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Sample records for plasmalogen analogue bearing

  1. Identification of plasmalogen in the gut of silkworm (Bombyx mori).

    Science.gov (United States)

    Aboshi, Takako; Nishida, Ritsuo; Mori, Naoki

    2012-08-01

    Herbivorous insect species are constantly challenged with endogenous and exogenous oxidative stress. Consequently, they possess an array of antioxidant enzymes and small molecular weight antioxidants. Lipid-soluble small molecular antioxidants, such as tocopherols, have not been well studied in insects but may play important antioxidant roles. In this study, we identified plasmalogen phosphatidylethanolamines (pPEs) as well as α-, β/γ-, δ-tocopherol in the larvae of the silkworm Bombyx mori by LCMS analyses and examined their distribution. Plasmalogen are reported to inhibit the metal ion induced oxidation. The composition of tocopherols was the same among gut contents, gut tissues, and the other tissues. However, plasmalogens, a unique class of glycerophospholipids rich in polyunsaturated fatty acids and containing a vinyl ether bond at the sn-1 position, were mainly distributed in gut tissues. Plasmalogens might protect gut tissues from oxidation stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Plasmalogens Inhibit APP Processing by Directly Affecting γ-Secretase Activity in Alzheimer's Disease

    Science.gov (United States)

    Rothhaar, Tatjana L.; Grösgen, Sven; Haupenthal, Viola J.; Burg, Verena K.; Hundsdörfer, Benjamin; Mett, Janine; Riemenschneider, Matthias; Grimm, Heike S.; Hartmann, Tobias; Grimm, Marcus O. W.

    2012-01-01

    Lipids play an important role as risk or protective factors in Alzheimer's disease (AD). Previously it has been shown that plasmalogens, the major brain phospholipids, are altered in AD. However, it remained unclear whether plasmalogens themselves are able to modulate amyloid precursor protein (APP) processing or if the reduced plasmalogen level is a consequence of AD. Here we identify the plasmalogens which are altered in human AD postmortem brains and investigate their impact on APP processing resulting in Aβ production. All tested plasmalogen species showed a reduction in γ-secretase activity whereas β- and α-secretase activity mainly remained unchanged. Plasmalogens directly affected γ-secretase activity, protein and RNA level of the secretases were unaffected, pointing towards a direct influence of plasmalogens on γ-secretase activity. Plasmalogens were also able to decrease γ-secretase activity in human postmortem AD brains emphasizing the impact of plasmalogens in AD. In summary our findings show that decreased plasmalogen levels are not only a consequence of AD but that plasmalogens also decrease APP processing by directly affecting γ-secretase activity, resulting in a vicious cycle: Aβ reduces plasmalogen levels and reduced plasmalogen levels directly increase γ-secretase activity leading to an even stronger production of Aβ peptides. PMID:22547976

  3. Human and great ape red blood cells differ in plasmalogen levels and composition.

    Science.gov (United States)

    Moser, Ann B; Steinberg, Steven J; Watkins, Paul A; Moser, Hugo W; Ramaswamy, Krishna; Siegmund, Kimberly D; Lee, D Rick; Ely, John J; Ryder, Oliver A; Hacia, Joseph G

    2011-06-17

    Plasmalogens are ether phospholipids required for normal mammalian developmental, physiological, and cognitive functions. They have been proposed to act as membrane antioxidants and reservoirs of polyunsaturated fatty acids as well as influence intracellular signaling and membrane dynamics. Plasmalogens are particularly enriched in cells and tissues of the human nervous, immune, and cardiovascular systems. Humans with severely reduced plasmalogen levels have reduced life spans, abnormal neurological development, skeletal dysplasia, impaired respiration, and cataracts. Plasmalogen deficiency is also found in the brain tissue of individuals with Alzheimer disease. In a human and great ape cohort, we measured the red blood cell (RBC) levels of the most abundant types of plasmalogens. Total RBC plasmalogen levels were lower in humans than bonobos, chimpanzees, and gorillas, but higher than orangutans. There were especially pronounced cross-species differences in the levels of plasmalogens with a C16:0 moiety at the sn-1 position. Humans on Western or vegan diets had comparable total RBC plasmalogen levels, but the latter group showed moderately higher levels of plasmalogens with a C18:1 moiety at the sn-1 position. We did not find robust sex-specific differences in human or chimpanzee RBC plasmalogen levels or composition. Furthermore, human and great ape skin fibroblasts showed only modest differences in peroxisomal plasmalogen biosynthetic activity. Human and chimpanzee microarray data indicated that genes involved in plasmalogen biosynthesis show cross-species differential expression in multiple tissues. We propose that the observed differences in human and great ape RBC plasmalogens are primarily caused by their rates of biosynthesis and/or turnover. Gene expression data raise the possibility that other human and great ape cells and tissues differ in plasmalogen levels. Based on the phenotypes of humans and rodents with plasmalogen disorders, we propose that cross

  4. Human and great ape red blood cells differ in plasmalogen levels and composition

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    Ely John J

    2011-06-01

    Full Text Available Abstract Background Plasmalogens are ether phospholipids required for normal mammalian developmental, physiological, and cognitive functions. They have been proposed to act as membrane antioxidants and reservoirs of polyunsaturated fatty acids as well as influence intracellular signaling and membrane dynamics. Plasmalogens are particularly enriched in cells and tissues of the human nervous, immune, and cardiovascular systems. Humans with severely reduced plasmalogen levels have reduced life spans, abnormal neurological development, skeletal dysplasia, impaired respiration, and cataracts. Plasmalogen deficiency is also found in the brain tissue of individuals with Alzheimer disease. Results In a human and great ape cohort, we measured the red blood cell (RBC levels of the most abundant types of plasmalogens. Total RBC plasmalogen levels were lower in humans than bonobos, chimpanzees, and gorillas, but higher than orangutans. There were especially pronounced cross-species differences in the levels of plasmalogens with a C16:0 moiety at the sn-1 position. Humans on Western or vegan diets had comparable total RBC plasmalogen levels, but the latter group showed moderately higher levels of plasmalogens with a C18:1 moiety at the sn-1 position. We did not find robust sex-specific differences in human or chimpanzee RBC plasmalogen levels or composition. Furthermore, human and great ape skin fibroblasts showed only modest differences in peroxisomal plasmalogen biosynthetic activity. Human and chimpanzee microarray data indicated that genes involved in plasmalogen biosynthesis show cross-species differential expression in multiple tissues. Conclusion We propose that the observed differences in human and great ape RBC plasmalogens are primarily caused by their rates of biosynthesis and/or turnover. Gene expression data raise the possibility that other human and great ape cells and tissues differ in plasmalogen levels. Based on the phenotypes of humans and

  5. Antineoplastic Activities of MT81 and Its Structural Analogue in Ehrlich Ascites Carcinoma-Bearing Swiss Albino Mice

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    Sujata Maiti Choudhury

    2010-01-01

    Full Text Available Many fungal toxins exhibit in vitro and in vivo antineoplastic effects on various cancer cell types. Luteoskyrin, a hydroxyanthraquinone has been proved to be a potent inhibitor against Ehrlich ascites tumor cells. The comparative antitumor activity and antioxidant status of MT81 and its structural analogue [Acetic acid-MT81 (Aa-MT81] having polyhydroxyanthraquinone structure were assessed against Ehrlich ascites carcinoma (EAC tumor in mice. The in vitro cytotoxicity was measured by the viability of EAC cells after direct treatment of the said compounds. In in vivo study, MT81 and its structural analogue were administered (i.p. at the two different doses (5, 7 mg MT81; 8.93, 11.48 mg Aa-MT81/kg body weight for 7 days after 24 hrs. of tumor inoculation. The activities were assessed using mean survival time (MST, increased life span (ILS, tumor volume, viable tumor cell count, peritoneal cell count, protein percentage and hematological parameters. Antioxidant status was determined by malondialdehyde (MDA and reduced glutathione (GSH content, and by the activity of superoxide dismutase (SOD and catalase (CA T. MT81 and its structural analogues increased the mean survival time, normal peritoneal cell count. They decreased the tumor volume, viable tumor cell count, hemoglobin percentage and packed cell volume. Differential counts of WBC, total counts of RBC & WBC that altered by EAC inoculation, were restored in a dose-dependent manner. Increased MDA and decreased GSH content and reduced activity of SOD, and catalase in EAC bearing mice were returned towards normal after the treatment of MT81 and its structural analogue. Being less toxic than parent toxin MT81, the structural analogue showed more prominent antineoplastic activities against EAC cells compared to MT81. At the same time, both compounds exhibit to some extent antioxidant potential for the EAC-bearing mice.

  6. Peramivir analogues bearing hydrophilic side chains exhibit higher activities against H275Y mutant than wild-type influenza virus.

    Science.gov (United States)

    Chiu, Din-Chi; Lin, Tzu-Chen; Huang, Wen-I; Cheng, Ting-Jen; Tsai, Keng-Chang; Fang, Jim-Min

    2017-11-29

    Peramivir is an effective anti-influenza drug in the clinical treatment of influenza, but its efficacy toward the H275Y mutant is reduced. The previously reported cocrystal structures of inhibitors in the mutant neuraminidase (NA) suggest that the hydrophobic side chain should be at the origin of reduced binding affinity. In contrast, zanamivir having a hydrophilic glycerol side chain still possesses high affinity toward the H275Y NA. We thus designed five peramivir analogues (5-9) carrying hydrophilic glycol or glycerol side chains, and evaluated their roles in anti-influenza activity, especially for the H275Y mutant. The synthetic sequence involves a key step of (3 + 2) cycloaddition reactions between alkenes and nitrile oxides to construct the scaffold of peramivir carrying the desired hydrophilic side chains and other appropriate functional groups. The molecular docking experiments reveal that the hydrophilic side chain can provide extra hydrogen bonding with the translocated Glu-276 residue in the H275Y NA active site. Thus, the H275Y mutant may be even more sensitive than wild-type virus toward the peramivir analogues bearing hydrophilic side chains. Notably, the peramivir analogue bearing a glycerol side chain inhibits the H275Y mutant with an IC 50 value of 35 nM, which is better than the WSN virus by 9 fold.

  7. 8-Amido-Bearing pseudomycin B (PSB) analogue: novel antifungal agents.

    Science.gov (United States)

    Zhang, Y Z; Sun, X; Zeckner, D J; Sachs, R K; Current, W L; Chen, S H

    2001-01-22

    During the course of a structure-activity relationship (SAR) study on novel depsinonapeptide pseudomycin B, we synthesized a total of 12 8-amidopseudomycin analogues via standard two-step sequence from either ZPSB 2 or AllocPSB 3. A number of these amides exhibited good in vitro antifungal activities.

  8. Deuterium nuclear magnetic resonance studies on the plasmalogens and the glycerol acetals of plasmalogens of Clostridium butyricum and Clostridium beijerinckii

    International Nuclear Information System (INIS)

    Malthaner, M.; Seelig, J.; Johnston, N.C.; Goldfine, H.

    1987-01-01

    Deuterium nuclear magnetic resonance was used to investigate the structure of different lipid fractions isolated from the anaerobic bacteria Clostridium butyricum and Clostridium beijerinckii. The fractions isolated from C. butyricum were (1) phosphatidylethanolamine/plasmenylethanolamine and (2) the glycerol acetal of plasmenylethanolamine, and from C. beijerinckii similar fractions containing principally (1) phosphatidyl-N-monomethylethanolamine, along with its plasmalogen, and (2) the glycerol acetal of this plasmalogen were isolated. The third fraction from both species consisted largely of the acidic lipids phosphatidylglycerol and cardiolipin along with plasmalogen forms of these lipids. Palmitic acid with deuterium labels at C-2, C-3, or C-4 or oleic acid with deuterium labels at C-2 and C-9,10 was added to the growth medium and incorporated to various extents in the lipid fractions. Biochemical analysis showed that palmitic acid and oleic acid were preferentially bound to the sn-2 and sn-1 positions, respectively, of the glycerol backbone when both fatty acids were added to the medium. From the 2 H NMR spectra, the hydrocarbon chain ordering near the lipid-water interface could be determined and appeared to be similar for all three lipid fractions. The deuterium quadrupole splitting and order parameter were low at the C-2 segment and increased by almost a factor of 2 at positions C-3 and C-4 for cells fed with deuteriated palmitic acid along with unlabeled oleic acid. These results agree with previous findings on pure diacyl lipids in which the sn-2 chain was found to adopt a bent conformation at the carbon segment C-2. However, two unusual quadrupole splittings could be detected for the plasmalogens. By comparison with other model systems it could be concluded that the double bond is aligned essentially parallel with the long axis of the hydrocarbon chains

  9. In vitro and in vivo plasmalogen replacement evaluations in rhizomelic chrondrodysplasia punctata and Pelizaeus-Merzbacher disease using PPI-1011, an ether lipid plasmalogen precursor

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    Wood Paul L

    2011-10-01

    Full Text Available Abstract Background Childhood peroxisomal disorders and leukodystrophies are devastating diseases characterized by dysfunctional lipid metabolism. Plasmalogens (ether glycerophosphoethanolamine lipids are decreased in these genetic disorders. The biosynthesis of plasmalogens is initiated in peroxisomes but completed in the endoplasmic reticulum. We therefore undertook a study to evaluate the ability of a 3-substituted, 1-alkyl, 2-acyl glyceryl ether lipid (PPI-1011 to replace plasmalogens in rhizomelic chrondrodysplasia punctata type 1 (RCDP1 and rhizomelic chrondrodysplasia punctata type 2 (RCDP2 lymphocytes which possess peroxisomal mutations culminating in deficient plasmalogen synthesis. We also examined plasmalogen synthesis in Pelizaeus-Merzbacher disease (PMD lymphocytes which possess a proteolipid protein-1 (PLP1 missense mutation that results in abnormal PLP1 folding and it's accumulation in the endoplasmic reticulum (ER, the cellular site of the last steps in plasmalogen synthesis. In vivo incorporation of plasmalogen precursor into tissue plasmalogens was also evaluated in the Pex7 mouse model of plasmalogen deficiency. Results In both RCDP1 and RCDP2 lymphocytes, PPI-1011 repleted the target ethanolamine plasmalogen (PlsEtn16:0/22:6 in a concentration dependent manner. In addition, deacylation/reacylation reactions resulted in repletion of PlsEtn 16:0/20:4 in both RCDP1 and RCDP2 lymphocytes, repletion of PlsEtn 16:0/18:1 and PlsEtn 16:0/18:2 in RCDP2 lymphocytes, and partial repletion of PlsEtn 16:0/18:1 and PlsEtn 16:0/18:2 in RCDP1 lymphocytes. In the Pex7 mouse, oral dosing of labeled PPI-1011 demonstrated repletion of tissue levels of the target plasmalogen PlsEtn 16:0/22:6 with phospholipid remodeling also resulting in significant repletion of PlsEtn 16:0/20:4 and PlsEtn 16:0/18:1. Metabolic conversion of PPI-1011 to the target plasmalogen was most active in the liver. Conclusions Our data demonstrate that PPI-1011 is activated

  10. Membrane plasmalogen composition and cellular cholesterol regulation: a structure activity study

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    Su-Myat Khine K

    2010-06-01

    Full Text Available Abstract Background Disrupted cholesterol regulation leading to increased circulating and membrane cholesterol levels is implicated in many age-related chronic diseases such as cardiovascular disease (CVD, Alzheimer's disease (AD, and cancer. In vitro and ex vivo cellular plasmalogen deficiency models have been shown to exhibit impaired intra- and extra-cellular processing of cholesterol. Furthermore, depleted brain plasmalogens have been implicated in AD and serum plasmalogen deficiencies have been linked to AD, CVD, and cancer. Results Using plasmalogen deficient (NRel-4 and plasmalogen sufficient (HEK293 cells we investigated the effect of species-dependent plasmalogen restoration/augmentation on membrane cholesterol processing. The results of these studies indicate that the esterification of cholesterol is dependent upon the amount of polyunsaturated fatty acid (PUFA-containing ethanolamine plasmalogen (PlsEtn present in the membrane. We further elucidate that the concentration-dependent increase in esterified cholesterol observed with PUFA-PlsEtn was due to a concentration-dependent increase in sterol-O-acyltransferase-1 (SOAT1 levels, an observation not reproduced by 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA reductase inhibition. Conclusion The present study describes a novel mechanism of cholesterol regulation that is consistent with clinical and epidemiological studies of cholesterol, aging and disease. Specifically, the present study describes how selective membrane PUFA-PlsEtn enhancement can be achieved using 1-alkyl-2-PUFA glycerols and through this action reduce levels of total and free cholesterol in cells.

  11. Gaucher disease: plasmalogen levels in relation to primary lipid abnormalities and oxidative stress.

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    Moraitou, Marina; Dimitriou, Evangelia; Dekker, Nick; Monopolis, Ioannis; Aerts, Johannes; Michelakakis, Helen

    2014-01-01

    Plasmalogens represent a unique class of phospholipids. Reduced red blood cell plasmalogen levels in Gaucher disease patients were reported, correlating to total disease burden. The relation between plasmalogen abnormalities in Gaucher disease patients and primary glycosphingolipid abnormalities, malonyldialdehyde levels, an indicator of lipid peroxidation, and the total antioxidant status was further investigated. Significant reduction of C16:0 and C18:0 plasmalogens in red blood cells of Gaucher disease patients was confirmed. In parallel, a significant increase in the glucosylceramide/ceramide ratio in red blood cell membranes, as well as an average 200-fold increase in plasma glucosylsphingosine levels was observed. Red blood cell malonyldialdehyde levels were significantly increased in patients, whereas their total antioxidant status was significantly reduced. A negative correlation between plasmalogen species and glucosylceramide, ceramide, glucosylceramide/ceramide ratio, glucosylsphingosine and malonyldialdehyde, significant for the C16:0 species and all the above parameters with the exception of malonyldialdehyde levels, was found along with a positive non-significant correlation with the total antioxidant status. Our results indicate that increased lipid peroxidation and reduced total antioxidant status exist in Gaucher disease patients. They demonstrate a clear link between plasmalogen levels and the primary glycolipid abnormalities characterizing the disorder and an association with the increased oxidative stress observed in Gaucher disease patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Possible role for plasmalogens in protecting animal cells against photosensitized killing

    International Nuclear Information System (INIS)

    Zoeller, R.A.; Morand, O.H.; Raetz, C.R.

    1988-01-01

    Chinese hamster ovary (CHO) cells incorporate 12-(1'-pyrene) dodecanoic acid (P12) into membrane lipids. Exposure of P12-labeled cells to long wavelength ultraviolet light causes cell killing, presumably because excitation of the pyrene moiety (a photosensitizer) leads to the generation of reactive oxygen species. Cytotoxicity is dependent upon the concentration of P12 used to label the cells, and time of UV exposure, and the presence of oxygen during irradiation. CHO mutant cells deficient in plasmalogen biosynthesis and peroxisome assembly are several orders of magnitude more sensitive to P12/UV treatment than wild-type cells, permitting direct selection of one wild-type cell in 1 X 10(4) mutant cells. A major factor responsible for the P12/UV hypersensitivity of these mutants appears to be the absence of plasmalogens. Supplementation of the mutants with 1-O-hexadecyl-sn-glycerol restores plasmalogen levels and nearly normal resistance to P12/UV treatment, whereas the biogenesis of peroxisomes is not restored. The P12/UV hypersensitivity of the plasmalogen-deficient mutants, together with the selective, P12/UV-induced decomposition of plasmalogens in wild-type cells, documented in the accompanying manuscript, suggest that the vinyl ether linkage of plasmalogens plays a direct role in protecting animal cell membranes against certain oxidative stresses

  13. Tyrocidine A Analogues Bearing the Planar d-Phe-2-Abz Turn Motif: How Conformation Impacts Bioactivity.

    Science.gov (United States)

    Cameron, Alan J; Edwards, Patrick J B; Harjes, Elena; Sarojini, Vijayalekshmi

    2017-12-14

    The d-Phe-Pro β-turn of the cyclic β-hairpin antimicrobial decapeptide tyrocidine A, (Tyrc A) was substituted with the d-Phe-2-aminobenzoic acid (2-Abz) motif in a synthetic analogue (1). The NMR structure of 1 demonstrated that compound 1 retained the β-hairpin structure of Tyrc A with additional planarity, resulting in approximately 30-fold reduced hemolysis than Tyrc A. Although antibacterial activity was partially compromised, a single Gln to Lys substitution (2) restored activity equivalent to Tyrc A against S. aureus, enhanced activity against two Gram negative strains and maintained the reduced hemeloysis of 1. Analysis by transmission electron microscopy (TEM) suggested a membrane lytic mechanism of action for these peptides. Compound 2 also exhibits nanomolar antifungal activity in synergy with amphotericin B. The d-Phe-2-Abz turn may serve as a tool for the synthesis of structurally predictable β-hairpin libraries. Unlike traditional β-turn motifs such as d-Pro-Gly, both the 2-Abz and d-Phe rings may be further functionalized.

  14. 1.45 A resolution crystal structure of recombinant PNP in complex with a pM multisubstrate analogue inhibitor bearing one feature of the postulated transition state

    International Nuclear Information System (INIS)

    Chojnowski, Grzegorz; Breer, Katarzyna; Narczyk, Marta; Wielgus-Kutrowska, Beata; Czapinska, Honorata; Hashimoto, Mariko; Hikishima, Sadao; Yokomatsu, Tsutomu; Bochtler, Matthias; Girstun, Agnieszka; Staron, Krzysztof; Bzowska, Agnieszka

    2010-01-01

    Low molecular mass purine nucleoside phosphorylases (PNPs, E.C. 2.4.2.1) are homotrimeric enzymes that are tightly inhibited by immucillins. Due to the positive charge on the ribose like part (iminoribitol moiety) and protonation of the N7 atom of the purine ring, immucillins are believed to act as transition state analogues. Over a wide range of concentrations, immucillins bind with strong negative cooperativity to PNPs, so that only every third binding site of the enzyme is occupied (third-of-the-sites binding). 9-(5',5'-difluoro-5'-phosphonopentyl)-9-deazaguanine (DFPP-DG) shares with immucillins the protonation of the N7, but not the positive charge on the ribose like part of the molecule. We have previously shown that DFPP-DG interacts with PNPs with subnanomolar inhibition constant. Here, we report additional biochemical experiments to demonstrate that the inhibitor can be bound with the same K d (∼190 pM) to all three substrate binding sites of the trimeric PNP, and a crystal structure of PNP in complex with DFPP-DG at 1.45 A resolution, the highest resolution published for PNPs so far. The crystals contain the full PNP homotrimer in the asymmetric unit. DFPP-DG molecules are bound in superimposable manner and with full occupancies to all three PNP subunits. Thus the postulated third-of-the-sites binding of immucillins should be rather attribute to the second feature of the transition state, ribooxocarbenium ion character of the ligand or to the coexistence of both features characteristic for the transition state. The DFPP-DG/PNP complex structure confirms the earlier observations, that the loop from Pro57 to Gly66 covering the phosphate-binding site cannot be stabilized by phosphonate analogues. The loop from Glu250 to Gln266 covering the base-binding site is organized by the interactions of Asn243 with the Hoogsteen edge of the purine base of analogues bearing one feature of the postulated transition state (protonated N7 position).

  15. Covalent adduct formation between the plasmalogen-derived modification product 2-chlorohexadecanal and phloretin

    OpenAIRE

    ?llen, Andreas; Nusshold, Christoph; Glasnov, Toma; Saf, Robert; Cantillo, David; Eibinger, Gerald; Reicher, Helga; Fauler, G?nter; Bernhart, Eva; Hallstrom, Seth; Kogelnik, Nora; Zangger, Klaus; Oliver Kappe, C.; Malle, Ernst; Sattler, Wolfgang

    2015-01-01

    Hypochlorous acid added as reagent or generated by the myeloperoxidase (MPO)-H2O2-Cl? system oxidatively modifies brain ether-phospholipids (plasmalogens). This reaction generates a sn2-acyl-lysophospholipid and chlorinated fatty aldehydes. 2-Chlorohexadecanal (2-ClHDA), a prototypic member of chlorinated long-chain fatty aldehydes, has potent neurotoxic potential by inflicting blood?brain barrier (BBB) damage. During earlier studies we could show that the dihydrochalcone-type polyphenol phlo...

  16. Effect of ethanol amine plasmalogens on Fe-induced peroxidation of arachidonic acid in dipalmitoylphosphatidylcholine vesicles.

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    Omodeo Salè, M F; Rizzo, A M; Masserini, M

    2000-12-01

    We have investigated the influence of ethanolamine plasmalogens on iron-induced oxidation of arachidonic acid in dipalmitoylphosphatidylcholine (DPPC) vesicles. Lipoperoxidation was induced by the addition of 50 microM FeSO4 and studied above (50 degrees C) and below (15 degrees C) the gel-to liquid transition temperature of the vesicles, at two different pH values (7.4 or 6.4). The extent of peroxidation was measured as thiobarbituric reactive product formed and the influence exerted by ethanolamine plasmalogens (PEPL) in this process was compared to that of dipalmitoylphosphatidylethanolamine (DPPE) and diacylphosphatidylethanolamines (DAPE). The extent of peroxidation of arachidonic acid embedded in DPPC vesicles was similar at the two temperatures and greater at 50 degrees C under acidic conditions. However, the peroxidative process was significantly decreased at 50 degrees C in the presence of PEPL, but not of DPPE or DAPE and the inhibitory effect was enhanced at pH 6.4. The possibility that a different phase distribution of the phospholipids, namely a transition from a lamellar to a hexagonal phase, may play a role in the scavenger effect of ethanolamine plasmalogens is discussed.

  17. Functional characteristics of spirilloxanthin and keto-bearing Analogues in light-harvesting LH2 complexes from Rhodobacter sphaeroides with a genetically modified carotenoid synthesis pathway.

    Science.gov (United States)

    Niedzwiedzki, Dariusz M; Dilbeck, Preston L; Tang, Qun; Mothersole, David J; Martin, Elizabeth C; Bocian, David F; Holten, Dewey; Hunter, C Neil

    2015-01-01

    Light-harvesting 2 (LH2) complexes from a genetically modified strain of the purple photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. Carotenoid synthesis in the Rba. sphaeroides strain was engineered to redirect carotenoid production away from spheroidene into the spirilloxanthin synthesis pathway. The strain assembles LH2 antennas with substantial amounts of spirilloxanthin (total double-bond conjugation length N=13) if grown anaerobically and of keto-bearing long-chain analogs [2-ketoanhydrorhodovibrin (N=13), 2-ketospirilloxanthin (N=14) and 2,2'-diketospirilloxanthin (N=15)] if grown semi-aerobically (with ratios that depend on growth conditions). We present the photophysical, electronic, and vibrational properties of these carotenoids, both isolated in organic media and assembled within LH2 complexes. Measurements of excited-state energy transfer to the array of excitonically coupled bacteriochlorophyll a molecules (B850) show that the mean lifetime of the first singlet excited state (S1) of the long-chain (N≥13) carotenoids does not change appreciably between organic media and the protein environment. In each case, the S1 state appears to lie lower in energy than that of B850. The energy-transfer yield is ~0.4 in LH2 (from the strain grown aerobically or semi-aerobically), which is less than half that achieved for LH2 that contains short-chain (N≤11) analogues. Collectively, the results suggest that the S1 excited state of the long-chain (N≥13) carotenoids participates little if at all in carotenoid-to-BChl a energy transfer, which occurs predominantly via the carotenoid S2 excited state in these antennas. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Oral bioavailability of the ether lipid plasmalogen precursor, PPI-1011, in the rabbit: a new therapeutic strategy for Alzheimer's disease

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    Wood Paul L

    2011-12-01

    Full Text Available Abstract Introduction Docosahexaenoic acid (DHA and DHA-containing ethanolamine plasmalogens (PlsEtn are decreased in the brain, liver and the circulation in Alzheimer's disease. Decreased supply of plasmalogen precursors to the brain by the liver, as a result of peroxisomal deficits is a process that probably starts early in the AD disease process. To overcome this metabolic compromise, we have designed an orally bioavailable DHA-containing ether lipid precursor of plasmalogens. PPI-1011 is an alkyl-diacyl plasmalogen precursor with palmitic acid at sn-1, DHA at sn-2 and lipoic acid at sn-3. This study outlines the oral pharmacokinetics of this precursor and its conversion to PlsEtn and phosphatidylethanolamines (PtdEtn. Methods Rabbits were dosed orally with PPI-1011 in hard gelatin capsules for time-course and dose response studies. Incorporation into PlsEtn and PtdEtn was monitored by LC-MS/MS. Metabolism of released lipoic acid was monitored by GC-MS. To monitor the metabolic fate of different components of PPI-1011, we labeled the sn-1 palmitic acid, sn-2 DHA and glycerol backbone with13C and monitored their metabolic fates by LC-MS/MS. Results PPI-1011 was not detected in plasma suggesting rapid release of sn-3 lipoic acid via gut lipases. This conclusion was supported by peak levels of lipoic acid metabolites in the plasma 3 hours after dosing. While PPI-1011 did not gain access to the plasma, it increased circulating levels of DHA-containing PlsEtn and PtdEtn. Labeling experiments demonstrated that the PtdEtn increases resulted from increased availability of DHA released via remodeling at sn-2 of phospholipids derived from PPI-1011. This release of DHA peaked at 6 hrs while increases in phospholipids peaked at 12 hr. Increases in circulating PlsEtn were more complex. Labeling experiments demonstrated that increases in the target PlsEtn, 16:0/22:6, consisted of 2 pools. In one pool, the intact precursor received a sn-3

  19. Identification of Plasmalogen Cardiolipins from Pectinatus by Liquid Chromatography-High Resolution Electrospray Ionization Tandem Mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Matoulková, D.; Kyselová, I.; Sigler, Karel

    2013-01-01

    Roč. 48, č. 12 (2013), s. 1237-1251 ISSN 0024-4201 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Pectinatus * Plasmalogens * Cardiolipins Subject RIV: EE - Microbiology, Virology Impact factor: 2.353, year: 2013

  20. Biosynthesis of ether-phospholipids including plasmalogens, peroxisomes and human disease: new insights into an old problem

    NARCIS (Netherlands)

    Wanders, Ronald J. A.; Brites, Pedro

    2010-01-01

    Ether-phospholipids represent an important subclass of phospholipids in animal cell membranes characterized by the presence of an ether bond at the sn-I position and the enrichment of PUFAs at the sn-2 position. Of the different ether-phospholipids, plasmalogens are the most abundant form and their

  1. Analogue Gravity

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    Barceló Carlos

    2005-12-01

    Full Text Available Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  2. Analogue Gravity

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    Carlos Barceló

    2011-05-01

    Full Text Available Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  3. Covalent adduct formation between the plasmalogen-derived modification product 2-chlorohexadecanal and phloretin

    Science.gov (United States)

    Üllen, Andreas; Nusshold, Christoph; Glasnov, Toma; Saf, Robert; Cantillo, David; Eibinger, Gerald; Reicher, Helga; Fauler, Günter; Bernhart, Eva; Hallstrom, Seth; Kogelnik, Nora; Zangger, Klaus; Oliver Kappe, C.; Malle, Ernst; Sattler, Wolfgang

    2015-01-01

    Hypochlorous acid added as reagent or generated by the myeloperoxidase (MPO)-H2O2-Cl− system oxidatively modifies brain ether-phospholipids (plasmalogens). This reaction generates a sn2-acyl-lysophospholipid and chlorinated fatty aldehydes. 2-Chlorohexadecanal (2-ClHDA), a prototypic member of chlorinated long-chain fatty aldehydes, has potent neurotoxic potential by inflicting blood–brain barrier (BBB) damage. During earlier studies we could show that the dihydrochalcone-type polyphenol phloretin attenuated 2-ClHDA-induced BBB dysfunction. To clarify the underlying mechanism(s) we now investigated the possibility of covalent adduct formation between 2-ClHDA and phloretin. Coincubation of 2-ClHDA and phloretin in phosphatidylcholine liposomes revealed a half-life of 2-ClHDA of approx. 120 min, decaying at a rate of 5.9 × 10−3 min−1. NMR studies and enthalpy calculations suggested that 2-ClHDA-phloretin adduct formation occurs via electrophilic aromatic substitution followed by hemiacetal formation on the A-ring of phloretin. Adduct characterization by high-resolution mass spectroscopy confirmed these results. In contrast to 2-ClHDA, the covalent 2-ClHDA-phloretin adduct was without adverse effects on MTT reduction (an indicator for metabolic activity), cellular adenine nucleotide content, and barrier function of brain microvascular endothelial cells (BMVEC). Of note, 2-ClHDA-phloretin adduct formation was also observed in BMVEC cultures. Intraperitoneal application and subsequent GC–MS analysis of brain lipid extracts revealed that phloretin is able to penetrate the BBB of C57BL/6J mice. Data of the present study indicate that phloretin scavenges 2-ClHDA, thereby attenuating 2-ClHDA-mediated brain endothelial cell dysfunction. We here identify a detoxification pathway for a prototypic chlorinated fatty aldehyde (generated via the MPO axis) that compromises BBB function in vitro and in vivo. PMID:25576489

  4. Plasmalogens rescue neuronal cell death through an activation of AKT and ERK survival signaling.

    Directory of Open Access Journals (Sweden)

    Md Shamim Hossain

    Full Text Available Neuronal cells are susceptible to many stresses, which will cause the apoptosis and neurodegenerative diseases. The precise molecular mechanism behind the neuronal protection against these apoptotic stimuli is necessary for drug discovery. In the present study, we have found that plasmalogens (Pls, which are glycerophospholipids containing vinyl ether linkage at sn-1 position, can protect the neuronal cell death upon serum deprivation. Interestingly, caspse-9, but not caspase-8 and caspase-12, was cleaved upon the serum starvation in Neuro-2A cells. Pls treatments effectively reduced the activation of caspase-9. Furthermore, cellular signaling experiments showed that Pls enhanced phosphorylation of the phosphoinositide 3-kinase (PI3K-dependent serine/threonine-specific protein kinase AKT and extracellular-signal-regulated kinases ERK1/2. PI3K/AKT inhibitor LY294002 and MAPK/ERK kinase (MEK inhibitor U0126 treatments study clearly indicated that Pls-mediated cell survival was dependent on the activation of these kinases. In addition, Pls also inhibited primary mouse hippocampal neuronal cell death induced by nutrient deprivation, which was associated with the inhibition of caspase-9 and caspase-3 cleavages. It was reported that Pls content decreased in the brain of the Alzheimer's patients, which indicated that the reduction of Pls content could endanger neurons. The present findings, taken together, suggest that Pls have an anti-apoptotic action in the brain. Further studies on precise mechanisms of Pls-mediated protection against cell death may lead us to establish a novel therapeutic approach to cure neurodegenerative disorders.

  5. Natural analogue studies in crystalline rock: the influence of water-bearing fractures on radionuclide immobilisation in a granitic rock repository

    International Nuclear Information System (INIS)

    Alexander, W.R.; MacKenzie, A.B.; Scott, R.D.; McKinley, I.G.

    1990-06-01

    Current Swiss concepts for the disposal of radioactive waste involve disposal in deep mined repositories to ensure that only insignificant quantities of radionuclides will ever reach the surface and so enter the biosphere. The rock formations presently considered as potential candidates for hosting radwaste repositories have thus been selected on the basis of their capacity to isolate radionuclides from the biosphere. An important factor in ensuring such containment is a very low solute transport rate through the host formation. However, it is considered likely that, in the formations of interest in the Swiss programme (eg. granites, argillaceous sediments, anhydrite), the rocks will be fractured to some extent even at repository depth. In the instance of the cumulative failure of near-field barriers in the repository, these hydraulically connected fractures in the host formation could be very important far-field routes of migration (and possible sites of retardation) of radionuclides dissolved in the groundwaters. In this context, the so-called 'matrix diffusion' mechanism is potentially very important for radionuclide retardation. This report is the culmination of a programme which has attempted to assess the potential influence of these water-bearing fractures on radionuclide transport in a crystalline rock radwaste repository. 162 refs., 36 figs., 16 tabs

  6. Gas chromatography/mass spectrometry analysis of very long chain fatty acids, docosahexaenoic acid, phytanic acid and plasmalogen for the screening of peroxisomal disorders

    NARCIS (Netherlands)

    Takemoto, Yasuhiko; Suzuki, Yasuyuki; Horibe, Ryoko; Shimozawa, Nobuyuki; Wanders, Ronald J. A.; Kondo, Naomi

    2003-01-01

    Very long chain fatty acids (VLCFAs) and docosahexaenoic acid (DHA), phytanic acid, and plasmalogens are usually measured individually. A novel method for the screening of peroxisomal disorders, using gas chromatography/mass spectrometry (GC/MS), was developed. Saturated and unsaturated fatty acids,

  7. BALANOL ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to a solid phase methodology for the preparation of a combinatorial library of structural analogues of the natural product balanol (ophiocordin, azepinostatin), which is a protein kinase C (PKC) and protein kinase A (PKA) inhibitor. The method comprises solid...

  8. Quantum analogue computing.

    Science.gov (United States)

    Kendon, Vivien M; Nemoto, Kae; Munro, William J

    2010-08-13

    We briefly review what a quantum computer is, what it promises to do for us and why it is so hard to build one. Among the first applications anticipated to bear fruit is the quantum simulation of quantum systems. While most quantum computation is an extension of classical digital computation, quantum simulation differs fundamentally in how the data are encoded in the quantum computer. To perform a quantum simulation, the Hilbert space of the system to be simulated is mapped directly onto the Hilbert space of the (logical) qubits in the quantum computer. This type of direct correspondence is how data are encoded in a classical analogue computer. There is no binary encoding, and increasing precision becomes exponentially costly: an extra bit of precision doubles the size of the computer. This has important consequences for both the precision and error-correction requirements of quantum simulation, and significant open questions remain about its practicality. It also means that the quantum version of analogue computers, continuous-variable quantum computers, becomes an equally efficient architecture for quantum simulation. Lessons from past use of classical analogue computers can help us to build better quantum simulators in future.

  9. Neuronal Orphan G-Protein Coupled Receptor Proteins Mediate Plasmalogens-Induced Activation of ERK and Akt Signaling.

    Directory of Open Access Journals (Sweden)

    Md Shamim Hossain

    Full Text Available The special glycerophospholipids plasmalogens (Pls are enriched in the brain and reported to prevent neuronal cell death by enhancing phosphorylation of Akt and ERK signaling in neuronal cells. Though the activation of Akt and ERK was found to be necessary for the neuronal cells survival, it was not known how Pls enhanced cellular signaling. To answer this question, we searched for neuronal specific orphan GPCR (G-protein coupled receptor proteins, since these proteins were believed to play a role in cellular signal transduction through the lipid rafts, where both Pls and some GPCRs were found to be enriched. In the present study, pan GPCR inhibitor significantly reduced Pls-induced ERK signaling in neuronal cells, suggesting that Pls could activate GPCRs to induce signaling. We then checked mRNA expression of 19 orphan GPCRs and 10 of them were found to be highly expressed in neuronal cells. The knockdown of these 10 neuronal specific GPCRs by short hairpin (sh-RNA lentiviral particles revealed that the Pls-mediated phosphorylation of ERK was inhibited in GPR1, GPR19, GPR21, GPR27 and GPR61 knockdown cells. We further found that the overexpression of these GPCRs enhanced Pls-mediated phosphorylation of ERK and Akt in cells. Most interestingly, the GPCRs-mediated cellular signaling was reduced significantly when the endogenous Pls were reduced. Our cumulative data, for the first time, suggest a possible mechanism for Pls-induced cellular signaling in the nervous system.

  10. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  11. A comprehensive lipidomic screen of pancreatic β-cells using mass spectroscopy defines novel features of glucose-stimulated turnover of neutral lipids, sphingolipids and plasmalogens

    Directory of Open Access Journals (Sweden)

    Gemma L. Pearson

    2016-06-01

    Full Text Available Objective: Glucose promotes lipid remodelling in pancreatic β-cells, and this is thought to contribute to the regulation of insulin secretion, but the metabolic pathways and potential signalling intermediates have not been fully elaborated. Methods: Using mass spectrometry (MS we quantified changes in approximately 300 lipid metabolites in MIN6 β-cells and isolated mouse islets following 1 h stimulation with glucose. Flux through sphingolipid pathways was also assessed in 3H-sphinganine-labelled cells using TLC. Results: Glucose specifically activates the conversion of triacylglycerol (TAG to diacylglycerol (DAG. This leads indirectly to the formation of 18:1 monoacylglycerol (MAG, via degradation of saturated/monounsaturated DAG species, such as 16:0_18:1 DAG, which are the most abundant, immediate products of glucose-stimulated TAG hydrolysis. However, 16:0-containing, di-saturated DAG species are a better direct marker of TAG hydrolysis since, unlike the 18:1-containing DAGs, they are predominately formed via this route. Using multiple reaction monitoring, we confirmed that in islets under basal conditions, 18:1 MAG is the most abundant species. We further demonstrated a novel site of glucose to enhance the conversion of ceramide to sphingomyelin (SM and galactosylceramide (GalCer. Flux and product:precursor analyses suggest regulation of the enzyme SM synthase, which would constitute a separate mechanism for localized generation of DAG in response to glucose. Phosphatidylcholine (PC plasmalogen (P species, specifically those containing 20:4, 22:5 and 22:6 side chains, were also diminished in the presence of glucose, whereas the more abundant phosphatidylethanolamine plasmalogens were unchanged. Conclusion: Our results highlight 18:1 MAG, GalCer, PC(P and DAG/SM as potential contributors to metabolic stimulus-secretion coupling. Author Video: Author Video Watch what authors say about their articles Keywords: Pancreatic β-cell, Insulin

  12. Plasmalogen enrichment in exosomes secreted by a nematode parasite versus those derived from its mouse host: implications for exosome stability and biology

    Directory of Open Access Journals (Sweden)

    Fabio Simbari

    2016-07-01

    Full Text Available Extracellular vesicles (EVs mediate communication between cells and organisms across all 3 kingdoms of life. Several reports have demonstrated that EVs can transfer molecules between phylogenetically diverse species and can be used by parasites to alter the properties of the host environment. Whilst the concept of vesicle secretion and uptake is broad reaching, the molecular composition of these complexes is expected to be diverse based on the physiology and environmental niche of different organisms. Exosomes are one class of EVs originally defined based on their endocytic origin, as these derive from multivesicular bodies that then fuse with the plasma membrane releasing them into the extracellular environment. The term exosome has also been used to describe any small EVs recovered by high-speed ultracentrifugation, irrespective of origin since this is not always well characterized. Here, we use comparative global lipidomic analysis to examine the composition of EVs, which we term exosomes, that are secreted by the gastrointestinal nematode, Heligmosomoides polygyrus, in relation to exosomes secreted by cells of its murine host. Ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS analysis reveals a 9- to 62-fold enrichment of plasmalogens, as well as other classes of ether glycerophospholipids, along with a relative lack of cholesterol and sphingomyelin (SM in the nematode exosomes compared with those secreted by murine cells. Biophysical analyses of the membrane dynamics of these exosomes demonstrate increased rigidity in those from the nematode, and parallel studies with synthetic vesicles support a role of plasmalogens in stabilizing the membrane structure. These results suggest that nematodes can maintain exosome membrane structure and integrity through increased plasmalogens, compensating for diminished levels of other lipids, including cholesterol and SM. This work also illuminates the prevalence of

  13. Statin action enriches HDL3 in polyunsaturated phospholipids and plasmalogens and reduces LDL-derived phospholipid hydroperoxides in atherogenic mixed dyslipidemia

    Science.gov (United States)

    Tan, Ricardo; Giral, Philippe; Robillard, Paul; Kontush, Anatol; Chapman, M. John

    2016-01-01

    Atherogenic mixed dyslipidemia associates with oxidative stress and defective HDL antioxidative function in metabolic syndrome (MetS). The impact of statin treatment on the capacity of HDL to inactivate LDL-derived, redox-active phospholipid hydroperoxides (PCOOHs) in MetS is indeterminate. Insulin-resistant, hypertriglyceridemic, hypertensive, obese males were treated with pitavastatin (4 mg/day) for 180 days, resulting in marked reduction in plasma TGs (−41%) and LDL-cholesterol (−38%), with minor effects on HDL-cholesterol and apoAI. Native plasma LDL (baseline vs. 180 days) was oxidized by aqueous free radicals under mild conditions in vitro either alone or in the presence of the corresponding pre- or poststatin HDL2 or HDL3 at authentic plasma mass ratios. Lipidomic analyses revealed that statin treatment i) reduced the content of oxidizable polyunsaturated phosphatidylcholine (PUPC) species containing DHA and linoleic acid in LDL; ii) preferentially increased the content of PUPC species containing arachidonic acid (AA) in small, dense HDL3; iii) induced significant elevation in the content of phosphatidylcholine and phosphatidylethanolamine (PE) plasmalogens containing AA and DHA in HDL3; and iv) induced formation of HDL3 particles with increased capacity to inactivate PCOOH with formation of redox-inactive phospholipid hydroxide. Statin action attenuated LDL oxidability Concomitantly, the capacity of HDL3 to inactivate redox-active PCOOH was enhanced relative to HDL2, consistent with preferential enrichment of PE plasmalogens and PUPC in HDL3. PMID:27581680

  14. Analogue MIMO Detection

    Directory of Open Access Journals (Sweden)

    McNamara Darren

    2006-01-01

    Full Text Available In this contribution we propose an analogue receiver that can perform turbo detection in MIMO systems. We present the case for a receiver that is built from nonlinear analogue devices, which perform detection in a "free-flow" network (no notion of iterations. This contribution can be viewed as an extension of analogue turbo decoder concepts to include MIMO detection. These first analogue implementations report reductions of few orders of magnitude in the number of required transistors and in consumed energy, and the same order of improvement in processing speed. It is anticipated that such analogue MIMO decoder could bring about the same advantages, when compared to traditional digital implementations.

