WorldWideScience

Sample records for analogue resonance studies

  1. 1H nuclear magnetic resonance studies of the conformation of an ATP analogue at the active site of Na,K-ATPase from kidney medulla

    International Nuclear Information System (INIS)

    Stewart, J.M.M.; Grisham, C.M.

    1988-01-01

    1 H nuclear magnetic relaxation measurements have been used to determine the three-dimensional conformation of an ATP analogue, Co(NH 3 ) 4 ATP, at the active site of sheep kidney Na,K-ATPase. Previous studies have shown that Co(NH 4 ) 4 ATP is a competitive inhibitor with respect to MnATP for the Na,K-ATPase and that Mn 2+ bound to a single, high-affinity site on the ATPase can be an effective paramagnetic probe for nuclear relaxation studies of the Na-K-ATPase. From the paramagnetic effect of Mn 2+ bound to the APTase on the longitudinal relaxation rates of the protons of Co(NH 3 ) 4 ATP at the substrate site (at 300 and 361 MHz), Mn-H distances to seven protons on the bound nucleotide were determined. Taken together with previous 31 P nuclear relaxation data, these measurements are consistent with a single nucleotide conformation at the active site. The nucleotide adopts a bent configuration, in which the triphosphate chain lies nearly parallel to the adenine moiety. The glycosidic torsion angle is 35 0 , and the conformation of the ribose ring is slightly N-type. The bound Mn 2+ lies above and in the plane of the adenine ring. The distances from Mn 2+ to N 6 and N 7 are too large for first coordination sphere complexes but are appropriate for second-sphere complexes involving, for example, intervening hydrogen-bonded water molecules. The NMR data also indicate that the structure of the bound ATP analogue is independent of the conformational state of the enzyme

  2. /sup 1/H nuclear magnetic resonance studies of the conformation of an ATP analogue at the active site of Na,K-ATPase from kidney medulla

    Energy Technology Data Exchange (ETDEWEB)

    MacD. Stewart, J.M.; Grisham, C.M.

    1988-06-28

    /sup 1/H nuclear magnetic relaxation measurements have been used to determine the three-dimensional conformation of an ATP analogue, Co(NH/sub 3/)/sub 4/ATP, at the active site of sheep kidney Na,K-ATPase. Previous studies have shown that Co(NH/sub 4/)/sub 4/ATP is a competitive inhibitor with respect to MnATP for the Na,K-ATPase and that Mn/sup 2 +/ bound to a single, high-affinity site on the ATPase can be an effective paramagnetic probe for nuclear relaxation studies of the Na-K-ATPase. From the paramagnetic effect of Mn/sup 2 +/ bound to the APTase on the longitudinal relaxation rates of the protons of Co(NH/sub 3/)/sub 4/ATP at the substrate site (at 300 and 361 MHz), Mn-H distances to seven protons on the bound nucleotide were determined. Taken together with previous /sup 31/P nuclear relaxation data, these measurements are consistent with a single nucleotide conformation at the active site. The nucleotide adopts a bent configuration, in which the triphosphate chain lies nearly parallel to the adenine moiety. The glycosidic torsion angle is 35/sup 0/, and the conformation of the ribose ring is slightly N-type. The bound Mn/sup 2 +/ lies above and in the plane of the adenine ring. The distances from Mn/sup 2 +/ to N/sub 6/ and N/sub 7/ are too large for first coordination sphere complexes but are appropriate for second-sphere complexes involving, for example, intervening hydrogen-bonded water molecules. The NMR data also indicate that the structure of the bound ATP analogue is independent of the conformational state of the enzyme.

  3. Resonant electrodynamic heating of stellar coronal loops: An LRC circuit analogue

    Science.gov (United States)

    Ionson, J. A.

    1980-01-01

    The electrodynamic coupling of stellar coronal loops to underlying beta velocity fields. A rigorous analysis revealed that the physics can be represented by a simple yet equivalent LRC circuit analogue. This analogue points to the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Although the width of this spatial resonance, as well as the induced currents and coronal velocity field, explicitly depend upon viscosity and resistivity, the resonant form of the generalized electrodynamic heating function is virtually independent of irreversibilities. This is a classic feature of high quality resonators that are externally driven by a broad band source of spectral power. Applications to solar coronal loops result in remarkable agreement with observations.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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. ...

