Database (Denmark)

    Baran, Ismet; Tutum, Cem Celal; Hattel, Jesper Henri

    2012-01-01

    In the present study the deterministic thermo-chemical pultrusion simulation of a composite rod taken from the literature [7] is used as a validation case. The predicted centerline temperature and cure degree profiles of the rod match well with those in the literature [7]. Following the validation...

  8. Embedded cladding surface thermocouples on Zircaloy-sheathed heater rods

    International Nuclear Information System (INIS)

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

  9. Fuel rod behaviour analysis during normal reactor operation

    International Nuclear Information System (INIS)

    This paper describes thermal model and dimensional changes of a fuel rod. Using a fuel rod design computer program FUELROD we have analysed its behaviour for various irradiation of core in steady-state and during power cycling according to the daily powe demand. (author)

  10. Optimized Control Rods of the BR2 Reactor

    International Nuclear Information System (INIS)

    At the present time the BR-2 reactor uses control elements with cadmium as neutron absorbing part. The lower section of the control element is a beryllium assembly cooled by light water. Due to the burn up of the lower end of the cadmium section during the reactor operation, the presently used rods for reactivity control of the BR-2 reactor have to be replaced by new ones. Considered are various types Control Rods with full active part of the following materials: cadmium (Cd), hafnium (Hf), europium oxide (Eu2O3) and gadolinium (Gd2O3). Options to decrease the burn up of the control rod material in the hot spot, such as use of stainless steel in the lower active part of the Control Rod are discussed. Comparison with the characteristics of the presently used Control Rods types is performed. The changing of the characteristics of different types Control Rods and the perturbation effects on the reactor neutronics during the BR-2 fuel cycle are investigated. The burn up of the Control Rod absorbing material, total and differential control rods worth, macroscopic and effective microscopic absorption cross sections, fuel and reactivity evolution are evaluated during approximately 30 operating cycles.

  11. Material operating behaviour of ABB BWR control rods

    International Nuclear Information System (INIS)

    The BWR control rods made by ABB use boron carbide (B4C and hafnium as absorber material within a cladding of stainless steel. The general behaviour under operation has proven to be very good. ABB and many of their control rod customers have performed extensive inspection programs of control rod behaviour. However, due to changes in the material properties under fast and thermal neutron irradiation defects may occur in the control rods at high neutron fluences. Examinations of irradiated control rod materials have been performed in hot cell laboratories. The examinations have revealed the defect mechanism Irradiation Assisted Stress Corrosion Cracking (IASCC) to appear in the stainless steel cladding. For IASCC to occur three factors have to act simultaneously. Stress, material sensitization and an oxidising environment. Stress may be obtained from boron carbide swelling due to irradiation. Stainless steel may be sensitized to intergranular stress corrosion cracking under irradiation. Normally the reactor environment in a BWR is oxidising. The presentation focuses on findings from hot cell laboratory work on irradiated ABB BWR control rods and studies of irradiated control rod materials in the hot cells at PSI. Apart from physical, mechanical and microstructural examinations, isotope analyses were performed to describe the local isotopic burnup of boron. Consequences (such as possible B4C washout) of a under operation in a ABB BWR, after the occurrence of a crack is discussed based on neutron radiographic examinations of control rods operated with cracks. (author)

  12. Waste management aspects during the reprocessing of irradiated thorium rods

    International Nuclear Information System (INIS)

    Irradiated thorium rods were processed at RDL in two campaigns to recover the fissile material. The major steps involved in the process are rod charging, dissolution, solvent extraction and reconversion. The radioactive wastes that are generated from various stages of process, their management and disposal are discussed. (author)

  13. Rigid-rod push–pull naphthalenediimide photosystems

    OpenAIRE

    Sakai, Naomi; Sisson, Adam L.; Bhosale, Sheshanath; Fürstenberg, Alexandre; Banerji, Natalie Renuka; Vauthey, Eric; Matile, Stefan

    2007-01-01

    Design, synthesis and evaluation of advanced rigid-rod pi-stack photosystems with asymmetric scaffolds are reported. The influence of push-pull rods on self-organization, photoinduced charge separation and photosynthetic activity is investigated and turns out to be surprisingly small overall.

  14. Optimized Control Rods of the BR2 Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kalcheva, Silva; Koonen, E.

    2007-09-15

    At the present time the BR-2 reactor uses control elements with cadmium as neutron absorbing part. The lower section of the control element is a beryllium assembly cooled by light water. Due to the burn up of the lower end of the cadmium section during the reactor operation, the presently used rods for reactivity control of the BR-2 reactor have to be replaced by new ones. Considered are various types Control Rods with full active part of the following materials: cadmium (Cd), hafnium (Hf), europium oxide (Eu2O3) and gadolinium (Gd2O3). Options to decrease the burn up of the control rod material in the hot spot, such as use of stainless steel in the lower active part of the Control Rod are discussed. Comparison with the characteristics of the presently used Control Rods types is performed. The changing of the characteristics of different types Control Rods and the perturbation effects on the reactor neutronics during the BR-2 fuel cycle are investigated. The burn up of the Control Rod absorbing material, total and differential control rods worth, macroscopic and effective microscopic absorption cross sections, fuel and reactivity evolution are evaluated during approximately 30 operating cycles.