  15. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  16. Impact of a Standard Rodent Chow Diet on Tissue n-6 Fatty Acids, Δ9-Desaturation Index, and Plasmalogen Mass in Rats Fed for One Year.

    Science.gov (United States)

    Pédrono, F; Boulier-Monthéan, N; Catheline, D; Legrand, P

    2015-11-01

    Although many studies focus on senescence mechanisms, few habitually consider age as a biological parameter. Considering the effect of interactions between food and age on metabolism, here we depict the lipid framework of 12 tissues isolated from Sprague-Dawley rats fed standard rodent chow over 1 year, an age below which animals are commonly studied. The aim is to define relevant markers of lipid metabolism influenced by age in performing a fatty acid (FA) and dimethylacetal profile from total lipids. First, our results confirm impregnation of adipose and muscular tissues with medium-chain FA derived from maternal milk during early infancy. Secondly, when animals were switched to standard croquettes, tissues were remarkably enriched in n-6 FA and especially 18:2n-6. This impregnation over time was coupled with a decrease of the desaturation index and correlated with lower activities of hepatic Δ5- and Δ6-desaturases. In parallel, we emphasize the singular status of testis, where 22:5n-6, 24:4n-6, and 24:5n-6 were exceptionally accumulated with growth. Thirdly, 18:1n-7, usually found as a discrete FA, greatly accrued over the course of time, mostly in liver and coupled with Δ9-desaturase expression. Fourthly, skeletal muscle was characterized by a surprising enrichment of 22:6n-3 in adults, which tended to decline in older rats. Finally, plasmalogen-derived dimethylacetals were specifically abundant in brain, erythrocytes, lung, and heart. Most notably, a shift in the fatty aldehyde moiety was observed, especially in brain and erythrocytes, implying that red blood cell analysis could be a good indicator of brain plasmalogens.

  17. A preliminary feasibility study on natural analogue in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byung Yun

    2000-03-01

    Preliminary study on the assessment of natural analogue study in Korea for the deep geological disposal of high-level radioactive waste was carried out. The project on natural analogue study in other countries are introduced. The uranium-bearing deposit in Okcheon belt are summarized, which reported to be uranium-bearing minerals in order to assess to feasibility for natural analogue study in Korea. Among the uranium-bearing deposits, the Deokpyeong area, reported to be the highest reservoir and grade, are selected as the study site, and the elementary investigation, including survey of radioactivity and geochemistry are carried out. According to the investigation of surface environment, the radioactivity and uranium content in the surface water and shallow groundwater does not show any anormal values. However, the radioactivity is expected to be increased in depth and the groundwater reacted with uranium-bearing graphite formation shows high unanium content, indicating the potential possibility for natural analogue study in Korea. In future, if more detail study are performed, the assessment of natural analogue study in Korea are expected.

  18. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  19. Grizzly bear

    Science.gov (United States)

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  20. A novel lunar bed rest analogue.

    Science.gov (United States)

    Cavanagh, Peter R; Rice, Andrea J; Licata, Angelo A; Kuklis, Matthew M; Novotny, Sara C; Genc, Kerim O; Englehaupt, Ricki K; Hanson, Andrea M

    2013-11-01

    Humans will eventually return to the Moon and thus there is a need for a ground-based analogue to enable the study of physiological adaptations to lunar gravity. An important unanswered question is whether or not living on the lunar surface will provide adequate loading of the musculoskeletal system to prevent or attenuate the bone loss that is seen in microgravity. Previous simulations have involved tilting subjects to an approximately 9.5 degrees angle to achieve a lunar gravity component parallel to the long-axis of the body. However, subjects in these earlier simulations were not weight-bearing, and thus these protocols did not provide an analogue for load on the musculoskeletal system. We present a novel analogue which includes the capability to simulate standing and sitting in a lunar loading environment. A bed oriented at a 9.5 degrees angle was mounted on six linear bearings and was free to travel with one degree of freedom along rails. This allowed approximately 1/6 body weight loading of the feet during standing. "Lunar" sitting was also successfully simulated. A feasibility study demonstrated that the analogue was tolerated by subjects for 6 d of continuous bed rest and that the reaction forces at the feet during periods of standing were a reasonable simulation of lunar standing. During the 6 d, mean change in the volume of the quadriceps muscles was -1.6% +/- 1.7%. The proposed analogue would appear to be an acceptable simulation of lunar gravity and deserves further exploration in studies of longer duration.

  1. Analogue circuits simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mendo, C

    1988-09-01

    Most analogue simulators have evolved from SPICE. The history and description of SPICE-like simulators are given. From a mathematical formulation of the electronic circuit the following analysis are possible: DC, AC, transient, noise, distortion, Worst Case and Statistical.

  2. Synthesis of ribavirin 2’-Me-C-nucleoside analogues

    Directory of Open Access Journals (Sweden)

    Fanny Cosson

    2017-04-01

    Full Text Available An efficient synthetic pathway leading to two carbonated analogues of ribavirin is described. The key-steps in the synthesis of these ribosyltriazoles bearing a quaternary carbon atom in the 2’-position are an indium-mediated alkynylation and a 1,3-dipolar cyclization.

  3. ACTINOMYCIN D ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to new compounds being structurally and functionally similar to Actinomycin D and to combinatorial libraries of such compounds. The Actinomycin D analogues according to the present invention comprise two linear or cyclic peptide moieties constituted by $g...

  4. Cobalamin analogues in humans

    DEFF Research Database (Denmark)

    Hardlei, Tore Forsingdal; Obeid, Rima; Herrmann, Wolfgang

    2013-01-01

    BACKGROUND: Haptocorrin (HC) carries cobalamin analogues (CorA), but whether CorA are produced in the body is unknown. All cobalamins (Cbl) to the foetus are delivered by the Cbl-specific protein transcobalamin (TC), and therefore analysis of cord serum for CorA may help to clarify the origin...

  5. NATURAL ANALOGUE SYNTHESIS REPORT

    International Nuclear Information System (INIS)

    Simmons, A.M.

    2004-01-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the Yucca Mountain Site Description (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature along with results of quantitative studies conducted specifically for the Yucca Mountain Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement-drift degradation, waste-form degradation, waste-package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated-zone (SZ) transport, impact of radionuclide release on the biosphere

  6. Natural Analogue Synthesis Report

    Energy Technology Data Exchange (ETDEWEB)

    A. M. Simmons

    2002-05-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the ''Yucca Mountain Site Description'' (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature, along with results of quantitative studies conducted specifically for the Yucca Mountain Site Characterization Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement drift degradation, waste form degradation, waste package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated zone (SZ) transport

  7. CEC natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1986-01-01

    The second meeting of the CEC Natural Analogue Working Group took place on June 17-19, 1986, hosted by the Swiss NAGRA in Interlaken (CH). A review of recent progress in natural analogue programmes was carried out, and complemented by detailed discussions about geomicrobiology, archaeological analogues, natural colloids, and use of analogues to increase confidence in safety assessments for radioactive waste disposal. A statement drafted by the Group, and the presentations made, are put together in this report

  8. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  9. CEC Natural Analogue Working Group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1989-01-01

    The central theme for the third meeting of the CEC analogue working group was ''How can analogue data be used for performance assessments, both in support of the results and for presentation to the public''. This report puts together the most recent achievements in this field, together with a review of on-going natural analogue programmes

  10. Natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.

    1986-01-01

    A Natural Analogue Working Group was established by the Commission of the European Communities in 1985. The purpose of this group is to bring together modellers with earth scientists and others, so that maximum benefit can be obtained from natural analogue studies with a view to safe geological disposal of radioactive waste. The first meeting of this group was held in Brussels from November 5 to 7, 1985. The discussions mainly concerned the identification of the modellers' needs and of the earth scientists' capacity to provide for them. Following the debates, a written statement was produced by the Group; this document forms the core of the present Report. Notes and outlines of many of the presentations made are grouped in four appendixes. The valuable contribution of all those involved in the meeting is gratefully acknowledged

  11. Targeted metabolomics reveals reduced levels of polyunsaturated choline plasmalogens and a smaller dimethylarginine/arginine ratio in the follicular fluid of patients with a diminished ovarian reserve.

    Science.gov (United States)

    de la Barca, J M Chao; Boueilh, T; Simard, G; Boucret, L; Ferré-L'Hotellier, V; Tessier, L; Gadras, C; Bouet, P E; Descamps, P; Procaccio, V; Reynier, P; May-Panloup, P

    2017-11-01

    Does the metabolomic profile of the follicular fluid (FF) of patients with a diminished ovarian reserve (DOR) differ from that of patients with a normal ovarian reserve (NOR)? The metabolomic signature of the FF reveals a significant decrease in polyunsaturated choline plasmalogens and methyl arginine transferase activity in DOR patients compared to NOR patients. The composition of the FF reflects the exchanges between the oocyte and its microenvironment during its acquisition of gametic competence. Studies of the FF have allowed identification of biomarkers and metabolic pathways involved in various pathologies affecting oocyte quality, but no large metabolomic analysis in the context of ovarian ageing and DOR has been undertaken so far. This was an observational study of the FF retrieved from 57 women undergoing in vitro fertilization at the University Hospital of Angers, France, from November 2015 to September 2016. The women were classified in two groups: one including 28 DOR patients, and the other including 29 NOR patients, serving as controls. Patients were enrolled in the morning of oocyte retrieval after ovarian stimulation. Once the oocytes were isolated for fertilization and culture, the FF was pooled and centrifuged for analysis. A targeted quantitative metabolomic analysis was performed using high-performance liquid chromatography coupled with tandem mass spectrometry, and the Biocrates Absolute IDQ p180 kit. The FF levels of 188 metabolites and several sums and ratios of metabolic significance were assessed by multivariate and univariate analyses. A total of 136 metabolites were accurately quantified and used for calculating 23 sums and ratios. Samples were randomly divided into training and validation sets. The training set, allowed the construction of multivariate statistical models with a projection-supervised method, i.e. orthogonal partial least squares discriminant analysis (OPLS-DA), applied to the full set of metabolites, or the penalized

  12. Aspartame and Its Analogues

    Science.gov (United States)

    Pavlova, L. A.; Komarova, T. V.; Davidovich, Yurii A.; Rogozhin, S. V.

    1981-04-01

    The results of studies on the biochemistry of the sweet taste are briefly reviewed. The methods of synthesis of "aspartame" — a sweet dipeptide — are considered, its structural analogues are described, and quantitative estimates are made of the degree of sweetness relative to sucrose. Attention is concentrated mainly on problems of the relation between the structure of the substance and its taste in the series of aspartyl derivatives. The bibliography includes 118 references.

  13. The Palmottu analogue project

    International Nuclear Information System (INIS)

    Ahonen, L.; Blomqvist, R.; Suksi, J.

    1993-01-01

    The report gives a summary of the results of investigations carried out in 1992 at the Palmottu natural analogue study site, which is a small U-Th mineralization in Nummi-Pusula, southwestern Finland. Additionally, the report includes several separate articles dealing with various aspects of the Palmottu Analogue Project: (1) deep groundwater flow, (2) interpretation of hydraulic connections, (3) characterization of groundwater colloids, (4) uranium mineral-groundwater equilibrium, (5) water-rock interaction and (6) modelling of in situ matrix diffusion. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes (1) structural interpretations partly based on geophysical measurements, (2) hydrological studies including hydraulic drill-hole measurements, (3) flow modelling, (4) hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, (5) mineralogical studies, (6) geochemical interpretation and modelling, (7) studies of radionuclide mobilization and retardation including matrix diffusion, and (8) modelling of uranium series data. Palaeohydrogeological aspects, due to the anticipated future glaciation of the Fennoscandian Shield, are of special interest. Quaternary sediments are studied to gain information on post-glacial migration in the overburden. (orig.)

  14. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  15. Journal Bearings

    Directory of Open Access Journals (Sweden)

    Renato Brancati

    1999-01-01

    determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

  16. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  17. Revealing Television's Analogue Heroes

    Directory of Open Access Journals (Sweden)

    Vanessa Jackson

    2013-12-01

    Full Text Available In this article I will argue that we need to create new archival models in order to preserve and share knowledge of historical, ‘hidden’ television professions and production cultures. Oral history traditions of recording life stories give us a useful starting point. Engineering ‘encounters’ between skilled television technicians, and the now obsolete equipment they operated in the 1970s and 80s, is challenging for a myriad of reasons, but videoing the interaction of man and machine provides us with a rich insight into how analogue television was produced and broadcast. Social media enables us to disseminate these histories in new and innovative ways..

  18. Identification of long and very long chain fatty acids, plasmalogen-C16:0 and phytanic acid as new lipid biomarkers in Tunisian coronary artery disease patients.

    Science.gov (United States)

    Hadj Ahmed, Samia; Koubaa, Nadia; Kharroubi, Wafa; Zarrouk, Amira; Mnari, Amira; Batbout, Fethi; Gamra, Habib; Hammami, Sonia; Lizard, Gérard; Hammami, Mohamed

    2017-07-01

    Long and very long chain fatty acids (LCFAs and VLCFAs) may play an active role in coronary artery diseases (CAD) etiology. Our aim was to evaluate the associations between LCPUFAs (C20:4n-6; C20:5n-3 and C22:6n-3) and VLCSFAs (C22:0, C24:0; and C26:0), as well as markers of peroxisomal integrity evaluated by phytanic acid and plasmalogen-C16:0 (PL-C16:0) in addition to the markers of lipid peroxidation (malondialdehyde [MDA] and conjugated dienes [CD]) and inflammation (high sensitivity C-reactive protein [hs-CRP]) with vascular severity evaluated by Gensini score in order to determine their possible effects on CAD in Tunisian population. Lipidomic strategy based on GC/MS-SIM was used to quantify LCPUFAs, VLCSFAs, and PL-C16:0 in red blood cells of CAD patients, non-CAD patients, and controls. We observed a significant increase in phytanic acid, PL-C16:0 and VLCFAs, particularly C26:0, in CAD group compared to controls. Further our findings showed positive correlations of C26:0 with MDA and with vascular severity score (Gensini score). In addition, a significant negative correlation was shown between hs-CRP and C22:6 n-3 (r=-0.297; p=0.002) and a significant positive association was observed between hs-CRP and C20:4 n-6 levels (r=0.196; p=0.039). Our results show changes in LCPUFAs and VLCSFAs concentrations in RBC among study groups, and suggest alterations in fatty acids metabolism regulated by elongase and desaturase enzymes. The positive correlations of C20:4n-6 and the negative correlations of C22:6n-3, simultaneously with Gensini score and hs-CRP, suggest a link of both inflammation and vascular severity complication of CAD with LCPUFAs and VLCSFAs. Induction of lipid oxidation, can be one of the outcomes of LCFAs and VLCFAs accumulation in vascular tissues and, thus, playing an important role in the pathogenesis of atherosclerosis. Quantification of LCPUFAs and VLCSFAs, phytanic acid and PL-C16:0 simultaneously, would be of great value for the screening of

  19. Fungal growth inhibitory properties of new phytosphingolipid analogues.

    Science.gov (United States)

    Mormeneo, D; Manresa, A; Casas, J; Llebaria, A; Delgado, A

    2008-04-01

    To study the growth inhibitory properties of a series of phytosphingosine (PHS) and phytoceramide (PHC) analogues. A panel of two yeast (Candida albicans and Saccharomyces cerevisiae) and six moulds (Aspergillus repens, Aspergillus niger, Penicillium chrysogenum, Cladosporium cladosporioides, Arthroderma uncinatum and Penicillium funiculosum) has been used in this study. A series of new PHS and PHC analogues differing at the sphingoid backbone and the functional group at C1 position were synthesized. Among PHS analogues, 1-azido derivative 1c, bearing the natural D-ribo stereochemistry, showed a promising growth inhibitory profile. Among PHC analogues, compound 12, with a bulky N-pivaloyl group and a Z double bond at C3 position of the sphingoid chain, was the most active growth inhibitor. Minimal inhibitory concentration values were in the range of 23-48 micromol l(-1) for 1c and 44-87 micromol l(-1) for 12. Only scattered data on the antifungal activity of phytosphingolipids have been reported in the literature. This is the first time that a series of analogues of this kind are tested and compared to discern their structural requirements for antifungal activity.

  20. Alligator Rivers analogue project

    International Nuclear Information System (INIS)

    Duerden, P.

    1990-01-01

    Australian Nuclear Science and Technology Organization has extensively evaluated uranium ore bodies in the Alligator Rivers Uranium Province in Australia as analogues of radioactive waste repositories. The work was extended for a three-year program as an international project based on the Koongarra uranium deposit and sponsored by the OECD Nuclear Energy Agency. The technical program comprises six major sub-projects involving modelling and experimental work: modelling of radionuclide migration; hydrogeology of the Koongarra uranium deposit; uranium/thorium series disequilibria studies; groundwater and colloid studies; fission product studies; transuranic nuclide studies; an outline of the technical programs and a summary of progress in the technical sub-projects is given. This is followed by a series of technical reports which briefly describe current research tasks, and which have been separately indexed

  1. A Short Term Analogue Memory

    DEFF Research Database (Denmark)

    Shah, Peter Jivan

    1992-01-01

    A short term analogue memory is described. It is based on a well-known sample-hold topology in which leakage currents have been minimized partly by circuit design and partly by layout techniques. Measurements on a test chip implemented in a standard 2.4 micron analogue CMOS process show a droop...

  2. Biosynthesis of plasmalogens by the microsomal fraction of Fischer R-3259 sarcoma. Influence of specific 2-acyl chains on the desaturation of 1-alkyl-2-acyl-sn-gycero-3-phosphoethanolamine

    Energy Technology Data Exchange (ETDEWEB)

    Wykle, R.L.; Schremmer, J.M.

    1979-08-07

    In the Fischer R-3259 sarcoma, ethanolamine plasmalogens are synthesized from 1-akyl-2-acyl-sn-glycero-3-phosphoethanolamine by a microsomal desaturase that inserts a ..delta../sup 1/ double bond in the alkyl chain. In the present study, a series of 1-(1-/sup 14/C)hexadecyl-2-acyl-GPE substrates containing specific acyl groups ranging from C/sub 2/ /sub 0/ to C/sub 20/ /sub 4/ at the 2 position were prepared and tested as substrates for the microsomal ..delta../sup 1/-alkyl desaturase. The microsomal preparations contained an acyl hydrolase that removed the C/sub 2/ /sub 0/, C/sub 4/ /sub 0/, and C/sub 7/ /sub 0/ acyl groups from the 2 position. By inhibiting the hydrolase with diisopropyl fluorophosphate, it was possible to test conversion of the unaltered substrates to plasmalogens. The alkyl desaturase exhibited little discrimination among the specific acyl derivatives tested. The highest rate of desaturation was obtained with 1-(1-/sup 14/C)-hexadecyl-2-acyl-GPE synthesized in situ in the microsomes via acylation of 1-(1-/sup 14/C)hexadecyl-GPE; this rate was threefold that observed with exogenously acylated substrates. The 1-(1-/sup 14/C)hexadecyl-2-acyl-GPE synthesized in situ contained highly unsaturated acyl groups; no selectivity of the desaturase for specific acyl chains was detected when the different molecular species of 1-(1-/sup 14/C)alkyl-2-acyl-GPE and 1-(1-/sup 14/C)alk-1'-eyl-2-acyl-GPE were compared. The short-chain substrates, being moe hydrophilic, mimicked the chromatographic behavior of 1-alkyl-GPE, yet they did not resemble the lyso compound in its higher conversion to plasmalogens. Thus, despite their similar R/sub f/ values, the packing of the short-chain acyl homologues in the membrane may be quite different from that of the lyso compound. Binding of 1-hexadecyl-2-acyl-GPE and 1-hexadecyl-GPE to microsomal membranes was similar.

  3. Lipidomic analysis of bacterial plasmalogens

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Křesinová, Zdena; Kolouchová, I.; Sigler, Karel

    2012-01-01

    Roč. 57, č. 5 (2012), s. 463-472 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GAP503/11/0215; GA MŠk 2B06156 Institutional support: RVO:61388971 Keywords : plasmogens * lipids * liquid chromatography Subject RIV: EE - Microbiology, Virology Impact factor: 0.791, year: 2012

  4. Chemopreventive properties of curcumin analogues ...

    African Journals Online (AJOL)

    Chemopreventive properties of curcumin analogues, ... These compounds .... using microscope with 400 × magnification. APC ... Figure 3: Microscopic images of rat colorectal tissue stained with APC rabbit polyclonal antibody with different.

  5. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  6. Introduction to electronic analogue computers

    CERN Document Server

    Wass, C A A

    1965-01-01

    Introduction to Electronic Analogue Computers, Second Revised Edition is based on the ideas and experience of a group of workers at the Royal Aircraft Establishment, Farnborough, Hants. This edition is almost entirely the work of Mr. K. C. Garner, of the College of Aeronautics, Cranfield. As various advances have been made in the technology involving electronic analogue computers, this book presents discussions on the said progress, including some acquaintance with the capabilities of electronic circuits and equipment. This text also provides a mathematical background including simple differen

  7. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  8. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  9. Causal structure of analogue spacetimes

    International Nuclear Information System (INIS)

    Barcelo, Carlos; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt

    2004-01-01

    The so-called 'analogue models of general relativity' provide a number of specific physical systems, well outside the traditional realm of general relativity, that nevertheless are well-described by the differential geometry of curved spacetime. Specifically, the propagation of perturbations in these condensed matter systems is described by 'effective metrics' that carry with them notions of 'causal structure' as determined by an exchange of quasi-particles. These quasi-particle-induced causal structures serve as specific examples of what can be done in the presence of a Lorentzian metric without having recourse to the Einstein equations of general relativity. (After all, the underlying analogue model is governed by its own specific physics, not necessarily by the Einstein equations.) In this paper we take a careful look at what can be said about the causal structure of analogue spacetimes, focusing on those containing quasi-particle horizons, both with a view to seeing what is different from standard general relativity, and what the similarities might be. For definiteness, and because the physics is particularly simple to understand, we will phrase much of the discussion in terms of acoustic disturbances in moving fluids, where the underlying physics is ordinary fluid mechanics, governed by the equations of traditional hydrodynamics, and the relevant quasi-particles are the phonons. It must however be emphasized that this choice of example is only for the sake of pedagogical simplicity and that our considerations apply generically to wide classes of analogue spacetimes

  10. Natural and Semisynthetic Analogues of Manadoperoxide B Reveal New Structural Requirements for Trypanocidal Activity

    Science.gov (United States)

    Chianese, Giuseppina; Scala, Fernando; Calcinai, Barbara; Cerrano, Carlo; Dien, Henny A.; Kaiser, Marcel; Tasdemir, Deniz; Taglialatela-Scafati, Orazio

    2013-01-01

    Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1), namely 12-isomanadoperoxide B (2) and manadoperoxidic acid B (3). These compounds were isolated along with a new short chain dicarboxylate monoester (4), bearing some interesting relationships with the polyketide endoperoxides found in this sponge. Some semi-synthetic analogues of manadoperoxide B (6–8) were prepared and evaluated for antitrypanosomal activity and cytotoxicity. These studies revealed crucial structure–activity relationships that should be taken into account in the design of optimized and simplified endoperoxyketal trypanocidal agents. PMID:23989650

  11. Natural and Semisynthetic Analogues of Manadoperoxide B Reveal New Structural Requirements for Trypanocidal Activity

    Directory of Open Access Journals (Sweden)

    Orazio Taglialatela-Scafati

    2013-08-01

    Full Text Available Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1, namely 12-isomanadoperoxide B (2 and manadoperoxidic acid B (3. These compounds were isolated along with a new short chain dicarboxylate monoester (4, bearing some interesting relationships with the polyketide endoperoxides found in this sponge. Some semi-synthetic analogues of manadoperoxide B (6–8 were prepared and evaluated for antitrypanosomal activity and cytotoxicity. These studies revealed crucial structure–activity relationships that should be taken into account in the design of optimized and simplified endoperoxyketal trypanocidal agents.

  12. Status of natural analogue studies

    International Nuclear Information System (INIS)

    Sekine, Keiichi

    1994-03-01

    This report is based on the materials for the meeting at the Nuclear Safety Commission of Japan held on September 1993. Details are as follows: Alteration of glass as the study of alteration of natural minerals; alteration of uranium minerals, migration of uranium and thorium series radionuclides, alteration of chlorite, fixation of uranium alteration of minerals and migration of uranium as the study of alligator rivers analogue project held at Koongarra uranium deposit, Australia. (author)

  13. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  14. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  15. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  16. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  17. Natural and archaeological analogues: a review

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1987-01-01

    In this chapter natural analogues in the geomedia for various aspects of radioactive waste disposal are discussed. Particular reference is made to the Okla Natural Reactor in Gabon. Igneous contact zones are discussed and natural analogues of waste-form materials. The importance of archaeological remains and anthropogenic materials left by man, in assessing weathering conditions and serving as radioactive waste analogues, is also emphasised. (UK)

  18. The Valles natural analogue project

    International Nuclear Information System (INIS)

    Stockman, H.; Krumhansl, J.; Ho, C.; McConnell, V.

    1994-12-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a highlevel waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, X-ray diffraction; and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and 39 Ar/ 4O isotopic composition. Overall,the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 meters of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks

  19. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  20. Synthesis of Novel Synthetic Vitamin K Analogues Prepared by Introduction of a Heteroatom and a Phenyl Group That Induce Highly Selective Neuronal Differentiation of Neuronal Progenitor Cells.

    Science.gov (United States)

    Kimura, Kimito; Hirota, Yoshihisa; Kuwahara, Shigefumi; Takeuchi, Atsuko; Tode, Chisato; Wada, Akimori; Osakabe, Naomi; Suhara, Yoshitomo

    2017-03-23

    We synthesized novel vitamin K 2 analogues that incorporated a heteroatom and an aromatic ring in the side chain and evaluated their effect on the selective differentiation of neuronal progenitor cells into neurons in vitro. The results showed that a menaquinone-2 analogue bearing a p-fluoroaniline had the most potent activity, which was more than twice as great as the control. In addition, the neuronal selectivity was more than 3 times greater than the control.

  1. CO2 Capture with Enzyme Synthetic Analogue

    Energy Technology Data Exchange (ETDEWEB)

    Cordatos, Harry

    2010-11-08

    Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.

  2. Synthesis and anticancer evaluation of spermatinamine analogues

    KAUST Repository

    Moosa, Basem; Sagar, Sunil; Li, Song; Esau, Luke; Kaur, Mandeep; Khashab, Niveen M.

    2016-01-01

    analogues and their cytotoxic evaluation against three human cancer cell lines i.e. cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF-7), and prostate carcinoma (DU145). Analogues 12, 14 and 15 were found to be the most potent against one or more cell

  3. Roller bearing geometry design

    Science.gov (United States)

    Savage, M.; Pinkston, B. H. W.

    1976-01-01

    A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

  4. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  5. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  6. Gear bearing drive

    Science.gov (United States)

    Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  7. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  8. Comparison of Two Kinds of 64Cu Labelled Octreotide Analogues

    Directory of Open Access Journals (Sweden)

    HAN Zhen-yi1;LIANG Ji-xin1;HU Ji2;LUO Hong-yi1;QING Jing2;CHEN Yu-qing2;LI Guang2;LI Hong-yu1,2

    2016-10-01

    Full Text Available Octreotide analogues DOTA-TOC and DOTA-TATE were labeled with 64Cu. The influences of the ratio of peptide mass to 64Cu activity, pH value, temperature and reaction time on labeling yield were investigated. The optimum labeling was determined. In vitro stability tests in saline and 10% bovine serum had been carried out. Biodistribution of the two radiolabelled compounds in normal mice and Micro PET imaging in nude mice bearing U87MG tumor had been evaluated. The results showed that the labeling yields of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE were higher than 95%. Two kinds of octreotide analogues labeled with 64Cu were quite stable in saline and decomposed slowly in 10% bovine serum at 37 ℃. Biodistribution results in normal mice showed that two 64Cu labelled tracers had similar profiles. Both of the compounds washed out from the blood quickly. High uptake of radioactivity in liver and kidneys indicated the tracers were excreted via both hepatobiliary system and renal system. At the same time, compared to 64Cu-DOTA-TOC, higher radioactivity accumulation of 64Cu-DOTA-TATE in liver and kidneys was observed. Micro PET images of U87MG tumor-bearing nude mice with 64Cu-DOTA-TOC and 64Cu-DOTA-TATE showed the tumors very clearly. The radioactivity uptake of 64Cu-DOTA-TATE in tumor was higher than that of 64Cu-DOTA-TOC. This work has paved the way for further preclinical and clinical application of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE as PET tumor imaging agents.

  9. Mutnovsky and Gorely Volcanoes, Kamchatka as Planetary Analogue Sites

    Science.gov (United States)

    Evdokimova, N.; Izbekov, P. E.; Krupskaya, V.; Muratov, A.

    2016-12-01

    Recent advances in Mars studies suggest that volcanic rocks, which dominated Martian surface in the past, have been exposed to alteration processes in a water-bearing environment during Noachian, before 3.7 Gy. Active volcanoes on Earth are natural laboratories, where volcanic processes and their associated products can be studied directly. This is particularly important for studying of alteration of juvenile volcanic products in aqueous environment because of the transient nature of some of the alteration products, as well as the environment itself. Terrestrial analogues help us to better understand processes on Mars; they are particularly useful as a test sites for preparation to future Mars missions. In this presentation we describe planetary analogue sites at Mutnovsky and Gorely Volcanoes in Kamchatka, which might be helpful for comparative studies and preparation to future Mars missions. Mutnovsky and Gorely Volcanoes are located 75 km south of Petropavlovsk-Kamchatsky, in the southern part of the Kamchatka Peninsula, Russia. The modern volcanic landscape in the area was shaped in Holocene (recent 10,000 years) through intermittent eruption of magmas ranging in composition from basalts to dacites and rhyodacites, with basaltic andesite lavas dominating in the modern relief. Two localities could be of a particular interest: (1) Mutnovsky NW thermal field featuring processes of active hydrothermal alteration of lavas of basaltic andesite and (2) dry lake at the bottom of Gorely caldera featuring products of mechanical disintegration of basaltic andesite lavas by eolian processes with short seasonal sedimentation in aqueous environment.

  10. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  11. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  12. Tribology of alternative bearings.

    Science.gov (United States)

    Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

    2006-12-01

    The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

  13. Synthesis and biological evaluation of febrifugine analogues.

    Science.gov (United States)

    Mai, Huong Doan Thi; Thanh, Giang Vo; Tran, Van Hieu; Vu, Van Nam; Vu, Van Loi; Le, Cong Vinh; Nguyen, Thuy Linh; Phi, Thi Dao; Truong, Bich Ngan; Chau, Van Minh; Pham, Van Cuong

    2014-12-01

    A series of febrifugine analogues were designed and synthesized. Antimalarial activity evaluation of the synthetic compounds indicated that these derivatives had a strong inhibition against both chloroquine-sensitive and -resistant Plasmodium falciparum parasites. Many of them were found to be more active than febrifugine hydrochloride. The tested analogues had also a significant cytotoxicity against four cancer cell lines (KB, MCF7, LU1 and HepG2). Among the synthetic analogues, two compounds 17b and 17h displayed a moderate cytotoxicity while they exhibited a remarkable antimalarial activity.

  14. Antimicrobial Activity of Resveratrol Analogues

    Directory of Open Access Journals (Sweden)

    Malik Chalal

    2014-06-01

    Full Text Available Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew. Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold. The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups and antimicrobial activity.

  15. Condensed matter analogues of cosmology

    Science.gov (United States)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

  16. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  17. Rethinking of the criteria for natural analogue study. A case of Tono natural analogue study

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1996-01-01

    Natural analogue regarding long-term performance of the geological disposal system for radioactive waste isolation is essentially the study of geochemical process which has been evolved in geological environment. All geochemical studies, however, will not be nominated as natural analogue studies. It is, therefore, important to be clear the criteria for natural analogue study with the view of analogy by following three categories, (1) Conceptual model development, (2) Data provision and (3) Model testing, for the concept of geological disposal and safety assessment model. Rethinking of the criteria for natural analogue study through the case of Tono Natural Analogue Study, and the usefulness of natural analogue study for the safety assessment of geological disposal system in Japan have been presented in this paper. (author)

  18. International video project on natural analogues

    International Nuclear Information System (INIS)

    Guentensperger, Marcel

    1993-01-01

    A natural analogue can be defined as a natural process which has occurred in the past and is studied in order to test predictions about the future evolution of similar processes. In recent years, natural analogues have been used increasingly to test the mathematical models required for repository performance assessment. Analogues are, however, also of considerable use in public relations as they allow many of the principles involved in demonstrating repository safety to be illustrated in a clear manner using natural systems with which man is familiar. The international Natural Analogue Working Group (NAWG), organised under the auspices of the CEC, has recognised that such PR applications are of considerable importance and should be supported from a technical level. At the NAWG meeting in Pitlochry, Scotland (June 1990), it was recommended that the possibilities for making a video film on this topic be investigated and Nagra was requested to take the lead role in setting up such a project

  19. Natural analogues and radionuclide transport model validation

    International Nuclear Information System (INIS)

    Lever, D.A.

    1987-08-01

    In this paper, some possible roles for natural analogues are discussed from the point of view of those involved with the development of mathematical models for radionuclide transport and with the use of these models in repository safety assessments. The characteristic features of a safety assessment are outlined in order to address the questions of where natural analogues can be used to improve our understanding of the processes involved and where they can assist in validating the models that are used. Natural analogues have the potential to provide useful information about some critical processes, especially long-term chemical processes and migration rates. There is likely to be considerable uncertainty and ambiguity associated with the interpretation of natural analogues, and thus it is their general features which should be emphasized, and models with appropriate levels of sophistication should be used. Experience gained in modelling the Koongarra uranium deposit in northern Australia is drawn upon. (author)

  20. The Planetary Terrestrial Analogues Library (PTAL)

    Science.gov (United States)

    Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

    2018-04-01

    The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

  1. A standardised study to compare prostate cancer targeting efficacy of five radiolabelled bombesin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Rogier P.J. [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Erasmus MC, Department of Experimental Urology, Rotterdam (Netherlands); Mueller, Cristina; Melis, Marleen L.; Breeman, Wout A.P.; Blois, Erik de; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Reneman, Suzanne; Bangma, Chris H.; Weerden, Wytske M. van [Erasmus MC, Department of Experimental Urology, Rotterdam (Netherlands)

    2010-07-15

    Prostate-specific antigen (PSA)-based screening for prostate cancer (PC) has dramatically increased early diagnosis. Current imaging techniques are not optimal to stage early PC adequately. A promising alternative to PC imaging is peptide-based scintigraphy using radiolabelled bombesin (BN) analogues that bind to gastrin-releasing peptide receptors (GRPR) being overexpressed in PC. When labelled to appropriate radionuclides BN targeting of GRPRs may also provide applications for peptide radionuclide receptor therapy (PRRT). Assessment studies under identical experimental conditions allowing a reliable comparison of the potential of such analogues are lacking. This study was performed to evaluate and directly compare five promising radiolabelled BN analogues for their targeting efficacy for PC under standardised conditions. The BN agonists [{sup 111}In]DOTA-PESIN, [{sup 111}In]AMBA, [{sup 111}In]MP2346 and [{sup 111}In]MP2653 and one antagonist [{sup 99m}Tc]Demobesin-1 were evaluated in GRPR-overexpressing human PC-3 tumour-bearing mice to determine peptide stability in vivo, biodistribution and GRPR targeting potential by animal SPECT/CT imaging and ex vivo autoradiography. HPLC analysis of blood showed intact Demobesin-1 at 5 and 15 min after injection (64.1{+-}1.6% and 41.0{+-}01%, respectively) being much less for the other compounds. AMBA, the second most stable analogue, showed 36.1{+-}2.7% and 9.8{+-}1.1% intact peptide after 5 and 15 min. PC-3 tumour uptake at 1 h was comparable for Demobesin-1, AMBA, PESIN and MP2346 (3.0{+-}0.4, 2.7{+-}0.5, 2.3{+-}0.5 and 2.1{+-}0.9%ID/g, respectively), but very low for MP2653 (0.9 {+-} 0.2%ID/g). In addition, MP2346 showed undesirably high uptake in the kidneys (7.9{+-}1.9%ID/g) being significantly less for the other analogues. AMBA, MP2346 and PESIN revealed favourable increases in tumour to blood ratios over time while changes in tumour to kidney and pancreas ratios for Demobesin-1 from 1 to 24 h after injection were

  2. Magnetically leviated superconducting bearing

    Science.gov (United States)

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  3. Between Analogue and Digital Diagrams

    Directory of Open Access Journals (Sweden)

    Zoltan Bun

    2012-10-01

    Full Text Available This essay is about the interstitial. About how the diagram, as a method of design, has lead fromthe analogue deconstruction of the eighties to the digital processes of the turn of the millennium.Specifically, the main topic of the text is the interpretation and the critique of folding (as a diagramin the beginning of the nineties. It is necessary then to unfold its relationship with immediatelypreceding and following architectural trends, that is to say we have to look both backwards andforwards by about a decade. The question is the context of folding, the exchange of the analogueworld for the digital. To understand the process it is easier to investigate from the fields of artand culture, rather than from the intentionally perplicated1 thoughts of Gilles Deleuze. Both fieldsare relevant here because they can similarly be used as the yardstick against which the era itselfit measured. The cultural scene of the eighties and nineties, including performing arts, movies,literature and philosophy, is a wide milieu of architecture. Architecture responds parallel to itsera; it reacts to it, and changes with it and within it. Architecture is a medium, it has always beena medium, yet the relations are transformed. That’s not to say that technical progress, for exampleusing CAD-software and CNC-s, has led to the digital thinking of certain movements ofarchitecture, (it is at most an indirect tool. But the ‘up-to-dateness’ of the discipline, however,a kind of non-servile reading of an ‘applied culture’ or ‘used philosophy’2 could be the key.(We might recall here, parenthetically, the fortunes of the artistic in contemporary mass society.The proliferation of museums, the magnification of the figure of the artist, the existence of amassive consumption of printed and televised artistic images, the widespread appetite for informationabout the arts, all reflect, of course, an increasingly leisured society, but also relateprecisely to the fact

  4. Actuators for Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Eric H. Maslen

    2017-10-01

    Full Text Available The literature of active magnetic bearing (AMB technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [...

  5. Structural, Biochemical, and Computational Studies Reveal the Mechanism of Selective Aldehyde Dehydrogenase 1A1 Inhibition by Cytotoxic Duocarmycin Analogues.

    Science.gov (United States)

    Koch, Maximilian F; Harteis, Sabrina; Blank, Iris D; Pestel, Galina; Tietze, Lutz F; Ochsenfeld, Christian; Schneider, Sabine; Sieber, Stephan A

    2015-11-09

    Analogues of the natural product duocarmycin bearing an indole moiety were shown to bind aldehyde dehydrogenase 1A1 (ALDH1A1) in addition to DNA, while derivatives without the indole solely addressed the ALDH1A1 protein. The molecular mechanism of selective ALDH1A1 inhibition by duocarmycin analogues was unraveled through cocrystallization, mutational studies, and molecular dynamics simulations. The structure of the complex shows the compound embedded in a hydrophobic pocket, where it is stabilized by several crucial π-stacking and van der Waals interactions. This binding mode positions the cyclopropyl electrophile for nucleophilic attack by the noncatalytic residue Cys302, thereby resulting in covalent attachment, steric occlusion of the active site, and inhibition of catalysis. The selectivity of duocarmycin analogues for ALDH1A1 is unique, since only minor alterations in the sequence of closely related protein isoforms restrict compound accessibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Synthesis and biochemical evaluation of benzoylbenzophenone thiosemicarbazone analogues as potent and selective inhibitors of cathepsin L

    DEFF Research Database (Denmark)

    Parker, Erica N; Song, Jiangli; Kishore Kumar, G D

    2015-01-01

    selective in their inhibition of cathepsin L compared to cathepsin B. Thiosemicarbazone analogue 32 inhibited invasion through Matrigel of MDA-MB-231 breast cancer cells by 70% at 10μM. Thiosemicarbazone analogue 8 significantly inhibited the invasive potential of PC-3ML prostate cancer cells by 92% at 5μ......Upregulation of cathepsin L in a variety of tumors and its ability to promote cancer cell invasion and migration through degradation of the extracellular matrix suggest that cathepsin L is a promising biological target for the development of anti-metastatic agents. Based on encouraging results from......) was well-tolerated in a CDF1 mouse model bearing an implanted C3H mammary carcinoma, and showed efficacy in tumor growth delay. Low cytotoxicity, inhibition of cell invasion, and in vivo tolerability are desirable characteristics for anti-metastatic agents functioning through an inhibition of cathepsin L...

  7. Delayed child-bearing.

    Science.gov (United States)

    Johnson, Jo-Ann; Tough, Suzanne

    2012-01-01

    To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

  8. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  9. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  10. Stacked magnet superconducting bearing

    International Nuclear Information System (INIS)

    Rigney, T.K. II; Saville, M.P.

    1993-01-01

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

  11. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  12. Magnetic translator bearings

    Science.gov (United States)

    Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

    1990-01-01

    A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

  13. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  14. Insulin analogues with improved absorption characteristics.

    Science.gov (United States)

    Brange, J; Hansen, J F; Langkjaer, L; Markussen, J; Ribel, U; Sørensen, A R

    1992-01-01

    The insulin preparations available today are not ideal for therapy as s.c. injection does not provide a physiological insulin profile. With the aim to improve the absorption properties recombinant DNA technology has been utilized to design novel insulin molecules with changed physico-chemical characteristics and hence altered subcutaneous absorption kinetics. Soluble, long-acting human insulin analogues in which the isoelectric point has been increased from 5.4 to approx. 7 are absorbed very slowly, providing a more constant basal insulin delivery with lower day-to-day variation than present protracted preparations. In addition they have better storage stability. Rapid-acting human insulin analogues with largely reduced self-association are absorbed substantially faster from subcutaneous tissue than current regular insulin and thus are better suited for bolus injection. The absorption kinetics of these analogues have been able to explain the mechanism behind the dose effect on insulin absorption rate.

  15. Synthesis and anticancer evaluation of spermatinamine analogues

    KAUST Repository

    Moosa, Basem

    2016-02-04

    Spermatinamine was isolated from an Australian marine sponge, Pseudoceratina sp. as an inhibitor of isoprenylcystiene carboxyl methyltransferase (Icmt), an attractive and novel anticancer target. Herein, we report the synthesis of spermatinamine analogues and their cytotoxic evaluation against three human cancer cell lines i.e. cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF-7), and prostate carcinoma (DU145). Analogues 12, 14 and 15 were found to be the most potent against one or more cell lines with the IC50 values in the range of 5 - 10 μM. The obtained results suggested that longer polyamine linker along with aromatic oxime substitution provided the most potent analogue compounds against cancer cell lines.

  16. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  17. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  18. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  19. Self lubricating fluid bearings

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1980-01-01

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr

  20. Analogue alternative the electronic analogue computer in Britain and the USA, 1930-1975

    CERN Document Server

    Small, James S

    2013-01-01

    We are in the midst of a digital revolution - until recently, the majority of appliances used in everyday life have been developed with analogue technology. Now, either at home or out and about, we are surrounded by digital technology such as digital 'film', audio systems, computers and telephones. From the late 1940s until the 1970s, analogue technology was a genuine alternative to digital, and the two competing technologies ran parallel with each other. During this period, a community of engineers, scientists, academics and businessmen continued to develop and promote the analogue computer.

  1. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan G., E-mail: gmalecki@us.edu.pl [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Łakomska, Iwona, E-mail: iwolak@chem.umk.pl [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Maroń, Anna [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Szala, Marcin [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland); Fandzloch, Marzena [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Nycz, Jacek E., E-mail: jacek.nycz@us.edu.pl [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland)

    2015-05-15

    The pseudotetrahedral complexes of [Cu(PPh{sub 3}){sub 2}(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh{sub 3}){sub 2}(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%.