  9. The glaciogenic reservoir analogue studies project (GRASP)

    DEFF Research Database (Denmark)

    Moscariello, A.; Moreau, Julien; Vegt, P. van der

    increasing the risk associated with developing effectively these reservoirs. Therefore a analogue-based predictive stratigraphical and sedimentological model can help to steer drilling strategy and reduce uncertainties and associated risks. For this purpose the GRASP joint industry programme was established......Tunnel galleys are common features in Palaeozoic glacigenic succession in North Afrcica and Middle East and they are amongst the most challenging target for hydrocarbon exploration and developing drilling in these regions. Similarly, these buried valleys form important groundwater reservoirs...... in Quaternary glaciated areas and their nature and sediment composition is critical to drive a sustainable production strategy and assess their vulnerability. Seismic resolution however, often limits the understanding of channel valleys morphology, 3D geometry and internal reservoir distribution, thus...

  10. 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.

  11. Theoretical study on absorption and emission spectra of adenine analogues.

    Science.gov (United States)

    Liu, Hongxia; Song, Qixia; Yang, Yan; Li, Yan; Wang, Haijun

    2014-04-01

    Fluorescent nucleoside analogues have attracted much attention in studying the structure and dynamics of nucleic acids in recent years. In the present work, we use theoretical calculations to investigate the structural and optical properties of four adenine analogues (termed as A1, A2, A3, and A4), and also consider the effects of aqueous solution and base pairing. The results show that the fluorescent adenine analogues can pair with thymine to form stable H-bonded WC base pairs. The excited geometries of both adenine analogues and WC base pairs are similar to the ground geometries. The absorption and emission maxima of adenine analogues are greatly red shifted compared with nature adenine, the oscillator strengths of A1 and A2 are stronger than A3 and A4 in both absorption and emission spectra. The calculated low-energy peaks in the absorption spectra are in good agreement with the experimental data. In general, the aqueous solution and base pairing can slightly red-shift both the absorption and emission maxima, and can increase the oscillator strengths of absorption spectra, but significantly decrease the oscillator strengths of A3 in emission spectra.

  12. 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)

  13. Analogue model studies of induction effects at auroral latitudes

    Directory of Open Access Journals (Sweden)

    A. Viljanen

    1995-11-01

    Full Text Available In addition to field observations and numerical models, geomagnetic induction effects can be studied by scaled analogue model experiments. We present here results of analogue model studies of the auroral electrojet with an Earth model simulating the Arctic Ocean and inland conductivity structures in northern Fennoscandia. The main elements of the analogue model used were salt water simulating the host rock, an aluminium plate corresponding to the ocean and graphite pieces producing the inland highly conducting anomalies. The electrojet was a time-harmonic line current flowing at a (simulated height of 100 km above northern Fennoscandia. The period simulated was 9 min. The analogue model results confirmed the well-known rapid increase of the vertical field when the coast is approached from the continent. The increase of the horizontal field due to induced ocean currents was demonstrated above the ocean, as well as the essentially negligible effect of these currents on the horizontal field on the continent. The behaviour of the magnetic field is explained with a simple two-dimensional thin-sheet model. The range, or the adjustment distance, of the ocean effect inland was found to be some hundreds of kilometers, which also agrees with earlier results of the Siebert-Kertz separation of IMAGE magnetometer data. The modelled inland anomalies evidently had too large conductivities, but on the other hand, their influence decayed on scales of only some tens of kilometers. Analogue model results, thin-sheet calculations, and field observations show that the induction effect on the horizontal magnetic field Bx near the electrojet is negligible. On the other hand, the vertical component Bz is clearly affected by induced currents in the ocean. Evidence of this is the shift of the zero point of Bz 0-1° southwards from the maximum of Bx. The importance of these results are discussed, emphasizing the determination of ionospheric currents.

  14. Natural analogue study of volcanic glass

    International Nuclear Information System (INIS)

    Arai, T.; Yusa, Y.; Sasaki, N.; Tsunoda, N.; Takano, H.

    1989-02-01

    A considerable range in alteration rates of basaltic glasses in various environments has been reported in previous studies. However, these studies paid only cursory attention to the environmental conditions under which the glass had been altered. In this study, the alteration of basaltic glasses was investigated and the environmental conditions and the alteration rate were discussed. Two sample ages were represented: 280 years and 2800 years. Basaltic glasses and their alteration layers were analyzed by electron probe microanalyzer (EMPA) and the thickness of the alteration layers were measured by scanning electron microscope (SEM). The ground water collected near the sampling point of Zunazawa Scoria (2800 years) and the pore water of both samples were analyzed. The alteration temperature and flow rate of water are estimated to be about 13degC and 0.2 l/cm 2 /y respectively on the basis of meteorological data. The alteration layers of young aged basaltic glasses in freshwater conditions are similar to those of leached borosilicate glasses. The alteration rates of these basaltic glasses are estimated to be several μm/1000y. The elemental concentrations in the ground water can be roughly explained as the result of leaching of the glasses. (author)