  15. Control rod studies in small and medium sized fast reactors

    International Nuclear Information System (INIS)

    Control rods are the primary safety mechanism in the operation of fast reactors. Neutronic parameters associated with the control rods have to be evaluated precisely for studying the behaviour of the reactor under various operating conditions. Control rods are strong neutron absorbers discretely distributed in the reactor core. Accurate estimation of control rod parameters demand, in principle transport theory solutions in exact geometry. But computer codes for such evaluations usually consume exorbitantly large computer time and memory for even a single parameter evaluation. During the design of reactors, evaluation of these parameters will be required for many configurations of control rods. In this paper, the method used at Indira Gandhi Centre for Atomic Research for estimating the parameters associated with control rods is presented. Diffusion theory solutions were used for computations. A scheme using three dimensional geometry represented by triangular meshes and diffusion theory solutions in few energy groups for control rod parameter evaluation is presented. This scheme was employed in estimating the control rod parameters in a 500 Mw(e) fast reactor. Error due to group collapsing is estimated by comparing with 25 group calculations in three dimensions for typical cases. (author). 5 refs, 4 figs, 3 tabs

  16. Axial Thermal Rotation of Slender Rods

    Science.gov (United States)

    Li, Dichuan; Fakhri, Nikta; Pasquali, Matteo; Biswal, Sibani Lisa

    2011-05-01

    Axial rotational diffusion of rodlike polymers is important in processes such as microtubule filament sliding and flagella beating. By imaging the motion of small kinks along the backbone of chains of DNA-linked colloids, we produce a direct and systematic measurement of axial rotational diffusivity of rods both in bulk solution and near a wall. The measured diffusivities decrease linearly with the chain length, irrespective of the distance from a wall, in agreement with slender-body hydrodynamics theory. Moreover, the presence of small kinks does not affect the chain’s axial diffusivity. Our system and measurements provide insights into fundamental axial diffusion processes of slender objects, which encompass a wide range of entities including biological filaments and linear polymer chains.

  17. Wear behaviour of coated sucker rod couplings

    Energy Technology Data Exchange (ETDEWEB)

    Sonego, G.H. [Black Max Downhole Tool Ltd., Alta (Canada)] Bellow, D.G. [Alberta Univ., Edmonton, AB (Canada)

    1997-12-31

    Excessive wear of sucker rod couplings and oil field tubing can cause mechanical breakdowns in conventionally pumped oil wells, especially where sand particles contaminate the crude oil. To reduce the wear of the standard AISI 8630 steel couplings they are sometimes coated with hard spray metal particles. Such coatings add an extra expense and it is questionable whether the improved wear resistance of the coupling is justified, especially if it will result in increased wear of the softer oil well tubing. This paper evaluates three such coatings: nickel tungsten, nickel chromium, and titanium oxide. These are compared with an uncoated coupling in a water and a water-sand environment. An economic assessment of the wear results is also presented. (author)

  18. Crud deposition modeling on BWR fuel rods

    International Nuclear Information System (INIS)

    Deposition of boiling water reactor (BWR) system corrosion products (crud) on operating fuel rods has resulted in performance-limiting conditions in a number of plants. The operational impact of performance-limiting conditions involving crud deposition can be detrimental to a BWR operator, resulting in unplanned or increased frequency of fuel inspections, fuel failure and associated radiological consequences, operational restrictions including core power derate and/or forced shutdowns to remove failed fuel, premature discharge of individual bundles or entire reloads, and/or undesirable core design restrictions. To facilitate improved management of crud-related fuel performance risks, EPRI has developed the CORAL (Crud DepOsition Risk Assessment ModeL) tool. This paper presents a summary of the CORAL elements and benchmarking results. Applications of CORAL as a tool for fuel performance risk assessment are also discussed. (author)

  19. Dynamics of gas-fluidized granular rods

    Science.gov (United States)

    Daniels, L. J.; Park, Y.; Lubensky, T. C.; Durian, D. J.

    2009-04-01

    We study a quasi-two-dimensional monolayer of granular rods fluidized by a spatially and temporally homogeneous upflow of air. By tracking the position and orientation of the particles, we characterize the dynamics of the system with sufficient resolution to observe ballistic motion at the shortest time scales. Particle anisotropy gives rise to dynamical anisotropy and superdiffusive dynamics parallel to the rod’s long axis, causing the parallel and perpendicular mean-square displacements to become diffusive on different time scales. The distributions of free times and free paths between collisions deviate from exponential behavior, underscoring the nonthermal character of the particle motion. The dynamics show evidence of rotational-translational coupling similar to that of an anisotropic Brownian particle. We model rotational-translational coupling in the single-particle dynamics with a modified Langevin model using nonthermal noise sources. This suggests a phenomenological approach to thinking about collections of self-propelling particles in terms of enhanced memory effects.

  20. Wideband Circularly Polarized Dielectric Rod Antenna

    Directory of Open Access Journals (Sweden)

    Min Guo

    2012-01-01

    Full Text Available A new dielectric rod antenna (DRA is introduced to produce circular polarization (CP over a wide frequency band without a complex feed network. Along with the simulated results, measured results of the antenna prototype are presented, showing a 3 dB axial ratio (AR CP bandwidth of 17.7%. The radiation characteristics of the fabricated antenna are also demonstrated showing the measured gain of better than 6.2 dBi. Moreover, the measured impedance bandwidth (VSWR ≤2 reaches 20.1%, from 8.75 GHz to 10.7 GHz, while the CP beamwidth (AR ≤3 dB at the central frequency is measured over 120°.