  2. Prussian Blue Analogues of Reduced Dimensionality

    NARCIS (Netherlands)

    Gengler, Regis Y. N.; Toma, Luminita M.; Pardo, Emilio; Lloret, Francesc; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Gournis, Dimitrios; Rudolf, Petra

    2012-01-01

    Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While

  3. The Palmottu analogue project: overview for 1993

    International Nuclear Information System (INIS)

    Ruskeeniemi, T.; Blomqvist, R.; Suksi, J.; Niini, H.

    1994-01-01

    This article gives a summary of the activities carried out within the Palmottu analogue project in 1993. It consists of (1) an introductory part, followed by (2) a geological description of the site, and (3)an up-to-date summary of the results of the project. (orig.) (33 refs., 6 figs.)

  4. Somatostatin analogue scintigraphy and tuberculosis: case report

    International Nuclear Information System (INIS)

    Biancheri, I.; Rudenko, B.; Vautrin, P.; Raddoul, J.; Lamfichek, N.; Kantelip, B.; Mantion, G.

    2005-01-01

    Scintigraphy using a radiolabelled somatostatin analogue (111 In-pentetreotide) is useful in the detection of neuroendocrine tumors. But this radiopharmaceutical accumulates also in solid tumours or in inflammatory diseases such as granulomatosis. We present a case of 111 In-pentetreotide uptake in a tuberculous adenopathy. (author)

  5. Analogue computer display of accelerator beam optics

    International Nuclear Information System (INIS)

    Brand, K.

    1984-01-01

    Analogue computers have been used years ago by several authors for the design of magnetic beam handling systems. At Bochum a small analogue/hybrid computer was combined with a particular analogue expansion and logic control unit for beam transport work. This apparatus was very successful in the design and setup of the beam handling system of the tandem accelerator. The center of the stripper canal was the object point for the calculations, instead of the high energy acceleration tube a drift length was inserted into the program neglecting the weak focusing action of the tube. In the course of the installation of a second injector for heavy ions it became necessary to do better calculations. A simple method was found to represent accelerating sections on the computer and a particular way to simulate thin lenses was adopted. The analogue computer system proved its usefulness in the design and in studies of the characteristics of different accelerator installations over many years. The results of the calculations are in very good agreement with real accelerator data. The apparatus is the ideal tool to demonstrate beam optics to students and accelerator operators since the effect of a change of any of the parameters is immediately visible on the oscilloscope

  6. Scintigraphy with labelled analogues of the somatostatin

    International Nuclear Information System (INIS)

    Duet, M.; Ajzenberg, C.; Warnet, A.; Mundler, O.

    1998-01-01

    The receptors of the somatostatin have been localized in a big number of tumors, whom a great number are neuro-endocrine tumors. However, some tumors that have not this differentiation (breast cancer, lymphomas, cerebral tumors) possess them as well. Analogues of somatostatin, labelled with isotopes having a gamma emission, allow from now their detection in vivo. (N.C.)

  7. Ultrasound exfoliation of inorganic analogues of graphene

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Henych, Jiří; Slušná, Michaela; Ecorchard, Petra

    2014-01-01

    Roč. 9, APR (2014), s. 1-14 ISSN 1556-276X R&D Projects: GA ČR(CZ) GA14-05146S Institutional support: RVO:61388980 Keywords : Ultrasound * Exfoliation * Graphene inorganic analogues Subject RIV: CA - Inorganic Chemistry Impact factor: 2.779, year: 2014

  8. MARSI: metabolite analogues for rational strain improvement

    DEFF Research Database (Denmark)

    Cardoso, João G. R.; Zeidan, Ahmad A; Jensen, Kristian

    2018-01-01

    reactions in an organism can be used to predict effects of MAs on cellular phenotypes. Here, we present the Metabolite Analogues for Rational Strain Improvement (MARSI) framework. MARSI provides a rational approach to strain improvement by searching for metabolites as targets instead of genes or reactions...

  9. Nanoprecipitation in bearing steels

    International Nuclear Information System (INIS)

    Barrow, A.T.W.; Rivera-Diaz-del-Castillo, P.E.J.

    2011-01-01

    θ-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The θ-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  10. Superconducting bearings in flywheels

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A.; Campbell, A.M.; Ganney, I.; Lo, W. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Twardowski, T. [International Energy Systems, Chester High Road, Neston, South Wirral (United Kingdom); Dawson, B. [British Nuclear Fuels, Capenhurst, South Wirral (United Kingdom)

    1998-05-01

    Investigations are being carried out into the use of superconducting magnetic bearings to levitate energy storage flywheels. In a planned program of work, Cambridge University are aiming to produce a practical bearing system for Pirouette(TM). The Pirouette(TM) system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will provide up to 50 kW). IES (a British Nuclear Fuels subsidiary) the owners of the Pirouette(TM) machine have supplied Cambridge with a flywheel. This flywheel weighs >40 kg and is being levitated using an Evershed-type arrangement in which the superconductor is being used to stabilize the interaction between two magnets. To date we have demonstrated stable levitation in static and low speed tests in a rig designed for low speeds of rotation in air. A second rig which is currently under construction at BNFL will run in vacuum at speeds of up to 50 (orig.) 5 refs.

  11. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  12. Cephalostatin analogues--synthesis and biological activity.

    Science.gov (United States)

    Flessner, Timo; Jautelat, Rolf; Scholz, Ulrich; Winterfeldt, Ekkehard

    2004-01-01

    Starting off in the early 90's the field of cephalostatin analogues has continually expanded over the last 10 years. First syntheses prepared symmetric analogues like 14b (119) and 26 (65), which were subsequently desymmetrized to provide analogues like beta-hydroxy ketone 31 (19). Importantly the straightforward approach provided already compounds with mu-molar potency and the same pattern of activity as cephalostatin 1 (1) (see Chapter 2.1). Chemically more demanding, two new methods for the directed synthesis of (bissteroidal) pyrazines were devised and subsequently applied to a wide variety of differently functionalized coupling partners. These new methods allowed for the synthesis of various analogues (Chapter 2.2.; and, last but not least, for the totals synthesis of several cephalostatin natural products; Chapter 1.). Functionalization and derivatization of the 12-position was performed (Chapter 2.1 and 3) and synthetic approaches to establish the D-ring double bond were successfully investigated (Chapter 3). [figure: see text] Dealing synthetically with the spiroketal moiety, novel oxidative opening procedures on monomeric delta 14, 15-steroids were devised as well as intensive studies regarding spiroketal synthesis and spiroketal rearrangements were conducted (Chapter 3.2. and 4.). Last but not least direct chemical modification of ritterazines and cephalostatins were studied, which provided a limited number of ritterazine analogues (Chapter 4.). All these synthetic activities towards analogues are summarized in Fig. 18. During this period of time the growing number of cephalostatins and ritterazines on the one hand and of analogues on the other hand provided several SAR trends, which can guide future analogue synthesis. The combined SAR findings are displayed in Fig. 19. So far it is apparent that: Additional methoxylations or hydroxylations in the steroidal A ring core structure (1-position) are slightly decreasing activity (compare cephalostatin 1 1 to

  13. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  14. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  15. Effect of atmospheric organic complexation on iron-bearing dust solubility

    OpenAIRE

    Paris , R.; Desboeufs , K. V.

    2013-01-01

    International audience; Recent studies reported that the effect of organic complexation may be a potentially important process to be considered by models estimating atmospheric iron flux to the ocean. In this study, we investigated this process effect by a series of dissolution experiments on iron-bearing dust in the presence or the absence of various organic compounds (acetate, formate, oxalate, malonate, succinate, glutarate, glycolate, lactate, tartrate and humic acid as an analogue of hum...

  16. Synthesis and structure-activity relationships of constrained heterocyclic analogues of combretastatin A4.

    Science.gov (United States)

    Arthuis, Martin; Pontikis, Renée; Chabot, Guy G; Seguin, Johanne; Quentin, Lionel; Bourg, Stéphane; Morin-Allory, Luc; Florent, Jean-Claude

    2011-09-05

    A series of combretastatin A4 (CA4) analogues with a lactam or lactone ring fused to the trimethoxyphenyl or the B-phenyl moiety were synthesized in an efficient and stereoselective manner by using a domino Heck-Suzuki-Miyaura coupling reaction. The vascular-disrupting potential of these conformationally restricted CA4 analogues was assessed by various in vitro assays: inhibition of tubulin polymerization, modification of endothelial cell morphology, and disruption of endothelial cell cords. Compounds were also evaluated for their growth inhibitory effects against murine and human tumor cells. B-ring-constrained derivatives that contain an oxindole ring (in contrast to compounds with a benzofuranone ring) as well as analogues bearing a six-membered lactone core fused to the trimethoxyphenyl ring are endowed with significant biological activity. The most potent compound of this series (oxindole 9 b) is of particular interest, as it combines chemical stability and a biological activity profile characteristic of a vascular-disrupting agent. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis and biological evaluation of enantiomerically pure cyclopropyl analogues of combretastatin A4.

    Science.gov (United States)

    Ty, Nancy; Pontikis, Renée; Chabot, Guy G; Devillers, Emmanuelle; Quentin, Lionel; Bourg, Stéphane; Florent, Jean-Claude

    2013-03-01

    To evaluate the influence of stereochemistry on biological activities of cis-cyclopropyl combretastatin A4 (CA4) analogues, we have prepared several cyclopropyl compounds in their pure enantiomeric forms. The key reactions in our synthesis are the cyclopropanation of a (Z)-alkenylboron compound bearing a chiral auxiliary, and the cross-coupling of both enantiomeric cyclopropyl trifluoroborate salts with aryl and olefinic halides. Three pairs of cis-cyclopropyl CA4 analogues were evaluated for their potential antivascular activities. The diarylcyclopropyl compounds with SR-configuration (-)-1b, (-)-2b and the cyclopropylvinyl enantiomer (+)-3a with RR-configuration were the most potent tubulin polymerization inhibitors. A correlation was noted between anti-tubulin activity and rounding up activity of endothelial cells. The cytotoxic activity on B16 melanoma cells was in the submicromolar range for most compounds, but unlike the anti-tubulin activity, there was no difference in cytotoxic activity between racemic and enantiomerically pure forms for the three series of compounds. Molecular docking studies within the colchicine binding site of tubulin were in good agreement with the tubulin polymerization inhibitory data and confirmed the importance of the configuration of the synthesized cis-cyclopropyl CA4 analogues for potential antivascular activities. Copyright © 2013. Published by Elsevier Ltd.

  18. Biological evaluation of dopamine analogues containing phenylboronic acid group as new boron carriers

    International Nuclear Information System (INIS)

    Ito, Y.; Mizuno, T.; Yoshino, K.; Ban, H.S.; Nakamura, H.; Hiratsuka, J.; Ishikawa, A.; Ohki, H.

    2011-01-01

    As new BNCT reagents, we designed and synthesized dopamine analogues containing phenylboronic acid group, N-3,4-dihydroxyphenethyl-4-dihydroxyborylbenzamide (dopamine–PCBA) and N-[2-(3,4-dihydroxyphenetyl)ethyl]-3-(4-dihydroxyborylphenyl)promionamide (dopamine–CEBA). The efficacies of these compounds have not been investigated for biological samples. Therefore we have carried out experiments with cultured tumor cells and tumor-bearing mice, and evaluated possibility of these compounds as boron carriers. Dopamine–PCBA and dopamine–CEBA were synthesized by coupling between p-carboxyphenylboronic acid (PCBA) or 4-(2-carboxyethyl)benzeneboronic acid (CEBA) and 3,4-(dibenzyloxy)phenethylamine hydrochloride (DBPA-HCl) followed by catalytic hydrogenation using Pd catalyst. The effect of compounds on cell vitality was determined by MTT assay in various cells. In vivo biodistribution of compounds was determined in Balb/c and DDY mice in bearing implanted CT26 cells. These results have demonstrated that dopamine–CEBA was less toxic. - Highlights: ► Dopamine analogues containing phenylboronic acid are synthesized as BNCT reagents. ► Their cytotoxicity is almost lower than that of BSH. ► Boron uptake with dopamine–PCBA is larger than that of BSH. ► Dopamine analogs showed lesser boron accumulation property into spleen than BPA.

  19. Superconducting bearings for flywheel applications

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, Asger Bech

    2001-05-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

  20. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  1. Boron hydride analogues of the fullerenes

    International Nuclear Information System (INIS)

    Quong, A.A.; Pederson, M.R.; Broughton, J.Q.

    1994-01-01

    The BH moiety is isoelectronic with C. We have studied the stability of the (BH) 60 analogue of the C 60 fullerene as well as the dual-structure (BH) 32 icosahedron, both of them being putative structures, by performing local-density-functional electronic calculations. To aid in our analysis, we have also studied other homologues of these systems. We find that the latter, i.e., the dual structure, is the more stable although the former is as stable as one of the latter's lower homologues. Boron hydrides, it seems, naturally form the dual structures used in algorithmic optimization of complex fullerene systems. Fully relaxed geometries are reported as well as electron affinities and effective Hubbard U parameters. These systems form very stable anions and we conclude that a search for BH analogues of the C 60 alkali-metal supeconductors might prove very fruitful

  2. Studies of natural analogues and geological systems

    International Nuclear Information System (INIS)

    Brandberg, F.; Grundfelt, B.; Hoeglund, L.; Skagius K.; Karlsson, F.; Smellie, J.

    1993-04-01

    This review has involved studies of natural analogues and natural geological systems leading to the identification and quantification of processes and features of importance to the performance and safety of repositories for radioactive waste. The features and processes selected for the study comprise general geochemical issues related to the performance of the near- and far-field, the performance and durability of construction materials and the effects of glaciation. For each of these areas a number of potentially important processes for repository performance have been described, and evidence for their existence, as well as quantification of parameters of models describing the processes have been sought from major natural analogue studies and site investigations. The review has aimed at covering a relatively broad range of issues at the expense of in-depth analysis. The quantitative data presented are in most cases compilations of data from the literature; in a few cases results of evaluations made within the current project are included

  3. Lead optimization of antimalarial propafenone analogues.

    Science.gov (United States)

    Lowes, David; Pradhan, Anupam; Iyer, Lalitha V; Parman, Toufan; Gow, Jason; Zhu, Fangyi; Furimsky, Anna; Lemoff, Andrew; Guiguemde, W Armand; Sigal, Martina; Clark, Julie A; Wilson, Emily; Tang, Liang; Connelly, Michele C; Derisi, Joseph L; Kyle, Dennis E; Mirsalis, Jon; Guy, R Kiplin

    2012-07-12

    Previously reported studies identified analogues of propafenone that had potent antimalarial activity, reduced cardiac ion channel activity, and properties that suggested the potential for clinical development for malaria. Careful examination of the bioavailability, pharmacokinetics, toxicology, and efficacy of this series of compounds using rodent models revealed orally bioavailable compounds that are nontoxic and suppress parasitemia in vivo. Although these compounds possess potential for further preclinical development, they also carry some significant challenges.

  4. The Brookhaven electron analogue, 1953--1957

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, M.

    1991-12-18

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary.

  5. Electromagnetic wave analogue of electronic diode

    OpenAIRE

    Shadrivov, Ilya V.; Powell, David A.; Kivshar, Yuri S.; Fedotov, Vassili A.; Zheludev, Nikolay I.

    2010-01-01

    An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by ...

  6. The Brookhaven electron analogue, 1953--1957

    International Nuclear Information System (INIS)

    Plotkin, M.

    1991-01-01

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary

  7. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  8. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  9. Journal bearing impedance descriptions for rotordynamic applications

    NARCIS (Netherlands)

    Childs, D.W.; Moes, H.; Leeuwen, van H.J.

    1977-01-01

    Bearing impedance vectors are introduced for plain journal bearings which define the bearing reaction force components as a function of the bearing motion. Impedance descriptions are developed directly for the approximate Ocvirk (short) and Sommerfeld (long) bearing solutions. The impedance vector

  10. Stabilised 111In-labelled DTPA- and DOTA-conjugated neurotensin analogues for imaging and therapy of exocrine pancreatic cancer

    International Nuclear Information System (INIS)

    Visser, M. de; Krenning, E.P.; Jong, M. de; Janssen, P.J.J.M.; Srinivasan, A.; Reubi, J.C.; Waser, B.; Erion, J.L.; Schmidt, M.A.

    2003-01-01

    Neurotensin (NT) receptors are overexpressed in exocrine pancreatic cancer and Ewing's sarcoma. The potential utility of native NT in cancer diagnosis and therapy is, however, limited by its rapid degradation in vivo. Therefore, NT analogues were synthesised with modified lysine and arginine derivatives to enhance stability and coupled either to DTPA, to enable high specific activity labelling with indium-111 for imaging, or to DOTA, to enable high specific activity labelling with β-emitting radionuclides, such as lutetium-177 and yttrium-90. Based on serum stability (4 h incubation at 37 C in human serum) and receptor binding affinity, the five most promising analogues were selected and further evaluated in in vitro internalisation studies in human colorectal adenocarcinoma HT29 cells, which overexpress NT receptors. All five NT analogues bound with high affinity to NT receptors on human exocrine pancreatic tumour sections. The analogues could be labelled with 111 In to a high specific activity. The 111 In-labelled compounds were found to be very stable in serum. Incubation of HT29 cells with the 111 In-labelled analogues at 37 C showed rapid receptor-mediated uptake and internalisation. The most promising analogue, peptide 2530 [DTPA-(Pip)Gly-Pro-(PipAm)Gly-Arg-Pro-Tyr-tBuGly-Leu-OH] was further tested in vivo in a biodistribution study using HT29 tumour-bearing nude mice. The results of this study showed low percentages of injected dose per gram tissue of this 111 In-labelled 2530 analogue in receptor-negative organs like blood, spleen, pancreas, liver, muscle and femur. Good uptake was found in the receptor-positive HT29 tumour and high uptake was present in the kidneys. Co-injection of excess unlabelled NT significantly reduced tumour uptake, showing that tumour uptake is a receptor-mediated process. With their enhanced stability, maintained high receptor affinity and rapid receptor-mediated internalisation, the 111 In-labelled DTPA- and DOTA-conjugated NT

  11. Analogue to Digital and Digital to Analogue Converters (ADCs and DACs): A Review Update

    CERN Document Server

    Pickering, J.

    2015-06-15

    This is a review paper updated from that presented for CAS 2004. Essentially, since then, commercial components have continued to extend their performance boundaries but the basic building blocks and the techniques for choosing the best device and implementing it in a design have not changed. Analogue to digital and digital to analogue converters are crucial components in the continued drive to replace analogue circuitry with more controllable and less costly digital processing. This paper discusses the technologies available to perform in the likely measurement and control applications that arise within accelerators. It covers much of the terminology and 'specmanship' together with an application-oriented analysis of the realisable performance of the various types. Finally, some hints and warnings on system integration problems are given.

  12. Eastern slopes grizzly bear project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

  13. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  14. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  15. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  16. Epilepsy as an Analogue of Learned Helplessness.

    Science.gov (United States)

    DeVellis, Robert F.; And Others

    The occurrence of unpredictable and often unavoidable aversive seizures in epilepsy bears a striking resemblance to the conditions known to induce learned helplessness. Additionally, depression and other characteristics associated with helplessness seem to occur more frequently among persons with epilepsy. Data from a national survey of…

  17. Water-bearing explosive compositions

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G M

    1970-12-21

    An explosive water-bearing composition, with high detonation velocity, comprises a mixture of (1) an inorganic oxidizer salt; (2) nitroglycerine; (3) nitrocellulose; (4) water; and (5) a water thickening agent. (11 claims)

  18. Breast cancer imaging using radiolabelled somatostatin analogues

    International Nuclear Information System (INIS)

    Dalm, Simone U.; Melis, Marleen; Emmering, Jasper; Kwekkeboom, Dik J.; Jong, Marion de

    2016-01-01

    Imaging and therapy using radiolabelled somatostatin analogues are methods successfully used in patients with somatostatin receptor (SSTR)-expressing neuroendocrine tumours. Since these techniques were first introduced, many improvements have been made. SSTR expression has also been reported on breast cancer (BC). Currently mammography, magnetic resonance imaging and ultrasound are the most frequent methods used for BC imaging. Since SSTR expression on BC was demonstrated, clinical studies examining the feasibility of visualizing primary BC using SSTR radioligands have been performed. However, to date SSTR-mediated nuclear imaging is not used clinically in BC patients. The aim of this review is to assess whether recent improvements made within nuclear medicine may enable SSTR-mediated imaging to play a role in BC management. For this we critically analysed results of past studies and discussed the potential of the improvements made within nuclear medicine on SSTR-mediated nuclear imaging of BC. Seven databases were searched for publications on BC imaging with SSTR radioligands. The papers found were analysed by 3 individual observers to identify whether the studies met the pre-set inclusion criteria defined as studies in which nuclear imaging using radiolabelled SST analogues was performed in patients with breast lesions. Twenty-four papers were selected for this review including studies on SSTR-mediated nuclear imaging in BC, neuroendocrine BC and other breast lesions. The analysed studies were heterogeneous with respect to the imaging method, imaging protocol, patient groups and the radiolabelled SST analogues used. Despite the fact that the analysed studies were heterogeneous, sensitivity for primary BC ranged from 36–100%. In a subset of the studies LN lesions were visualized, but sensitivity was lower compared to that for primary tumours. A part of the studies included benign lesions and specificity ranged from 22–100%. Furthermore, false negatives and

  19. The Greenland analogue project. Yearly report 2010

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J; Brinkerhoff, D; Johnson, J [University of Montana, Missoula (United States); Ruskeeniemi, T; Engstroem, J; Kukkonen, I [Geological Survey of Finland (Finland); and others

    2012-04-15

    A four-year field and modelling study of the Greenland ice sheet and subsurface conditions, Greenland Analogue Project (GAP), has been initiated collaboratively by SKB, Posiva and NWMO to advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository. The study site encompasses a land terminus portion of the Greenland ice sheet, east of Kangerlussuaq, and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project begins in 2009 and is scheduled for completion in 2012. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with cold climate conditions and glacial cycles, and their impact on the long-term performance of deep geological repositories for spent nuclear fuel, will be significantly improved by studying a modern analogue. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a better understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. This report was produced by the GAP team members and presents an overview of the activities within the GAP during the interval January 1 to December 31, 2010, as well as research results obtained during this time frame. Research for the GAP is ongoing, and additional results related to the data presented here may become available in the future and will be presented in subsequent annual reports. (orig.)

  20. The Greenland analogue project. Yearly report 2010

    International Nuclear Information System (INIS)

    Harper, J.; Brinkerhoff, D.; Johnson, J.; Ruskeeniemi, T.; Engstroem, J.; Kukkonen, I.

    2012-04-01

    A four-year field and modelling study of the Greenland ice sheet and subsurface conditions, Greenland Analogue Project (GAP), has been initiated collaboratively by SKB, Posiva and NWMO to advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository. The study site encompasses a land terminus portion of the Greenland ice sheet, east of Kangerlussuaq, and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project begins in 2009 and is scheduled for completion in 2012. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with cold climate conditions and glacial cycles, and their impact on the long-term performance of deep geological repositories for spent nuclear fuel, will be significantly improved by studying a modern analogue. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a better understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. This report was produced by the GAP team members and presents an overview of the activities within the GAP during the interval January 1 to December 31, 2010, as well as research results obtained during this time frame. Research for the GAP is ongoing, and additional results related to the data presented here may become available in the future and will be presented in subsequent annual reports. (orig.)

  1. Failure analysis of superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Amit; Campbell, A M; Coombs, T A [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2006-06-01

    The dynamics of superconductor bearings in a cryogenic failure scenario have been analyzed. As the superconductor warms up, the rotor goes through multiple resonance frequencies, begins to slow down and finally touches down when the superconductor goes through its transition temperature. The bearing can be modelled as a system of springs with axial, radial and cross stiffness. These springs go through various resonant modes as the temperature of the superconductor begins to rise. We have presented possible explanations for such behavio0008.

  2. Superconducting composite for magnetic bearings

    International Nuclear Information System (INIS)

    Rigney, T.K. II.

    1995-01-01

    A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material. 7 figs

  3. The Lehmer Matrix and Its Recursive Analogue

    Science.gov (United States)

    2010-01-01

    LU factorization of matrix A by considering det A = det U = ∏n i=1 2i−1 i2 . The nth Catalan number is given in terms of binomial coefficients by Cn...for failing to comply with a collection of information if it does not display a currently valid OMB control number . 1. REPORT DATE 2010 2. REPORT...TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE The Lehmer matrix and its recursive analogue 5a. CONTRACT NUMBER 5b

  4. Nuclear waste geochemistry: natural and anthropic analogues

    International Nuclear Information System (INIS)

    Petit, J.C.

    1997-01-01

    The geochemical evolution of nuclear waste storage is difficult to describe, due to the long time scales involved, the radioactivity confinement complexity and the un-natural radionuclides which evolution is not known. In order to carry out a long term prediction, a special approach is used, based on a combination of experiments conducted in laboratories and in situ, modelizations and comparisons with process and material analogues (natural or man-made, such as basaltic and rhyolitic volcanic glasses, plutonium, historical and archaeological artefacts)

  5. Electronic analogue simulator of radio cardiograms

    International Nuclear Information System (INIS)

    Roux, G.; Lansiart, A.; Vernejoul, P. de; Kellershohn, C.

    1967-01-01

    The various parameters of the heart pump and of the blood circulation can be determined by radio-cardio-graphical techniques. The curves thus obtained can be more easily used in radiocardiography if the electronic analogue simulator described here is employed. The experimental and simulated radio-cardiograms are made to coincide by varying the electrical parameters of the simulator. Using simple charts it is possible to obtain directly the actual original physiological parameters from these electrical parameters. Some examples are given showing the excellent accuracy obtained in the determination of ejection indices by the simulator. (authors) [fr

  6. Natural Analogues of CO2 Geological Storage

    International Nuclear Information System (INIS)

    Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2007-01-01

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  7. Digital and analogue industrial radiography, application fields

    International Nuclear Information System (INIS)

    Willems, Peter; Millord, Erik Yardin

    2000-01-01

    Full text: Reusable phosphor screens for computer radiography (CR), amorphous selenium screens for direct radiography (DR), film digitalisation (FD) constitute imaging methods accepted by industry and are used for non-destructive radiographic testing (RT). Economic pressures are involving and affecting digital RT technology. Standards and codes for film radiography and radioscopy qualification do no longer cover the wide range of digital RT applications. It will be our task to optimise the performance of digital RT characterisation and to create appropriate examination methods to use all these new and existent technologies. In the meantime, an increasing automation and control of manual methods of analogue radiography can as well be expected. (author)

  8. U.S. Nuclear Regulatory Commission natural analogue research program

    International Nuclear Information System (INIS)

    Kovach, L.A.; Ott, W.R.

    1995-01-01

    This article describes the natural analogue research program of the U.S. Nuclear Regulatory Commission (US NRC). It contains information on the regulatory context and organizational structure of the high-level radioactive waste research program plan. It also includes information on the conditions and processes constraining selection of natural analogues, describes initiatives of the US NRC, and describes the role of analogues in the licensing process

  9. Conformationally restrained aromatic analogues of fosmidomycin and FR900098.

    Science.gov (United States)

    Kurz, Thomas; Schlüter, Katrin; Pein, Miriam; Behrendt, Christoph; Bergmann, Bärbel; Walter, Rolf D

    2007-07-01

    The synthesis and in-vitro antimalarial activity of conformationally restrained bis(pivaloyloxymethyl) ester analogues of the natural product fosmidomycin is presented. In contrast to alpha-aryl-substituted analogues, conformationally restrained aromatic analogues exhibit only moderate in-vitro antimalarial activity against the chloroquine-sensitive strain 3D7 of Plasmodium falciparum. The most active derivative displays an IC(50) value of 47 microM.

  10. Synthesis of New Acadesine (AICA-riboside Analogues Having Acyclic d-Ribityl or 4-Hydroxybutyl Chains in Place of the Ribose

    Directory of Open Access Journals (Sweden)

    Gennaro Piccialli

    2013-08-01

    Full Text Available The antiviral activity of certain acyclic nucleosides drew our attention to the fact that the replacement of the furanose ring by an alkyl group bearing hydroxyl(s could be a useful structural modification to modulate the biological properties of those nucleosides. Herein, we report on the synthesis of some novel acadesine analogues, where the ribose moiety is mimicked by a d-ribityl or by a hydroxybutyl chain.

  11. Andrographolide and analogues in cancer prevention.

    Science.gov (United States)

    Mishra, Siddhartha Kumar; Tripathi, Swati; Shukla, Archana; Oh, Seung Hyun; Kim, Hwan Mook

    2015-01-01

    Andrographis paniculata is a medicinal plant traditionally used for treatment of cough and cold, fever, laryngitis, and several infectious diseases. Extracts of A. paniculata have shown versatile potency against various diseases including cancer. The active biomolecules of A. paniculata mainly are lactone and diterpene. Andrographolide and analogues have been widely used for prevention of different diseases. Andrographolides have shown potent antiinflammatory and anticancer activities. It showed potentials as chemopreventive agents by suppressing growth of cancer cells by inhibiting NF-kappaB, PI3K/AKT and other kinase pathways and by inducing apoptosis. Andrographolide induced both intrinsic and extrinsic apoptosis pathway in different cancer cells via expression of different anti-apoptotic protein like Bax, p53, and activated caspases. Andrographolide was successfully used as an antineoplastic drug in cancer chemotherapy. Andrographolide inhibited the growth of human breast, prostate, and hepatoma tumors. Andrographolide and analogues need to be subjected to further clinical and biomedical studies in cancer chemoprevention. Andrographolide could be potent anticancer agent when used in combination with other chemotherapeutic agents.

  12. Statistical analogues of thermodynamic extremum principles

    Science.gov (United States)

    Ramshaw, John D.

    2018-05-01

    As shown by Jaynes, the canonical and grand canonical probability distributions of equilibrium statistical mechanics can be simply derived from the principle of maximum entropy, in which the statistical entropy S=- {k}{{B}}{\\sum }i{p}i{log}{p}i is maximised subject to constraints on the mean values of the energy E and/or number of particles N in a system of fixed volume V. The Lagrange multipliers associated with those constraints are then found to be simply related to the temperature T and chemical potential μ. Here we show that the constrained maximisation of S is equivalent to, and can therefore be replaced by, the essentially unconstrained minimisation of the obvious statistical analogues of the Helmholtz free energy F = E ‑ TS and the grand potential J = F ‑ μN. Those minimisations are more easily performed than the maximisation of S because they formally eliminate the constraints on the mean values of E and N and their associated Lagrange multipliers. This procedure significantly simplifies the derivation of the canonical and grand canonical probability distributions, and shows that the well known extremum principles for the various thermodynamic potentials possess natural statistical analogues which are equivalent to the constrained maximisation of S.

  13. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  14. PEGylation of 99mTc-labeled bombesin analogues improves their pharmacokinetic properties

    International Nuclear Information System (INIS)

    Daepp, Simone; Garayoa, Elisa Garcia; Maes, Veronique; Brans, Luc; Tourwe, Dirk A.; Mueller, Cristina; Schibli, Roger

    2011-01-01

    Introduction: Radiolabeled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumors in which BN 2 /gastrin-releasing peptide (GRP) receptors are overexpressed. However, the low in vivo stability of BN conjugates may limit their clinical application. In an attempt to improve their pharmacokinetics and counteract their rapid enzymatic degradation, we prepared a series of polyethylene glycol (PEG)-ylated BN(7-14) analogues for radiolabeling with 99m Tc(CO) 3 and evaluated them in vitro and in vivo. Methods: Derivatization of a stabilized (N α His)Ac-BN(7-14)[Cha 13 ,Nle 14 ] analogue with linear PEG molecules of various sizes [5 kDa (PEG 5 ), 10 kDa (PEG 10 ) and 20 kDa (PEG 20 )] was performed by PEGylation of the ε-amino group of a β 3 hLys-βAla-βAla spacer between the stabilized BN sequence and the (N α His)Ac chelator. The analogues were then radiolabeled by employing the 99m Tc-tricarbonyl technique. Binding affinity and internalization/externalization studies were performed in vitro in human prostate carcinoma PC-3 cells. Stability was investigated in vitro in human plasma and in vivo in Balb/c mice. Finally, single photon emission computed tomography (SPECT)/X-ray computed tomography studies were performed in nude mice bearing PC-3 tumor xenografts. Results: PEGylation did not affect the binding affinity of BN analogues, as the binding affinity for BN 2 /GRP receptors remained high (K d 5 molecule showed the best pharmacokinetics in vivo, i.e., faster blood clearance and preferential renal excretion. The tumor uptake of the 99m Tc-PEG 5 -Lys-BN conjugate was slightly higher compared to that of the non-PEGylated analogue (3.91%±0.44% vs. 2.80%±0.28% injected dose per gram 1 h postinjection, p.i.). Tumor retention was also increased, resulting in a threefold higher amount of radioactivity in the tumor at 24 h p.i. Furthermore, decreased hepatobiliary excretion and increased tumor-to-nontarget ratios (tumor

  15. Superconductor bearings, flywheels and transportation

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Rothfeld, R; Riedel, T; Goebel, B; Wippich, D; Schirrmeister, P

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN 2 . More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  16. Noise estimation of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2003-01-01

    Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  17. Space Analogue Environments: Are the Populations Comparable?

    Science.gov (United States)

    Sandal, G. M.

    Background: Much of our present understanding about psychology in space is based on studies of groups operating in so-called analogue environments where personnel are exposed to many of the same stressors as those experienced by astronauts in space. One possible problem with extrapolating results is that personnel operating in various hazardous and confined environments might differ in characteristics influencing coping, interaction, and performance. The object of this study was to compare the psychological similarity of these populations in order to get a better understanding of whether this extrapolation is justifiable. The samples investigated include polar crossings (N= 22), personnel on Antarctic research stations (N= 183), several military occupations (N= 187), and participants in space simulation studies (N=20). Methods: Personnel in each of these environments were assessed using the Personality Characteristic Inventory (PCI) and Utrecht Coping List (UCL). The PCI is a multidimensional trait assessment battery that measures various aspects of achievement orientation and social competence. The UCL is a questionnaire designed to assess habitual coping strategies when encountering stressful or demanding situations. Results: Only minor differences in use of habitual coping strategies were evident across the different samples. In relation to personality scores, the military subjects and participants in space simulation studies indicated higher competitiveness and negative instrumentality compared to both the personnel on Antarctic research stations and participants in polar expedition. Among the personnel on Antarctic research stations, significant gender differences were found with women scoring lower on competitiveness, negative instrumentality and impatience/irritability. Compared to the other samples, the participants in polar expeditions were found to be more homogeneous in personality and no significant gender differences were evident on the traits that

  18. Glaciation and geosphere evolution - Greenland Analogue Project

    International Nuclear Information System (INIS)

    Hirschorn, S.; Vorauer, A.; Belfadhel, M.B.; Jensen, M.

    2011-01-01

    The deep geological repository concept for the long-term management of used nuclear fuel involves the containment and isolation of used nuclear fuel in a suitable geological formation. A key objective of the Canadian Nuclear Waste Management Organization (NWMO) geoscience technical research program is to advance the understanding of geosphere stability and its resilience to perturbations over time frames of relevance to a deep geological repository. Glaciation has been identified as the most probable and intense perturbation relevant to a deep geological repository associated with long-term climate change in northern latitudes. Given that the North American continent has been re-glaciated nine times over the past million years, it is strongly expected that a deep geological repository within a suitable crystalline or sedimentary rock formation in Canada will be subject to glaciation events associated with long-term climate change. As such, NWMO's geoscience research program has placed particular emphasis on investigations of the response of the geosphere to glaciations. As surface conditions change from present day conditions to periglacial, followed by ice-sheet cover of variable thickness and rapid glacial retreat, transient geochemical, hydraulic, mechanical and temperature conditions will be simultaneously imposed on groundwater systems. NWMO research activities related to glaciation events and their impacts on groundwater system evolution are being undertaken using a multi-disciplinary approach aimed at collecting multiple lines of evidence. These investigations include assessment of the: Impact of an ice sheet on groundwater composition at repository depth using the Greenland Ice Sheet as an analogue to future glaciations in North America; Expected physical and temporal surface boundary conditions related to potential future glaciation events by estimating the magnitude and time rate of change of ice sheet thickness, ground surface temperature and

  19. Changes in plain bearing technology

    CERN Document Server

    Koring, Rolf

    2012-01-01

    A unique fusion of theoretical and practical knowledge, Changes in Plain Bearing Technology, by Rolf Koring, covers a meaningful range of expertise in this field.Drawing from years of experience in design development, materials selection, and their correlation to real-life part failure, this title, co-published by SAE International and expert Verlag (Germany), concentrates on hydrodynamic bearings lined with white metals, also known as Babbits.Written under the assumption that even the most mature body of knowledge can be revisited and improved, Changes in Plain Bearing Technology is a courageous and focused approach to questioning accepted test results and looking at alternative material compounds, and their application suitability.The process, which leads to innovative answers on how the technology is transforming itself to respond to new market requirements, shows how interdisciplinary thinking can recognize new potential in long-established industrial modus operandi.Tackling the highly complex issue of co...

  20. 'Dodo' and 'Baby Bear' Trenches

    Science.gov (United States)

    2008-01-01

    NASA's Phoenix Mars Lander's Surface Stereo Imager took this image on Sol 11 (June 5, 2008), the eleventh day after landing. It shows the trenches dug by Phoenix's Robotic Arm. The trench on the left is informally called 'Dodo' and was dug as a test. The trench on the right is informally called 'Baby Bear.' The sample dug from Baby Bear will be delivered to the Phoenix's Thermal and Evolved-Gas Analyzer, or TEGA. The Baby Bear trench is 9 centimeters (3.1 inches) wide and 4 centimeters (1.6 inches) deep. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  1. Electromagnetic wave analogue of an electronic diode

    International Nuclear Information System (INIS)

    Shadrivov, Ilya V; Powell, David A; Kivshar, Yuri S; Fedotov, Vassili A; Zheludev, Nikolay I

    2011-01-01

    An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of rotation of the polarization state and is also a key component in optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinarily strong nonlinear wave propagation effect in the same way as the electronic diode function is provided by the nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differs by a factor of 65.

  2. Reflective analogue optical link operating issues

    CERN Document Server

    Batten, Jeremy

    1996-01-01

    The proposed readout of analogue data from CMS tracker will use an optical fibre link. The choice of transmitter/receiver technology, however, has been the subject of intense research and development by the RD23 collaboration. One solution uses passive devices, multi-quantum well modulators, at the detector front end, and continuous wave driving lasers at the readout back end. This system has been tested at Imperial College. We report on the following: problems of noise associated with multimoded behaviour of a degraded laser; measurements of laser wavelength dependence on both drive current and temperature; and modulator reflectance dependence on laser wavelength. We extrapolate the findings to system issues, highlighting the degree of temperature control required of the driving laser.

  3. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    Foda, O.

    1984-06-01

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP-violation, the Witten effect [a shift in the electric charge of a magnetic monopole due to CP-non-conservation] is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a theta R-tilde R term in the Lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (author)

  4. Gravitational analogue of the Witten effect

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O. (International Centre for Theoretical Physics, Trieste (Italy))

    1985-07-22

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed.

  5. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    Foda, O.

    1985-01-01

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (orig.)

  6. Solution Processed PEDOT Analogues in Electrochemical Supercapacitors.

    Science.gov (United States)

    Österholm, Anna M; Ponder, James F; Kerszulis, Justin A; Reynolds, John R

    2016-06-01

    We have designed fully soluble ProDOTx-EDOTy copolymers that are electrochemically equivalent to electropolymerized PEDOT without using any surfactants or dispersants. We show that these copolymers can be incorporated as active layers in solution processed thin film supercapacitors to demonstrate capacitance, stability, and voltage similar to the values of those that use electrodeposited PEDOT as the active material with the added advantage of the possibility for large scale, high-throughput processing. These Type I supercapacitors provide exceptional cell voltages (up to 1.6 V), highly symmetrical charge/discharge behavior, promising long-term stability exceeding 50 000 charge/discharge cycles, as well as energy (4-18 Wh/kg) and power densities (0.8-3.3 kW/kg) that are comparable to those of electrochemically synthesized analogues.

  7. Synthesis of an Orthogonal Topological Analogue of Helicene

    DEFF Research Database (Denmark)

    Wixe, Torbjörn; Wallentin, Carl‐Johan; Johnson, Magnus T.

    2013-01-01

    The synthesis of an orthogonal topological pentamer analogue of helicene is presented. This analogue forms a tubular structure with its aromatic systems directed parallel to the axis of propagation, which creates a cavity with the potential to function as a host molecule. The synthetic strategy r...

  8. Uncertainties and credibility building of safety analyses. Natural analogues

    International Nuclear Information System (INIS)

    Laciok, A.

    2001-07-01

    The substance of natural analogues and their studies is defined as a complementary method to laboratory and in-situ experiments and modelling. The role of natural analogues in the processes of development of repositories is defined, mainly in performance assessment of repository system and communication with public. The criteria for identification of natural analogues which should be evaluated in the phase of initiation of new studies are specified. Review part of this report is divided to study of natural analogues and study of anthropogenic and industrial analogues. The main natural analogue studies performed in various countries, in different geological setting, with various aims are characterized. New results acquired in recently finished studies are included: Palmottu (2nd phase of project financed by European Commission), Oklo (results of research financed also by European Commission), Maqarin (3rd phase) and other information obtained from last meetings and workshops of NAWG. In view of the fact that programmes of development of deep repositories in Czech and Slovak Republics are interconnected, the natural analogues studies carried out in the Czech republic are incorporated in separate chapter - study of uranium accumulation in Tertiary clays at Ruprechtov site and study of degradation of natural glasses. In final part the areas of natural analogue studies as an integral part of development of deep geological repository are proposed along with characterization of broader context and aspects of realization of these studies (international cooperation, preparation and evaluation of procedures, communication with public). (author)

  9. Insulin analogues and severe hypoglycaemia in type 1 diabetes

    DEFF Research Database (Denmark)

    Kristensen, P L; Hansen, L S; Jespersen, M J

    2012-01-01

    The effect of insulin analogues on glycaemic control is well-documented, whereas the effect on avoidance of severe hypoglycaemia remains tentative. We studied the frequency of severe hypoglycaemia in unselected patients with type 1 diabetes treated with insulin analogues, human insulin, or mixed...

  10. Stabilization of neurotensin analogues: effect on peptide catabolism, biodistribution and tumor binding

    Energy Technology Data Exchange (ETDEWEB)

    Bruehlmeier, Matthias E-mail: peter.blaeuenstein@psi.ch; Garayoa, Elisa Garcia; Blanc, Alain; Holzer, Barbara; Gergely, Suzanne; Tourwe, Dirk; Schubiger, Pius August; Blaeuenstein, Peter

    2002-04-01

    Neurotensin (NT) receptors in pancreatic and other neuroendocrine tumors are promising targets for imaging and therapeutic purposes. Here, we report on the effect of distinct changes in the peptide chain on catabolism in vitro for five radiolabeled [{sup 99m}Tc] neurotensin analogues having high affinity for neurotensin receptors. Substitution of NT(1-7) by (N{alpha}His)Ac--the Tc-binding moiety--combined with a reduced bond 8-9 (CH{sub 2}NH), N-methylation of peptide bonds or replacement of Ile(12) by tertiary leucin (Tle) led to peptide stabilization of various degrees. Biodistribution studies in nude mice bearing HT29 xenografts showed higher tumor uptake with more stable peptides, yielding high tumor to blood ratios of up to 70.

  11. Magnetic properties of Proxima Centauri b analogues

    Science.gov (United States)

    Zuluaga, Jorge I.; Bustamante, Sebastian

    2018-03-01

    The discovery of a planet around the closest star to our Sun, Proxima Centauri, represents a quantum leap in the testability of exoplanetary models. Unlike any other discovered exoplanet, models of Proxima b could be contrasted against near future telescopic observations and far future in-situ measurements. In this paper we aim at predicting the planetary radius and the magnetic properties (dynamo lifetime and magnetic dipole moment) of Proxima b analogues (solid planets with masses of ∼ 1 - 3M⊕ , rotation periods of several days and habitable conditions). For this purpose we build a grid of planetary models with a wide range of compositions and masses. For each point in the grid we run the planetary evolution model developed in Zuluaga et al. (2013). Our model assumes small orbital eccentricity, negligible tidal heating and earth-like radiogenic mantle elements abundances. We devise a statistical methodology to estimate the posterior distribution of the desired planetary properties assuming simple lprior distributions for the orbital inclination and bulk composition. Our model predicts that Proxima b would have a mass 1.3 ≤Mp ≤ 2.3M⊕ and a radius Rp =1.4-0.2+0.3R⊕ . In our simulations, most Proxima b analogues develop intrinsic dynamos that last for ≥4 Gyr (the estimated age of the host star). If alive, the dynamo of Proxima b have a dipole moment ℳdip >0.32÷2.9×2.3ℳdip , ⊕ . These results are not restricted to Proxima b but they also apply to earth-like planets having similar observed properties.

  12. Evolving a polymerase for hydrophobic base analogues.

    Science.gov (United States)

    Loakes, David; Gallego, José; Pinheiro, Vitor B; Kool, Eric T; Holliger, Philipp

    2009-10-21

    Hydrophobic base analogues (HBAs) have shown great promise for the expansion of the chemical and coding potential of nucleic acids but are generally poor polymerase substrates. While extensive synthetic efforts have yielded examples of HBAs with favorable substrate properties, their discovery has remained challenging. Here we describe a complementary strategy for improving HBA substrate properties by directed evolution of a dedicated polymerase using compartmentalized self-replication (CSR) with the archetypal HBA 5-nitroindole (d5NI) and its derivative 5-nitroindole-3-carboxamide (d5NIC) as selection substrates. Starting from a repertoire of chimeric polymerases generated by molecular breeding of DNA polymerase genes from the genus Thermus, we isolated a polymerase (5D4) with a generically enhanced ability to utilize HBAs. The selected polymerase. 5D4 was able to form and extend d5NI and d5NIC (d5NI(C)) self-pairs as well as d5NI(C) heteropairs with all four bases with efficiencies approaching, or exceeding, those of the cognate Watson-Crick pairs, despite significant distortions caused by the intercalation of the d5NI(C) heterocycles into the opposing strand base stack, as shown by nuclear magnetic resonance spectroscopy (NMR). Unlike Taq polymerase, 5D4 was also able to extend HBA pairs such as Pyrene: varphi (abasic site), d5NI: varphi, and isocarbostyril (ICS): 7-azaindole (7AI), allowed bypass of a chemically diverse spectrum of HBAs, and enabled PCR amplification with primers comprising multiple d5NI(C)-substitutions, while maintaining high levels of catalytic activity and fidelity. The selected polymerase 5D4 promises to expand the range of nucleobase analogues amenable to replication and should find numerous applications, including the synthesis and replication of nucleic acid polymers with expanded chemical and functional diversity.

  13. Natural analogues of nuclear waste glass corrosion

    International Nuclear Information System (INIS)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-01

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses

  14. MAQARIN natural analogue study: phase III

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, W R; Mazurek, M; Waber, H N [Univ. of Berne (Switzerland). Institutes of Geology, Mineralogy and Petrology, Rock-Water Interaction Group (GGWW); Arlinger, J; Erlandson, A C; Hallbeck, L; Pedersen, K [Goeteborg University (Sweden). Dept. of General and Marine Microbiology; Boehlmann, W; Fritz, P; Geyer, S; Geyer, W; Hanschman, G; Kopinke, F D; Poerschmann, J [Umweltforschungszentrum Leipzig-Halle (Germany); Chambers, A V; Haworth, A; Ilett, D; Linklater, C M; Tweed, C J [AEA Technology plc, Harwell (United Kingdom); Chenery, S R.N.; Kemp, S J; Milodowski, A E; Pearce, J M; Reeder, S; Rochelle, C A; Smith, B; Wetton, P D; Wragg, J [British Geological Survey, Keyworth (United Kingdom); Clark, I D [Univ. of Ottawa (Canada). Dept. of Geology; Hodginson, E; Hughes, C R [Univ. of Manchester (United Kingdom). Dept. of Earth Sciences; Hyslop, E K [British Geological Survey, Edinburgh (United Kingdom); Karlsson, F [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Khoury, H N; Salameh, E [Univ. of Jordan, Amman (Jordan); Lagerblad, B [Cement Institute, Stockholm (Sweden); Longworth, G [Univ. of Manchester (United Kingdom). Dept. of Geology; Pitty, A F [Private consultant, Norwich (United Kingdom); Savage, D [QuantiSci Ltd, Melton Mowbray (United Kingdom); Smellie, J A.T. [ed.; Conterra AB, Uppsala (Sweden)

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH){sub 2} type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the `alkali disturbed zone` of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  15. MAQARIN natural analogue study: phase III

    International Nuclear Information System (INIS)

    Alexander, W.R.; Mazurek, M.; Waber, H.N.; Arlinger, J.; Erlandson, A.C.; Hallbeck, L.; Pedersen, K.; Chambers, A.V.; Haworth, A.; Ilett, D.; Linklater, C.M.; Tweed, C.J.; Chenery, S.R.N.; Kemp, S.J.; Milodowski, A.E.; Pearce, J.M.; Reeder, S.; Rochelle, C.A.; Smith, B.; Wetton, P.D.; Wragg, J.; Clark, I.D.; Karlsson, F.; Khoury, H.N.; Salameh, E.; Lagerblad, B.; Longworth, G.; Savage, D.; Smellie, J.A.T.

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH) 2 type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the 'alkali disturbed zone' of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  16. Natural analogues in Posiva's Safety Case

    International Nuclear Information System (INIS)

    Marcos, Nuria; Seppaelae, T.

    2008-01-01

    The Safety Case is a broader concept than Performance Assessment that allows better the use of natural analogues and observations from nature to understand the behaviour of the system and the processes at the site. Natural analogues are mostly use to add confidence to the safety of geological disposal with respect to: Design (depth and multi-barrier system), Materials (long-term durability), and Processes (understanding the long-term behaviour/evolution of the system). Ice ages and erosion: largest boulders released and transported by ice during the most recent ice age are well below 20 m. 25 glacial cycles would be necessary to erode in this fashion 500 m of bedrock. During the last million years only about 8-9 glacial cycles are known to have occurred. Geosphere stability: Minor possibility of damaging earthquakes due to the geological position of the Olkiluoto site in the Fennoscandian Shield. Magnitudes of earthquakes historically and over the last 40 years have been less than 3 in the area next to Olkiluoto. Stability, U, and flow rates at Olkiluoto: Shallow ground-waters: Assuming a discharge flow rate (DFR) of about 200000 m"3/km"2/year, the average concentration of U in gw was 3.7 μg/L. At depth 375 m: Assuming a discharge flow rate of about 1680 m"3/km"2/year, the average concentration of U in gw was 0.21 μg/L. At depth 475 m: Discharge flow rate of about 730 m"3/km"2/year, the average concentration of U in gw was 0.04 μg/L

  17. MAQARIN natural analogue study: phase III

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, W R; Mazurek, M; Waber, H N [Univ. of Berne (Switzerland). Institutes of Geology, Mineralogy and Petrology, Rock-Water Interaction Group (GGWW); Arlinger, J; Erlandson, A C; Hallbeck, L; Pedersen, K [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology; Boehlmann, W; Fritz, P; Geyer, S; Geyer, W; Hanschman, G; Kopinke, F D; Poerschmann, J [Umweltforschungszentrum Leipzig-Halle (Germany); Chambers, A V; Haworth, A; Ilett, D; Linklater, C M; Tweed, C J [AEA Technology plc, Harwell (United Kingdom); Chenery, S R.N.; Kemp, S J; Milodowski, A E; Pearce, J M; Reeder, S; Rochelle, C A; Smith, B; Wetton, P D; Wragg, J [British Geological Survey, Keyworth (United Kingdom); Clark, I D [Univ. of Ottawa (Canada). Dept. of Geology; Hodginson, E; Hughes, C R [Univ. of Manchester (United Kingdom). Dept. of Earth Sciences; Hyslop, E K [British Geological Survey, Edinburgh (United Kingdom); Karlsson, F [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Khoury, H N; Salameh, E [Univ. of Jordan, Amman (Jordan); Lagerblad, B [Cement Inst., Stockholm (Sweden); Longworth, G [Univ. of Manchester (United Kingdom). Dept. of Geology; Pitty, A F [Private consultant, Norwich (United Kingdom); Savage, D [QuantiSci Ltd, Melton Mowbray (United Kingdom); Smellie, J A.T. [ed.; Conterra AB, Uppsala (Sweden)

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH){sub 2} type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the `alkali disturbed zone` of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  18. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  19. Analogue Hawking radiation from astrophysical black-hole accretion

    International Nuclear Information System (INIS)

    Das, Tapas K

    2004-01-01

    We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass

  20. N-fluoroalkylated and N-alkylated analogues of the dopaminergic D-2 receptor antagonist raclopride

    International Nuclear Information System (INIS)

    Lannoye, G.S.; Moerlein, S.M.; Parkinson, D.; Welch, M.J.

    1990-01-01

    A series of raclopride [(S)-2-[(3,5-dichloro-6-methoxy-2- hydroxybenzamido)methyl]-1-ethylpyrrolidine] derivatives bearing pyrrolidino N-fluoroalkyl or -alkyl substituents were synthesized and evaluated as potential dopaminergic receptor-based positron tomography radiopharmaceuticals. Radiosynthetic procedures for producing the corresponding N-[18F]fluoroalkylated analogues of raclopride from 18F- (beta+, t1/2 = 110 min) in high specific activity were also developed. In vitro binding assays using competitive displacement of [3H]spiperone from primate caudate tissue indicated that the N-alkylated analogues of raclopride had Ki values of 5-40 nM, whereas the corresponding values for analogous N-fluoroalkylated derivatives ranged from 90-160 nM. The relatively low D-2 binding affinity of these fluorinated salicylamides was corroborated by in vivo tissue biodistribution results in rodents. On the basis of structure-binding correlations, the impact of intramolecular hydrogen bonding, ligand basicity, and steric bulk on the affinity of the benzamides for D-2 receptor binding are discussed. Strategies are presented for the development of alternative fluorinated salicylamides that are both receptor active and metabolically stable

  1. Synthesis and properties of ApA analogues with shortened phosphonate internucleotide linkage.

    Science.gov (United States)

    Králíková, Sárka; Buděšínský, Miloš; Barvík, Ivan; Masojídková, Milena; Točík, Zdeněk; Rosenberg, Ivan

    2011-01-01

    A complete series of the 2 '-5 ' and 3 '-5 ' regioisomeric types of r(ApA) and 2 '-d(ApA) analogues with the α-hydroxy-phosphonate C3 '-O-P-CH(OH)-C4 ″ internucleotide linkage, isopolar but non-isosteric with the phosphodiester one, were synthesized and their hybridization properties with polyU studied. Due to the chirality on the 5 '-carbon atom of the modified internucleotide linkage bearing phosphorus and hydroxy moieties, each regioisomeric type of ApA dimer is split into epimeric pairs. To examine the role of the 5 '-hydroxyl of the α-hydroxy-phosphonate moiety during hybridization, the appropriate r(ApA) analogues with 3 '(2 ')-O-P-CH(2)-C4 ″ linkage lacking the 5 '-hydroxyl were synthesized. Nuclear magnetic resonance (NMR) spectroscopy study on the conformation of the modified sugar-phosphate backbone, along with the hybridization measurements, revealed remarkable differences in the stability of complexes with polyU, depending on the 5 '-carbon atom configuration. Potential usefulness of the α-hydroxy-phosphonate linkage in modified oligoribonucleotides is discussed.

  2. Analogues of uracil nucleosides with intrinsic fluorescence (NIF-analogues): synthesis and photophysical properties.

    Science.gov (United States)

    Segal, Meirav; Fischer, Bilha

    2012-02-28

    Uridine cannot be utilized as fluorescent probe due to its extremely low quantum yield. For improving the uracil fluorescence characteristics we extended the natural chromophore at the C5 position by coupling substituted aromatic rings directly or via an alkenyl or alkynyl linker to create fluorophores. Extension of the uracil base was achieved by treating 5-I-uridine with the appropriate boronic acid under the Suzuki coupling conditions. Analogues containing an alkynyl linker were obtained from 5-I-uridine and the suitable boronic acid in a Sonogashira coupling reaction. The uracil fluorescent analogues proposed here were designed to satisfy the following requirements: a minimal chemical modification at a position not involved in base-pairing, resulting in relatively long absorption and emission wavelengths and high quantum yield. 5-((4-Methoxy-phenyl)-trans-vinyl)-2'-deoxy-uridine, 6b, was found to be a promising fluorescent probe. Probe 6b exhibits a quantum yield that is 3000-fold larger than that of the natural chromophore (Φ 0.12), maximum emission (478 nm) which is 170 nm red shifted as compared to uridine, and a Stokes shift of 143 nm. In addition, since probe 6b adopts the anti conformation and S sugar puckering favored by B-DNA, it makes a promising nucleoside analogue to be incorporated in an oligonucleotide probe for detection of genetic material.

  3. Analogue to Digital and Digital to Analogue (AD/DA) Conversion Techniques: An Overview

    CERN Multimedia

    CERN. Geneva

    2002-01-01

    The basic ideas behind modern Analogue to Digital and Digital to Analogue (AD/DA) conversion methods will be introduced: a general view of the importance of these devices will be given, along with the digital representation of time-varying, real-world analogue signals. Some CERN applications will be outlined. The variety of conversion methods, their limitations, error sources and measurement methods will form the major part of this presentation. A review of the technological progress in this field over the last 30 years will be presented, concluding with the present 'state of the art' and a quick look at what is just around the corner. This Technical Training Seminar is in the framework of the FEED-2002 Lecture Series, and it is a prerequisite to attending to any of the FEED-2002 Terms. FEED-2002 is a two-term course that will review the techniques dealing with closed loop systems, focussing on time-invariant linear systems. (free attendance, no registration required) More information on the FEED-2002 ...

  4. The correct "ball bearings" data.

    Science.gov (United States)

    Caroni, C

    2002-12-01

    The famous data on fatigue failure times of ball bearings have been quoted incorrectly from Lieblein and Zelen's original paper. The correct data include censored values, as well as non-fatigue failures that must be handled appropriately. They could be described by a mixture of Weibull distributions, corresponding to different modes of failure.

  5. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  6. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  7. Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue?

    Science.gov (United States)

    Gardiner, Nicholas; Robb, Laurence; Searle, Michael; Morley, Christopher

    2015-04-01

    contrasting minerals endowment. The Mogok-Mandalay-Mergui (MMM) Belt hosts crustal-melt S-type granites with significant tin-tungsten mineralization, and contains the historically major tungsten deposit of Mawchi. The Wuntho-Popa Arc comprises I-type granites and granodiorites with porphyry-type copper-gold and epithermal gold mineralization, and includes the world-class Monywa copper mine. Recent U-Pb radiometric age dating has shown the potential for the two belts to be both active from the Late Cretaceous to Eocene. The spatial juxtaposition of these two sub-parallel belts, the implication of contemporary magmatism, and their distinct but consistent metallogenic endowment bears strong similarities to the metallogenic belts of the South American Cordillera. Here we investigate whether they together represent the magmatic and metallogenic expression of an Andean-type setting in Myanmar during the subduction of Neo-Tethys. In this analogue the Wuntho-Popa Arc represents a proximal I-type magmatic belt sited immediately above the eastwards-verging Neo-Tethys subduction zone. Exhibiting porphyry-type copper-gold and epithermal gold mineralization, this would therefore be the Myanmar equivalent of the Andean coastal copper belts. Conversely, the parallel MMM Belt, comprised of more distal crustal-melt S-type tin granites, would have an analogue in the Bolivian tin belt.

  8. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  9. TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

    Science.gov (United States)

    Longhurst, G.E.

    1961-07-11

    A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

  10. Estimating Wear Of Installed Ball Bearings

    Science.gov (United States)

    Keba, John E.; Mcvey, Scott E.

    1993-01-01

    Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

  11. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    Directory of Open Access Journals (Sweden)

    Jarosław KACZOR

    2014-06-01

    Full Text Available Durability deep groove ball bearings depends on factors (called attributes design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bearings to work three-bearing shafts, including elasticity and resilience three-bearing shafts.

  12. The Greenland Analogue Project. Yearly Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    A deep geological repository for spent nuclear fuel needs to be designed to keep used nuclear fuel isolated from mankind and the environment for a million years. Within this time frame glacial conditions are expected in regions that have been glaciated in the past two to ten million years. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, including its hydrology, which may impact repository safety. Glaciation impact assessments have to-date used over-simplified models and conservative assumptions, for example in the representation of ice sheet hydrology, that do not reflect the complexity of natural systems and processes. This is largely due to lack of direct observations of such processes from existing ice sheets, which if more readily available could help reduce uncertainties and provide a strong scientific basis for the treatment of glacial impacts in safety assessments. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories for spent nuclear fuel will be significantly improved by studying a modern analogue. To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of

  13. The Greenland Analogue Project. Yearly Report 2009

    International Nuclear Information System (INIS)

    2010-12-01

    A deep geological repository for spent nuclear fuel needs to be designed to keep used nuclear fuel isolated from mankind and the environment for a million years. Within this time frame glacial conditions are expected in regions that have been glaciated in the past two to ten million years. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, including its hydrology, which may impact repository safety. Glaciation impact assessments have to-date used over-simplified models and conservative assumptions, for example in the representation of ice sheet hydrology, that do not reflect the complexity of natural systems and processes. This is largely due to lack of direct observations of such processes from existing ice sheets, which if more readily available could help reduce uncertainties and provide a strong scientific basis for the treatment of glacial impacts in safety assessments. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories for spent nuclear fuel will be significantly improved by studying a modern analogue. To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of

  14. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  15. Use of analogues to build technologists' confidence: NAnet

    International Nuclear Information System (INIS)

    Noseck, Ulrich

    2008-01-01

    The relevance of analogues to radioactive waste management stems from the long timescales that have to be considered. Periods up to a million or more years into the future need to be considered and these are beyond experimental investigation and human experience. Within the last years the term 'Natural Analogue' has got a much wider meaning and includes man-made analogues as well. The role of natural analogues in the safety case depends amongst others on the time scale to be covered. Therefore, it is useful to classify them by the time period addressed in the study. Here it is referred to: industrial analogues which started earliest 150 years ago, archaeological analogues, which cover time frames between the past 10 000 and 150 years, and geological analogues, which usually cover time frames of more than 10 000 years and in most cases more than million years. The current interest in analogues in different countries is reflected by several recent review projects with emphasis on the application of natural analogue study results in performance assessment. The most recent international review was performed within the 5. EURATOM Framework of the EC by the NAnet project, a network on the review of natural analogue studies with emphasis on the application of analogues in long-term safety assessment and communication. The overall aim of the NAnet project was to review the past and present use and understanding of natural analogues, and to make recommendations for their future use. The project covered 'traditional' natural analogue studies, such as large-scale investigations of radionuclide transport around uranium ore bodies, and process or mechanistic analogue studies such as those examining natural glass and bentonite clay stability. To complete the picture, a restricted range of other studies of natural systems which employ a similar philosophy to analogues was also included in the scope. These included studies which have examined radionuclide transport and retardation

  16. A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

    Directory of Open Access Journals (Sweden)

    Arno Verlee

    2017-02-01

    Full Text Available For the synthesis of m-sulfamoylbenzamide analogues, small molecules which are known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonylbenzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total, 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m-sulfamoylbenzamide analogues.

  17. A Low-cost Multi-channel Analogue Signal Generator

    CERN Document Server

    Müller, F; The ATLAS collaboration; Shen, W; Stamen, R

    2009-01-01

    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The signal generator was successfully used as independent test bed for the ATLAS Level-1 Trigger Pre-Processor, providing up to 16 analogue signals.

  18. Conjugate dynamical systems: classical analogue of the quantum energy translation

    International Nuclear Information System (INIS)

    Torres-Vega, Gabino

    2012-01-01

    An aspect of quantum mechanics that has not been fully understood is the energy shift generated by the time operator. In this study, we introduce the use of the eigensurfaces of dynamical variables and commutators in classical mechanics to study the classical analogue of the quantum translation of energy. We determine that there is a conjugate dynamical system that is conjugate to Hamilton's equations of motion, and then we generate the analogue of the time operator and use it in the translation of points along the energy direction, i.e. the classical analogue of the Pauli theorem. The theory is illustrated with a nonlinear oscillator model. (paper)

  19. UK Natural Analogue Coordinating Group: fourth annual report

    International Nuclear Information System (INIS)

    Read, D.; Hooker, P.J.

    1992-01-01

    HMIP has a research programme investigating some naturally radioactive sites as geochemical analogues of radionuclide migration. All of the analogue sites under investigation, both in the U.K. and overseas, are located where elevated uranium concentrations occur naturally. Coordination of the programme is achieved through the UK Natural Analogue Co-ordinating Group (NACG) which has met three times in this reporting period. The NACG is steered by the British Geological Survey. Its purpose is to ensure that the different research projects have an integrated function aimed at increasing our understanding of natural geochemical processes. Effort is also being expended in testing research models which may be used in such assessments. (author)

  20. Long-term predictions using natural analogues

    International Nuclear Information System (INIS)

    Ewing, R.C.

    1995-01-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10 3 -10 5 years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., open-quotes natural analoguesclose quotes) provide perhaps the only means of partial open-quotes validation,close quotes as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10 3 -10 8 years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the open-quotes validationclose quotes of performance assessments

  1. Can stroke patients use visual analogue scales?

    Science.gov (United States)

    Price, C I; Curless, R H; Rodgers, H

    1999-07-01

    Visual analogue scales (VAS) have been used for the subjective measurement of mood, pain, and health status after stroke. In this study we investigated how stroke-related impairments could alter the ability of subjects to answer accurately. Consent was obtained from 96 subjects with a clinical stroke (mean age, 72.5 years; 50 men) and 48 control subjects without cerebrovascular disease (mean age, 71.5 years; 29 men). Patients with reduced conscious level or severe dysphasia were excluded. Subjects were asked to rate the tightness that they could feel on the (unaffected) upper arm after 3 low-pressure inflations with a standard sphygmomanometer cuff, which followed a predetermined sequence (20 mm Hg, 40 mm Hg, 0 mm Hg). Immediately after each change, they rated the perceived tightness on 5 scales presented in a random order: 4-point rating scale (none, mild, moderate, severe), 0 to 10 numerical rating scale, mechanical VAS, horizontal VAS, and vertical VAS. Standard tests recorded deficits in language, cognition, and visuospatial awareness. Inability to complete scales with the correct pattern was associated with any stroke (P<0.001). There was a significant association between success using scales and milder clinical stroke subtype (P<0.01). Within the stroke group, logistic regression analysis identified significant associations (P<0.05) between impairments (cognitive and visuospatial) and inability to complete individual scales correctly. Many patients after a stroke are unable to successfully complete self-report measurement scales, including VAS.

  2. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  3. Design of Two Alternative Routes for the Synthesis of Naftifine and Analogues as Potential Antifungal Agents

    Directory of Open Access Journals (Sweden)

    Rodrigo Abonia

    2018-02-01

    Full Text Available Two practical and efficient approaches have been implemented as alternative procedures for the synthesis of naftifine and novel diversely substituted analogues 16 and 20 in good to excellent yields, mediated by Mannich-type reactions as the key step of the processes. In these approaches, the γ-aminoalcohols 15 and 19 were obtained as the key intermediates and their subsequent dehydration catalyzed either by Brønsted acids like H2SO4 and HCl or Lewis acid like AlCl3, respectively, led to naftifine, along with the target allylamines 16 and 20. The antifungal assay results showed that intermediates 18 (bearing both a β-aminoketo- and N-methyl functionalities in their structures and products 20 were the most active. Particularly, structures 18b, 18c, and the allylamine 20c showed the lowest MIC values, in the 0.5–7.8 µg/mL range, against the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes. Interesting enough, compound 18b bearing a 4-Br as the substituent of the phenyl ring, also displayed high activity against Candida albicans and Cryptococcus neoformans with MIC80 = 7.8 µg/mL, being fungicide rather than fungistatic with a relevant MFC value = 15.6 µg/mL against C. neoformans.

  4. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  5. Research In Diagnosing Bearing Defects From Vibrations

    Science.gov (United States)

    Zoladz, T.; Earhart, E.; Fiorucci, T.

    1995-01-01

    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  6. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  7. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  8. Bearing-Mounting Concept Accommodates Thermal Expansion

    Science.gov (United States)

    Nespodzany, Robert; Davis, Toren S.

    1995-01-01

    Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

  9. Bears and pipeline construction in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

    1990-06-01

    Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

  10. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  11. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13.1236 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear...

  12. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  13. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  14. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  15. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  16. The BEAR Beamline at Elettra

    International Nuclear Information System (INIS)

    Nannarone, S.; Pasquali, L.; Selvaggi, G.; Borgatti, F.; DeLuisa, A.; Doyle, B.P.; Gazzadi, G.C.; Giglia, A.; Finetti, P.; Pedio, M.; Mahne, N.; Naletto, G.; Pelizzo, M.G.; Tondello, G.

    2004-01-01

    The BEAR (Bending Magnet for Emission Absorption and Reflectivity) beamline is installed at the right exit of the 8.1 bending magnet at ELETTRA. The beamline - in operation since January 2003 - delivers linear and circularly polarized radiation in the 5 - 1600 eV energy range. The experimental station is composed of a UHV chamber for reflectivity, absorption, fluorescence and angle resolved photoemission measurements and a UHV chamber for in-situ sample preparation

  17. BEAR

    DEFF Research Database (Denmark)

    Houmøller, Sabina Storbjerg; Wolff, Anne; Hougaard, Dan Dupont

    2017-01-01

    profiling and fitting strategies. Data from 2000 patients are collected from the departments of Audiology in Odense and Aalborg University Hospital. Some of the registered variables include gender, age, and health related questions, noise exposure and whether they are suffering from tinnitus. The database...... subgroups of HA users, including experienced versus new HA users will be made. Previous noise exposure and the relation to the occurrence of tinnitus will be investigated as well....

  18. Glucagon-like peptide-1 analogues: An overview

    Directory of Open Access Journals (Sweden)

    Vishal Gupta

    2013-01-01

    Full Text Available Abnormalities of the incretin axis have been implicated in the pathogenesis of type 2 diabetes mellitus. Glucagon-like peptide-1 (GLP-1 and gastroinhibitory intestinal peptide constitutes >90% of all the incretin function. Augmentation of GLP-1 results in improvement of beta cell health in a glucose-dependant manner (post-prandial hyperglycemia and suppression of glucagon (fasting hyperglycemia, amongst other beneficial pleiotropic effects. Native GLP-1 has a very short plasma half-life and novel methods have been developed to augment its half life, such that its anti-hyperglycemic effects can be exploited. They can be broadly classified as exendin-based therapies (exenatide, exenatide once weekly, DPP-4-resistant analogues (lixisenatide, albiglutide, and analogues of human GLP-1 (liraglutide, taspoglutide. Currently, commercially available analogues are exenatide, exenatide once weekly, and liraglutide. This review aims to provide an overview of most GLP-1 analogues.

  19. an assessment of billing electricity consumers via analogue meters

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. This paper assesses the perception of billing consumers via analogue meter in Kano Electricity ... the successor companies of Power Holding Company ... Nassarawa computer center was established in 1991. .... The value 7.2 is.

  20. Solistatinol, a novel phenolic compactin analogue from Penicillium solitum

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Lange, Lene; Schnorr, Kirk

    2007-01-01

    Solistatinol, a novel phenolic compactin analogue, has been isolated from Penicillium solitum using a UV-guided strategy. The structure and relative stereochemistry were determined by NMR spectroscopy and mass spectrometry. The absolute stereochemistry was determined by chemical degradation...

  1. From BPA to its analogues: Is it a safe journey?

    Science.gov (United States)

    Usman, Afia; Ahmad, Masood

    2016-09-01

    Bisphenol-A (BPA) is one of the most abundant synthetic chemicals in the world due to its uses in plastics. Its widespread exposure vis-a-vis low dose effects led to a reduction in its safety dose and imposition of ban on its use in infant feeding bottles. This restriction paved the way for the gradual market entry of its analogues. However, their structural similarity to BPA has put them under surveillance for endocrine disrupting potential. The application of these analogues is increasing and so are the studies reporting their toxicity. This review highlights the reasons which led to the ban of BPA and also reports the exposure and toxicological data available on its analogues. Hence, this compilation is expected to answer in a better way whether the replacement of BPA by these analogues is safer or more harmful? Copyright © 2016. Published by Elsevier Ltd.

  2. Synthesis and antiplatelet activity of thioaryloxyacids analogues of clofibric acid.

    Science.gov (United States)

    Ammazzalorso, Alessandra; Amoroso, Rosa; Baraldi, Mario; Bettoni, Giancarlo; Braghiroli, Daniela; De Filippis, Barbara; Giampietro, Letizia; Tricca, Maria L; Vezzalini, Francesca

    2005-09-01

    The thiophene-, benzothiazole- and pyridine-thioaryloxyacids analogues of clofibric acid were synthesized and their antiplatelet activity was screened. Some compounds exhibited antiaggregating properties. The platelet-related haemostasis was measured on a PFA-100 analyzer using bull blood.

  3. Modeling of NAD+ analogues in horse liver alcohol dehydrogenase

    NARCIS (Netherlands)

    Beijer, N.A.; Buck, H.M.; Sluyterman, L.A.A.E.; Meijer, E.M.

    1990-01-01

    So far, the interactions of nicotinamide adenine dinucleotide (NAD+) derivatives with dehydrogenases are not very well understood. This hampers the introduction of NAD+ analogues with improved characteristics concerning industrial application. We have developed an AMBER molecular mechanics model in

  4. Algorithmic fundamentals of computerized tomography and of transverse analogue tomography

    International Nuclear Information System (INIS)

    Heckmann, K.

    1981-01-01

    Computerized tomography and transverse analogue tomography are two different approaches to the same goal, namely, transverse tomography. The algorithm is discussed and compared. Transverse tomography appears capable of further development, judging by this comparison. (orig.) [de

  5. Analogue and Mixed-Signal Integrated Circuits for Space Applications

    CERN Document Server

    2014-01-01

    The purpose of AMICSA 2014 (organised in collaboration of ESA and CERN) is to provide an international forum for the presentation and discussion of recent advances in analogue and mixed-signal VLSI design techniques and technologies for space applications.

  6. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues.

    NARCIS (Netherlands)

    Rolleman, E.J.; Melis, M.; Valkema, R.; Boerman, O.C.; Krenning, E.P.; Jong, M. de

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides

  7. an assessment of billing electricity consumers via analogue meters

    African Journals Online (AJOL)

    DR. AMINU

    Keywords: Electricity Distribution, Consumers, Analogue Meter, Billing, Nigeria. INTRODUCTION. Electricity ... the energy usage of a typical electricity consumer in one month is several ..... improve on distribution network. In addition it should.

  8. Insulin analogues in pregnancy and specific congenital anomalies

    DEFF Research Database (Denmark)

    de Jong, Josta; Garne, Ester; Wender-Ozegowska, Ewa

    2016-01-01

    Insulin analogues are commonly used in pregnant women with diabetes. It is not known if the use of insulin analogues in pregnancy is associated with any higher risk of congenital anomalies in the offspring compared with use of human insulin. We performed a literature search for studies of pregnant...... women with pregestational diabetes using insulin analogues in the first trimester and information on congenital anomalies. The studies were analysed to compare the congenital anomaly rate among foetuses of mothers using insulin analogues with foetuses of mothers using human insulin. Of 29 studies, we...... samples in the included studies provided insufficient statistical power to identify a moderate increased risk of specific congenital anomalies. Copyright © 2015 John Wiley & Sons, Ltd....

  9. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  10. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  11. 3-alkyl fentanyl analogues: Structure-activity-relationship study

    OpenAIRE

    Vučković, Sonja; Savić-Vujović, Katarina; Srebro, Dragana; Ivanović, Milovan; Došen-Mićović, Ljiljana; Stojanović, Radan; Prostran, Milica

    2012-01-01

    Introduction. Fentanyl belongs to 4-anilidopiperidine class of synthetic opioid analgesics. It is characterized by high potency, rapid onset and short duration of action. A large number of fentanyl analogues have been synthesized so far, both to establish the structure-activity-relationship (SAR) and to find novel, clinically useful analgesic drugs. Objective. In this study, newly synthesized 3-alkyl fentanyl analogues were examined for analgesic activity and compared with fentanyl. Methods. ...

  12. Analogue Signal Processing: Collected Papers 1994-95

    DEFF Research Database (Denmark)

    1996-01-01

    This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of Electronics Institute, Technical University of Denmark, in 1994 and 1995.......This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of Electronics Institute, Technical University of Denmark, in 1994 and 1995....

  13. Analogue Signal Processing: Collected Papers 1996-97

    DEFF Research Database (Denmark)

    1997-01-01

    This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of the Department of Information Technology, Technical University of Denmark, in 1996 and 1997.......This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of the Department of Information Technology, Technical University of Denmark, in 1996 and 1997....

  14. Synthesis of tritium labelled phosphonate analogues of sphinganine-1-phosphate

    International Nuclear Information System (INIS)

    Schick, Andreas; Schwarzmann, Guenter; Kolter, Thomas; Sandhoff, Konrad

    1997-01-01

    Tritiated phosphonate analogues 9 and 10 are prepared as analogues of sphinganine-1-phosphate 4. The key step in this synthesis is the catalytic tritiation of the triple bond in reduction of the protected diethyl-3-(S)-tert.-butoxycarbonylamino -4-hydroxy-5-tridecinyl-1-phosphonate by means of sodium boro[ 3 H]hydride as tritium source. These compounds are synthesized to study their metabolic stability and to evaluate their biological properties. (author)

  15. The Greenland Analogue Project, Yearly Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-08-15

    To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a realistic understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. The project includes three sub-projects (A-C) with specific individual objectives, which collectively aim at contributing knowledge and input to the overall project aim. Three field campaigns were carried out in SPA during 2009. These campaigns focused on: (1) deployment and maintenance of AWS and GPS stations and to test the deep-look radar equipment; (2) investigating the hydrological processes and feedbacks and testing of passive seismic equipment; (3) downloading of weather station data and GPS data and winterizing the equipment. An extensive archive of real-time satellite remote sensing datasets has been obtained to be able to better constraint the surface elevation and dynamics of basal hydrological mechanisms. From this archive it has been possible to obtain Russell Glacier Cachment (RGC)-wide constraints on annual, seasonal and specific temporal snapshots of surface speed, initial lake and moulin distribution, drainage and network connections along with the temporal

  16. The Greenland Analogue Project, Yearly Report 2009

    International Nuclear Information System (INIS)

    2011-08-01

    To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a realistic understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. The project includes three sub-projects (A-C) with specific individual objectives, which collectively aim at contributing knowledge and input to the overall project aim. Three field campaigns were carried out in SPA during 2009. These campaigns focused on: (1) deployment and maintenance of AWS and GPS stations and to test the deep-look radar equipment; (2) investigating the hydrological processes and feedbacks and testing of passive seismic equipment; (3) downloading of weather station data and GPS data and winterizing the equipment. An extensive archive of real-time satellite remote sensing datasets has been obtained to be able to better constraint the surface elevation and dynamics of basal hydrological mechanisms. From this archive it has been possible to obtain Russell Glacier Cachment (RGC)-wide constraints on annual, seasonal and specific temporal snapshots of surface speed, initial lake and moulin distribution, drainage and network connections along with the temporal

  17. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  18. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  19. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  20. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  1. Servo Reduces Friction In Flexure Bearing

    Science.gov (United States)

    Clingman, W. Dean

    1991-01-01

    Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

  2. Characterisation of insulin analogues therapeutically available to patients

    KAUST Repository

    Adams, Gary G.

    2018-03-29

    The structure and function of clinical dosage insulin and its analogues were assessed. This included \\'native insulins\\' (human recombinant, bovine, porcine), \\'fast-acting analogues\\' (aspart, glulisine, lispro) and \\'slow-acting analogues\\' (glargine, detemir, degludec). Analytical ultracentrifugation, both sedimentation velocity and equilibrium experiments, were employed to yield distributions of both molar mass and sedimentation coefficient of all nine insulins. Size exclusion chromatography, coupled to multi-angle light scattering, was also used to explore the function of these analogues. On ultracentrifugation analysis, the insulins under investigation were found to be in numerous conformational states, however the majority of insulins were present in a primarily hexameric conformation. This was true for all native insulins and two fast-acting analogues. However, glargine was present as a dimer, detemir was a multi-hexameric system, degludec was a dodecamer (di-hexamer) and glulisine was present as a dimer-hexamer-dihexamer system. However, size-exclusion chromatography showed that the two hexameric fast-acting analogues (aspart and lispro) dissociated into monomers and dimers due to the lack of zinc in the mobile phase. This comprehensive study is the first time all nine insulins have been characterised in this way, the first time that insulin detemir have been studied using analytical ultracentrifugation and the first time that insulins aspart and glulisine have been studied using sedimentation equilibrium. The structure and function of these clinically administered insulins is of critical importance and this research adds novel data to an otherwise complex functional physiological protein.

  3. Application of natural analogues in the Yucca Mountain project - overview

    International Nuclear Information System (INIS)

    Simmons, Ardyth M.

    2003-01-01

    The Natural Analogue Synthesis Report (NASR) [1] provides a compilation of information from analogues that test, corroborate, and add confidence to process models and model predictions pertinent to total system performance assessment (TSPA). The report updated previous work [2] with new literature examples and results of quantitative studies conducted by the Yucca Mountain Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate greater understanding of processes expected to occur during postclosure of a proposed Yucca Mountain repository. Natural analogues, as used here, refer to either natural or anthropogenic systems in which processes similar to those expected to occur in a nuclear waste repository are thought to have occurred over long time periods (decades to millenia) and large spatial scales (up to tens of kilometers). In the past, the YMP has used analogues for testing and building confidence in conceptual and numerical process models in a number of ways. Yucca Mountain mineral alteration phases provided a self-analogue for postclosure alteration [3]. Thermodynamic parameters for silica minerals of the Wairakai, New Zealand geothermal field were added to databases used in geochemical modeling [4]. Scoping calculations of radionuclide transport using the Yucca Mountain TSPA numerical model were conducted for the Peqa Blanca site [5]. Eruption parameters from the Cerro Negro volcano, Nicaragua, were used to verify codes that model ash plume dispersion [6]. Analogues have also been used in supplemental science and performance analyses to provide multiple lines of evidence in support of both analyses and model reports (AMRs) [7]; in screening arguments for inclusion or exclusion of features, events, and processes (FEP)s in TSPAs; in the quantification of uncertainties [7]; in expert elicitations of volcanic and seismic hazards [8, 9] and in peer reviews [10]. Natural analogues may be applied

  4. Habitability & Astrobiology Research in Mars Terrestrial Analogues

    Science.gov (United States)

    Foing, Bernard

    2014-05-01

    We performed a series of field research campaigns (ILEWG EuroMoonMars) in the extreme Utah desert relevant to Mars environments, and in order to help in the interpretation of Mars missions measurements from orbit (MEX, MRO) or from the surface (MER, MSL), or Moon geochemistry (SMART-1, LRO). We shall give an update on the sample analysis in the context of habitability and astrobiology. Methods & Results: In the frame of ILEWG EuroMoonMars campaigns (2009 to 2013) we deployed at Mars Desert Research station, near Hanksville Utah, a suite of instruments and techniques [A, 1, 2, 9-11] including sample collection, context imaging from remote to local and microscale, drilling, spectrometers and life sensors. We analyzed how geological and geochemical evolution affected local parameters (mineralogy, organics content, environment variations) and the habitability and signature of organics and biota. Among the important findings are the diversity in the composition of soil samples even when collected in close proximity, the low abundances of detectable PAHs and amino acids and the presence of biota of all three domains of life with significant heterogeneity. An extraordinary variety of putative extremophiles was observed [3,4,9]. A dominant factor seems to be soil porosity and lower clay-sized particle content [6-8]. A protocol was developed for sterile sampling, contamination issues, and the diagnostics of biodiversity via PCR and DGGE analysis in soils and rocks samples [10, 11]. We compare the 2009 campaign results [1-9] to new measurements from 2010-2013 campaigns [10-12] relevant to: comparison between remote sensing and in-situ measurements; the study of minerals; the detection of organics and signs of life. Keywords: field analogue research, astrobiology, habitability, life detection, Earth-Moon-Mars, organics References [A] Foing, Stoker & Ehrenfreund (Editors, 2011) "Astrobiology field Research in Moon/Mars Analogue Environments", Special Issue of International

  5. PEGylation of {sup 99m}Tc-labeled bombesin analogues improves their pharmacokinetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Daepp, Simone; Garayoa, Elisa Garcia [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Maes, Veronique; Brans, Luc; Tourwe, Dirk A. [Department of Organic Chemistry, Vrije Universiteit Brussel, 1050 Brussels (Belgium); Mueller, Cristina [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Schibli, Roger, E-mail: roger.schibli@psi.ch [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich (Switzerland)

    2011-10-15

    Introduction: Radiolabeled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumors in which BN{sub 2}/gastrin-releasing peptide (GRP) receptors are overexpressed. However, the low in vivo stability of BN conjugates may limit their clinical application. In an attempt to improve their pharmacokinetics and counteract their rapid enzymatic degradation, we prepared a series of polyethylene glycol (PEG)-ylated BN(7-14) analogues for radiolabeling with {sup 99m}Tc(CO){sub 3} and evaluated them in vitro and in vivo. Methods: Derivatization of a stabilized (N{sup {alpha}H}is)Ac-BN(7-14)[Cha{sup 13},Nle{sup 14}] analogue with linear PEG molecules of various sizes [5 kDa (PEG{sub 5}), 10 kDa (PEG{sub 10}) and 20 kDa (PEG{sub 20})] was performed by PEGylation of the {epsilon}-amino group of a {beta}{sup 3}hLys-{beta}Ala-{beta}Ala spacer between the stabilized BN sequence and the (N{sup {alpha}H}is)Ac chelator. The analogues were then radiolabeled by employing the {sup 99m}Tc-tricarbonyl technique. Binding affinity and internalization/externalization studies were performed in vitro in human prostate carcinoma PC-3 cells. Stability was investigated in vitro in human plasma and in vivo in Balb/c mice. Finally, single photon emission computed tomography (SPECT)/X-ray computed tomography studies were performed in nude mice bearing PC-3 tumor xenografts. Results: PEGylation did not affect the binding affinity of BN analogues, as the binding affinity for BN{sub 2}/GRP receptors remained high (K{sub d}<0.9 nM). However, in vitro binding kinetics of the PEGylated analogues were slower. Steady-state condition was reached after 4 h, and the total cell binding was 10 times lower than that for the non-PEGylated counterpart. Besides, PEGylation improved the stability of BN conjugates in vitro and in vivo. The BN derivative conjugated with a PEG{sub 5} molecule showed the best pharmacokinetics in vivo, i.e., faster blood clearance and

  6. Identification of Bearing Failure Using Signal Vibrations

    Science.gov (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

    2018-04-01

    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  7. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  8. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  9. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  10. Development and Evaluation of Titanium Spacesuit Bearings

    Science.gov (United States)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  11. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  12. Assessment of six dissimilarity metrics for climate analogues

    Science.gov (United States)

    Grenier, Patrick; Parent, Annie-Claude; Huard, David; Anctil, François; Chaumont, Diane

    2013-04-01

    Spatial analogue techniques consist in identifying locations whose recent-past climate is similar in some aspects to the future climate anticipated at a reference location. When identifying analogues, one key step is the quantification of the dissimilarity between two climates separated in time and space, which involves the choice of a metric. In this communication, spatial analogues and their usefulness are briefly discussed. Next, six metrics are presented (the standardized Euclidean distance, the Kolmogorov-Smirnov statistic, the nearest-neighbor distance, the Zech-Aslan energy statistic, the Friedman-Rafsky runs statistic and the Kullback-Leibler divergence), along with a set of criteria used for their assessment. The related case study involves the use of numerical simulations performed with the Canadian Regional Climate Model (CRCM-v4.2.3), from which three annual indicators (total precipitation, heating degree-days and cooling degree-days) are calculated over 30-year periods (1971-2000 and 2041-2070). Results indicate that the six metrics identify comparable analogue regions at a relatively large scale, but best analogues may differ substantially. For best analogues, it is also shown that the uncertainty stemming from the metric choice does generally not exceed that stemming from the simulation or model choice. A synthesis of the advantages and drawbacks of each metric is finally presented, in which the Zech-Aslan energy statistic stands out as the most recommended metric for analogue studies, whereas the Friedman-Rafsky runs statistic is the least recommended, based on this case study.

  13. Insulin analogues and cancer: a note of caution

    Directory of Open Access Journals (Sweden)

    Joseph A.M.J.L. eJanssen

    2014-05-01

    Full Text Available Abstract In view of the lifelong exposure and large patient populations involved, insulin analogues with an increased mitogenic effect in comparison to human insulin may potentially constitute a major health problem, since these analogues may possibly induce the growth of pre-existing neoplasms. At present, the available data suggest that insulin analogues are safe. In line with these findings, we observed that serum of diabetic patients treated with insulin analogues, compared to that of diabetic patients treated with human insulin, did not induce an increased phosphorylation of tyrosine residues of the insulin-like growth factor-I receptor (IGF-IR. However, the classical model of the IGF-IR signaling may be insufficient to explain (all mitogenic effects of insulin analogues since also non-canonical signaling pathways of the IGF-IR may play a major role in this respect. Although phosphorylation of tyrosine residues of the IGF-IR is generally considered to be the initial activation step within the intracellular IGF-IR signaling pathway, it has been found that cells undergo a signaling switch under hyperglycemic conditions. After this switch, a completely different mechanism is utilized to activate the mitogenic (mitogen-activated protein kinase (MAPK pathways of the IGF-IR that is independent from tyrosine phosphorylation of the IGF-IR. At present it is unknown whether activation of this alternative intracellular pathway of the IGF-IR occurs during hyperglycemia in vivo and whether it is stronger in patients treated with (some insulin analogues than in patients treated with human insulin. In addition, it is unknown whether the insulin receptors (IRs also undergo a signaling switch during hyperglycemia. This should be investigated in future studies. Finally, relative overexpression of IR isoform A (IR-A in (pre cancer tissues may play a key role in the development and progression of human cancers during treatment with insulin (analogues. Further

  14. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  16. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  17. MARKOV GRAPHS OF ONE–DIMENSIONAL DYNAMICAL SYSTEMS AND THEIR DISCRETE ANALOGUES AND THEIR DISCRETE ANALOGUES

    Directory of Open Access Journals (Sweden)

    SERGIY KOZERENKO

    2016-04-01

    Full Text Available One feature of the famous Sharkovsky’s theorem is that it can be proved using digraphs of a special type (the so–called Markov graphs. The most general definition assigns a Markov graph to every continuous map from the topological graph to itself. We show that this definition is too broad, i.e. every finite digraph can be viewed as a Markov graph of some one–dimensional dynamical system on a tree. We therefore consider discrete analogues of Markov graphs for vertex maps on combinatorial trees and characterize all maps on trees whose discrete Markov graphs are of the following types: complete, complete bipartite, the disjoint union of cycles, with every arc being a loop.

  18. Structure-activity relationships of lipopolysaccharide sequestration in guanylhydrazone-bearing lipopolyamines.

    Science.gov (United States)

    Wu, Wenyan; Sil, Diptesh; Szostak, Michal L; Malladi, Subbalakshmi S; Warshakoon, Hemamali J; Kimbrell, Matthew R; Cromer, Jens R; David, Sunil A

    2009-01-15

    The toxicity of gram-negative bacterial endotoxin (lipopolysaccharide, LPS) resides in its structurally highly conserved glycolipid component called lipid A. Our major goal has been to develop small-molecules that would sequester LPS by binding to the lipid A moiety, so that it could be useful for the prophylaxis or adjunctive therapy of gram-negative sepsis. We had previously identified in rapid-throughput screens several guanylhydrazones as potent LPS binders. We were desirous of examining if the presence of the guanylhydrazone (rather than an amine) functionality would afford greater LPS sequestration potency. In evaluating a congeneric set of guanylhydrazone analogues, we find that C(16) alkyl substitution is optimal in the N-alkylguanylhydrazone series; a homospermine analogue with the terminal amine N-alkylated with a C(16) chain with the other terminus of the molecule bearing an unsubstituted guanylhydrazone moiety is marginally more active, suggesting very slight, if any, steric effects. Neither C(16) analogue is significantly more active than the N-C(16)-alkyl or N-C(16)-acyl compounds that we had characterized earlier, indicating that basicity of the phosphate-recognizing cationic group, is not a determinant of LPS sequestration activity.

  19. A review of bear farming and bear trade in Lao People's Democratic Republic

    Directory of Open Access Journals (Sweden)

    E. Livingstone

    2018-01-01

    Full Text Available This study reviews the bear farming industry in Lao PDR with the objective of documenting the current number of commercial bear facilities (i.e. captive bear facilities judged to be trading in bear bile and/or bears and bear parts and the number of bears contained within these facilities, noting changes since it was last examined between 2000 and 2012 by Livingstone and Shepherd (2014. We surveyed all known commercial bear facilities and searched for previously unrecorded facilities. We compared our records with Livingstone and Shepherd (2014 and corrected some duplicate records from their study. In 2017, we recorded seven commercial facilities; four dedicated bear farms, and three tiger farms that were reportedly also keeping bears. We found that between 2012 and 2017 the recorded number of dedicated bear farms reduced by two, and the recorded number of tiger farms also keeping bears increased by one. Within the same period, the total number of captive bears among all facilities in Lao PDR hardly changed (+one, but the number of bears within each facility did. The northern facilities, owned by ethnic Chinese, have expanded since 2012, and central and southern facilities have downsized or closed. While bear farming appears to be downsizing in Lao PDR overall, efforts to phase it out are undermined by the expansion of foreign owned facilities in the north, within Special and Specific Economic Zones that largely cater to a Chinese market, and where the Lao government's efforts to enforce laws and protect wildlife appear to be lacking. Closing the facilities in the north will require political will and decisive law enforcement. Keywords: Bear farms, Bear bile, Gall bladder, Urso-deoxycholic acid, Bear bile extraction facilities, Lao PDR, Ursus thibetanus

  20. Morphogenesis of Antarctic Paleosols: Martian Analogue

    Science.gov (United States)

    Mahaney, W. C.; Dohm, J. M.; Baker, V. R.; Newsom, Horton E.; Malloch, D.; Hancock, R. G. V.; Campbell, Iain; Sheppard, D.; Milner, M. W.

    2001-11-01

    Samples of horizons in paleosols from the Quartermain Mountains of the Antarctic Dry Valleys (Aztec and New Mountain areas) were analyzed for their physical characteristics, mineralogy, chemical composition, and microbiology to determine the accumulation and movement of salts and other soluble constituents and the presence/absence of microbial populations. Salt concentrations are of special interest because they are considered to be a function of age, derived over time, in part from nearby oceanic and high-altitude atmospheric sources. The chemical composition of ancient Miocene-age paleosols in these areas is the direct result of the deposition and weathering of airborne-influxed salts and other materials, as well as the weathering of till derived principally from local dolerite and sandstone outcrops. Paleosols nearer the coast have greater contents of Cl, whereas near the inland ice sheet, nitrogen tends to increase on a relative basis. The accumulation and vertical distribution of salts and other soluble chemical elements indicate relative amounts of movement in the profile over long periods of time, in the order of several million years. Four of the six selected subsamples from paleosol horizons in two ancient soil profiles contained nil concentrations of bacteria and fungi. However, two horizons at depths of between 3 and 8 cm, in two profiles, yielded several colonies of the fungi Beauveria bassiana and Penicillium brevicompactum, indicating very minor input of organic carbon. Beauveria bassiana is often reported in association with insects and is used commercially for the biological control of some insect pests. Penicillium species are commonly isolated from Arctic, temperate, and tropical soils and are known to utilize a wide variety of organic carbon and nitrogen compounds. The cold, dry soils of the Antarctic bear a close resemblance to various present and past martian environments where similar weathering could occur and possible microbial populations

  1. On the robustness of entanglement in analogue gravity systems

    International Nuclear Information System (INIS)

    Bruschi, D E; Friis, N; Fuentes, I; Weinfurtner, S

    2013-01-01

    We investigate the possibility of generating quantum-correlated quasi-particles utilizing analogue gravity systems. The quantumness of these correlations is a key aspect of analogue gravity effects and their presence allows for a clear separation between classical and quantum analogue gravity effects. However, experiments in analogue systems, such as Bose–Einstein condensates (BECs) and shallow water waves, are always conducted at non-ideal conditions, in particular, one is dealing with dispersive media at non-zero temperatures. We analyse the influence of the initial temperature on the entanglement generation in analogue gravity phenomena. We lay out all the necessary steps to calculate the entanglement generated between quasi-particle modes and we analytically derive an upper bound on the maximal temperature at which given modes can still be entangled. We further investigate a mechanism to enhance the quantum correlations. As a particular example, we analyse the robustness of the entanglement creation against thermal noise in a sudden quench of an ideally homogeneous BEC, taking into account the super-sonic dispersion relations. (paper)

  2. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  3. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  4. Double-stabilized neurotensin analogues as potential radiopharmaceuticals for NTR-positive tumors

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Garayoa, Elisa [Center for Radiopharmaceutical Science, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)]. E-mail: elisa.garcia@psi.ch; Maes, Veronique [Vrije Universiteit Brussel, Department of Organic Chemistry, B-1050 Brussel (Belgium); Blaeuenstein, Peter [Center for Radiopharmaceutical Science, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Blanc, Alain [Center for Radiopharmaceutical Science, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Hohn, Alexander [Center for Radiopharmaceutical Science, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Tourwe, Dirk [Vrije Universiteit Brussel, Department of Organic Chemistry, B-1050 Brussel (Belgium); Schubiger, P. August [Center for Radiopharmaceutical Science, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2006-05-15

    Introduction: Overexpression of neurotensin (NT) receptors in exocrine pancreatic cancer and other neuroendocrine cancers make them interesting targets for tumor imaging and therapy. Modifications at the cleavage bonds 8-9 and 11-12 led to the synthesis of NT-XII, NT-XIII and NT-XVIII, three new stabilized analogues. (N{alpha}His)Ac was coupled to the N-terminus for labeling with [{sup 99m}Tc]-tricarbonyl. Methods: Stability was tested in vitro in human plasma and HT-29 cells. Binding to NT1 receptors and internalization/efflux were analyzed in intact HT-29 cells. Biodistribution studies were performed in nude mice bearing HT-29 xenografts. Results: All analogues were very stable in human plasma, with half-lives of 20-21 days. Degradation in HT-29 cells was more rapid (t {sub 1/2} of 6.5, 5 and 2.5 h for NT-XII, NT-XIII and NT-XVIII, respectively). They also showed high affinity and specificity for NT1 receptors. Bound activity was rapidly internalized at 37{sup o}C. The pattern of externalization was different. NT-XII was released more slowly than NT-XIII and NT-XVIII (half of the activity still inside the cells after 24 h). Bigger differences were found in the biodistribution studies. NT-XII showed the highest tumor uptake as well as the best tumor to nontumor ratios. Conclusion: The modifications introduced in NT(8-13) increased plasma stability, maintaining unaffected the in vitro binding properties. The best biodistribution corresponded to NT-XII, which shows to be a good candidate for NT1 receptors overexpressing tumors. First clinical trials are ongoing.

  5. Double-stabilized neurotensin analogues as potential radiopharmaceuticals for NTR-positive tumors.

    Science.gov (United States)

    García-Garayoa, Elisa; Maes, Veronique; Bläuenstein, Peter; Blanc, Alain; Hohn, Alexander; Tourwé, Dirk; Schubiger, P August

    2006-05-01

    Overexpression of neurotensin (NT) receptors in exocrine pancreatic cancer and other neuroendocrine cancers make them interesting targets for tumor imaging and therapy. Modifications at the cleavage bonds 8-9 and 11-12 led to the synthesis of NT-XII, NT-XIII and NT-XVIII, three new stabilized analogues. (NalphaHis)Ac was coupled to the N-terminus for labeling with [(99m)Tc]-tricarbonyl. Stability was tested in vitro in human plasma and HT-29 cells. Binding to NT1 receptors and internalization/efflux were analyzed in intact HT-29 cells. Biodistribution studies were performed in nude mice bearing HT-29 xenografts. All analogues were very stable in human plasma, with half-lives of 20-21 days. Degradation in HT-29 cells was more rapid (t(1/2) of 6.5, 5 and 2.5 h for NT-XII, NT-XIII and NT-XVIII, respectively). They also showed high affinity and specificity for NT1 receptors. Bound activity was rapidly internalized at 37 degrees C. The pattern of externalization was different. NT-XII was released more slowly than NT-XIII and NT-XVIII (half of the activity still inside the cells after 24 h). Bigger differences were found in the biodistribution studies. NT-XII showed the highest tumor uptake as well as the best tumor to nontumor ratios. The modifications introduced in NT(8-13) increased plasma stability, maintaining unaffected the in vitro binding properties. The best biodistribution corresponded to NT-XII, which shows to be a good candidate for NT1 receptors overexpressing tumors. First clinical trials are ongoing.

  6. Double-stabilized neurotensin analogues as potential radiopharmaceuticals for NTR-positive tumors

    International Nuclear Information System (INIS)

    Garcia-Garayoa, Elisa; Maes, Veronique; Blaeuenstein, Peter; Blanc, Alain; Hohn, Alexander; Tourwe, Dirk; Schubiger, P. August

    2006-01-01

    Introduction: Overexpression of neurotensin (NT) receptors in exocrine pancreatic cancer and other neuroendocrine cancers make them interesting targets for tumor imaging and therapy. Modifications at the cleavage bonds 8-9 and 11-12 led to the synthesis of NT-XII, NT-XIII and NT-XVIII, three new stabilized analogues. (NαHis)Ac was coupled to the N-terminus for labeling with [ 99m Tc]-tricarbonyl. Methods: Stability was tested in vitro in human plasma and HT-29 cells. Binding to NT1 receptors and internalization/efflux were analyzed in intact HT-29 cells. Biodistribution studies were performed in nude mice bearing HT-29 xenografts. Results: All analogues were very stable in human plasma, with half-lives of 20-21 days. Degradation in HT-29 cells was more rapid (t 1/2 of 6.5, 5 and 2.5 h for NT-XII, NT-XIII and NT-XVIII, respectively). They also showed high affinity and specificity for NT1 receptors. Bound activity was rapidly internalized at 37 o C. The pattern of externalization was different. NT-XII was released more slowly than NT-XIII and NT-XVIII (half of the activity still inside the cells after 24 h). Bigger differences were found in the biodistribution studies. NT-XII showed the highest tumor uptake as well as the best tumor to nontumor ratios. Conclusion: The modifications introduced in NT(8-13) increased plasma stability, maintaining unaffected the in vitro binding properties. The best biodistribution corresponded to NT-XII, which shows to be a good candidate for NT1 receptors overexpressing tumors. First clinical trials are ongoing

  7. Time scales of foam stability in shallow conduits: Insights from analogue experiments

    Science.gov (United States)

    Spina, L.; Scheu, B.; Cimarelli, C.; Arciniega-Ceballos, A.; Dingwell, D. B.

    2016-10-01

    Volcanic systems can exhibit periodical trends in degassing activity, characterized by a wide range of time scales. Understanding the dynamics that control such periodic behavior can provide a picture of the processes occurring in the feeding system. Toward this end, we analyzed the periodicity of outgassing in a series of decompression experiments performed on analogue material (argon-saturated silicone oil plus glass beads/fibers) scaled to serve as models of basaltic magma. To define the effects of liquid viscosity and crystal content on the time scale of outgassing, we investigated both: (1) pure liquid systems, at differing viscosities (100 and 1000 Pa s), and (2) particle-bearing suspensions (diluted and semidiluted). The results indicate that under dynamic conditions (e.g., decompressive bubble growth and fluid ascent within the conduit), the periodicity of foam disruption may be up to several orders of magnitude less than estimates based on the analysis of static conditions. This difference in foam disruption time scale is inferred to result from the contribution of bubble shear and bubble growth to inter-bubble film thinning. The presence of particles in the semidiluted regime is further linked to shorter bubble bursting times, likely resulting from contributions of the presence of a solid network and coalescence processes to the relative increase in bubble breakup rates. Finally, it is argued that these experiments represent a good analogue of gas-piston activity (i.e., the periodical rise-and-fall of a basaltic lava lake surface), implying a dominant role for shallow foam accumulation as a source process for these phenomena.

  8. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  9. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  10. Novel Penicillin-Type Analogues Bearing a Variable Substituted 2-Azetidinone Ring at Position 6: Synthesis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Margherita De Rosa

    2015-12-01

    Full Text Available The synthesis and the biological activity of novel semi-synthetic β-lactam compounds containing an azetidinone moiety joined to the amino-nitrogen of the (+-6-aminopenicillanic acid (6-APA as new antibacterial agents is reported. The synthesized compounds were screened for their in vitro antimicrobial activity against a panel of Gram positive and Gram negative pathogens and environmental bacteria. Tested compounds displayed good antimicrobial activity against all tested Gram positive bacteria and for Staphylococcus aureus and Staphylococcus epidermidis antimicrobial activity resulted higher than that of the reference antibiotic. Additionally, in vitro cytotoxic screening was also carried out indicating that the compounds do not cause a cell vitality reduction effective at concentration next to and above those shown to be antimicrobial.

  11. Novel Penicillin-Type Analogues Bearing a Variable Substituted 2-Azetidinone Ring at Position 6: Synthesis and Biological Evaluation.

    Science.gov (United States)

    De Rosa, Margherita; Vigliotta, Giovanni; Palma, Giuseppe; Saturnino, Carmela; Soriente, Annunziata

    2015-12-10

    The synthesis and the biological activity of novel semi-synthetic β-lactam compounds containing an azetidinone moiety joined to the amino-nitrogen of the (+)-6-aminopenicillanic acid (6-APA) as new antibacterial agents is reported. The synthesized compounds were screened for their in vitro antimicrobial activity against a panel of Gram positive and Gram negative pathogens and environmental bacteria. Tested compounds displayed good antimicrobial activity against all tested Gram positive bacteria and for Staphylococcus aureus and Staphylococcus epidermidis antimicrobial activity resulted higher than that of the reference antibiotic. Additionally, in vitro cytotoxic screening was also carried out indicating that the compounds do not cause a cell vitality reduction effective at concentration next to and above those shown to be antimicrobial.

  12. Synthesis and characterization of an iron complex bearing a cyclic tetra-N-heterocyclic carbene ligand: An artifical heme analogue?

    KAUST Repository

    Anneser, Markus R.

    2015-04-20

    An iron(II) complex with a cyclic tetradentate ligand containing four N-heterocyclic carbenes was synthesized and characterized by means of NMR and IR spectroscopies, as well as by single-crystal X-ray structure analysis. The iron center exhibits an octahedral coordination geometry with two acetonitrile ligands in axial positions, showing structural analogies with porphyrine-ligated iron complexes. The acetonitrile ligands can readily be substituted by other ligands, for instance, dimethyl sulfoxide, carbon monoxide, and nitric oxide. Cyclic voltammetry was used to examine the electronic properties of the synthesized compounds. © 2015 American Chemical Society.

  13. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  14. Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

    Science.gov (United States)

    Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

    2012-04-20

    Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

  15. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  16. Asymmetric Synthesis of Potential Precursors of the HIV Drug MC1220 and Its Analogues by Hydrogenation of (1-Arylvinyl)pyrimidines

    DEFF Research Database (Denmark)

    Loksha, Yasser M.; Pedersen, Erik B.

    2018-01-01

    Because MC1220 is a promising microbicide with anti-HIV-1 activity, the possibility for asymmetric synthesis of its potential precursors is explored. Here, we investigate asymmetric reduction of the vinyl double bond of 6-(1-arylvinyl)pyrimidine derivatives to their corresponding ethylidene analo...... analogues. Catalysts with ligands bearing trivalent phosphorus ligating the soft metals rhodium(I), ruthenium(II), or iridium(I) are used for asymmetric reduction of the vinyl derivatives 5a-e. The enantioselective reduction reaches 92% ee and about 71% conversion for reduction of the 6...

  17. Concise synthesis of new bridged-nicotine analogues

    DEFF Research Database (Denmark)

    Crestey, François; Hooyberghs, Geert; Kristensen, Jesper Langgaard

    2012-01-01

    This study describes a very efficient strategy for the synthesis of two new bridged-nicotine analogues. Starting from either 4- or 3-chloropyridine the desired tricyclic ring systems are accessed in just three steps in 23% and 40% overall yield, respectively.......This study describes a very efficient strategy for the synthesis of two new bridged-nicotine analogues. Starting from either 4- or 3-chloropyridine the desired tricyclic ring systems are accessed in just three steps in 23% and 40% overall yield, respectively....

  18. Naturally occurring crystalline phases: analogues for radioactive waste forms

    International Nuclear Information System (INIS)

    Haaker, R.F.; Ewing, R.C.

    1981-01-01

    Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, scheelite;sodalite, spinel, apatite, monazite, uraninite, hollandite-priderite, perovskite, and zirconolite. For each phase in geochemistry, occurrence, alteration and radiation effects are described. A selected bibliography for each phase is included

  19. Analogues of luteinizing hormone-releasing hormone containing cytotoxic groups.

    Science.gov (United States)

    Janáky, T; Juhász, A; Bajusz, S; Csernus, V; Srkalovic, G; Bokser, L; Milovanovic, S; Redding, T W; Rékási, Z; Nagy, A

    1992-02-01

    In an attempt to produce better cytotoxic analogues, chemotherapeutic antineoplastic radicals including an alkylating nitrogen mustard derivative of D-phenylalanine (D-melphalan), reactive cyclopropane, anthraquinone derivatives [2-(hydroxymethyl)anthraquinone and the anticancer antibiotic doxorubicin], and an antimetabolite (methotrexate) were coupled to suitably modified agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH). Analogues with D-lysine6 and D-ornithine6 or N epsilon-(2,3-diaminopropionyl)-D-lysine and N delta-(2,3-diaminopropionyl)-D-ornithine were used as carriers for one or two cytotoxic moieties. The enhanced biological activities produced by the incorporation of D amino acids into position 6 of the agonistic analogues were further increased by the attachment of hydrophobic cytotoxic groups, resulting in compounds with 10-50 times higher activity than LH-RH. Most of the monosubstituted agonistic analogues showed high affinities for the membrane receptors of human breast cancer cells, while the receptor binding affinities of peptides containing two cytotoxic side chains were lower. Antagonistic carriers [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,D-Lys6,D-Ala10] LH-RH [where Nal(2) is 3-(2-naphthyl)alanine], [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,N epsilon-(2,3-diaminopropionyl)-D-Lys6,D-Ala10]LH-RH, and their D-Pal(3)3 homologs [Pal(3) is 3-(3-pyridyl)alanine] as well as [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Pal(3)3,Tyr5,N epsilon-(2,3-diamino-propionyl)-D-Lys6,D-Ala10]LH-RH were linked to cytotoxic compounds. The hybrid molecules inhibited ovulation in rats at doses of 10 micrograms and suppressed LH release in vitro. The receptor binding of cytotoxic analogues was decreased compared to the precursor peptides, although analogues with 2-(hydroxymethyl)anthraquinone hemiglutarate had high affinities. All of the cytotoxic analogues tested inhibited [3H]thymidine incorporation into DNA in cultures of human breast and prostate cancer cell lines

  20. A Low-cost Multi-channel Analogue Signal Generator

    CERN Document Server

    Muller, F; Shen, W; Stamen, R

    2009-01-01

    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The implementation of the signal generator is presented as well as an application where it was successfully utilized.

  1. Design of a saturated analogue and digital current transducer

    International Nuclear Information System (INIS)

    Pross, Alexander

    2002-01-01

    This project describes the development of a new analogue and digital current transducer, providing a range of new theoretical design methods for these novel devices. The main control feature is the limit cycling operation, and the novel use of the embedded sigma-delta modulator sensor structure to derive a low component count digital sensor. The research programme was initiated into the design, development and evaluation of a novel non-Hall sensing analogue and digital current transducer. These transducers are used for measurement of high currents in power systems applications. The investigation is concerned with a new design which uses a magnetic ferrite core without an air gap for current measurement. The motivation for this work was to design a new control circuit which provides a low component count, and utilises the non-linear properties of the magnetic ferrite core to transmit direct current. The use of a limit cycle control circuit was believed to be particularly suitable for the analogue and digital transducers, for two main reasons: the low component count, and the output signal is directly digital. In line with the motivations outlined above, the outcome of the research has witnessed the design, development and evaluation of a practically realisable analogue and digital current transducer. The design procedure, which is documented in this thesis, is considered to be a major contribution to the field of transducers design and development using a control systems approach. Mathematical models for both analogue and digital transducers were developed and the resulting model based predictions were found to be in good agreement with measured results. Simplification of the new model sensing device was achieved by approximating the non-linear ferrite core using FFT analysis. This is also considered to be a significant contribution. The development analogue and digital current censors employed a sampled data control systems design and utilised limit cycling

  2. Naturally occurring crystalline phases: analogues for radioactive waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Haaker, R.F.; Ewing, R.C.

    1981-01-01

    Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, scheelite;sodalite, spinel, apatite, monazite, uraninite, hollandite-priderite, perovskite, and zirconolite. For each phase in geochemistry, occurrence, alteration and radiation effects are described. A selected bibliography for each phase is included.

  3. Neurochemical binding profiles of novel indole and benzofuran MDMA analogues.

    OpenAIRE

    Shimshoni, JA; Winkler, I; Golan, E; Nutt, D

    2016-01-01

    3,4-Methylenedioxy-N-methylamphetamine (MDMA) has been shown to be effective in the treatment of post-traumatic stress disorder (PTSD) in numerous clinical trials. In the present study, we have characterized the neurochemical binding profiles of three MDMA-benzofuran analogues (1-(benzofuran-5-yl)-propan-2-amine, 5-APB; 1-(benzofuran-6-yl)-N-methylpropan-2-amine, 6-MAPB; 1-(benzofuran-5-yl)-N-methylpropan-2-amine, 5-MAPB) and one MDMA-indole analogue (1-(1H-indol-5-yl)-2-methylamino-propan-1-...

  4. Optimization of gefitinib analogues with potent anticancer activity.

    Science.gov (United States)

    Yin, Kai-Hao; Hsieh, Yi-Han; Sulake, Rohidas S; Wang, Su-Pei; Chao, Jui-I; Chen, Chinpiao

    2014-11-15

    The interactions of gefitinib (Iressa) in EGFR are hydrogen bonding and van der Waals forces through quinazoline and aniline rings. However the morpholino group of gefitinib is poorly ordered due to its weak electron density. A series of novel piperazino analogues of gefitinib where morpholino group substituted with various piperazino groups were designed and synthesized. Most of them indicated significant anti-cancer activities against human cancer cell lines. In particular, compounds 52-54 showed excellent potency against cancer cells. Convergent synthetic approach has been developed for the synthesis of gefitinib intermediate which can lead to gefitinib as well as numerous analogues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Analogue studies at the french atomic commission (CEA)

    International Nuclear Information System (INIS)

    Petit, J.C.

    1986-06-01

    The different research activities of the French Atomic Energy Commission in the analogue study field are presented. Most of them are conducted in collaboration with major research organisations, both french and international. In fact, the scientific community has been associated to these programmes at different steps of their realisation. The brief description presented illustrates the great diversity and complementarity of actions conducted by CEA for better understanding, through the study of natural analogues, the basic processes that will rule the long term behaviour of high level radwaste materials in a repository and hence contributing to hopefully guaranty disposal safety

  6. Natural analogues, paradigm for manmade repositories for radioactive wastes

    International Nuclear Information System (INIS)

    Pavelescu, M.; Pavelescu, A.

    2004-01-01

    Natural analogues are given by nature. They show the results of natural processes which have lasted thousands or millions of years. They provide an excellent example of what could happen in an underground site, offering in the same time the opportunity to test by observation and measurement, many of the geochemical processes that are expected to influence in a realistic and appropriate way, the predicted reliability of the radioactive waste repository over long periods of geological time. The natural analogue studies attempt to understand the multiprocessing complexity of the natural system, which contrasts with the limitations of the laboratory experiments and bring arguments to overcome the difficult time scale issue. By this the natural analogues are a useful paradigm for manmade repository for radioactive wastes. The paper discusses the implicit link in the public mind between natural analogues and manmade waste repository with an accent of the positive impact on public acceptance. It is also discussed the decisive qualities of the natural analogues concerning providing valid long term data and increasing the confidence of the public for manmade repositories. The debate is conducting in terms of sustainable development, having at base high-level principles in order to protect humans and their environment, both now and in the future, from potential hazards arising from such wastes. Safe radwaste management involves the application of technology and resources in a regulated manner so that the public, workers and the environment are protected in accordance with the accepted national and international standards. There are at least seven high-level principles which are mentioned in the paper. It is presented the general concept of the deep geological repository, very important for an acceptable solution for the management of nuclear waste, what is a prerequisite for a renewal of nuclear power. Further are introduced natural and archaeological (manufactured) analogue

  7. Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

    Science.gov (United States)

    Jett, T.; Hall, P.; Thom, R.

    1991-01-01

    Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

  8. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  9. Unbalance Response Prediction for Rotors on Ball Bearings Using Speed and Load Dependent Nonlinear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2003-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant bearing stiffness. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

  10. Phylogeography of mitochondrial DNA variation in brown bears and polar bears

    Science.gov (United States)

    Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

    2000-01-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

  11. Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

    Science.gov (United States)

    Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

    2000-05-01

    We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

  12. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics.

    Science.gov (United States)

    Tse, Peter W; Wang, Dong

    2017-02-14

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL). Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI) so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  13. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    Directory of Open Access Journals (Sweden)

    Peter W. Tse

    2017-02-01

    Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  14. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  15. Shaft Center Orbit in Dynamically Loaded Bearings

    DEFF Research Database (Denmark)

    Klit, Peder

    2005-01-01

    The aim of this work is to demonstrate how to utilize the bearings damping coe±cients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 [1]and described further in 1972 [2]. Several authors have re¯ned this metho...

  16. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  17. 33 CFR 117.543 - Bear Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bear Creek. 117.543 Section 117.543 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.543 Bear Creek. (a) The draws of the Baltimore...

  18. Measurement of Wear in Radial Journal Bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Ligterink, D.J.; de Gee, A.W.J.

    1996-01-01

    this article, the measurement of wear in radial journal bearings is discussed, where a distinction is made between stationary and non-stationary contact conditions. Starting with Holm/Archard's wear law, equations are derived for the calculation of the specific wear rate k of the bearing material as

  19. Stabilizing gas bearing in free piston machines

    Science.gov (United States)

    Dhar, Manmohan (Inventor)

    1992-01-01

    In a free piston engine, to reduce dynamic loads on the reciprocating elements caused by a time varying pressure gradient across the gas bearing and close clearance seals provided therein, drain galleries are incorporated at the ends of the gas bearings to isolate the same, and circumferentially spaced grooves are incorporated in the close clearance seal region.

  20. Accuracy of Spindle Units with Hydrostatic Bearings

    Directory of Open Access Journals (Sweden)

    Fedorynenko Dmytro

    2016-06-01

    Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

  1. On the dynamics of ball bearings

    NARCIS (Netherlands)

    Wensing, J.A.

    1998-01-01

    This investigation on the dynamic behaviour of ball bearings was motivated by the demand for silent bearings in noise-sensitive applications, especially in the household appliance and automotive industry. The present investigations are intended to provide a clear understanding of the role of the

  2. Effect of Weight-Bearing in Conservative and Operative Management of Fractures of the Base of the Fifth Metatarsal Bone

    Directory of Open Access Journals (Sweden)

    Jae-Yong Park

    2017-01-01

    Full Text Available Background. There is no established principle regarding weight-bearing in conservative and operative management of fifth metatarsal base fractures. Methods. We reviewed 86 patients with acute fifth metatarsal base fractures. Conservatively treated late or early weight-bearing patients were assigned to Group A or C, respectively. Operatively treated late or early weight-bearing patients were assigned to Group B or D, respectively. Results were evaluated by clinical union, bone resorption, and the American Orthopaedic Foot and Ankle Society (AOFAS and Visual Analogue Scale (VAS scores. Results. All 4 groups had bone union at a mean of 6.9 weeks (range, 5.1–15.0. There were no differences between the groups in the AOFAS and VAS scores. In the early weight-bearing groups, there were fewer cases of bone resorption, and the bone unions periods were earlier. Conclusions. Early weight-bearing may help this patient population. Moreover, conservative treatment could be an option in patients with underlying diseases.

  3. Nonlinear Dynamic Response of Compliant Journal Bearings

    Directory of Open Access Journals (Sweden)

    Glavatskih S.

    2012-07-01

    Full Text Available This paper investigates the dynamic response of the compliant tilting pad journal bearings subjected to synchronous excitation. Bearing compliance is affected by the properties of pad liner and pad support geometry. Different unbalance eccentricities are considered. It is shown that bearing dynamic response is non-linear. Journal orbit complexity increases with pad compliance though the orbit amplitudes are marginally affected at low loads. At high loads, the journal is forced to operate outside the bearing clearance. The polymer liner reduces the maximum oil film pressure by a factor of 2 when compared to the white metal liner. The nonlinear dynamic response of compliant tilting pad journal bearings is thoroughly discussed.

  4. The dynamic state monitoring of bearings system

    Directory of Open Access Journals (Sweden)

    Marek Krynke

    2015-03-01

    Full Text Available The article discusses the methods of dynamic state monitoring of bearings system. A vibration signal contains important technical information about the machine condition and is currently the most frequently used in diagnostic bearings systems. One of the main ad-vantages of machine condition monitoring is identifying the cause of failure of the bearings and taking preventative measures, otherwise the operation of such a machine will lead to frequent replacement of the bearings. Monitoring changes in the course of the operation of machin-ery repair strategies allows keeping the conditioned state of dynamic failure conditioned preventive repairs and repairs after-failure time. In addition, the paper also presents the fundamental causes of bearing failure and identifies mechanisms related to the creation of any type of damage.

  5. Transient response of two lobe aerodynamic journal bearing

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Yadav

    2018-03-01

    Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

  6. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

  7. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    OpenAIRE

    Jarosław KACZOR

    2014-01-01

    Durability deep groove ball bearings depends on factors (called attributes) design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bea...

  8. Failure of GIMBAL bearing in directional GYRO

    International Nuclear Information System (INIS)

    Pervaiz, R.; Baig, N.A.; Shahid, M.; Ahmad, A.; Chohan, G.Y.

    2003-01-01

    This paper relates to the directional gyro of a sensing device used in indigenously developed surface-to-surface missile. The assembling of more than one thousand components in the form of several sub assemblies including hundreds of silver solders of this device was done in the hundred-thousands-class clean room according to assembly procedure. Whereas more than twenty bearings including gimbals bearings were assembled in the ten-thousands-class clean room after inspection/ testing them on beating testing system as per routine. The device was entered in testing and adjustment phase after successful completion of assembly work. The directional gyro qualified all the tests except the most critical one, the drift-rate. The drift-rate of outer gimbal was 60% more than permissible limit whereas drift-rate of inner gimbal was found O.K. It was diagnosed that at least one inner gimbal bearing out of two had some problem. The results were same after rebalancing of gimbals three times. The directional gyro was disassembled in clean room and the radial-thrust-bearing was recovered and flange bearing which are inner gimbal bearings. They were checked on bearing testing system and it was found that flange-bearing had more friction than permissible limit and hence rejected but radial thrust bearing were declared O.K. The gyro was reassembled with new O.K. flange bearing and the assembly work was completed in all respects. The sensing device qualified all the tests including the drift-rate. This case study is being presented to emphasize the importance of careful assembly of gyro in clean environment. (author)

  9. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and bearing...

  10. Evaluation of the antibacterial spectrum of drosocin analogues

    NARCIS (Netherlands)

    Bikker, F.J.; Kaman-van Zanten, W.E.; Vries-van de Ruit, A.M.B.C. de; Voskamp-Visser, I.; Hooft, P.A.V. van; Mars-Groenendijk, R.H.; Visser, P.C. de; Noort, D.

    2006-01-01

    Drosocin is a 19-mer, cationic antimicrobial peptide from Drosophila melanogaster. The aim of the study was to examine the antibacterial spectrum of unglycosylated drosocin analogues. Furthermore, the amino acid sequence of DnaK, drosocin's intracellular target, from susceptible species was aligned

  11. Trehalose Analogues: Latest Insights in Properties and Biocatalytic Production

    Directory of Open Access Journals (Sweden)

    Maarten Walmagh

    2015-06-01

    Full Text Available Trehalose (α-d-glucopyranosyl α-d-glucopyranoside is a non-reducing sugar with unique stabilizing properties due to its symmetrical, low energy structure consisting of two 1,1-anomerically bound glucose moieties. Many applications of this beneficial sugar have been reported in the novel food (nutricals, medical, pharmaceutical and cosmetic industries. Trehalose analogues, like lactotrehalose (α-d-glucopyranosyl α-d-galactopyranoside or galactotrehalose (α-d-galactopyranosyl α-d-galactopyranoside, offer similar benefits as trehalose, but show additional features such as prebiotic or low-calorie sweetener due to their resistance against hydrolysis during digestion. Unfortunately, large-scale chemical production processes for trehalose analogues are not readily available at the moment due to the lack of efficient synthesis methods. Most of the procedures reported in literature suffer from low yields, elevated costs and are far from environmentally friendly. “Greener” alternatives found in the biocatalysis field, including galactosidases, trehalose phosphorylases and TreT-type trehalose synthases are suggested as primary candidates for trehalose analogue production instead. Significant progress has been made in the last decade to turn these into highly efficient biocatalysts and to broaden the variety of useful donor and acceptor sugars. In this review, we aim to provide an overview of the latest insights and future perspectives in trehalose analogue chemistry, applications and production pathways with emphasis on biocatalysis.

  12. Combinatorial Solid-Phase Synthesis of Balanol Analogues

    DEFF Research Database (Denmark)

    Nielsen, John; Lyngsø, Lars Ole

    1996-01-01

    The natural product balanol has served as a template for the design and synthesis of a combinatorial library using solid-phase chemistry. Using a retrosynthetic analysis, the structural analogues have been assembled from three relatively accessible building blocks. The solid-phase chemistry inclu...

  13. A Short Review on Cardiotonic Steroids and Their Aminoguanidine Analogues

    Directory of Open Access Journals (Sweden)

    Arturo San Feliciano

    2000-01-01

    Full Text Available A short review on cardiotonic steroids and their analogues is presented. The natural, semisynthetic and synthetic derivatives, as well as their mechanism of action and structure-activity relationships are shown, with a special reference to aminoguanidine derivatives.

  14. Synthesis and biological evaluation of novel gramicidin s analogues

    NARCIS (Netherlands)

    Tuin, A.W.; Palachanis, D.K.; Buizert, A.; Grotenbreg, G.M.; Spalburg, E.; Neeling, A.J. de; Mars-Groenendijk, R.H.; Noort, D.; Marel, G.A. van der; Overkleeft, H.S.; Overhand, M.

    2009-01-01

    The synthesis of three new analogues of the cyclic cationic antimicrobial peptide Gramicidin S is described. These derivatives contain a modified turn region in which the DPhe-Pro motif has been replaced by a constrained furanoid sugar amino acid or a flexible linear aminoethoxy acetic acid moiety.

  15. A new analogue of fatty alcohol from Tamarix hampeana L.

    Science.gov (United States)

    Aykac, Ahmet; Akgül, Yurdanur

    2010-01-01

    New analogues of a long-chain secondary alcohol (1) and laserine (2) were isolated from the flowers of Tamarix hampeana L. The isolated compounds were identified using 1D and 2D NMR, LCMS/APCI, and chemical methods. Laserine was isolated for the first time from T. hampeana L.

  16. An Analysis of an Autoclitic Analogue in Pigeons

    Science.gov (United States)

    Kuroda, Toshikazu; Lattal, Kennon A.; García-Penagos, Andrés

    2014-01-01

    Using a conditional discrimination procedure, pigeons were exposed to a nonverbal analogue of qualifying autoclitics such as "definitely" and "maybe." It has been suggested that these autoclitics are similar to tacts except that they are under the control of private discriminative stimuli. Instead of the conventional assumption…

  17. Difference in brain activations during appreciating paintings and photographic analogues

    Directory of Open Access Journals (Sweden)

    Yoshinori eMizokami

    2014-07-01

    Full Text Available Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies’ measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogues which included corresponding real images. We prepared for famous painters’ pictures and their photographic analogues which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogues including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogues. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved.

  18. BlockLevel Bayesian Diagnosis of Analogue Electronic Circuits

    NARCIS (Netherlands)

    Krishnan, Shaji; Krishnan, Shaji; Kerkhoff, Hans G.; Doornbosch, Klaas D.; Brand, Rudi

    2010-01-01

    Daily experience with product designers, test and diagnosis engineers it is realized that the depth of interaction among them, ought to be high for successful diagnosis of analogue circuits. With this knowledge in mind, a responsibility was undertaken to choose a popular diagnostic method and define

  19. An azumamide C analogue without the zinc-binding functionality

    DEFF Research Database (Denmark)

    Villadsen, Jesper; Kitir, Betül; Wich, Kathrine

    2014-01-01

    + - coordinating moiety. Herein, we describe the synthesis of an azumamide analogue lacking its native Zn 2+ -binding group and evaluation of its inhibitory activity against recombinant human HDAC1 – 11. Furthermore, kinetic investigation of the inhibitory mechanism of both parent natural product and synthetic...

  20. Reasoning by analogy: rational foundation of natural analogue studies

    International Nuclear Information System (INIS)

    Petit, J.-C.

    1992-01-01

    Long-term extrapolations concerning the safety of a nuclear waste repository cannot be satisfactorily made on the sole basis of short-term laboratory investigations. Most nuclear countries have hence developed an approach relying on the following research directions: 1. laboratory experiments; 2. in situ testing; 3. modeling; and 4. natural analogues, which are the only means by which very slow mechanisms can be identified and by which long-term predictions of models can be tested for pertinence (if not truly validated). Although the field of natural analogues has grown very rapidly in recent years, receiving support from varied specialists and institutions involved in radioactive waste disposal, there is not yet a full consensus on their actual usefulness. More problematic is the criticism sometimes made that analogical reasoning is not ''true science'' and that information retrieved from the study of natural analogues will always remain questionable. The present paper gives some clues about the exact status of reasoning by analogy, compared to more ''scientific'' ways of deriving information from investigated systems. It is not a thorough discussion of this very complex, and by far too philosophical issue but we hope, at least, to present to readers of papers devoted to natural analogue studies arguments showing that this approach has some sound foundation. (author)

  1. Analogues of estradiol as potential breast tumor imaging agents

    International Nuclear Information System (INIS)

    Gibson, R.E.; Rzeszotarski, W.J.; Ferriera, N.L.; Jagoda, E.M.; Reba, R.C.; Eckelman, W.C.

    1984-01-01

    The radioiodinated analogue of estradiol, 11β-methoxy-17α-[/sup 125/I]iodovinylestradiol (MIVE/sub 2/), has been shown to be a good candidate for the imaging of estrogen dependent breast tumors. Although there has been no extensive study on the sensitivity of radiotracers of this type, the authors have not observed localization of the radiotracer in metastatic lesions containing less than 20 fmole estrogen receptor/mg protein or in bone metasteses. In order to improve the sensitivity, they have examined several structural analogues of moxestrol (the parent structure for MIVE/sub 2/) for affinity to the ER isolated from immature rat uterus. The 11β-ethyl analogue (EEE/sub 2/) of ethynyl estradiol (EE/sub 2/) exhibits the highest affinity with the 11β-methyl analogue second best. Although the lipophilicity is also very high this compound should not be much more lipophilic than 16-iodoestradiol or MIVE/sub 2/ since the introduction of iodine increases the log P by greater than 1. The distribution of the tritiated derivative of EEE/sub 2/ is under study

  2. Block-level Bayesian diagnosis of analogue electronic circuits

    NARCIS (Netherlands)

    Krishnan, S.; Doornbos, K.D.; Brand, R.; Kerkhoff, H.G.

    2010-01-01

    Daily experience with product designers, test and diagnosis engineers it is realized that the depth of interaction among them, ought be high for sucessfull diagnosis of analogue circuits. With this knowledge in mind, a responsibility was undertaken to choose a popular diagnostic method and define a

  3. Vitamin E analogues and immune response in cancer treatment

    Czech Academy of Sciences Publication Activity Database

    Tomasetti, M.; Neužil, Jiří

    2007-01-01

    Roč. 76, - (2007), s. 463-491 ISSN 0083-6729 Institutional research plan: CEZ:AV0Z50520514; CEZ:AV0Z50520701 Keywords : vitamin E analogues * inducers of apoptosis * immune surveillance Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.889, year: 2007

  4. Influence of Bakuchiol, a JH analogue from Bemchi ( Psoralea ...

    African Journals Online (AJOL)

    The influence of a juvenile hormone analogue (JHA), bakuchiol on the silk yield of silkworm, Bombyx mori L. was studied involving two popular commercial hybrids, KA x NB4D2 (bivoltine x bivoltine) and PM x NB4D2 (multivoltine x bivoltine). The compound was administered topically to 5th instars at 24, 48, 72 and 96 h as ...

  5. Thymidine analogues to assess microperfusion in human tumors

    International Nuclear Information System (INIS)

    Janssen, Hilde L.; Ljungkvist, Anna S.; Rijken, Paul F.; Sprong, Debbie; Bussink, Jan; Kogel, Albert J. van der; Haustermans, Karin M.; Begg, Adrian C.

    2005-01-01

    Purpose: To validate the use of the thymidine analogues as local perfusion markers in human tumors (no labeling indicates no perfusion) by comparison with the well-characterized perfusion marker Hoechst 33342. Methods and Materials: Human tumor xenografts from gliomas and head-and-neck cancers were injected with iododeoxyuridine (IdUrd) or bromodeoxyuridine (BrdUrd) and the fluorescent dye Hoechst 33342. In frozen sections, each blood vessel was scored for the presence of IdUrd/BrdUrd labeling and Hoechst in surrounding cells. The percentage of analogue-negative vessels was compared with the fraction of Hoechst-negative vessels. Collocalization of the two markers was also scored. Results: We found considerable intertumor variation in the fraction of perfused vessels, measured by analogue labeling, both in the human tumor xenografts and in a series of tumor biopsies from head-and-neck cancer patients. There was a significant correlation between the Hoechst-negative and IdUrd/BrdUrd-negative vessels in the xenografts (r 85, p = 0.0004), despite some mismatches on a per-vessel basis. Conclusions: Thymidine analogues can be successfully used to rank tumors according to their fraction of perfused vessels. Whether this fraction correlates with the extent of acute hypoxia needs further confirmation

  6. Mutasynthesis of fluorinated pactamycin analogues and their antimalarial activity.

    Science.gov (United States)

    Almabruk, Khaled H; Lu, Wanli; Li, Yuexin; Abugreen, Mostafa; Kelly, Jane X; Mahmud, Taifo

    2013-04-05

    A mutasynthetic strategy has been used to generate fluorinated TM-025 and TM-026, two biosynthetically engineered pactamycin analogues produced by Streptomyces pactum ATCC 27456. The fluorinated compounds maintain excellent activity and selectivity toward chloroquine-sensitive and multidrug-resistant strains of malarial parasites as the parent compounds. The results also provide insights into the biosynthesis of 3-aminobenzoic acid in S. pactum.

  7. Using natural analogue studies in the secondary science curriculum

    International Nuclear Information System (INIS)

    Ebert, E.K.

    1995-01-01

    This paper discusses an atomic theory unit of a high school chemistry course taught in Nevada. The unit is based on the application of natural analogues to nuclear waste issues. The paper focuses on the students' reactions to the subject material

  8. Analogue Building Blocks Based on Digital CMOS Gates

    DEFF Research Database (Denmark)

    Mucha, Igor

    1996-01-01

    Low-performance analogue circuits built of digital MOS gates are presented. Depending on the threshold voltages of the technology used the final circuits can be operated using low supply voltages. The main advantage using the proposed circuits is the simplicity and ultimate compatibility...... with the design of digital circuits....

  9. Rubrene analogues with the aggregation-induced emission enhancement behaviour

    DEFF Research Database (Denmark)

    Zhang, Xiaoxu; Sørensen, Jakob Kryger; Fu, Xiaowei

    2014-01-01

    In the light of the principle of aggregation-induced emission enhancement (AIEE), the rubrene analogue with orange light-emitting properties is designed and synthesized by substituting the phenyl side groups of rubrene with thienyl groups. To the best of our knowledge, this is the first report on...

  10. Mammary analogue secretory carcinoma: A rare salivary gland tumour

    African Journals Online (AJOL)

    Salivary gland malignancy is rare, with a global annual incidence of. 3 per 100 000 people.[1,2] A rare salivary gland tumour, mammary analogue secretory carcinoma (MASC), has only recently been described.[3] The few reports and studies concerning MASC have been published in several pathology journals. We report ...

  11. Charged Analogues of Henning Knutsen Type Solutions in General Relativity

    Science.gov (United States)

    Gupta, Y. K.; Kumar, Sachin; Pratibha

    2011-11-01

    In the present article, we have found charged analogues of Henning Knutsen's interior solutions which join smoothly to the Reissner-Nordstrom metric at the pressure free interface. The solutions are singularity free and analyzed numerically with respect to pressure, energy-density and charge-density in details. The solutions so obtained also present the generalization of A.L. Mehra's solutions.

  12. Lysine-vasopressin analogues with glycoconjugates in position 8

    Czech Academy of Sciences Publication Activity Database

    Marcinkowska, A.; Borovičková, Lenka; Slaninová, Jiřina; Grzonka, Z.

    2006-01-01

    Roč. 80, č. 5 (2006), s. 759-766 ISSN 0137- 5083 Institutional research plan: CEZ:AV0Z40550506 Keywords : glycoconjugates * glycopeptides * lysine-vasopressin analogues Subject RIV: CC - Organic Chemistry Impact factor: 0.491, year: 2006

  13. Genomic Evidence of Widespread Admixture from Polar Bears into Brown Bears during the Last Ice Age.

    Science.gov (United States)

    Cahill, James A; Heintzman, Peter D; Harris, Kelley; Teasdale, Matthew D; Kapp, Joshua; Soares, Andre E R; Stirling, Ian; Bradley, Daniel; Edwards, Ceiridwen J; Graim, Kiley; Kisleika, Aliaksandr A; Malev, Alexander V; Monaghan, Nigel; Green, Richard E; Shapiro, Beth

    2018-05-01

    Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has mainly been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, whereas brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomics to reveal patterns of evolutionary change that are otherwise masked in contemporary data.

  14. Análogos de insulina Insulin analogues

    Directory of Open Access Journals (Sweden)

    Manuel E. Licea Puig

    2006-12-01

    diabetes mellitus (DM. The recombinant technology of deoxyribonucleic acid (DNA has allowed the development of human insulin; however, this has not totally solved the problems related to immunogenecity, among other problems. Therefore, the new technologies are applied to create insulin analogues. It is our purpose to review relevant pharmacological and clinical aspects related to the insulin analogues, as well as their usefulness in the treatment of DM. The insulin analogues result from biochemical modifications of human insulin. These modifications of the insulin molecule alter not only the absorption, but also the beginning and duration of the action, which offer advantages over the conventional insulins. At present, there are three rapid acting insulin analogues: insulin lispro, insulin aspart and glulisine; and three long acting analogues; glargine, detemir and albulin. Albulin is the latest long acting analogue reported. At present, it is being subjected to various in vitro and in vivo studies. Besides, there have been developed diverse formulations where the rapid acting insulin analogues are premixed with the long acting analogues. The rapid acting insulin analogues have showed a modest global benefit against the conventional insulins in type 1 diabetics. The long acting analogues focus their attention in those persons with DM with nocturnal hypoglycemic episodes. Longer term studies are necessary to confirm the safety and benefits of these preparations, as well as to determine their effect on the micro- and macroangiopathic complications of DM.

  15. Bear-ly” learning: Limits of abstraction in black bear cognition

    Directory of Open Access Journals (Sweden)

    Jennifer Vonk

    2018-02-01

    Full Text Available We presented two American black bears (Ursus americanus with a serial list learning memory task, and one of the bears with a matching-to-sample task. After extended training, both bears demonstrated some success with the memory task but failed to generalize the overarching rule of the task to novel stimuli. Matching to sample proved even more difficult for our bear to learn. We conclude that, despite previous success in training bears to respond to natural categories, quantity discriminations, and other related tasks, that bears may possess a cognitive limitation with regards to learning abstract rules. Future tests using different procedures are necessary to determine whether this is a limit of bears’ cognitive capacities, or a limitation of the current tasks as presented. Future tests should present a larger number of varying stimuli. Ideally, bears of various species should be tested on these tasks to demonstrate species as well as individual differences.

  16. Adakitic magmas: modern analogues of Archaean granitoids

    Science.gov (United States)

    Martin, Hervé

    1999-03-01

    Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assumed to be either (1) subduction (melting of a hot subducting slab), or (2) hot spot (melting of underplated basalts). These hypotheses are considered in the light of modern adakite genesis. Adakites are intermediate to felsic volcanic rocks, andesitic to rhyolitic in composition (basaltic members are lacking). They have trondhjemitic affinities (high-Na 2O contents and K 2O/Na 2O˜0.5) and their Mg no. (0.5), Ni (20-40 ppm) and Cr (30-50 ppm) contents are higher than in typical calc-alkaline magmas. Sr contents are high (>300 ppm, until 2000 ppm) and REE show strongly fractionated patterns with very low heavy REE (HREE) contents (Yb≤1.8 ppm, Y≤18 ppm). Consequently, high Sr/Y and La/Yb ratios are typical and discriminating features of adakitic magmas, indicative of melting of a mafic source where garnet and/or hornblende are residual phases. Adakitic magmas are only found in subduction zone environments, exclusively where the subduction and/or the subducted slab are young (subducted and where the adakitic character of the lavas correlates well with the young age of the subducting oceanic lithosphere. In typical subduction zones, the subducted lithosphere is older than 20 Ma, it is cool and the geothermal gradient along the Benioff plane is low such that the oceanic crust dehydrates before it reaches the solidus temperature of hydrated tholeiite. Consequently, the basaltic slab cannot melt. The released large ion lithophile element (LILE)-rich fluids rise up into the mantle wedge, inducing both its metasomatism and partial melting. Afterwards, the residue is made up of olivine+clinopyroxene+orthopyroxene, such that the partial melts are HREE-rich (low La/Yb and Sr

  17. Sulphamoylated 2-methoxyestradiol analogues induce apoptosis in adenocarcinoma cell lines.

    Directory of Open Access Journals (Sweden)

    Michelle Visagie

    Full Text Available 2-Methoxyestradiol (2ME2 is a naturally occurring estradiol metabolite which possesses antiproliferative, antiangiogenic and antitumor properties. However, due to its limited biological accessibility, synthetic analogues have been synthesized and tested in attempt to develop drugs with improved oral bioavailability and efficacy. The aim of this study was to evaluate the antiproliferative effects of three novel in silico-designed sulphamoylated 2ME2 analogues on the HeLa cervical adenocarcinoma cell line and estrogen receptor-negative breast adenocarcinoma MDA-MB-231 cells. A dose-dependent study (0.1-25 μM was conducted with an exposure time of 24 hours. Results obtained from crystal violet staining indicated that 0.5 μM of all 3 compounds reduced the number of cells to 50%. Lactate dehydrogenase assay was used to assess cytotoxicity, while the mitotracker mitochondrial assay and caspase-6 and -8 activity assays were used to investigate the possible occurrence of apoptosis. Tubulin polymerization assays were conducted to evaluate the influence of these sulphamoylated 2ME2 analogues on tubulin dynamics. Double immunofluorescence microscopy using labeled antibodies specific to tyrosinate and detyrosinated tubulin was conducted to assess the effect of the 2ME2 analogues on tubulin dynamics. An insignificant increase in the level of lactate dehydrogenase release was observed in the compounds-treated cells. These sulphamoylated compounds caused a reduction in mitochondrial membrane potential, cytochrome c release and caspase 3 activation indicating apoptosis induction by means of the intrinsic pathway in HeLa and MDA-MB-231 cells. Microtubule depolymerization was observed after exposure to these three sulphamoylated analogues.

  18. Neurochemical binding profiles of novel indole and benzofuran MDMA analogues.

    Science.gov (United States)

    Shimshoni, Jakob A; Winkler, Ilan; Golan, Ezekiel; Nutt, David

    2017-01-01

    3,4-Methylenedioxy-N-methylamphetamine (MDMA) has been shown to be effective in the treatment of post-traumatic stress disorder (PTSD) in numerous clinical trials. In the present study, we have characterized the neurochemical binding profiles of three MDMA-benzofuran analogues (1-(benzofuran-5-yl)-propan-2-amine, 5-APB; 1-(benzofuran-6-yl)-N-methylpropan-2-amine, 6-MAPB; 1-(benzofuran-5-yl)-N-methylpropan-2-amine, 5-MAPB) and one MDMA-indole analogue (1-(1H-indol-5-yl)-2-methylamino-propan-1-ol, 5-IT). These compounds were screened as potential second-generation anti-PTSD drugs, against a battery of human and non-human receptors, transporters, and enzymes, and their potencies as 5-HT 2 receptor agonist and monoamine uptake inhibitors determined. All MDMA analogues displayed high binding affinities for 5-HT 2a,b,c and NE α2 receptors, as well as significant 5-HT, DA, and NE uptake inhibition. 5-APB revealed significant agonist activity at the 5-HT 2a,b,c receptors, while 6-MAPB, 5-MAPB, and 5-IT exhibited significant agonist activity at the 5-HT 2c receptor. There was a lack of correlation between the results of functional uptake and the monoamine transporter binding assay. MDMA analogues emerged as potent and selective monoamine oxidase A inhibitors. Based on 6-MAPB favorable pharmacological profile, it was further subjected to IC 50 determination for monoamine transporters. Overall, all MDMA analogues displayed higher monoamine receptor/transporter binding affinities and agonist activity at the 5-HT 2a,c receptors as compared to MDMA.

  19. Analogue Electrical Circuit for Simulation of the Duffing-Holmes Equation

    DEFF Research Database (Denmark)

    Tamaseviciute, E.; Tamasevicius, A.; Mykolaitis, G.

    2008-01-01

    An extremely simple second order analogue electrical circuit for simulating the two-well Duffing-Holmes mathematical oscillator is described. Numerical results and analogue electrical simulations are illustrated with the snapshots of chaotic waveforms, phase portraits (Lissajous figures...

  20. Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

    Science.gov (United States)

    Cong, Feiyun; Chen, Jin; Dong, Guangming; Pecht, Michael

    2013-04-01

    Rolling element bearing faults are among the main causes of breakdown in rotating machines. In this paper, a rolling bearing fault model is proposed based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is taken into consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. The vibration response of the proposed fault signal model is investigated and the fault signal calculating equation is derived through dynamic and kinematic analysis. Outer race and inner race fault simulations are realized in the paper. The simulation process includes consideration of several parameters, such as the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. The rotating frequency sidebands will occur in the envelope spectrum in addition to the fault characteristic frequency. This appearance of sidebands will increase the difficulty of fault recognition in intelligent fault diagnosis. The experiments given in the paper have successfully verified the proposed signal model simulation results. The test rig design of the rotor bearing system simulated several operating conditions: (1) rotor bearing only; (2) rotor bearing with loader added; (3) rotor bearing with loader and rotor disk; and (4) bearing fault simulation without rotor influence. The results of the experiments have verified that the proposed rolling bearing signal model is important to the rolling bearing fault diagnosis of rotor-bearing systems.

  1. Polar bears and sea ice habitat change

    Science.gov (United States)

    Durner, George M.; Atwood, Todd C.; Butterworth, Andy

    2017-01-01

    The polar bear (Ursus maritimus) is an obligate apex predator of Arctic sea ice and as such can be affected by climate warming-induced changes in the extent and composition of pack ice and its impacts on their seal prey. Sea ice declines have negatively impacted some polar bear subpopulations through reduced energy input because of loss of hunting habitats, higher energy costs due to greater ice drift, ice fracturing and open water, and ultimately greater challenges to recruit young. Projections made from the output of global climate models suggest that polar bears in peripheral Arctic and sub-Arctic seas will be reduced in numbers or become extirpated by the end of the twenty-first century if the rate of climate warming continues on its present trajectory. The same projections also suggest that polar bears may persist in the high-latitude Arctic where heavy multiyear sea ice that has been typical in that region is being replaced by thinner annual ice. Underlying physical and biological oceanography provides clues as to why polar bear in some regions are negatively impacted, while bears in other regions have shown no apparent changes. However, continued declines in sea ice will eventually challenge the survival of polar bears and efforts to conserve them in all regions of the Arctic.

  2. Grizzly bear diet shifting on reclaimed mines

    Directory of Open Access Journals (Sweden)

    Bogdan Cristescu

    2015-07-01

    Full Text Available Industrial developments and reclamation change habitat, possibly altering large carnivore food base. We monitored the diet of a low-density population of grizzly bears occupying a landscape with open-pit coal mines in Canada. During 2009–2010 we instrumented 10 bears with GPS radiocollars and compared their feeding on reclaimed coal mines and neighboring Rocky Mountains and their foothills. In addition, we compared our data with historical bear diet for the same population collected in 2001–2003, before extensive mine reclamation occurred. Diet on mines (n=331 scats was dominated by non-native forbs and graminoids, while diets in the Foothills and Mountains consisted primarily of ungulates and Hedysarum spp. roots respectively, showing diet shifting with availability. Field visitation of feeding sites (n=234 GPS relocation clusters also showed that ungulates were the main diet component in the Foothills, whereas on reclaimed mines bears were least carnivorous. These differences illustrate a shift to feeding on non-native forbs while comparisons with historical diet reveal emergence of elk as an important bear food. Food resources on reclaimed mines attract bears from wilderness areas and bears may be more adaptable to landscape change than previously thought. The grizzly bear’s ready use of mines cautions the universal view of this species as umbrella indicative of biodiversity.

  3. Genetic control of biennial bearing in apple

    Science.gov (United States)

    Guitton, Baptiste; Kelner, Jean-Jacques; Velasco, Riccardo; Gardiner, Susan E.; Chagné, David; Costes, Evelyne

    2012-01-01

    Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using the 114 flowering individuals from an F1 population of 122 genotypes, from a ‘Starkrimson’ (strong biennial bearer)בGranny Smith’ (regular bearer) cross. The number of inflorescences, and the number and the mass of harvested fruit were recorded over 6 years and used to calculate 26 variables and indices quantifying yield, precocity of production, and biennial bearing. Inflorescence traits exhibited the highest genotypic effect, and three quantitative trait loci (QTLs) on linkage group (LG) 4, LG8, and LG10 explained 50% of the phenotypic variability for biennial bearing. Apple orthologues of flowering and hormone-related genes were retrieved from the whole-genome assembly of ‘Golden Delicious’ and their position was compared with QTLs. Four main genomic regions that contain floral integrator genes, meristem identity genes, and gibberellin oxidase genes co-located with QTLs. The results indicated that flowering genes are less likely to be responsible for biennial bearing than hormone-related genes. New hypotheses for the control of biennial bearing emerged from QTL and candidate gene co-locations and suggest the involvement of different physiological processes such as the regulation of flowering genes by hormones. The correlation between tree architecture and biennial bearing is also discussed. PMID:21963613

  4. Genomic sequencing of Pleistocene cave bears

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

    2005-04-01

    Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

  5. Eastern slopes grizzly bear project : project update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-01-01

    This report updates a study to examine the cumulative effects of human activities on the grizzly bears in the central Canadian Rockies. The project was initiated in 1994 to acquire accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of the study is used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers monitored 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers worked with representatives from Husky Oil and Rigel Energy on the development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over eight years indicates that the grizzly bears have few and infrequent offspring. Using the information gathered thus far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears suffer from high mortality, and the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The research concluded in November 2001 provides sufficient information to accurately asses the status of the grizzly bear population and habitat. The data will be analyzed and integrated in 2002 into models that reflect the variables affecting grizzly bears and a final report will be published.

  6. Deficiencies in fat-soluble vitamins in long-term users of somatostatin analogue

    NARCIS (Netherlands)

    Fiebrich, H. -B.; van den Berg, G.; Kema, I. P.; Links, T. P.; Kleibeuker, J. H.; van Beek, A. P.; Walenkamp, A. M. E.; Sluiter, W. J.; de Vries, E. G. E.

    2010-01-01

    P>Background Somatostatin analogues are administered to control hormone hypersecretion in acromegaly and carcinoid patients. Somatostatin analogues can increase fat in the stools, which can lead to loss of fat-soluble vitamins. The effect of long-term somatostatin analogue use on vitamin levels

  7. Nucleoside analogues are activated by bacterial deoxyribonucleoside kinases in a species-specific manner

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, Anders; On, Stephen L. W.

    2007-01-01

    To investigate the bactericidal activity of antiviral and anticancer nucleoside analogues against a variety of pathogenic bacteria and characterize the activating enzymes, deoxyribonucleoside kinases (dNKs). Several FDA-approved nucleoside analogue drugs were screened for their potential bacteric......-specific manner. Therefore, nucleoside analogues have a potential to be employed as antibiotics in the fight against emerging multiresistant bacteria....

  8. On Using Current Steering Logic in Mixed Analogue-digital Circuits

    DEFF Research Database (Denmark)

    Lehmann, Torsten

    1998-01-01

    The authors investigate power supply noise in mixed analogue-digital circuits, arising from communication between the analogue and digital parts of the circuit. Current steering techniques and proper buffering are used to show which noise currents can be reduced and which cannot. In addition......, a high-swing current steering buffer for driving analogue switches or external digital signals is proposed....

  9. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...... orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

  10. Microeconomic analysis of military aircraft bearing restoration

    Science.gov (United States)

    Hein, G. F.

    1976-01-01

    The risk and cost of a bearing restoration by grinding program was analyzed. A microeconomic impact analysis was performed. The annual cost savings to U.S. Army aviation is approximately $950,000.00 for three engines and three transmissions. The capital value over an indefinite life is approximately ten million dollars. The annual cost savings for U.S. Air Force engines is approximately $313,000.00 with a capital value of approximately 3.1 million dollars. The program will result in the government obtaining bearings at lower costs at equivalent reliability. The bearing industry can recover lost profits during a period of reduced demand and higher costs.

  11. Superconducting bearings for a LHe transfer pump

    Science.gov (United States)

    Kloeppel, S.; Muehsig, C.; Funke, T.; Haberstroh, C.; Hesse, U.; Lindackers, D.; Zielke, S.; Sass, P.; Schoendube, R.

    2017-12-01

    Superconducting bearings are used in a number of applications for high speed, low loss suspension. Most of these applications suspend a warm shaft and thus require continuous cooling, which leads to additional power consumption. Therefore, it seems advantageous to use these bearings in systems that are inherently cold. One respective application is a submerged pump for the transfer of liquid helium into mobile dewars. Centrifugal pumps require tight sealing clearances, especially for low viscosity fluids and small sizes. This paper covers the design and qualification of superconducting YBCO bearings for a laboratory sized liquid helium transfer pump. Emphasis is given to the axial positioning, which strongly influences the achievable volumetric efficiency.

  12. Camshaft bearing arrangement for overhead cam engine

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.

    1985-01-01

    In an assembly for an internal combustion engine comprising a cylinder block, a cylinder head detachably affixed to the cylinder block by a plurality of threaded fastening means, a plurality of poppet valves supported for reciprocation in the cylinder head and a camshaft for operating the poppet valves, the improvement is described comprising a cam carrier detachably affixed to the cylinder head and overlying the threaded fastening means, and a bearing cap affixed to the cam carrier. The cam carrier and the bearing cap have bearing surfaces for journaling the camshaft.

  13. Compressor ported shroud for foil bearing cooling

    Science.gov (United States)

    Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  14. Alligator Rivers Analogue project. Application of scenario development method in evaluation of the Koongarra Analogue. Final Report - Volume 16

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, K. [Kemakta Consultants co., Stockholm (Sweden); Wingefors, S. [Swedish Nuclear Power Inspectorate, Stockholm (Sweden)

    1992-12-31

    The study of natural analogues has been established as one of the most important methods for validation of concepts and models applied for the assessment of long-term performance of repositories for nuclear waste. The objectives of such studies range from detailed investigations of processes and features on a small scale to attempts of explaining the evolution of whole sites. For studies of specific processes it may well be as important to consider the larger scale settings as boundary conditions. This appreciation of context and an integrated view may be as important for evaluation of most natural analogues as for performance assessments. This is more evident the more the evaluation depends on a knowledge about the evolution of the natural analogue. The attempted formulation of scenarios of the Koongarra Analogue has been based on the external conditions and external features. A rapid weathering of the host rock, i.e. the chlorite schist, is assumed to have started around the onset of the Pleistocene Ice Age (ca 1.6 Ma BP). The eventual oxidation and mobilization of the uranium ore could then have occurred under unsaturated or saturated conditions. This leads to the following major scenarios: (1) Uranyl Phosphates formed under unsaturated conditions, with a periodical evolution of the dispersion fan in conjunction with alternating dry (glacial) and wet (interglacial) periods during the Pleistocene Ice Age; (2) Uranyl Phosphates formed under unsaturated conditions as a single event, taking place either early or late during the Pleistocene Ice Age; (3)Uranyl Phosphates formed under saturated conditions, in conjunction with periods of higher and lower flow due to the climatic cycling. Although the original objectives may not have been fully achieved, this work is believed to contribute to a better understanding of the Koongarra Analogue as well as to give a basis for further scenario work

  15. Alligator Rivers Analogue project. Application of scenario development method in evaluation of the Koongarra Analogue. Final Report - Volume 16

    International Nuclear Information System (INIS)

    Skagius, K.; Wingefors, S.

    1992-01-01

    The study of natural analogues has been established as one of the most important methods for validation of concepts and models applied for the assessment of long-term performance of repositories for nuclear waste. The objectives of such studies range from detailed investigations of processes and features on a small scale to attempts of explaining the evolution of whole sites. For studies of specific processes it may well be as important to consider the larger scale settings as boundary conditions. This appreciation of context and an integrated view may be as important for evaluation of most natural analogues as for performance assessments. This is more evident the more the evaluation depends on a knowledge about the evolution of the natural analogue. The attempted formulation of scenarios of the Koongarra Analogue has been based on the external conditions and external features. A rapid weathering of the host rock, i.e. the chlorite schist, is assumed to have started around the onset of the Pleistocene Ice Age (ca 1.6 Ma BP). The eventual oxidation and mobilization of the uranium ore could then have occurred under unsaturated or saturated conditions. This leads to the following major scenarios: (1) Uranyl Phosphates formed under unsaturated conditions, with a periodical evolution of the dispersion fan in conjunction with alternating dry (glacial) and wet (interglacial) periods during the Pleistocene Ice Age; (2) Uranyl Phosphates formed under unsaturated conditions as a single event, taking place either early or late during the Pleistocene Ice Age; (3)Uranyl Phosphates formed under saturated conditions, in conjunction with periods of higher and lower flow due to the climatic cycling. Although the original objectives may not have been fully achieved, this work is believed to contribute to a better understanding of the Koongarra Analogue as well as to give a basis for further scenario work

  16. Alligator Rivers Analogue project. Application of scenario development method in evaluation of the Koongarra Analogue. Final Report - Volume 16

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, K [Kemakta Consultants co., Stockholm (Sweden); Wingefors, S [Swedish Nuclear Power Inspectorate, Stockholm (Sweden)

    1993-12-31

    The study of natural analogues has been established as one of the most important methods for validation of concepts and models applied for the assessment of long-term performance of repositories for nuclear waste. The objectives of such studies range from detailed investigations of processes and features on a small scale to attempts of explaining the evolution of whole sites. For studies of specific processes it may well be as important to consider the larger scale settings as boundary conditions. This appreciation of context and an integrated view may be as important for evaluation of most natural analogues as for performance assessments. This is more evident the more the evaluation depends on a knowledge about the evolution of the natural analogue. The attempted formulation of scenarios of the Koongarra Analogue has been based on the external conditions and external features. A rapid weathering of the host rock, i.e. the chlorite schist, is assumed to have started around the onset of the Pleistocene Ice Age (ca 1.6 Ma BP). The eventual oxidation and mobilization of the uranium ore could then have occurred under unsaturated or saturated conditions. This leads to the following major scenarios: (1) Uranyl Phosphates formed under unsaturated conditions, with a periodical evolution of the dispersion fan in conjunction with alternating dry (glacial) and wet (interglacial) periods during the Pleistocene Ice Age; (2) Uranyl Phosphates formed under unsaturated conditions as a single event, taking place either early or late during the Pleistocene Ice Age; (3)Uranyl Phosphates formed under saturated conditions, in conjunction with periods of higher and lower flow due to the climatic cycling. Although the original objectives may not have been fully achieved, this work is believed to contribute to a better understanding of the Koongarra Analogue as well as to give a basis for further scenario work

  17. Public Perceptions of Bears and Management Interventions in Japan

    OpenAIRE

    Sakurai, Ryo; Jacobson, Susan K.

    2011-01-01

    Conservation of bears is a challenge globally. In Japan, Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) are considered a nuisance because of agricultural and property damage and personal human danger due to occasional human casualties. Reduction of human–bear conflicts in Japan would improve long-term conservation of bears and reduce risks to human health and safety. To understand Japanese perceptions of and experience with bears, we analyzed results of 5 public surveys...

  18. Management of brown bears (Ursus arctos) in Europe.

    OpenAIRE

    Klenzendorf, Sybille A.

    1997-01-01

    Management of Brown Bears (Ursus arctos) in Europe. Sybille A. Klenzendorf (Abstract) Successful conservation of brown bears (Ursus arctos) in Europe is associated with public acceptance of damages caused by bears. Recent increases in sheep depredation and beehive damage in central Austria resulted in the deaths of two bears there. Since bear numbers are low in most European populations, alternatives to the elimination of problem bears associated with dam...

  19. Synthesis and antioxidant activity of peptide-based ebselen analogues.

    Science.gov (United States)

    Satheeshkumar, Kandhan; Mugesh, Govindasamy

    2011-04-18

    A series of di- and tripeptide-based ebselen analogues has been synthesized. The compounds were characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2) , tert-butyl hydroperoxide (tBuOOH), and cumene hydroperoxide (Cum-OOH) as substrates, and glutathione (GSH) as a cosubstrate. Although all the peptide-based compounds have a selenazole ring similar to that of ebselen, the GPx activity of these compounds highly depends on the nature of the peptide moiety attached to the nitrogen atom of the selenazole ring. It was observed that the introduction of a phenylalanine (Phe) amino acid residue in the N-terminal reduces the activity in all three peroxide systems. On the other hand, the introduction of aliphatic amino acid residues such as valine (Val) significantly enhances the GPx activity of the ebselen analogues. The difference in the catalytic activity of dipeptide-based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide. Although the presence of the Val-Ala-CO(2) Me moiety facilitates the formation of a catalytically active selenol species, the reaction of ebselen analogues that has a Phe-Ile-CO(2) Me residue with GSH does not generate the corresponding selenol. To understand the antioxidant activity of the peptide-based ebselen analogues in the absence of GSH, these compounds were studied for their ability to inhibit peroxynitrite (PN)-mediated nitration of bovine serum albumin (BSA) and oxidation of dihydrorhodamine 123. In contrast to the GPx activity, the PN-scavenging activity of the Phe-based peptide analogues was found to be comparable to that of the Val-based compounds. However, the introduction of an additional Phe residue to the ebselen analogue that had a Val-Ala dipeptide significantly reduced the potency of the parent compound in PN-mediated nitration. Copyright

  20. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    OpenAIRE

    Peter W. Tse; Dong Wang

    2017-01-01

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To exten...

  1. Phosphorylation of inositol 1,4,5-trisphosphate analogues by 3-kinase and dephosphorylation of inositol 1,3,4,5-tetrakisphosphate analogues by 5-phosphatase

    NARCIS (Netherlands)

    Dijken, Peter van; Lammers, Aleida A.; Ozaki, Shoichiro; Potter, Barry V.L.; Erneux, Christophe; Haastert, Peter J.M. van

    1994-01-01

    A series of P-32-labeled D-myo-inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P-4] analogues was enzymically prepared from the corresponding D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P-3] analogues using recombinant rat brain Ins(1,4,5)P-3 3-kinase and [gamma-P-32]ATP. Ins(1,4,5)P-3 analogues

  2. Molecular phylogeny and SNP variation of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) derived from genome sequences.

    Science.gov (United States)

    Cronin, Matthew A; Rincon, Gonzalo; Meredith, Robert W; MacNeil, Michael D; Islas-Trejo, Alma; Cánovas, Angela; Medrano, Juan F

    2014-01-01

    We assessed the relationships of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. A total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (Ailuropoda melanoleuca) genome sequences as references. We identified 13.8 million single nucleotide polymorphisms (SNP) in the 3 species aligned to the polar bear genome. These data indicate that polar bears and brown bears share more SNP with each other than either does with black bears. Concatenation and coalescence-based analysis of consensus sequences of approximately 1 million base pairs of ultraconserved elements in the nuclear genome resulted in a phylogeny with black bears as the sister group to brown and polar bears, and all brown bears are in a separate clade from polar bears. Genotypes for 162 SNP loci of 336 bears from Alaska and Montana showed that the species are genetically differentiated and there is geographic population structure of brown and black bears but not polar bears.

  3. How to live with black bears

    Science.gov (United States)

    Lynn L. Rogers

    1988-01-01

    A black bear in camp requires caution but is not cause for great alarm. Most are timid enough to be scared away by yelling, waving, and banging pans. But a few are too accustomed to people to be bothered.

  4. Centrifuge advances using HTS magnetic bearings

    Science.gov (United States)

    Werfel, F. N.; Flögel-Delor, U.; Rothfeld, R.; Wippich, D.; Riedel, T.

    2001-05-01

    Passive magnetic bearings are of increasing technical interest. We performed experiments with centrifugal rotors to analyze gyroscopic forces in terms imbalance, rotor elasticity and damping. Centrifuge rotors need to be operated soft and stable without whirling the sediments. In order to evaluate optimal parameters critical and resonance behaviors are investigated. Eccentricities up 2 mm are safely passed by accelerating test wheels. In a simple model we describe the effect of passing critical rotational speeds. Measurements of bearing properties and wheel performance are presented. We have constructed a first prototype centrifuge designed with a HTS double bearing which operates a titanium rotor safely up to 30 000 rpm. A 15 W Stirling cooler serves cryogenics of the YBCO stators. From the experiments design guidelines for centrifugal applications with HTS bearings are given.

  5. Hydrostatic radial bearing of centrifugal pump

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    A hydrostatic radial pump is described characterized by the fact that part of the medium off-taken from delivery is used as a lubricating medium. Two additional bodies are placed alongside a hydrostatic bearing with coils in between them and the pump shaft; the coils have an opposite pitch. The feed channel for the hydrostatic bearing pocket is linked to delivery. The coil outlets are connected to the pump suction unit. Two rotating coils placed alongside the hydrostatic bearing will considerably simplify the communication channel design and reduce the dependence on the pump shaft deflections. The addition of another rotating coil in the close vicinity of the pump shaft or directly on the shaft further increases the efficiency. The bearing can be used in designing vertical circulating pumps for the cooling circuits of nuclear reactors. (J.B.)

  6. Ceramic Rail-Race Ball Bearings

    Science.gov (United States)

    Balzer, Mark A.; Mungas, Greg S.; Peters, Gregory H.

    2010-01-01

    Non-lubricated ball bearings featuring rail races have been proposed for use in mechanisms that are required to function in the presence of mineral dust particles in very low-pressure, dry environments with extended life. Like a conventional ball bearing, the proposed bearing would include an inner and an outer ring separated by balls in rolling contact with the races. However, unlike a conventional ball bearing, the balls would not roll in semi-circular or gothic arch race grooves in the rings: instead, the races would be shaped to form two or more rails (see figure). During operation, the motion of the balls would push dust particles into the spaces between the rails where the particles could not generate rolling resistance for the balls

  7. Bearings for the HFIR control plates

    International Nuclear Information System (INIS)

    Abbatiello, A.A.

    1975-08-01

    Recent accelerated wear of HFIR bearings seems to be a more advanced stage of the situation encountered in 1967. The latest observations are in agreement with the hypothesis that high-frequency impact loads at a 30 0 angle on these bearings are the apparent basic cause of their short life. In view of the limited possibilities for change at this stage of HFIR operation, the region of best payoff seems to be an increase in the load-carrying area at some acceptable sacrifice of low rolling friction. On this basis three types of bearings are proposed for test--two of these are journal types and one is a slider type. The next planned shutdown for major parts replacement provides an opportunity to test these modified bearing types in the HFIR under full mechanical operating conditions but without nuclear operation. The program is recommended for consideration and adoption. (U.S.)

  8. Mathematical simulation of bearing ring grinding process

    Science.gov (United States)

    Koltunov, I. I.; Gorbunova, T. N.; Tumanova, M. B.

    2018-03-01

    The paper suggests the method of forming a solid finite element model of the bearing ring. Implementation of the model allowed one to evaluate the influence of the inner cylindrical surface grinding scheme on the ring shape error.

  9. LIGHT-WEIGHT LOAD-BEARING STRUCTURE

    DEFF Research Database (Denmark)

    2009-01-01

    The invention relates to a light-weight load-bearing structure (1) with optimized compression zone (2), where along one or more compression zones (2) in the structure (1) to be cast a core (3) of strong concrete is provided, which core (3) is surrounded by concrete of less strength (4) compared...... to the core (3) of strong concrete. The invention also relates to a method of casting of light-weight load-bearing structures (1) with optimized compression zone (2) where one or more channels, grooves, ducts, pipes and/or hoses (5) formed in the load-bearing structure (1) serves as moulds for moulding one...... or more cores (3) of strong concrete in the light-weight load-bearing structure (1)....

  10. Covalently linked bisporphyrins bearing tetraphenylporphyrin and ...

    Indian Academy of Sciences (India)

    Covalently linked bisporphyrins bearing tetraphenylporphyrin and perbromoporphyrin units: Synthesis and their properties. Puttaiah Bhyrappa V Krishnan ... yields of the TPP moiety. Electrochemical redox and fluorescence data seem to suggest the possible existence of intramolecular interactions in these bisporphyrins.

  11. Cavitation Peening of Aerospace Bearings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — High-value bearings are a critical part of the safety, reliability, cost and performance of modern aircraft. A typical passenger jet will have 100 to 175 high-valve...

  12. Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

    Science.gov (United States)

    Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

    2016-03-01

    The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Genetic relationships of extant brown bears (Ursus arctos) and polar bears (Ursus maritimus).

    Science.gov (United States)

    Cronin, Matthew A; MacNeil, Michael D

    2012-01-01

    Polar bears (Ursus maritimus) and brown bears (Ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. We used previously published genotype data for 8 microsatellite DNA loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. Genetic distances (Nei standard distance = 1.157), the proportion of private alleles (52% of alleles are not shared by the species), and Bayesian cluster analysis are consistent with morphological and life-history characteristics that distinguish polar bears and brown bears as different species with little or no gene flow among extant populations.

  14. Tool Indicates Contact Angles In Bearing Raceways

    Science.gov (United States)

    Akian, Richard A.; Butner, Myles F.

    1995-01-01

    Tool devised for use in measuring contact angles between balls and races in previously operated ball bearings. Used on both inner and outer raceways of bearings having cross-sectional widths between approximately 0.5 and 2.0 in. Consists of integral protractor mounted in vertical plane on bracket equipped with leveling screws and circular level indicator. Protractor includes rotatable indicator needle and set of disks of various sizes to fit various raceway curvatures.

  15. Comments to a polar bear population model

    OpenAIRE

    Øritsland, Nils Are

    1985-01-01

    Larsen, T. & Ugland, K. I. (Polar Research 2 n.s., 117-118) note correctly that a Leslie matrix model treats cubs and females as independent units which is not the case for polar bears. Population projections using the Leslie model with hunting mortalities added are instructive first approximations in evaluations of field data, however, and are recommended as exercises also for polar bear biologists. An APL programme for such projections is available.

  16. Apparatus Would Measure Temperatures Of Ball Bearings

    Science.gov (United States)

    Gibson, John C.; Fredricks, Thomas H.

    1995-01-01

    Rig for testing ball bearings under radial and axial loads and measuring surface temperatures undergoing development. Includes extensible thermocouples: by means of bellows as longitudinal positioners, thermocouples driven into contact with bearing balls to sense temperatures immediately after test run. Not necessary to disassemble rig or to section balls to obtain indirect indications of maximum temperatures reached. Thermocouple measurements indicate temperatures better than temperature-sensitive paints.

  17. Encapsulated Ball Bearings for Rotary Micro Machines

    Science.gov (United States)

    2007-01-01

    occurrence as well as the overall tribological properties of the bearing mechanism. Firstly, the number of stainless steel balls influences not only the load...stacks.iop.org/JMM/17/S224 Abstract We report on the first encapsulated rotary ball bearing mechanism using silicon microfabrication and stainless steel balls...The method of capturing stainless steel balls within a silicon race to support a silicon rotor both axially and radially is developed for rotary micro

  18. Solving overvoltage protection problems by means of an analogue computer

    Energy Technology Data Exchange (ETDEWEB)

    Stephanides, N

    1964-03-21

    The importance of improving overvoltage protection and reducing insulation level for voltages of 525 and 765 kV is fully realized. A digital computer may be used to determine, according to the Bergson procedure, the voltage distribution at different points of a given network but this procedure is very time-wasting. An analogue simulation is described, which, by giving an instantaneous display of the overvoltage wave on the screen of a cathode ray oscillograph, is better suited for the overvoltage protection study and satisfies also the conditions related to wave reproducibility. The method of simulating inductors, capacitors, and lightning arrestors (by using transistors) is shown and special emphasis is put on the surge generator analogue for which thyration tubes are used in order to get a linear front-increase of the impulse testing wave. The results obtained are accurate within 1 to 2% as compared with calculated values. Ten figures and seven references are given.

  19. Highly potent metallopeptide analogues of luteinizing hormone-releasing hormone

    International Nuclear Information System (INIS)

    Bajusz, S.; Janaky, T.; Csernus, V.J.; Bokser, L.; Fekete, M.; Srkalovic, G.; Redding, T.W.; Schally, A.V.

    1989-01-01

    Metal complexes related to the cytotoxic complexes cisplatin [cis-diamminedichloroplatinum(II)] and transbis(salicylaldoximato)copper(II) were incorporated into suitably modified luteinizing hormone-releasing hormone (LH-RH) analogues containing D-lysine at position 6. Some of the metallopeptides thus obtained proved to be highly active LH-RH agonists or antagonists. Most metallopeptide analogues of LH-RH showed high affinities for the membrane receptors of rat pituitary and human breast cancer cells. Some of these metallopeptides had cytotoxic activity against human breast cancer and prostate cancer and prostate cancer cell lines in vitro. Such cytostatic metallopeptides could be envisioned as targeted chemotherapeutic agents in cancers that contain receptors for LH-RH-like peptides

  20. Aminopropyl carbazole analogues as potent enhancers of neurogenesis.

    Science.gov (United States)

    Yoon, Hye Jin; Kong, Sun-Young; Park, Min-Hye; Cho, Yongsung; Kim, Sung-Eun; Shin, Jae-Yeon; Jung, Sunghye; Lee, Jiyoun; Farhanullah; Kim, Hyun-Jung; Lee, Jeewoo

    2013-11-15

    Neural stem cells are multipotent and self-renewing cells that can differentiate into new neurons and hold great promise for treating various neurological disorders including multiple sclerosis, Parkinson's disease, and Alzheimer's disease. Small molecules that can trigger neurogenesis and neuroprotection are particularly useful not only because of their therapeutic implications but also because they can provide an invaluable tool to study the mechanisms of neurogenesis. In this report, we have developed and screened 25 aminopropyl carbazole derivatives that can enhance neurogenesis of cultured neural stem cells. Among these analogues, compound 9 demonstrated an excellent proneurogenic and neuroprotective activity with no apparent toxicity. We believe that compound 9 can serve as an excellent lead to develop various analogues and to study the underlying mechanisms of neurogenesis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Some fluorescence properties of dimethylaminochalcone and its novel cyclic analogues

    Science.gov (United States)

    Tomečková, Vladimíra; Poškrobová, Martina; Štefanišinová, Miroslava; Perjési, Pál

    2009-12-01

    This paper demonstrates the basic character (polarity, solubility, colour, absorption and fluorescence quantum yield) of synthetic dimethylaminochalcone ( 1) and its cyclic analogues measured in toluene, chloroform, dimethylsulfoxide and ethanol, which have been studied by absorption and fluorescence spectroscopy. The biologically active dye 4'-dimethylaminochalcone ( 1b) and its less flexible analogues 4-dimethylaminoindanone ( 2b), -tetralone ( 3b), and -benzosuberone ( 4b) are lipophilic molecules that displayed the best solubility in toluene and chloroform. The highest fluorescence and quantum yields of compounds 1 and 2 have been obtained in DMSO and chloroform. Quenching effect of fluorescence compounds ( 1- 4) has been studied in the mixture of the most polar organic solvents DMSO and water. In the presence of water, fluorescence of compound 1 has been quenched the best from all studied chalcones and emission maxima of molecules 1- 4 have been shifted to the longer wavelengths. Quenching effect of fluorescence by water was in order 1 > 2 > 3 > 4.

  2. From the Canadian High Arctic to Mars by Analogue

    Science.gov (United States)

    Soare, R. J.; Pollard, W. H.

    2002-12-01

    Planetary scientists are limited in their understanding of physical bodies in the solar system by the lack of primary data or knowledge. Analogue science is science practised in absentia, precisely in those instances when a non-terrestrial physical environment lies beyond one's direct, empirical grasp. Recognising that some environments on Earth may mirror present or past conditions on Mars, planetary scientists have invoked terrestrial analogues with increasing regularity over the last thirty years as fonts of putative understanding. Notwithstanding its ubiquity in planetary science, analogical reasoning has stood, by and large, unconstrained by rules or guidelines of usage. In order to redress this imbalance we propose to take two steps: 1. introduce primary data on newly discovered pingos at Axel Heiberg Island in the Canadian High Arctic, and 2. coalesce these and related data on Martian glacial, peri-glacial and fluvio-glacial landforms as a model with which to evaluate the meaningfulness of analogical reasoning in planetary science.

  3. Effect of sulfur analogue of lysine on bacterial protein biosynthesis

    International Nuclear Information System (INIS)

    Tanaka, Hidehiko; Soda, Kenji.

    1976-01-01

    S-(beta-Aminoethyl)-L-cysteine, a sulfur analogue of lysine inhibited strongly growth of Escherichia coli A-19, and weakly that of Corynebacterium sp. isolated from soil, but did not inhibit growth of Aerobacter aerogenes. In Corynebacterium sp. the inhibitory effect was markedly enhanced in the presence of L-threonine. The inhibition of growth by S-(beta-aminoethyl)-L-cysteine was rapidly reversed by the addition of L-lysine. S-(beta-Aminoethyl)-L-cysteine inhibited protein synthesis and the activity of lysyl-tRNA synthetase from E. coli and A. aerogenes. All the other lysine analogues tested inhibited the activity of enzyme, but S-(beta-aminoethyl)-L-cysteine derivatives, S-(beta-N-acetyl-aminoethyl)-L-cysteine and S-(beta-aminoethyl)-alpha-N-acetyl-L-cysteine were not effective. (auth.)

  4. Optical analogue of relativistic Dirac solitons in binary waveguide arrays

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Truong X., E-mail: truong.tran@mpl.mpg.de [Department of Physics, Le Quy Don University, 236 Hoang Quoc Viet str., 10000 Hanoi (Viet Nam); Max Planck Institute for the Science of Light, Günther-Scharowsky str. 1, 91058 Erlangen (Germany); Longhi, Stefano [Department of Physics, Politecnico di Milano and Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Piazza L. da Vinci 32, I-20133 Milano (Italy); Biancalana, Fabio [Max Planck Institute for the Science of Light, Günther-Scharowsky str. 1, 91058 Erlangen (Germany); School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh (United Kingdom)

    2014-01-15

    We study analytically and numerically an optical analogue of Dirac solitons in binary waveguide arrays in the presence of Kerr nonlinearity. Pseudo-relativistic soliton solutions of the coupled-mode equations describing dynamics in the array are analytically derived. We demonstrate that with the found soliton solutions, the coupled mode equations can be converted into the nonlinear relativistic 1D Dirac equation. This paves the way for using binary waveguide arrays as a classical simulator of quantum nonlinear effects arising from the Dirac equation, something that is thought to be impossible to achieve in conventional (i.e. linear) quantum field theory. -- Highlights: •An optical analogue of Dirac solitons in nonlinear binary waveguide arrays is suggested. •Analytical solutions to pseudo-relativistic solitons are presented. •A correspondence of optical coupled-mode equations with the nonlinear relativistic Dirac equation is established.

  5. Ribosome-catalyzed formation of an abnormal peptide analogue

    International Nuclear Information System (INIS)

    Roesser, J.R.; Chorghade, M.S.; Hecht, S.M.

    1986-01-01

    The peptidyl-tRNA analogue N-(chloracetyl) phenylalanyl-tRNA/sup Phe/ was prepared by chemical aminoacylation and prebound to the P site of Escherichia coli ribosomes in response to poly(uridylic acid). Admixture of phenylalanyl-tRNA/sup Phe/ to the A site resulted in the formation of two dipeptides, one of which was found by displacement of chloride ion from the peptidyl-tRNA. This constitutes the first example of ribosome-mediated formation of a peptide of altered connectivity and suggests a need for revision of the current model of peptide bond formation. Also suggested by the present finding is the feasibility of utilizing tRNAs to prepare polypeptides of altered connectivity in an in vitro protein biosynthesizing system. [ 32 P]-oligo(rA), [ 3 H]- and [ 14 C] phenylalanines were used in the assay of the peptidye-tRNA analogue

  6. Antimalarial activity of abietane ferruginol analogues possessing a phthalimide group.

    Science.gov (United States)

    González, Miguel A; Clark, Julie; Connelly, Michele; Rivas, Fatima

    2014-11-15

    The abietane-type diterpenoid (+)-ferruginol, a bioactive compound isolated from New Zealand's Miro tree (Podocarpus ferruginea), displays relevant pharmacological properties, including antimicrobial, cardioprotective, anti-oxidative, anti-plasmodial, leishmanicidal, anti-ulcerogenic, anti-inflammatory and anticancer. Herein, we demonstrate that ferruginol (1) and some phthalimide containing analogues 2-12 have potential antimalarial activity. The compounds were evaluated against malaria strains 3D7 and K1, and cytotoxicity was measured against a mammalian cell line panel. A promising lead, compound 3, showed potent activity with an EC50 = 86 nM (3D7 strain), 201 nM (K1 strain) and low cytotoxicity in mammalian cells (SI>290). Some structure-activity relationships have been identified for the antimalarial activity in these abietane analogues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Anti-cancer activities of diospyrin, its derivatives and analogues

    KAUST Repository

    Sagar, Sunil

    2010-09-01

    Natural products have played a vital role in drug discovery and development process for cancer. Diospyrin, a plant based bisnaphthoquinonoid, has been used as a lead molecule in an effort to develop anti-cancer drugs. Several derivatives/analogues have been synthesized and screened for their pro-apoptotic/anti-cancer activities so far. Our review is focused on the pro-apoptotic/anti-cancer activities of diospyrin, its derivatives/analogues and the different mechanisms potentially involved in the bioactivity of these compounds. Particular focus has been placed on the different mechanisms (both chemical and molecular) thought to underlie the bioactivity of these compounds. A brief bioinformatics analysis at the end of the article provides novel insights into the new potential mechanisms and pathways by which these compounds might exert their effects and lead to a better realization of the full therapeutic potential of these compounds as anti-cancer drugs. © 2010 Elsevier Masson SAS. All rights reserved.

  8. Anti-cancer activities of diospyrin, its derivatives and analogues

    KAUST Repository

    Sagar, Sunil; Kaur, Mandeep; Minneman, Kenneth P.; Bajic, Vladimir B.

    2010-01-01

    Natural products have played a vital role in drug discovery and development process for cancer. Diospyrin, a plant based bisnaphthoquinonoid, has been used as a lead molecule in an effort to develop anti-cancer drugs. Several derivatives/analogues have been synthesized and screened for their pro-apoptotic/anti-cancer activities so far. Our review is focused on the pro-apoptotic/anti-cancer activities of diospyrin, its derivatives/analogues and the different mechanisms potentially involved in the bioactivity of these compounds. Particular focus has been placed on the different mechanisms (both chemical and molecular) thought to underlie the bioactivity of these compounds. A brief bioinformatics analysis at the end of the article provides novel insights into the new potential mechanisms and pathways by which these compounds might exert their effects and lead to a better realization of the full therapeutic potential of these compounds as anti-cancer drugs. © 2010 Elsevier Masson SAS. All rights reserved.

  9. Optoelectronic analogue signal transfer for LHC detectors, 1991

    CERN Document Server

    Dowell, John D; Homer, R J; Jovanovic, P; Kenyon, I; Staley, R; Webster, K; Da Via, C; Feyt, J; Nappey, P; Stefanini, G; Dwir, B; Reinhart, F K; Davies, J; Green, N; Stewart, W; Young, T; Hall, G; Akesson, T; Jarlskog, G; Kröll, S; Nickerson, R; Jaroslawski, S; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    We propose to study and develop opto-electronic analogue front-ends based on electro-optic intensity modulators. These devices translate the detector electrical analogue signals into optical signals which are then transferred via optical fibres to photodetector receivers at the remote readout. In comparison with conventional solutions based on copper cables, this technique offers the advantages of high speed, very low power dissipation and transmission losses, compactness and immunity to electromagnetic interference. The linearity and dynamic range that can be obtained are more than adequate for central tracking detectors, and the proposed devices have considerable radiation- hardness capabilities. The large bandwidth and short transit times offer possibilities for improved triggering schemes. The proposed R&D programme is aimed at producing multi-channel "demonstrator" units for evaluation both in laboratory and beam tests. This will allow the choice of the most effective technology. A detailed study wil...

  10. Somatostatin analogues labelled with 99mTc

    International Nuclear Information System (INIS)

    Obenaus, Esteban R.; Crudo, Jose L.; Edreira, Martin M.; Castiglia, Silvia G.

    1999-01-01

    Biological and radiochemical studies have been carried out on two labelled somatostatin analogues, the peptide RC-150 and the Tyr 3 -Octreotide. Both analogues have been labelled with 99m Tc using the direct and the indirect method and MAG-3 and HYNIC as chelating agents. By the direct method RC-150 was labelled using sodium ascorbate and dithionite as reducing agents. The radiochemical purity was 70%. By the indirect method, in the case of RC-160 with MAG-3 a radiochemical purity higher than 70% was attained while a purity of 100% was reached in the case of Tyr 3 -Octreotide with HYNIC. The biological distribution of HYNIC-Tyr 3 -Octreotide has been studied in rats. (author)

  11. Higher-dimensional analogues of Donaldson-Witten theory

    International Nuclear Information System (INIS)

    Acharya, B.S.; Spence, B.

    1997-01-01

    We present a Donaldson-Witten-type field theory in eight dimensions on manifolds with Spin(7) holonomy. We prove that the stress tensor is BRST exact for metric variations preserving the holonomy and we give the invariants for this class of variations. In six and seven dimensions we propose similar theories on Calabi-Yau threefolds and manifolds of G 2 holonomy, respectively. We point out that these theories arise by considering supersymmetric Yang-Mills theory defined on such manifolds. The theories are invariant under metric variations preserving the holonomy structure without the need for twisting. This statement is a higher-dimensional analogue of the fact that Donaldson-Witten field theory on hyper-Kaehler 4-manifolds is topological without twisting. Higher-dimensional analogues of Floer cohomology are briefly outlined. All of these theories arise naturally within the context of string theory. (orig.)

  12. Active Vibration Control of Hydrodynamic Journal Bearings

    Science.gov (United States)

    Tůma, J.; Šimek, J.; Škuta, J.; Los, J.; Zavadil, J.

    Rotor instability is one of the most serious problems of high-speed rotors supported by sliding bearings. With constantly increasing parameters, new machines problems with rotor instability are encountered more and more often. Even though there are many solutions based on passive improvement of the bearing geometry to enlarge the operational speed range of the journal bearing, the paper deals with a working prototype of a system for the active vibration control of journal bearings with the use of piezoactuators. The actively controlled journal bearing consists of a movable bushing, which is actuated by two piezoactuators. It is assumed that the journal vibration is measured by a pair of proximity probes. Force produced by piezoactuators and acting at the bushing is controlled according to error signals derived from the proximity probe output signals. The active vibration control was tested with the use of a test rig, which consists of a rotor supported by two controllable journal bearings and driven by an inductive motor up to 23,000 rpm. As it was proved by experiments the active vibration control extends considerably the range of the rotor operational speed.

  13. Consumption choice by bears feeding on salmon.

    Science.gov (United States)

    Gende, S M; Quinn, T P; Willson, M F

    2001-05-01

    Consumption choice by brown (Ursus arctos) and black bears (U. americanus) feeding on salmon was recorded for over 20,000 bear-killed fish from 1994 to 1999 in Bristol Bay (sockeye salmon, Oncorhynchus nerka) and southeastern Alaska (pink, O. gorbuscha and chum salmon O. keta). These data revealed striking patterns of partial and selective consumption that varied with relative availability and attributes of the fish. As the availability of salmon decreased, bears consumed a larger proportion of each fish among both years and habitats. When availability was high (absolute number and density of salmon), bears consumed less biomass per captured fish, targeting energy-rich fish (those that had not spawned) or energy-rich body parts (eggs in females; brain in males). In contrast, individual fish were consumed to a much greater extent, regardless of sex or spawning status, in habitats or years of low salmon availability. The proportion of biomass consumed per fish was similar for males and females, when spawning status was statistically controlled, but bears targeted different body parts: the body flesh, brain and dorsal hump in males and the roe in females. Bears thus appeared to maximize energy intake by modifying the amount and body parts consumed, based on availability and attributes of spawning salmon.

  14. Adaptive Spindle Balancing Using Magnetically Levitated Bearings

    International Nuclear Information System (INIS)

    BARNEY, PATRICK S.; LAUFFER, JAMES P.; PETTEYS, REBECCA; REDMOND, JAMES M.; SULLIVAN, WILLIAM N.

    1999-01-01

    A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well as experimental implementation using a digital LMS controller

  15. Hydrostatic bearing with a stepped duct

    International Nuclear Information System (INIS)

    Krevsun, Eh.P.; Ivanov, A.A.

    1975-01-01

    A method for calculating and experimental data from tests on a hydrostatic bearing whose operating hydraulic channel is formed by two cylincrical surfaces, are presented. Unlike currently used hydrostatic bearings, the bearing described has no capillary choke or diaphragm choke at the entrance. This simplifies the construction and increases the reliability, especially when it is operated with corrosive liquids or liquids containing solid suspensoids and causing erosion and blockage of the choke structures. In order to obtain the calculated relations, the flow of a liquid from the bearing in the axial direction to one side through a part of an aperture of unit width was examined. The effect of rotating the axle, of flow in the circumferential direction, and curvature of the aperture was not considered. Isothermal and laminar flows were considered. Because of the simplicity of the hydraulic circuit and the satisfactory properties (bearing capability and flow rate), the bearing described may be used in pumps operating with corrosive liquids, with those containing solid suspensoids and in nuclear energy establishments. (author)

  16. 18F-Labelled metomidate analogues as adrenocortical imaging agents

    International Nuclear Information System (INIS)

    Erlandsson, Maria; Karimi, Farhad; Lindhe, Orjan; Langstroem, Bengt

    2009-01-01

    Introduction: Two- and one-step syntheses of 18 F-labelled analogues of metomidate, such as 2-[ 18 F]fluoroethyl 1-[(1R)-1-phenylethyl]-1H-imidazole-5-carboxylate (1), 2-[ 18 F]fluoroethyl 1-[(1R)-1-(4-chlorophenyl)ethyl]-1H-imidazole-5-carboxylate (2), 2-[ 18 F]fluoroethyl 1-[(1R)-1-(4-bromophenyl)ethyl]-1H-imidazole-5-carboxylate (3), 3-[ 18 F]fluoropropyl 1-[(1R)-1-(4-bromophenyl)ethyl]-1H-imidazole-5-carboxylate (4) and 3-[ 18 F]fluoropropyl 1-[(1R)-1-phenylethyl]-1H-imidazole-5-carboxylate (5) are presented. Methods: Analogues 1-5 were prepared by a two-step reaction sequence that started with the synthesis of either 2-[ 18 F]fluoroethyl 4-methylbenzenesulfonate or 3-[ 18 F]fluoropropyl 4-methylbenzenesulfonate. These were used as 18 F-alkylating agents in the second step, in which they reacted with the ammonium salt of a 1-[(1R)-1-phenylethyl]-1H-imidazole-5-carboxylic acid. One-step-labelling syntheses of 1, 2 and 5 were also explored. Analogues 1-4 were biologically validated by frozen-section autoradiography and organ distribution. Metabolite analysis was performed for 2 and 3. Results: The radiochemical yield of the two-step synthesis was in the range of 10-29% and that of the one-step synthesis was 25-37%. Using microwave irradiation in the one-step synthesis of 1 and 2 increased the radiochemical yield to 46±3% and 79±30%, respectively. Conclusion: Both the frozen-section autoradiography and organ distribution results indicated that analogue 2 has a potential as an adrenocortical imaging agent, having the highest degree of specific adrenal binding and best ratio of adrenal to organ uptake among the compounds studied.

  17. Application of analogue computers to radiotracer data processing

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    1979-01-01

    Some applications of analogue computers for processing the flow-system radiotracer-investigation data are presented. Analysis of the impulse response shaped to obtain the frequency response of the system under consideration can be performed on the basis of an estimated transfer function. Furthermore, simulation of the system behaviour for other excitation functions is discussed. Simple approach is made for estimating the model parameters in situations where the input signal is not approximated by the unit impulse function. (author)

  18. Synthetic histatin analogues with broad-spectrum antimicrobial activity.

    OpenAIRE

    Helmerhorst, E J; Van't Hof, W; Veerman, E C; Simoons-Smit, I; Nieuw Amerongen, A V

    1997-01-01

    Histatins are salivary histidine-rich cationic peptides, ranging from 7 to 38 amino acid residues in length, that exert a potent killing effect in vitro on Candida albicans. Starting from the C-terminal fungicidal domain of histatin 5 (residues 11-24, called dh-5) a number of substitution analogues were chemically synthesized to study the effect of amphipathicity of the peptide in helix conformation on candidacidal activity. Single substitutions in dh-5 at several positions did not have any e...

  19. Matrix diffusion model. In situ tests using natural analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rasilainen, K. [VTT Energy, Espoo (Finland)

    1997-11-01

    Matrix diffusion is an important retarding and dispersing mechanism for substances carried by groundwater in fractured bedrock. Natural analogues provide, unlike laboratory or field experiments, a possibility to test the model of matrix diffusion in situ over long periods of time. This thesis documents quantitative model tests against in situ observations, done to support modelling of matrix diffusion in performance assessments of nuclear waste repositories. 98 refs. The thesis includes also eight previous publications by author.

  20. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, V 220, Rotterdam (Netherlands); Boerman, Otto C. [Radboud University Hospital, Department of Nuclear Medicine, Nijmegen (Netherlands)

    2010-05-15

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  1. Synthetic analogues of natural semiochemicals as promising insect control agents

    International Nuclear Information System (INIS)

    Ujvary, Istvan; Toth, Miklos; Guerin, Patrick

    2000-01-01

    After decades of research and development, insect pheromones and other semiochemicals became indispensable tools of ecologically based agricultural pest and disease vector management programmes with main uses as: 1) detection and population monitoring of emerging and migrating insects, 2) mass trapping of insects, 3) combined formulation of semiochemicals and insecticides ('lure-and-kill'), and 4) mating disruption with specially formulated pheromone components. In spite of their demonstrated safety and biodegradability, the direct application of these semiochemicals for pest control has not fulfilled initial expectations. Nonetheless considerable field experience has been accumulated (Carde and Minks 1995). Evidently, two important factors limit the practical potential of these substances: 1) inherent in their particular mode of action, semiochemicals, especially pheromones, are effectively cleared by specific enzymes in the insect antennae, and 2) some of these compounds contain labile functional moieties that are prone to degradation (oxidation, isomerisation and polymerisation) under field conditions. Appropriate chemical modifications of these natural compounds, however, can circumvent these problems by providing synthetic analogues (sometimes also called parapheromones or antipheromones; for early studies, see Roelofs and Comeau 1971, Payne et al. 1973) which in ideal cases are not only more potent and environmentally acceptable but more economical as well. It should also be mentioned that many effective attractants have been discovered through the empirical screening of synthetic chemicals, some of which have actually turned out to be structural relatives of natural semiochemicals of the particular insect. In this paper, selected case studies of analogues of sex pheromones and kairomones will be presented. The examples from our work include nitrile bioisosteres of labile aldehyde pheromone components of the cranberry girdler moth, Chrysoteuchia topiaria

  2. Matrix diffusion model. In situ tests using natural analogues

    International Nuclear Information System (INIS)

    Rasilainen, K.

    1997-11-01

    Matrix diffusion is an important retarding and dispersing mechanism for substances carried by groundwater in fractured bedrock. Natural analogues provide, unlike laboratory or field experiments, a possibility to test the model of matrix diffusion in situ over long periods of time. This thesis documents quantitative model tests against in situ observations, done to support modelling of matrix diffusion in performance assessments of nuclear waste repositories

  3. Do film soundtracks contain nonlinear analogues to influence emotion?

    OpenAIRE

    Blumstein, Daniel T.; Davitian, Richard; Kaye, Peter D.

    2010-01-01

    A variety of vertebrates produce nonlinear vocalizations when they are under duress. By their very nature, vocalizations containing nonlinearities may sound harsh and are somewhat unpredictable; observations that are consistent with them being particularly evocative to those hearing them. We tested the hypothesis that humans capitalize on this seemingly widespread vertebrate response by creating nonlinear analogues in film soundtracks to evoke particular emotions. We used lists of highly rega...

  4. Cinnamoylated chloroquine analogues: A new structural class of antimalarial agents.

    Science.gov (United States)

    Gayam, Venkatareddy; Ravi, Subban

    2017-07-28

    A novel series of cinnamoylated chloroquine hybrid analogues were synthesized and evaluated as antimalarial agents. The trans cinnamic acid derivatives (3-8) were synthesized by utilizing substituted aldehydes and malanoic acid in DMF catalysed by DABCO. The final cinnamoylated chloroquine analogues (9-14) were synthesized by utilizing DCC coupling reagent. The amido chloroquine (17) was prepared from acid (16) and compound 2 in benzene using SOCl 2 as chlorinating agent. The corresponding ester (15) was prepared from 2-hydroxy acetophenone and 2-bromoacetates in actonitrile in presence of K 2 CO 3  as base followed by basic hydrolysis. The preparation of amide based chloroquine-chalcone analogues (18-22), were obtained by the combination of amido chloroquine (17) and aldehydes in 10% aq. KOH in methanol at room temperature. Further we prepared epichlorohydrin based chloroquine-chalcone analogues (25-28), by reacting the epoxide (24a, 24b and 24c) with 2 and methelenedioxy aniline. In vitro antimalarial activity against chloroquine sensitive strain 3D7, chloroquine resistant strain K1 of P. falciparum and in vitro cytotoxicity of compounds using VERO cell line was carried out. The synthesized molecules showed significant in vitro antimalarial activity especially against CQ resistant strain (K1). Among tested compounds, 13, 9 and 10 were found to be the most potent compounds of the series with IC 50 value of 44.06, 48.04 and 59.37 nM against chloroquine resistant K1 strain. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Synthesis and Evaluation of Febrifugine Analogues as Potential Antimalarial Agents

    OpenAIRE

    Zhu, Shuren; Meng, Li; Zhang, Quan; Wei, Lai

    2006-01-01

    Febrifugine is an alkaloid isolated from Dichroa febrifuga Lour as the active component against Plasmodium falciparum. Strong liver toxicity has precluded febrifugine as a potential clinical drug. In this study novel febrifugine analogues were designed and synthesized. Lower toxicity was achieved by reducing or eliminating the tendency of forming chemically reactive and toxic intermediates and metabolites. Synthesized compounds were evaluated in vitro against chloroquine sensitive (D6) and ch...

  6. Localisation and mechanism of renal retention of radiolabelled somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Melis, Marleen; Krenning, Eric P.; Bernard, Bert F.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Barone, Raffaella [UCL, Centre of Nuclear Medicine and Laboratory of PET, Brussels (Belgium); Visser, Theo J. [Erasmus MC, Department of Internal Medicine, Rotterdam (Netherlands)

    2005-10-01

    Radiolabelled somatostatin analogues, such as octreotide and octreotate, are used for tumour scintigraphy and radionuclide therapy. The kidney is the most important critical organ during such therapy owing to the reabsorption and retention of radiolabelled peptides. The aim of this study was to investigate in a rat model both the localisation and the mechanism of renal uptake after intravenous injection of radiolabelled somatostatin analogues. The multi-ligand megalin/cubilin receptor complex, responsible for reabsorption of many peptides and proteins in the kidney, is an interesting candidate for renal endocytosis of these peptide analogues. For localisation studies, ex vivo autoradiography and micro-autoradiography of rat kidneys were performed 1-24 h after injection of radiolabelled somatostatin analogues and compared with the renal anti-megalin immunohistochemical staining pattern. To confirm a role of megalin in the mechanism of renal retention of [{sup 111}In-DTPA]octreotide, the effects of three inhibitory substances were explored in rats. Renal ex vivo autoradiography showed high cortical radioactivity and lower radioactivity in the outer medulla. The distribution of cortical radioactivity was inhomogeneous. Micro-autoradiography indicated that radioactivity was only retained in the proximal tubules. The anti-megalin immunohistochemical staining pattern showed a strong similarity with the renal [{sup 111}In-DTPA]octreotide ex vivo autoradiograms. Biodistribution studies showed that co-injection of positively charged d-lysine reduced renal uptake to 60% of control. Sodium maleate reduced renal [{sup 111}In-DTPA]octreotide uptake to 15% of control. Finally, cisplatin pre-treatment of rats reduced kidney uptake to 70% of control. Renal retention of [{sup 111}In-DTPA]octreotide is confined to proximal tubules in the rat kidney, in which megalin-mediated endocytosis may play an important part. (orig.)

  7. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    International Nuclear Information System (INIS)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de; Boerman, Otto C.

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  8. A semi-analytical bearing model considering outer race flexibility for model based bearing load monitoring

    Science.gov (United States)

    Kerst, Stijn; Shyrokau, Barys; Holweg, Edward

    2018-05-01

    This paper proposes a novel semi-analytical bearing model addressing flexibility of the bearing outer race structure. It furthermore presents the application of this model in a bearing load condition monitoring approach. The bearing model is developed as current computational low cost bearing models fail to provide an accurate description of the more and more common flexible size and weight optimized bearing designs due to their assumptions of rigidity. In the proposed bearing model raceway flexibility is described by the use of static deformation shapes. The excitation of the deformation shapes is calculated based on the modelled rolling element loads and a Fourier series based compliance approximation. The resulting model is computational low cost and provides an accurate description of the rolling element loads for flexible outer raceway structures. The latter is validated by a simulation-based comparison study with a well-established bearing simulation software tool. An experimental study finally shows the potential of the proposed model in a bearing load monitoring approach.

  9. Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears.

    Science.gov (United States)

    Fortes, Gloria G; Grandal-d'Anglade, Aurora; Kolbe, Ben; Fernandes, Daniel; Meleg, Ioana N; García-Vázquez, Ana; Pinto-Llona, Ana C; Constantin, Silviu; de Torres, Trino J; Ortiz, Jose E; Frischauf, Christine; Rabeder, Gernot; Hofreiter, Michael; Barlow, Axel

    2016-10-01

    Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago. © 2016 John Wiley & Sons Ltd.

  10. Transdermal delivery of a melanotropic peptide hormone analogue

    International Nuclear Information System (INIS)

    Dawson, B.V.; Hadley, M.E.; Kreutzfeld, K.; Dorr, R.T.; Hruby, V.J.; Al-Obeidi, F.; Don, S.

    1988-01-01

    We previously reported that topical application of [Nl3 4 ,D-Phe 7 ]alpha-MSH, a superpotent analogue of alpha-melanocyte stimulating hormone, to mice induces a darkening of follicular melanocytes throughout the skin. We now report that the melanotropin analogue can be delivered across mouse but not rat skin in an in vitro model system. Passage of the analogue from the topically applied vehicle (polyethylene glycol) across the skin into a subcutaneous receiving vessel was demonstrated by both bioassay as well as by radioimmunoassay. The bioassay data demonstrate that percutaneous absorption of the melanotropin did not result in loss of biological activity of the peptide. The differential penetration of the peptide across rodent skin reveals that one cannot predict percutaneous absorption of a substance across the stratum corneum from studies on a single species. The present results are the first to demonstrate, by direct quantitative measurements, that a bioactive peptide can be delivered across the vertebrate integument in vitro. These studies point out the potential of a topically applied melanotropin for tanning of the skin and possibly for treatment of certain hypopigmentary disorders

  11. Upgrading of analogue cameras using modern PC based computer

    International Nuclear Information System (INIS)

    Pardom, M.F.; Matos, L.

    2002-01-01

    Aim: The use of computers along with analogue cameras enables them to perform tasks involving time-activity parameters. The INFORMENU system converts a modern PC computer into a dedicated nuclear medicine computer system with a total cost affordable to emerging economic countries, and easily adaptable to all existing cameras. Materials and Methods: In collaboration with nuclear medicine physicians, an application including hardware and software was developed by a private firm. The system runs smoothly on Windows 98 and its operation is very easy. The main features are comparable to the brand commercial computer systems; such as image resolution until 1024 x 1024, low count loss at high count rate, uniformity correction, integrated graphical and text reporting, and user defined clinical protocols. Results: The system is used in more than 20 private and public institutions. The count loss is less than 1% in all the routine work, improvement of uniformity correction of 3-5 times, improved utility of the analogue cameras. Conclusion: The INFORMENU system improves the utility of analogue cameras permitting the inclusion of dynamic clinical protocols and quantifications, helping the development of the nuclear medicine practice. The operation and maintenance costs were lowered. The end users improve their knowledge of modern nuclear medicine

  12. Manipulating lightcone fluctuations in an analogue cosmic string

    Directory of Open Access Journals (Sweden)

    Jiawei Hu

    2018-02-01

    Full Text Available We study the flight time fluctuations in an anisotropic medium inspired by a cosmic string with an effective fluctuating refractive index caused by fluctuating vacuum electric fields, which are analogous to the lightcone fluctuations due to fluctuating spacetime metric when gravity is quantized. The medium can be realized as a metamaterial that mimics a cosmic string in the sense of transformation optics. For a probe light close to the analogue string, the flight time variance is ν times that in a normal homogeneous and isotropic medium, where ν is a parameter characterizing the deficit angle of the spacetime of a cosmic string. The parameter ν, which is always greater than unity for a real cosmic string, is determined by the dielectric properties of the metamaterial for an analogue string. Therefore, the flight time fluctuations of a probe light can be manipulated by changing the electric permittivity and magnetic permeability of the analogue medium. We argue that it seems possible to fabricate a metamaterial that mimics a cosmic string with a large ν in laboratory so that a currently observable flight time variance might be achieved.

  13. Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold.

    Science.gov (United States)

    Petoral, Rodrigo M; Björefors, Fredrik; Uvdal, Kajsa

    2006-11-23

    Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

  14. q-bosons and the q-analogue quantized field

    International Nuclear Information System (INIS)

    Nelson, C.A.

    1994-01-01

    The q-analogue coherent states |z > q are used to identify physical signatures for the presence of a q-analogue quantized radiation field in the | > q classical limit where |z| is large. In this quantum-optics-like limit, the fractional uncertainties of most physical quantities (momentum, position, amplitude, phase) which characterize the quantum field are O(1). They only vanish as O(1/|z|) when q = 1. However, for the number operator, N, and the N-Hamiltonian for a free q-boson gas, H N = ℎω(N + 1/2), the fractional uncertainties do still approach zero. A signature for q-boson counting statistics is that (ΔN) 2 / → 0 as |z| → ∞. Except for its O(1) fractional uncertainty, the q-generalization of the Hermitian phase operator of Pegg and Barnett, φ q , still exhibits normal classical behavior. The standard number-phase uncertainty-relation, ΔN Δφ q = 1/2, and the approximate commutation relation, [N,φ q ] = i, still hold for the single-mode q-analogue quantized field. So, N and φ q are almost canonically conjugate operators in the |z > q classical limit. The |z > q CS's minimize this uncertainty relation for moderate |z| 2

  15. Simulated Milky Way analogues: implications for dark matter direct searches

    Science.gov (United States)

    Bozorgnia, Nassim; Calore, Francesca; Schaller, Matthieu; Lovell, Mark; Bertone, Gianfranco; Frenk, Carlos S.; Crain, Robert A.; Navarro, Julio F.; Schaye, Joop; Theuns, Tom

    2016-05-01

    We study the implications of galaxy formation on dark matter direct detection using high resolution hydrodynamic simulations of Milky Way-like galaxies simulated within the EAGLE and APOSTLE projects. We identify Milky Way analogues that satisfy observational constraints on the Milky Way rotation curve and total stellar mass. We then extract the dark matter density and velocity distribution in the Solar neighbourhood for this set of Milky Way analogues, and use them to analyse the results of current direct detection experiments. For most Milky Way analogues, the event rates in direct detection experiments obtained from the best fit Maxwellian distribution (with peak speed of 223-289 km/s) are similar to those obtained directly from the simulations. As a consequence, the allowed regions and exclusion limits set by direct detection experiments in the dark matter mass and spin-independent cross section plane shift by a few GeV compared to the Standard Halo Model, at low dark matter masses. For each dark matter mass, the halo-to-halo variation of the local dark matter density results in an overall shift of the allowed regions and exclusion limits for the cross section. However, the compatibility of the possible hints for a dark matter signal from DAMA and CDMS-Si and null results from LUX and SuperCDMS is not improved.

  16. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    Energy Technology Data Exchange (ETDEWEB)

    G. Saulnier and W. Statham

    2006-04-16

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table.

  17. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    International Nuclear Information System (INIS)

    G. Saulnier; W. Statham

    2006-01-01

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO 2 uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table

  18. Thymidine analogue-sparing highly active antiretroviral therapy (HAART).

    Science.gov (United States)

    Nolan, David; Mallal, Simon

    2003-02-01

    The use of alternative nucleoside reverse transcriptase inhibitors (NRTIs) to the thymidine analogues stavudine (d4T) and zidovudine(ZDV) has been advocated as a means of limiting long-term NRTI-associated toxicity, particularly the development of lipoatrophy or fat wasting. This approach reflects an increasing knowledge of the distinct toxicity profiles of NRTI drugs. However, recent clinical trials have demonstrated that the use of thymidine analogue NRTIs and newer alternative backbone NRTIs, such as tenofovir (TNF) and abacavir (ABC), is associated with comparable short-term efficacy and tolerability. Given the importance of toxicity profile differences in determining clinical management, it is important to recognise that d4T and ZDV cary significantly different risks for long-term NRTI toxicity. Recognising that all NRTIs, including thymidine analogues, have individual toxicity profiles provides a more appropriate basis for selecting optimal antiretroviral therapy. The safety and efficacy of TNF and ABC are also reviewed here, although the available data provide only limited knowledge of the long-term effects of these drugs in terms of toxicity and antiviral durability.

  19. Amphetamine-Like Analogues in Diabetes: Speeding towards Ketogenesis

    Directory of Open Access Journals (Sweden)

    Natalia M. Branis

    2015-01-01

    Full Text Available Obesity is common in patients with type 1 and type 2 diabetes. Amphetamine-like analogues comprise the most popular class of weight loss medications. We present a case of a 34-year-old African American female with a history of type 1 diabetes, dyslipidemia, and obesity who developed diabetic ketoacidosis (DKA after starting Diethylpropion for the purpose of weight loss. Shortly after starting Diethylpropion, she developed nausea, vomiting, and periumbilical pain. Blood work revealed glucose of 718 mg/dL, pH 7.32 (7.35–7.45, bicarbonate 16 mmol/L (22–29 mmol/L, and anion gap 19 mmol/L (8–16 mmol/L. Urine analysis demonstrated large amount of ketones. She was hospitalized and successfully treated for DKA. Diethylpropion was discontinued. Amphetamine-like analogues administration leads to norepinephrine release from the lateral hypothalamus which results in the appetite suppression. Peripheral norepinephrine concentration rises as well. Norepinephrine stimulates adipocyte lipolysis and thereby increases nonesterified fatty acids (NEFA availability. It promotes β-oxidation of NEFA to ketone bodies while decreasing metabolic clearance rate of ketones. In the setting of acute insulin deficiency these effects are augmented. Females are more sensitive to norepinephrine effects compared to males. In conclusion, amphetamine-like analogues lead to a release of norepinephrine which can result in a clinically significant ketosis, especially in the setting of insulin deficiency.

  20. Synthesis and preliminary pharmacological evaluation of asymmetric chloroquine analogues.

    Science.gov (United States)

    Witiak, D T; Grattan, D A; Heaslip, R J; Rahwan, R G

    1981-06-01

    Asymmetric chloroquine analogues (1-4) were prepared of known absolute configuration in order to assess stereochemical influences on selected biological activities. Since chloroquine has been shown to possess spasmolytic properties, analogues 1-4 were tested for similar pharmacological effects on smooth-muscle contraction. The (S)- and (R)-chlorochloroquine enantiomers (1 and 2, respectively) were more potent antispasmodics than the less lipophilic (S)- and (R)-hydroxychloroquines (3 and 4, respectively) when tested against KCl- or acetylcholine-induced contractions of the isolated mouse ileum. A membrane stabilizing mechanism of action for the chloroquine analogues is proposed since neither cellular toxicity nor calcium antagonism plays a role in the spasmolytic action of these compounds. Although compounds 1-4 also inhibited PGF2 alpha-induced contractions of the ileum, 1 was significantly more potent than 2; the latter in turn was equipotent to 3 and 4. It is tentatively proposed that 1 may possess stereoselective affinity for the PGF2 alpha receptor in the ileum. This observation may be further exploited to obtain more selective profiles of biological activity through molecular manipulation.

  1. Design and synthesis of biotin analogues reversibly binding with streptavidin.

    Science.gov (United States)

    Yamamoto, Tomohiro; Aoki, Kiyoshi; Sugiyama, Akira; Doi, Hirofumi; Kodama, Tatsuhiko; Shimizu, Yohei; Kanai, Motomu

    2015-04-01

    Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps). Synthesis of biotin carbamate 6 was accomplished from L-cysteine-derived chiral aldehyde 33 in 11% overall yield (over 7 steps). Surface plasmon resonance analysis of water-soluble biotin carbonate analogue 46 and biotin carbamate analogue 47 revealed that KD values of these compounds for binding to streptavidin were 6.7×10(-6)  M and 1.7×10(-10)  M, respectively. These values were remarkably greater than that of biotin (KD =10(-15)  M), and thus indicate the importance of the nitrogen atoms for the strong binding between biotin and streptavidin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Natural analogue studies as supplements to biomineralization research

    International Nuclear Information System (INIS)

    McNeil, M.B.

    1995-01-01

    Chemical reactions can alter the chemistry and crystal structure of solid objects over archeological or geological times, while preserving external physical shapes. The reactions resulting in these structures offer natural analogues to laboratory experiments in biomineralization and to biologically influenced alteration of nuclear waste packages, and thus, they offer the only available way of validating models that purport waste package behavior over archaeological or geological times. Potential uses of such analogues in the construction and validation of hypothetical mechanisms of microbiological corrosion and biomineralization are reviewed. Evidence from such analogues suggests that biofilms can control materials alteration in ways usually overlooked. The newly hypothesized mechanisms involve control by biofilms of the cation flow near the solid surface and offer plausible mechanisms for the formation of mixed-cation minerals under conditions that would lead to dealloying in abiotic experiments; they also account for the formation of unusual minerals [such as posnjakite, Cu 4 SO 4 (OH) 6· H 2 O] and mineral morphologies unusual in corrosion [malachite, Cu 2 CO 3 (OH) 2 , rarely forms botryoidally under corrosion conditions and its occasional presence on archaeological objects that appear to have undergone microbiological corrosion may be related to biofilm phenomena

  3. Decomposition of dioxin analogues and ablation study for carbon nanotube

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko

    2002-01-01

    Two application studies associated with the free electron laser are presented separately, which are the titles of 'Decomposition of Dioxin Analogues' and 'Ablation Study for Carbon Nanotube'. The decomposition of dioxin analogues by infrared (IR) laser irradiation includes the thermal destruction and multiple-photon dissociation. It is important for us to choose the highly absorbable laser wavelength for the decomposition. The thermal decomposition takes place by the irradiation of the low IR laser power. Considering the model of thermal decomposition, it is proposed that adjacent water molecules assist the decomposition of dioxin analogues in addition to the thermal decomposition by the direct laser absorption. The laser ablation study is performed for the aim of a carbon nanotube synthesis. The vapor by the ablation is weakly ionized in the power of several-hundred megawatts. The plasma internal energy is kept over an 8.5 times longer than the vacuum. The cluster was produced from the weakly ionized gas in the enclosed gas, which is composed of the rough particles in the low power laser more than the high power which is composed of the fine particles. (J.P.N.)

  4. Do film soundtracks contain nonlinear analogues to influence emotion?

    Science.gov (United States)

    Blumstein, Daniel T; Davitian, Richard; Kaye, Peter D

    2010-12-23

    A variety of vertebrates produce nonlinear vocalizations when they are under duress. By their very nature, vocalizations containing nonlinearities may sound harsh and are somewhat unpredictable; observations that are consistent with them being particularly evocative to those hearing them. We tested the hypothesis that humans capitalize on this seemingly widespread vertebrate response by creating nonlinear analogues in film soundtracks to evoke particular emotions. We used lists of highly regarded films to generate a set of highly ranked action/adventure, dramatic, horror and war films. We then scored the presence of a variety of nonlinear analogues in these film soundtracks. Dramatic films suppressed noise of all types, contained more abrupt frequency transitions and musical sidebands, and fewer noisy screams than expected. Horror films suppressed abrupt frequency transitions and musical sidebands, but had more non-musical sidebands, and noisy screams than expected. Adventure films had more male screams than expected. Together, our results suggest that film-makers manipulate sounds to create nonlinear analogues in order to manipulate our emotional responses.

  5. Manipulating lightcone fluctuations in an analogue cosmic string

    Science.gov (United States)

    Hu, Jiawei; Yu, Hongwei

    2018-02-01

    We study the flight time fluctuations in an anisotropic medium inspired by a cosmic string with an effective fluctuating refractive index caused by fluctuating vacuum electric fields, which are analogous to the lightcone fluctuations due to fluctuating spacetime metric when gravity is quantized. The medium can be realized as a metamaterial that mimics a cosmic string in the sense of transformation optics. For a probe light close to the analogue string, the flight time variance is ν times that in a normal homogeneous and isotropic medium, where ν is a parameter characterizing the deficit angle of the spacetime of a cosmic string. The parameter ν, which is always greater than unity for a real cosmic string, is determined by the dielectric properties of the metamaterial for an analogue string. Therefore, the flight time fluctuations of a probe light can be manipulated by changing the electric permittivity and magnetic permeability of the analogue medium. We argue that it seems possible to fabricate a metamaterial that mimics a cosmic string with a large ν in laboratory so that a currently observable flight time variance might be achieved.

  6. Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

    Science.gov (United States)

    Battler, Melissa M.; Osinski, Gordon R.; Lim, Darlene S. S.; Davila, Alfonso F.; Michel, Frederick A.; Craig, Michael A.; Izawa, Matthew R. M.; Leoni, Lisa; Slater, Gregory F.; Fairén, Alberto G.; Preston, Louisa J.; Banerjee, Neil R.

    2013-06-01

    Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ˜100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m × 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-ray diffraction and inductively coupled plasma emission spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarosite-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite

  7. Transient Vibration Prediction for Rotors on Ball Bearings Using Load-dependent Non-linear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2002-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic transient analysis requires bearing forces to be determined at each step of the transient solution. Analyses have been carried out to show the effect of accurate bearing transient forces (accounting for non-linear speed and load dependent bearing stiffness) as compared to conventional use of average rolling-element bearing stiffness. Bearing forces were calculated by COBRA-AHS (Computer Optimized Ball and Roller Bearing Analysis - Advanced High Speed) and supplied to the rotordynamics code ARDS (Analysis of Rotor Dynamic Systems) for accurate simulation of rotor transient behavior. COBRA-AHS is a fast-running 5 degree-of-freedom computer code able to calculate high speed rolling-element bearing load-displacement data for radial and angular contact ball bearings and also for cylindrical and tapered roller beatings. Results show that use of nonlinear bearing characteristics is essential for accurate prediction of rotordynamic behavior.

  8. Polar bears: the fate of an icon.

    Science.gov (United States)

    Fitzgerald, Kevin T

    2013-11-01

    Polar bears are one of the most iconic animals on our planet. Worldwide, even people who would never see one are drawn to these charismatic arctic ice hunters. They are the world's largest terrestrial carnivore, and despite being born on land, they spend most of their lives out on the sea ice and are considered a marine mammal. Current global studies estimate there are around 20,000 animals in some 19 discrete circumpolar populations. Aside from pregnant females denning in the winter months to give birth, the white bears do not hibernate. They spend their winters on the sea ice hunting seals, an activity they are spectacularly adapted for. Research on these animals is incredibly difficult because of the inhospitable surroundings they inhabit and how inaccessible they make the bears. For many years, the sum of our understanding of the natural history of polar bears came from tracks, scats, the remains of their kills, abandoned dens, and anecdotal observations of native hunters, explorers, and early biologists. Nonetheless, the last 40 years have seen a much better picture of their biology emerge thanks to, first, dedicated Canadian researchers and, later, truly international efforts of workers from many countries. Veterinarians have contributed to our knowledge of the bears by delivering and monitoring anesthesia, obtaining blood samples, performing necropsies, investigating their reproduction, conducting radiotelemetry studies, and examining their behavior. Recently, new technologies have been developed that revolutionize the study of the lives and natural history of undisturbed polar bears. These advances include better satellite radiotelemetry equipment and the development of remote-controlled miniature devices equipped with high-definition cameras. Such new modalities provide dramatic new insights into the life of polar bears. The remarkable degree of specialized adaptation to life on the sea ice that allowed the bears to be successful is the very reason that

  9. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    Energy Technology Data Exchange (ETDEWEB)

    G.J. Saulnier Jr; W. Statham

    2006-03-10

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 {+-} 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory

  10. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    International Nuclear Information System (INIS)

    G.J. Saulnier Jr; W. Statham

    2006-01-01

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO 2 uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 ± 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory analysis

  11. A circumpolar monitoring framework for polar bears

    Science.gov (United States)

    Vongraven, Dag; Aars, Jon; Amstrup, Steven C.; Atkinson, Stephen N.; Belikov, Stanislav; Born, Erik W.; DeBruyn, T.D.; Derocher, Andrew E.; Durner, George M.; Gill, Michael J.; Lunn, Nicholas J.; Obbard, Martyn E.; Omelak, Jack; Ovsyanikov, Nikita; Peacock, Elizabeth; Richardson, E.E.; Sahanatien, Vicki; Stirling, Ian; Wiig, Øystein

    2012-01-01

    Polar bears (Ursus maritimus) occupy remote regions that are characterized by harsh weather and limited access. Polar bear populations can only persist where temporal and spatial availability of sea ice provides adequate access to their marine mammal prey. Observed declines in sea ice availability will continue as long as greenhouse gas concentrations rise. At the same time, human intrusion and pollution levels in the Arctic are expected to increase. A circumpolar understanding of the cumulative impacts of current and future stressors is lacking, long-term trends are known from only a few subpopulations, and there is no globally coordinated effort to monitor effects of stressors. Here, we describe a framework for an integrated circumpolar monitoring plan to detect ongoing patterns, predict future trends, and identify the most vulnerable polar bear subpopulations. We recommend strategies for monitoring subpopulation abundance and trends, reproduction, survival, ecosystem change, human-caused mortality, human–bear conflict, prey availability, health, stature, distribution, behavioral change, and the effects that monitoring itself may have on polar bears. We assign monitoring intensity for each subpopulation through adaptive assessment of the quality of existing baseline data and research accessibility. A global perspective is achieved by recommending high intensity monitoring for at least one subpopulation in each of four major polar bear ecoregions. Collection of data on harvest, where it occurs, and remote sensing of habitat, should occur with the same intensity for all subpopulations. We outline how local traditional knowledge may most effectively be combined with the best scientific methods to provide comparable and complementary lines of evidence. We also outline how previously collected intensive monitoring data may be sub-sampled to guide future sampling frequencies and develop indirect estimates or indices of subpopulation status. Adoption of this framework

  12. Mass Loss Rates of Fasting Polar Bears.

    Science.gov (United States)

    Pilfold, Nicholas W; Hedman, Daryll; Stirling, Ian; Derocher, Andrew E; Lunn, Nicholas J; Richardson, Evan

    2016-01-01

    Polar bears (Ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the Arctic. As a consequence of climate change, sea ice breakup has become earlier and the duration of the open-water period through which polar bears must rely on fat reserves has increased. To date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts. We measured the incoming and outgoing mass of inactive polar bears (n = 142) that were temporarily detained by Manitoba Conservation and Water Stewardship during the open-water period near the town of Churchill, Manitoba, Canada, in 2009-2014. Polar bears were given access to water but not food and held for a median length of 17 d. Median mass loss rates were 1.0 kg/d, while median mass-specific loss rates were 0.5%/d, similar to other species with high adiposity and prolonged fasting capacities. Mass loss by unfed captive adult males was identical to that lost by free-ranging individuals, suggesting that terrestrial feeding contributes little to offset mass loss. The inferred metabolic rate was comparable to a basal mammalian rate, suggesting that while on land, polar bears can maintain a depressed metabolic rate to conserve energy. Finally, we estimated time to starvation for subadults and adult males for the on-land period. Results suggest that at 180 d of fasting, 56%-63% of subadults and 18%-24% of adult males in this study would die of starvation. Results corroborate previous assessments on the limits of polar bear capacity to withstand lengthening ice-free seasons and emphasize the greater sensitivity of subadults to changes in sea ice phenology.

  13. 49 CFR 215.107 - Defective plain bearing box: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing box: General. 215.107... Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in... the bearing; or (2) Have a detrimental effect on the lubrication of the journal and the bearings. ...

  14. 77 FR 77070 - Black Bear Hydro Partners, LLC;

    Science.gov (United States)

    2012-12-31

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 2727-086] Black Bear Hydro...: October 24, 2012. d. Submitted By: Black Bear Hydro Partners, LLC (Black Bear Hydro). e. Name of Project... designating Black Bear Hydro as the Commission's non-federal representative for carrying out informal...

  15. What Can We Learn?--The Algonquin Bear Attack.

    Science.gov (United States)

    Strickland, Dan

    1992-01-01

    Describes a bear attack in Algonquin Park in Lake Opeongo (Canada) in which a man and woman were killed. Hypothesizes that the bear deliberately preyed on its victims and concludes that the bear was physically normal. Despite this isolated attack, the chance of being attacked by a black bear when camping is virtually nonexistent. (KS)

  16. Wear numbers for ball cup and journal bearings

    NARCIS (Netherlands)

    Ligterink, D.J.; Moes, H.

    1980-01-01

    A wear number is defined for ball cup bearings and for journal bearings where the cup and the cylindrical bearing are made of soft material. This dimensionless wear number provides a relation between the following five quantities: the radius of the ball or the length of the journal bearing in

  17. 46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Tailshaft clearance; bearing weardown. 61.20-23 Section...; bearing weardown. (a) Water lubricated bearings, other than rubber, must be rebushed as follows: (1) Where the propelling machinery is located amidship, the after stern tube bearing must be rebushed when it is...

  18. Noise reduction of rotating machinery by viscoelastic bearing supports

    NARCIS (Netherlands)

    Tillema, H.G.

    2003-01-01

    The demand for silent rolling bearing applications, such as electric motors and gearboxes, has resulted in an investigation of viscoelastic bearing supports. By placing a thin viscoelastic layer between the bearing outer ring and the surrounding structure, vibrations of the shaft-bearing arrangement

  19. Downscaling of surface moisture flux and precipitation in the Ebro Valley (Spain using analogues and analogues followed by random forests and multiple linear regression

    Directory of Open Access Journals (Sweden)

    G. Ibarra-Berastegi

    2011-06-01

    Full Text Available In this paper, reanalysis fields from the ECMWF have been statistically downscaled to predict from large-scale atmospheric fields, surface moisture flux and daily precipitation at two observatories (Zaragoza and Tortosa, Ebro Valley, Spain during the 1961–2001 period. Three types of downscaling models have been built: (i analogues, (ii analogues followed by random forests and (iii analogues followed by multiple linear regression. The inputs consist of data (predictor fields taken from the ERA-40 reanalysis. The predicted fields are precipitation and surface moisture flux as measured at the two observatories. With the aim to reduce the dimensionality of the problem, the ERA-40 fields have been decomposed using empirical orthogonal functions. Available daily data has been divided into two parts: a training period used to find a group of about 300 analogues to build the downscaling model (1961–1996 and a test period (1997–2001, where models' performance has been assessed using independent data. In the case of surface moisture flux, the models based on analogues followed by random forests do not clearly outperform those built on analogues plus multiple linear regression, while simple averages calculated from the nearest analogues found in the training period, yielded only slightly worse results. In the case of precipitation, the three types of model performed equally. These results suggest that most of the models' downscaling capabilities can be attributed to the analogues-calculation stage.

  20. Bearing assemblies, apparatuses, and motor assemblies using the same

    Science.gov (United States)

    Sexton, Timothy N.; Cooley, Craig H.; Knuteson, Cody W.

    2015-12-29

    Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.

  1. Comment on "Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage".

    Science.gov (United States)

    Nakagome, Shigeki; Mano, Shuhei; Hasegawa, Masami

    2013-03-29

    Based on nuclear and mitochondrial DNA, Hailer et al. (Reports, 20 April 2012, p. 344) suggested early divergence of polar bears from a common ancestor with brown bears and subsequent introgression. Our population genetic analysis that traces each of the genealogies in the independent nuclear loci does not support the evolutionary model proposed by the authors.

  2. Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity.

    Science.gov (United States)

    Dubois, Sara; Fraser, David

    2013-09-12

    The "pot bears" received international media attention in 2010 after police discovered the intentional feeding of over 20 black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia, Canada. A two-phase random digit dialing survey of the community was conducted in 2011 to understand local perspectives on bear policy and management, before and after a summer of problem bear activity and government interventions. Of the 159 households surveyed in February 2011, most had neutral or positive attitudes towards bears in general, and supported the initial decision to feed the food-conditioned bears until the autumn hibernation. In contrast to wildlife experts however, most participants supported relocating the problem bears, or allowing them to remain in the area, ahead of killing; in part this arose from notions of fairness despite the acknowledged problems of relocation. Most locals were aware of the years of feeding but did not report it, evidently failing to see it as a serious form of harm, even after many bears had been killed. This underscores the importance of preventive action on wildlife feeding and the need to narrow the gap between public and expert opinion on the likely effects of relocation versus killing.

  3. Acoustic Emission Monitoring of Incipient in Journal Bearings - Part I : Detectability and measurement for bearing damages

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Chung, Min Hwa; Kim, Kyung Woong

    1994-01-01

    In contrast to the machinery using rolling element bearings, systems with journal bearings generally operate in large scale and under severe loading condition such as steam generator turbines and internal combustion engines. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is applied to the detection of incipient failure caused by several types of abnormal operating condition most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as hard particles in the lubrication layer, insufficient lubrication, and metallic contact in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings

  4. FRICTION TORQUE IN THE SLIDE BEARINGS

    Directory of Open Access Journals (Sweden)

    BONDARENKO L. N.

    2016-09-01

    Full Text Available Summary. Problem statement. Until now slide bearings are used widely in engineering. But the calculation is made on obsolete method that is based on undetermined parameters such as wear of the bearing shell. It is accepted in the literature that if the shaft and liner material are homogeneous, the workpiece surface are cylindrical as they wear and contact between them occurs at all points contact arc. Research objective. The purpose of this study is determine a friction torque in the slide bearings of power-basis parameters. Conclusions. Since the friction is primarily responsible for wear of cinematic pairs “pin – liner” and “pivot – liner” slide bearings. It is shown that the friction torquesof angles wrap, that are obtained by the formulas and given in literature, are not only qualitatively but also quantitatively, namely, the calculation by literature to the formulas the friction torques are proportional to the angle wrap and the calculation by improved formulas the friction torques are inversely proportional to the angle wrap due to the reduction the normal pressure. Underreporting friction torque at large angle wrap is between 40 and 15 %. The difference in the magnitude of friction torque in the run-in and run-out cinematic pairs with real method of machining is 2...3 %, which it is possible to declare of reducing the finish of contacting surface of slide bearings.

  5. Nonlinear Dynamical Analysis for a Plain Bearing

    Directory of Open Access Journals (Sweden)

    Ali Belhamra

    2014-03-01

    Full Text Available This paper investigates the nonlinear dynamic behavior for a plain classic bearing (fluid bearing lubricated by a non-Newtonian fluid of a turbo machine rotating with high speed; this type of fluid contains additives viscosity (couple-stress fluid film. The solution of the nonlinear dynamic problem of this type of bearing is determined with a spatial discretisation of the modified Reynolds' equation written in dynamic mode by using the optimized short bearing theory and a temporal discretisation for equations of rotor motion by the help of Euler's explicit diagram. This study analyzes the dynamic behavior of a rotor supported by two couple-stress fluid film journal lubricant enhances the dynamic stability of the rotor-bearing system considerably compared to that obtained when using a traditional Newtonian lubricant. The analysis shows that the dynamic behavior of a shaft which turns with high velocities is strongly nonlinear even for poor eccentricities of unbalance; the presence of parameters of couple stress allows strongly attenuating the will synchrony (unbalance and asynchrony (whipping amplitudes of vibrations of the shaft which supports more severe conditions (large unbalances.

  6. Identifying lubricant options for compressor bearing designs

    Science.gov (United States)

    Karnaz, J.; Seeton, C.; Dixon, L.

    2017-08-01

    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  7. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  8. Comparison of fixed-bearing and mobile-bearing total knee arthroplasty after high tibial osteotomy.

    Science.gov (United States)

    Hernigou, Philippe; Huys, Maxime; Pariat, Jacques; Roubineau, François; Flouzat Lachaniette, Charles Henri; Dubory, Arnaud

    2018-02-01

    There is no information comparing the results of fixed-bearing total knee replacement and mobile-bearing total knee replacement in the same patients previously treated by high tibial osteotomy. The purpose was therefore to compare fixed-bearing and mobile-bearing total knee replacements in patients treated with previous high tibial osteotomy. We compared the results of 57 patients with osteoarthritis who had received a fixed-bearing prosthesis after high tibial osteotomy with the results of 41 matched patients who had received a rotating platform after high tibial osteotomy. The match was made for length of follow-up period. The mean follow-up was 17 years (range, 15-20 years). The patients were assessed clinically and radiographically. The pre-operative knee scores had no statistically significant differences between the two groups. So was the case with the intra-operative releases, blood loss, thromboembolic complications and infection rates in either group. There was significant improvement in both groups of knees, and no significant difference was observed between the groups (i.e., fixed-bearing and mobile-bearing knees) for the mean Knee Society knee clinical score (95 and 92 points, respectively), or the Knee Society knee functional score (82 and 83 points, respectively) at the latest follow-up. However, the mean post-operative knee motion was higher for the fixed-bearing group (117° versus 110°). In the fixed-bearing group, one knee was revised because of periprosthetic fracture. In the rotating platform mobile-bearing group, one knee was revised because of aseptic loosening of the tibial component. The Kaplan-Meier survivorship for revision at ten years of follow-up was 95.2% for the fixed bearing prosthesis and 91.1% for the rotating platform mobile-bearing prosthesis. Although we did manage to detect significant differences mainly in clinical and radiographic results between the two groups, we found no superiority or inferiority of the mobile-bearing

  9. Assessing bear-human conflicts in the Yukon Territory

    OpenAIRE

    Lukie, Raechel Dawn

    2010-01-01

    Managing conflicts between bears and humans is vital for human safety and for the conservation of bears. This study investigated black bear (Ursus americanus) and grizzly bear (Ursus arctos) interactions with humans in 18 major communities of the Yukon Territory. I used an information theoretic approach to generate predictive models of the relative potential of bear-human interaction for the 9 conservation officer management regions in the Yukon Territory. I independently modeled interactions...

  10. On the future of controllable fluid film bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted......This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric...

  11. Nuclear fuel handling grapple carriage with self-lubricating bearing

    International Nuclear Information System (INIS)

    Wade, E.E.

    1978-01-01

    Disclosed is a nuclear fuel handling grapple carriage having a bearing with a lubricant reservoir that is capable of being refilled when the bearing and reservoir are submerged in a lubricant pool. The lubricant reservoir supplies lubricant to the bearing while the bearing allows a small amount of lubricant to leak passed appropriately placed seals creating a positive out flow of lubricant thereby preventing foreign material from entering the bearing

  12. Removable bearing arrangement for a wind turbine generator

    Science.gov (United States)

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

    2010-06-15

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  13. Bear bile: dilemma of traditional medicinal use and animal protection

    Science.gov (United States)

    Feng, Yibin; Siu, Kayu; Wang, Ning; Ng, Kwan-Ming; Tsao, Sai-Wah; Nagamatsu, Tadashi; Tong, Yao

    2009-01-01

    Bear bile has been used in Traditional Chinese Medicine (TCM) for thousands of years. Modern investigations showed that it has a wide range of pharmacological actions with little toxicological side effect and the pure compounds have been used for curing hepatic and biliary disorders for decades. However, extensive consumption of bear bile made bears endangered species. In the 1980's, bear farming was established in China to extract bear bile from living bears with "Free-dripping Fistula Technique". Bear farming is extremely inhumane and many bears died of illness such as chronic infections and liver cancer. Efforts are now given by non-governmental organizations, mass media and Chinese government to end bear farming ultimately. At the same time, systematic research has to be done to find an alternative for bear bile. In this review, we focused on the literature, laboratory and clinical results related to bear bile and its substitutes or alternative in English and Chinese databases. We examined the substitutes or alternative of bear bile from three aspects: pure compounds derived from bear bile, biles from other animals and herbs from TCM. We then discussed the strategy for stopping the trading of bear bile and issues of bear bile related to potential alternative candidates, existing problems in alternative research and work to be done in the future. PMID:19138420

  14. Bear bile: dilemma of traditional medicinal use and animal protection

    Directory of Open Access Journals (Sweden)

    Nagamatsu Tadashi

    2009-01-01

    Full Text Available Abstract Bear bile has been used in Traditional Chinese Medicine (TCM for thousands of years. Modern investigations showed that it has a wide range of pharmacological actions with little toxicological side effect and the pure compounds have been used for curing hepatic and biliary disorders for decades. However, extensive consumption of bear bile made bears endangered species. In the 1980's, bear farming was established in China to extract bear bile from living bears with "Free-dripping Fistula Technique". Bear farming is extremely inhumane and many bears died of illness such as chronic infections and liver cancer. Efforts are now given by non-governmental organizations, mass media and Chinese government to end bear farming ultimately. At the same time, systematic research has to be done to find an alternative for bear bile. In this review, we focused on the literature, laboratory and clinical results related to bear bile and its substitutes or alternative in English and Chinese databases. We examined the substitutes or alternative of bear bile from three aspects: pure compounds derived from bear bile, biles from other animals and herbs from TCM. We then discussed the strategy for stopping the trading of bear bile and issues of bear bile related to potential alternative candidates, existing problems in alternative research and work to be done in the future.

  15. Big bearings. Unsung hero; Kyodaina jikuuke. Hitome ni tsukanai hatarakimono

    Energy Technology Data Exchange (ETDEWEB)

    Nanba, S. [Koyo Seiko Co. Ltd., Osaka (Japan)

    1997-03-05

    This paper introduces examples of the use of big bearings. Bearings are divided largely into those used for radial load supporting and those used for thrust load supporting, while big bearings are often used for the latter usage. Thrust bearings include a cutter heat supporting bearing for tunnel excavator working underground, in addition to those used for swing motion of parabolic antennas and tower cranes. A bearing used in an excavator has an outer diameter of about half that of the excavator. The outer diameter of a shielding machine practically used in tunnel drilling currently has an outer diameter of 14,140 mm, and the outer diameter of the bearing is 7200 mm (bearing weighing 45 tons). Other big thrust bearings may include a swing tower swinging thrust bearing used in a continuous casting facility. Big radial bearings are used in iron and steel making facilities. This paper describes two examples of bearings used in this application. A spherical roller bearing to support converter trunion should be of an ultra big size to withstand total weight of about 1400 tons composed of a converter weight and weight of steel to be processed. A four-row cylindrical roller bearing to support the backup roll of a thick plate rolling mill is a bearing with durability against large loads to support reduction rolls whose size have become increasingly large. 2 refs., 5 figs.

  16. Active Magnetic Bearings – Magnetic Forces

    DEFF Research Database (Denmark)

    Kjølhede, Klaus

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision characterization...... of the magnetic forces are led by using different experimental tests: (I) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor; (II) by measuring the input current and bearing...

  17. Robust bearing estimation for 3-component stations

    International Nuclear Information System (INIS)

    CLAASSEN, JOHN P.

    2000-01-01

    A robust bearing estimation process for 3-component stations has been developed and explored. The method, called SEEC for Search, Estimate, Evaluate and Correct, intelligently exploits the inherent information in the arrival at every step of the process to achieve near-optimal results. In particular the approach uses a consistent framework to define the optimal time-frequency windows on which to make estimates, to make the bearing estimates themselves, to construct metrics helpful in choosing the better estimates or admitting that the bearing is immeasurable, and finally to apply bias corrections when calibration information is available to yield a single final estimate. The algorithm was applied to a small but challenging set of events in a seismically active region. It demonstrated remarkable utility by providing better estimates and insights than previously available. Various monitoring implications are noted from these findings

  18. Experimental investigations of active air bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar; Morosi, Stefano

    2012-01-01

    Along with traditional oil lubrication, increasing demand for high-speed applications has renewed attention to gas bearings technology. Traditional aerostatic and aerodynamic gas lubrication has been widely used in a variety of applications, ranging from high-speed spindles to micro and meso......-scale turbomachinery. The present paper deals with experimental rotordynamic testing of a flexible rotor supported by hybrid aerostaticaerodynamic gas journal bearing equipped with an electronic radial air injection system. From a rotordynamic point of view there are two phenomena that limit the widespread...... of traditional gas lubrication: 1) Low damping makes operation across critical speed dangerous, as even low level of unbalance can generate large vibration responses. This is especially problematic for gas bearing applications, which often operate in the supercritical region. Moreover, 2) An upper bound...

  19. Powder metallurgy bearings for advanced rocket engines

    Science.gov (United States)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  20. PEGylation, increasing specific activity and multiple dosing as strategies to improve the risk-benefit profile of targeted radionuclide therapy with 177Lu-DOTA-bombesin analogues

    Science.gov (United States)

    2012-01-01

    Background Radiolabelled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumours, in which BN2/gastrin-releasing peptide receptors are overexpressed. We describe the influence of the specific activity of a 177Lu-DOTA-PEG5k-Lys-B analogue on its therapeutic efficacy and compare it with its non-PEGylated counterpart. Methods Derivatisation of a stabilised DOTA-BN(7–14)[Cha13,Nle14] analogue with a linear PEG molecule of 5 kDa (PEG5k) was performed by PEGylation of the ϵ-amino group of a β3hLys-βAla-βAla spacer between the BN sequence and the DOTA chelator. The non-PEGylated and the PEGylated analogues were radiolabelled with 177Lu. In vitro evaluation was performed in human prostate carcinoma PC-3 cells, and in vivo studies were carried out in nude mice bearing PC-3 tumour xenografts. Different specific activities of the PEGylated BN analogue and various dose regimens were evaluated concerning their therapeutic efficacy. Results The specificity and the binding affinity of the BN analogue for BN2/GRP receptors were only slightly reduced by PEGylation. In vitro binding kinetics of the PEGylated analogue was slower since steady-state condition was reached after 4 h. PEGylation improved the stability of BN conjugate in vitro in human plasma by a factor of 5.6. The non-PEGylated BN analogue showed favourable pharmacokinetics already, i.e. fast blood clearance and renal excretion, but PEGylation improved the in vivo behaviour further. One hour after injection, the tumour uptake of the PEG5k-BN derivative was higher compared with that of the non-PEGylated analogue (3.43 ± 0.63% vs. 1.88 ± 0.4% ID/g). Moreover, the increased tumour retention resulted in a twofold higher tumour accumulation at 24 h p.i., and increased tumour-to-non-target ratios (tumour-to-kidney, 0.6 vs. 0.4; tumour-to-liver, 8.8 vs. 5.9, 24 h p.i.). In the therapy study, both 177Lu-labelled BN analogues significantly inhibited tumour

  1. Big Bear Exploration Ltd. 1998 annual report

    International Nuclear Information System (INIS)

    1999-01-01

    During the first quarter of 1998 Big Bear completed a purchase of additional assets in the Rainbow Lake area of Alberta in which light oil purchase was financed with new equity and bank debt. The business plan was to immediately exploit these light oil assets, the result of which would be increased reserves, production and cash flow. Although drilling results in the first quarter on the Rainbow Lake properties was mixed, oil prices started to free fall and drilling costs were much higher than expected. As a result, the company completed a reduced program which resulted in less incremental loss and cash flow than it budgeted for. On April 29, 1998, Big Bear entered into agreement with Belco Oil and Gas Corp. and Moan Investments Ltd. for the issuance of convertible preferred shares at a gross value of $15,750,000, which shares were eventually converted at 70 cents per share to common equity. As a result of the continued plunge in oil prices, the lending value of the company's assets continued to fall, requiring it to take action in order to meet its financial commitments. Late in the third quarter Big Bear issued equity for proceeds of $11,032,000 which further reduced the company's debt. Although the company has been extremely active in identifying and pursuing acquisition opportunities, it became evident that Belco Oil and Gas Corp. and Big Bear did nor share common criteria for acquisitions, which resulted in the restructuring of their relationship in the fourth quarter. With the future of oil prices in question, Big Bear decided that it would change its focus to that of natural gas and would refocus ts efforts to acquire natural gas assets to fuel its growth. The purchase of Blue Range put Big Bear in a difficult position in terms of the latter's growth. In summary, what started as a difficult year ended in disappointment

  2. Quantum Analogues: From Phase Transitions to Black Holes and Cosmology

    International Nuclear Information System (INIS)

    Liberati, Stefano

    2008-01-01

    'And I cherish more than anything else the analogies, my most trustworthy masters. They know all the secrets of nature, and they ought to be least neglected in geometry.' These words of the great astronomer Johannes Kepler embody the philosophy behind the research recounted in this interesting book-a book composed of nine selected lectures (and a nice introduction by Bill Unruh) from the international workshop on 'Quantum Simulations via Analogues', which was held in the Max Planck Institute for the Physics of Complex Systems in Dresden during the summer of 2005. Analogue models of (and for) gravity have a long and distinguished history dating back to the earliest years of general relativity. However the last decade has seen a remarkable and steady development of analogue gravity models based on condensed matter systems, leading to some hundreds of published articles, numerous workshops, and several books. While the main driver for this booming field has definitely been the puzzling physics associated with quantum effects in black holes, more recently much attention has also been devoted to other interesting issues-such as cosmological particle production or the cosmological constant problem. Moreover, together with these new themes there has been a persistent interest in the possibility of simulating cosmic topological defects in the laboratory (although it should be said that momentum for this line of research has been somewhat weakened by the progressive decrease of interest in cosmological topological defects as an alternative to inflationary scenarios). All these aspects are faithfully accounted for in this book, which does a good job at presenting a vivid snapshot of many (if not quite all) of the most interesting lines of research in the field. All the articles have a self-consistent structure-which allows one to read them in arbitrary order and appreciate the full richness of each topic. However, when considered together I would say that they also provide a

  3. Grizzly bear habitat selection is scale dependent.

    Science.gov (United States)

    Ciarniello, Lana M; Boyce, Mark S; Seip, Dale R; Heard, Douglas C

    2007-07-01

    The purpose of our study is to show how ecologists' interpretation of habitat selection by grizzly bears (Ursus arctos) is altered by the scale of observation and also how management questions would be best addressed using predetermined scales of analysis. Using resource selection functions (RSF) we examined how variation in the spatial extent of availability affected our interpretation of habitat selection by grizzly bears inhabiting mountain and plateau landscapes. We estimated separate models for females and males using three spatial extents: within the study area, within the home range, and within predetermined movement buffers. We employed two methods for evaluating the effects of scale on our RSF designs. First, we chose a priori six candidate models, estimated at each scale, and ranked them using Akaike Information Criteria. Using this method, results changed among scales for males but not for females. For female bears, models that included the full suite of covariates predicted habitat use best at each scale. For male bears that resided in the mountains, models based on forest successional stages ranked highest at the study-wide and home range extents, whereas models containing covariates based on terrain features ranked highest at the buffer extent. For male bears on the plateau, each scale estimated a different highest-ranked model. Second, we examined differences among model coefficients across the three scales for one candidate model. We found that both the magnitude and direction of coefficients were dependent upon the scale examined; results varied between landscapes, scales, and sexes. Greenness, reflecting lush green vegetation, was a strong predictor of the presence of female bears in both landscapes and males that resided in the mountains. Male bears on the plateau were the only animals to select areas that exposed them to a high risk of mortality by humans. Our results show that grizzly bear habitat selection is scale dependent. Further, the

  4. The sweet lung: Chewing gummi bear aspiration.

    Science.gov (United States)

    Tavladaki, Theonimfi; Fitrolaki, Michaela-Diana; Spanaki, Anna-Maria; Ilia, Staurula; Geromarkaki, Elissabet; Briassoulis, George

    2012-07-01

    Inhalation of foreign bodies, a leading cause of accidental death, is most common in preschool children. In this article we report our experience with a 5-year-old Greek girl who presented with a 24-hour history of sore throat, chest pain, and shortness of breath. Emergency bronchoscopy was performed and multiple small chewing gummi bear (HARIBO) particles impacted in the orifices of the right main bronchus and right lobar and segmentalinic bronchi were successfully removed and aspirated. Aspiration of gummi bears, which is for the first time reported, may cause a silent choking episode leading to life-threatening bronchi obstruction at multiple sites, even in children older than 4 years.

  5. Closure Welding of Plutonium Bearing Storage Containers

    International Nuclear Information System (INIS)

    Cannell, G.R.

    2002-01-01

    A key element in the Department of Energy (DOE) strategy for the stabilization, packaging and storage of plutonium-bearing materials involves closure welding of DOE-STD-3013 Outer Containers (3013 container). The 3013 container provides the primary barrier and pressure boundary preventing release of plutonium-bearing materials to the environment. The final closure (closure weld) of the 3013 container must be leaktight, structurally sound and meet DOE STD 3013 specified criteria. This paper focuses on the development, qualification and demonstration of the welding process for the closure welding of Hanford PFP 3013 outer containers

  6. Hydrodynamic bearing lubricated with magnetic fluids

    International Nuclear Information System (INIS)

    Urreta, H; Leicht, Z; Sanchez, A; Agirre, A; Kuzhir, P; Magnac, G

    2009-01-01

    This paper summarizes the work carried out in the development of hydrodynamic lubricated journal bearings with magnetic fluids. Two different fluids have been analyzed, one ferrofluid from FERROTEC APG s10n and one magnetorheological fluid from LORD Corp., MRF122-2ED. Theoretical analysis has been carried out with numerical solutions of Reynolds equation, based on apparent viscosity modulation for ferrofluid and Bingham model for MR fluid. To validate this model, one test bench has been designed, manufactured and set up, where preliminary results shown in this paper demonstrate that magnetic fluids can be used to develop active journal bearings.

  7. Intramolecular hydrogen bonding in malonaldehyde and its radical analogues.

    Science.gov (United States)

    Lin, Chen; Kumar, Manoj; Finney, Brian A; Francisco, Joseph S

    2017-09-28

    High level Brueckner doubles with triples correction method-based ab initio calculations have been used to investigate the nature of intramolecular hydrogen bonding and intramolecular hydrogen atom transfer in cis-malonaldehyde (MA) and its radical analogues. The radicals considered here are the ones that correspond to the homolytic cleavage of C-H bonds in cis-MA. The results suggest that cis-MA and its radical analogues, cis-MA RS , and cis-MA RA , both exist in planar geometry. The calculated intramolecular O-H⋯O=C bond in cis-MA is shorter than that in the radical analogues. The intramolecular hydrogen bond in cis-MA is stronger than in its radicals by at least 3.0 kcal/mol. The stability of a cis-malonaldehyde radical correlates with the extent of electron spin delocalization; cis-MA RA , in which the radical spin is more delocalized, is the most stable MA radical, whereas cis-MA RS , in which the radical spin is strongly localized, is the least stable radical. The natural bond orbital analysis indicates that the intramolecular hydrogen bonding (O⋯H⋯O) in cis-malonaldehyde radicals is stabilized by the interaction between the lone pair orbitals of donor oxygen and the σ * orbital of acceptor O-H bond (n → σ * OH ). The calculated barriers indicate that the intramolecular proton transfer in cis-MA involves 2.2 kcal/mol lower barrier than that in cis-MA RS .

  8. Alligator Rivers Analogue Project. Final Report - Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Duerden, P [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia); Lever, D A [AEA Technology, Harwell (United Kingdom); Sverjensky, D A [Johns Hopkins Univ., Baltimore, MD (United States); Townley, L R [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Wembley, WA (Australia). Div. of Water Resources

    1992-07-01

    This summary report, which highlights the work and findings of the Alligator Rivers Analogue Project (ARAP) is one of a series of 16 volumes, listed below. Detailed descriptions and results are provided in Volumes 2 to 16. Full acknowledgment to individual contributions is provided in the individual reports, and in Appendix I of this report. The findings from the technical studies are discussed in the context of assessments of the long-term performance of geological repositories for radioactive wastes, which are being undertaken in many countries. They are also considered in an integrated 'Scenario Development' approach, aimed to understand the formation of the ore deposit. Despite their inherent uncertainties, the findings provide a basis for assessing the way in which radionuclides will migrate in environments with a variety of geologic settings and over a range of different geologic timescales. Thus, section 2 of this report discusses the concept of using uranium deposits as natural analogues and refers to a number of such studies, including those at the Koongarra deposit in the Alligator Rivers Region of the Northern Territory of Australia. Section 3 reviews early scientific work in the Alligator Rivers Region and summarises the results of the analogue studies undertaken between 1981 and 1987 that were funded by the US Nuclear Regulatory Commission (USNRC) and the UK Department of the Environment (UKDoE). Section 4 describes the objectives of ARAP and the manner in which the study was conducted and provides a general outline of the project and a summary of the findings. A general description of the Koongarra ore deposit, the focus of ARAP, is provided in Section 5, with Sections 6-13 providing summaries of the work carried out to characterise the site in detail and provide data for modelling. Sections 14-18 discuss how this data was used in modelling and how the results may be applied for performance assessment studies. Finally, Section 19 considers the

  9. Recombinant erythropoietin and analogues: a challenge for doping control.

    Science.gov (United States)

    Pascual, J A; Belalcazar, V; de Bolos, C; Gutiérrez, R; Llop, E; Segura, J

    2004-04-01

    Erythropoietin (EPO) increases the number of circulating erythrocytes and thus muscle oxygenation. The availability of the recombinant protein (rEPO) has increased the risk of its illegal use in sports, its detection being a difficult challenge. Five different hematopoietic parameters were initially chosen as indirect markers of rEPO abuse: concentration of serum EPO, concentration of serum-soluble transferrin receptors (sTFr), hematocrit, percentage of reticulocytes, and percentage of macrocytes. New models considering only hemoglobin, serum EPO concentration, and percentage of reticulocytes are simpler and seem to be more sensitive when low doses of rEPO are used. A more direct method of urine analysis (isoelectrofocusing, double blotting, and chemiluminescent detection) based on the charge differences between rEPO and endogenous EPO, related to their carbohydrate composition, provides proof of rEPO use. Furthermore, this approach permits the detection of darbepoetin, a direct analogue of EPO also known as NESP ("new erythropoiesis stimulating protein"). Recently a protein conjugate, "synthetic erythropoiesis protein" (SEP), containing precision-length, monodisperse, negatively charged polymers instead of oligosaccharides has been synthesized. Finally, EPO-mimetics are molecules capable of acting as EPO in dimerizing the EPO receptor. Two kinds of EPO-mimetics have been described: peptides and nonpeptides. The enhancement of oxygen availability to muscles by rEPO, analogues, and mimetics constitutes one of the main challenges to doping control. Major steps have already been developed for detection ofrEPO and some analogues. In the near future, the transfection to an athlete's body of genes that code for erythropoietin might be an emerging doping issue, and sports authorities have incorporated "gene doping" among the prohibited practices.

  10. Migrastatin analogues inhibit canine mammary cancer cell migration and invasion.

    Directory of Open Access Journals (Sweden)

    Kinga Majchrzak

    Full Text Available BACKGROUND: Cancer spread to other organs is the main cause of death of oncological patients. Migration of cancer cells from a primary tumour is the crucial step in the complex process of metastasis, therefore blocking this process is currently the main treatment strategy. Metastasis inhibitors derived from natural products, such as, migrastatin, are very promising anticancer agents. Thus, the aim of our study was to investigate the effect of six migrastatin analogues (MGSTA-1 to 6 on migration and invasion of canine mammary adenocarcinoma cell lines isolated from primary tumours and their metastases to the lungs. Canine mammary tumours constitute a valuable tool for studying multiple aspect of human cancer. RESULTS: OUR RESULTS SHOWED THAT TWO OF SIX FULLY SYNTHETIC ANALOGUES OF MIGRASTATIN: MGSTA-5 and MGSTA-6 were potent inhibitors of canine mammary cancer cells migration and invasion. These data were obtained using the wound healing test, as well as trans-well migration and invasion assays. Furthermore, the treatment of cancer cells with the most effective compound (MGSTA-6 disturbed binding between filamentous F-actin and fascin1. Confocal microscopy analyses revealed that treatment with MGSTA-6 increased the presence of unbound fascin1 and reduced co-localization of F-actin and fascin1 in canine cancer cells. Most likely, actin filaments were not cross-linked by fascin1 and did not generate the typical filopodial architecture of actin filaments in response to the activity of MGSTA-6. Thus, administration of MGSTA-6 results in decreased formation of filopodia protrusions and stress fibres in canine mammary cancer cells, causing inhibition of cancer migration and invasion. CONCLUSION: Two synthetic migrastatin analogues (MGSTA-5 and MGSTA-6 were shown to be promising compounds for inhibition of cancer metastasis. They may have beneficial therapeutic effects in cancer therapy in dogs, especially in combination with other anticancer drugs

  11. Alligator Rivers Analogue Project. Final Report - Volume 1

    International Nuclear Information System (INIS)

    Duerden, P.; Lever, D.A.; Sverjensky, D.A.; Townley, L.R.

    1992-01-01

    This summary report, which highlights the work and findings of the Alligator Rivers Analogue Project (ARAP) is one of a series of 16 volumes, listed below. Detailed descriptions and results are provided in Volumes 2 to 16. Full acknowledgment to individual contributions is provided in the individual reports, and in Appendix I of this report. The findings from the technical studies are discussed in the context of assessments of the long-term performance of geological repositories for radioactive wastes, which are being undertaken in many countries. They are also considered in an integrated 'Scenario Development' approach, aimed to understand the formation of the ore deposit. Despite their inherent uncertainties, the findings provide a basis for assessing the way in which radionuclides will migrate in environments with a variety of geologic settings and over a range of different geologic timescales. Thus, section 2 of this report discusses the concept of using uranium deposits as natural analogues and refers to a number of such studies, including those at the Koongarra deposit in the Alligator Rivers Region of the Northern Territory of Australia. Section 3 reviews early scientific work in the Alligator Rivers Region and summarises the results of the analogue studies undertaken between 1981 and 1987 that were funded by the US Nuclear Regulatory Commission (USNRC) and the UK Department of the Environment (UKDoE). Section 4 describes the objectives of ARAP and the manner in which the study was conducted and provides a general outline of the project and a summary of the findings. A general description of the Koongarra ore deposit, the focus of ARAP, is provided in Section 5, with Sections 6-13 providing summaries of the work carried out to characterise the site in detail and provide data for modelling. Sections 14-18 discuss how this data was used in modelling and how the results may be applied for performance assessment studies. Finally, Section 19 considers the

  12. Design of insulin analogues for meal-related therapy.

    Science.gov (United States)

    Brange, J

    1993-01-01

    The human insulin in replacement therapy has a hexameric structure. Hexamerization of the insulin molecule facilitates biosynthesis and beta-cell storage of insulin, but is unnecessary for biologic activity and appears to contribute to delayed absorption of exogenous insulin from the subcutis. Insulin analogues with reduced self-association that are produced through recombinant DNA techniques have been shown to have in vivo activity comparable to that of human insulin and absorption kinetics characterized by higher and more constant rates of disappearance from the subcutaneous injection site. In preliminary studies in patients receiving insulin therapy, monomeric insulin analogues have been found to provide glycemic control in the postprandial period that is at least equivalent to that of human insulin. Findings in these studies suggest that the use of such analogues may provide meal-related insulin effects closer to those observed in the physiologic state by limiting excessive postprandial glucose excursions and decreasing the risk of late hypoglycemia. Banting and Best revolutionized diabetes therapy 70 years ago with the extraction of insulin from animal pancreas glands (J Lab Clin Med 7:464-472, 1922). Since that time, many refinements of the therapeutic properties of pharmaceutical preparations of the hormone have been introduced. Until recently, however, such advances have been limited to improvements in insulin purity, insulin species, and adjustment of the composition of the vehicle with respect to auxiliary substances and other additives. With the advent of recombinant DNA techniques, it has become possible to optimize the insulin molecule itself for purposes of replacement therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Are Structural Analogues to Bisphenol A Safe Alternatives?

    DEFF Research Database (Denmark)

    Rosenmai, Anna Kjerstine; Dybdahl, Marianne; Pedersen, Mikael

    2014-01-01

    Background: Bisphenol A (BPA) is a chemical with widespread human exposure suspected of causing low-dose effects. Thus, a need for developing alternatives to BPA exists. Structural analogues of BPA have already been detected in foods and humans. Due to the structural analogy of the alternatives......, there is a risk of effects similar to BPA.Objectives: The aim was to elucidate and compare the hazards of bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF), bisphenol S (BPS) and 4-cumylphenol (HPP) to BPA.Methods: In vitro studies on steroidogenesis, receptor activity, and biomarkers of effect, as well...

  14. A high speed digital-to-analogue converter

    International Nuclear Information System (INIS)

    Hallgren, B.I.

    1974-02-01

    An 8-bit Digital-to-Analogue converter of the current-weighting type has been constructed using 8 monolithic integrated circuit transistor arrays -one for each bit. The D/A-converter has a voltage output within the range 0 to -2V. The settling time to within half of the least significant bit is about 50 nsec. The temperature dependence and transient response of the converter has been analysed using computer aided design techniques. A comparison is made between the experimental and simulated transient performance. (Auth.)

  15. Optical analogues of nanostructures with Rashba–Dresselhaus interactions

    International Nuclear Information System (INIS)

    Dragoman, Daniela

    2014-01-01

    We demonstrate that light propagation through uniaxial crystals with suitably oriented optical axes is quantitatively analogous to electron propagation in a two-dimensional electron gas in the presence of Rashba and/or Dresselhaus effects. It is shown that, through an appropriate shaping of light beams and a rigorous control of their incidence angle on properly oriented uniaxial crystals, it is possible to investigate independently the effects of angular divergence and energy broadening on electron wavefunction evolution. Such optical analogues could be useful in designing spintronic devices, in particular those relying on the equality of Rashba and Dresselhaus coefficients. (paper)

  16. Galaxies and Saturn's rings: Gravitational analogues of nonneutral plasmas

    International Nuclear Information System (INIS)

    Mark, J.W.K.

    1985-01-01

    Orbit and collective dynamics in disk galaxies and in Saturn's rings are gravitational analogues of those occurring in nonneutral plasmas. The interesting problems for such ''gravitational plasmas'' are analogous to single-disk studies of transverse dynamics in particle beams. Of particular interest are various orbit-resonances with spiral density and bending waves in these disks which are analogous to electrostatic waves in nonneutral beam plasmas. The background physics, terminology and results of astrophysical investigations in these fields are surveyed in this paper. 53 refs., 19 figs., 1 tab

  17. Application of FPGA's in Flexible Analogue Electronic Image Generator Design

    Directory of Open Access Journals (Sweden)

    Peter Kulla

    2006-01-01

    Full Text Available This paper focuses on usage of the FPGAs (Field Programmable Gate Arrays Xilinx as a part of our more complex workdedicated to design of flexible analogue electronic images generator for application in TV measurement technique or/and TV servicetechnique or/and education process. The FPGAs performs here the role of component colour R, G, B, synchronization and blanking signals source. These signals are next processed and amplified in other parts of the generator as NTSC/PAL source encoder and RF modulator. The main aim of this paper is to show the possibilities how with suitable development software use a FPGAs in analog TV technology.

  18. Combinatorial interpretations of binomial coefficient analogues related to Lucas sequences

    OpenAIRE

    Sagan, Bruce; Savage, Carla

    2009-01-01

    Let s and t be variables. Define polynomials {n} in s, t by {0}=0, {1}=1, and {n}=s{n-1}+t{n-2} for n >= 2. If s, t are integers then the corresponding sequence of integers is called a Lucas sequence. Define an analogue of the binomial coefficients by C{n,k}={n}!/({k}!{n-k}!) where {n}!={1}{2}...{n}. It is easy to see that C{n,k} is a polynomial in s and t. The purpose of this note is to give two combinatorial interpretations for this polynomial in terms of statistics on integer partitions in...

  19. Uranium series disequilibrium studies at the Broubster analogue site

    International Nuclear Information System (INIS)

    Longworth, G.; Ivanovich, M.; Wilkins, M.A.

    1990-11-01

    Uranium series measurements at a natural analogue site at Broubster, Caithness have been used to investigate radionuclide migration over periods ranging from several hundred to 10 6 years. The measured values for the uranium concentration and activity values 234 U/ 238 U and 230 Th/ 234 U indicate that the geochemical system is more complicated than that originally proposed of uranium dispersion and water transport into a peat bog. There appears to be little thorium mobility although there is evidence for an appreciable fraction of thorium on the colloidal phase. (author)

  20. Uranium series disequilibrium studies at the Broubster analogue site

    International Nuclear Information System (INIS)

    Longworth, G.; Ivanovich, M.; Wilkins, M.A.

    1989-09-01

    Uranium series measurements at a natural analogue site at Broubster, Caithness have been used to investigate radionuclide migration over a period of several hundred to 10 6 years. The measured values for the uranium concentration and activity ratios 234 U/ 238 U and 230 Th/ 234 U indicate that the geochemical system is more complicated than that originally proposed of uranium dispersion and water transport into a peat bog. There appears to be little thorium mobility although there is evidence for an appreciable fraction of thorium on the colloidal phases. (author)