  15. Mortar alteration: experimental study and ancient analogues

    International Nuclear Information System (INIS)

    Rassineux, Francois

    1987-01-01

    As the durability of cemented matrices is a matter of great importance in numerous domains, notably for the long term reliability of surface storages of radioactive wastes, the objective of this research thesis is to define mechanisms of evolution of cemented matrices when in contact with diluted aqueous solutions. The author notably studied the influence of the lixiviation mode on the evolution of two mortars having different compositions (pH, CO 2 pressure, system containment, and cement mineralogical nature appear to be the main governing parameters), the alteration (dissolution is the prevailing process in the interaction between cemented matrices and a diluted solution such as rain water), and ancient binders (archaeological binders containing mineral phases such as hydrated calcium silicates or hydro-grossulars). The obtained results lead to the definition of alteration mechanisms in modern cements, and highlight factors governing the durability of these materials when submitted to meteoric alteration [fr

  16. Biologically relevant conformational features of linear and cyclic proteolipid protein (PLP) peptide analogues obtained by high-resolution nuclear magnetic resonance and molecular dynamics

    Science.gov (United States)

    Kordopati, Golfo G.; Tzoupis, Haralambos; Troganis, Anastassios N.; Tsivgoulis, Gerasimos M.; Golic Grdadolnik, Simona; Simal, Carmen; Tselios, Theodore V.

    2017-09-01

    Proteolipid protein (PLP) is one of the main proteins of myelin sheath that are destroyed during the progress of multiple sclerosis (MS). The immunodominant PLP139-151 epitope is known to induce experimental autoimmune encephalomyelitis (EAE, animal model of MS), wherein residues 144 and 147 are recognized by T cell receptor (TCR) during the formation of trimolecular complex with peptide-antigen and major histocompability complex. The conformational behavior of linear and cyclic peptide analogues of PLP, namely PLP139-151 and cyclic (139-151) (L144, R147) PLP139-151, have been studied in solution by means of nuclear magnetic resonance (NMR) methods in combination with unrestrained molecular dynamics simulations. The results indicate that the side chains of mutated amino acids in the cyclic analogue have different spatial orientation compared with the corresponding side chains of the linear analogue, which can lead to reduced affinity to TCR. NMR experiments combined with theoretical calculations pave the way for the design and synthesis of potent restricted peptides of immunodominant PLP139-151 epitope as well as non peptide mimetics that rises as an ultimate goal.

  17. Crossover from plasmonic analogue of Fano resonance to Autler-Townes splitting in a double guide mode resonances system

    Science.gov (United States)

    Wei, Buzheng; Ren, Guobin; Jian, Shuisheng

    2017-09-01

    The plasmonic analogy from Fano resonance to Autler-Townes splitting (ATS) in mid-infrared spectral range is observed assisted by a dual parallel graphene-coated grating structure. The analytical derivation exhibits a height-dependent resonance which is crucial for discerning Fano resonance from ATS. The mechanism of generating a transparency window seeks a trade-off between Fano resonance and ATS at threshold height. While within the critical height, Fano resonance dominates. The Akaike Information Criterion test is used to discern these two effects quantitatively. Moreover, the device pronounces a good tunability accompanied with a slowing light application. Our ideas open up a new insight view of designing or constructing highly integrated, multi-functional graphene-based metamaterials in nanoscale.

  18. Pocos de Caldas, Minas Gerais, Brazil: a natural analogue study

    International Nuclear Information System (INIS)

    Smellie, J.

    1989-01-01

    The Pocos de Caldas natural analogue project is an internationally funded project hosted by Brazil; the contributary organizations are SKB (Sweden), NAGRA (Switzerland), DOE (United Kingdom) and the DOE (United States). The Project is a multidisciplinary study of two mineralized areas within an alkaline igneous caldera complex located near the town of Pocos de Caldas in the state of Minas Gerais. One area, the Osamu Utsumi mine, is characterized by redox deposits of secondary remobilized pitchblende, and the other area, Morro do Ferro, comprises a highly weathered deposit of thorium and REE with subordinate uranium. The project, scheduled for three years (1986-1989), is now entering its third and final year. The pilot and feasibility studies, which characterized the first year, helped to establish the major drilling programme and the sampling protocols for both rock and groundwater studies which constituted the major part of the second year. The latest status of the investigations are briefly reported

  19. Applications of natural analogue studies to Yucca Mountain as a potential high level radioactive waste repository

    International Nuclear Information System (INIS)

    1995-02-01

    The 5-member group convened in Las Vegas, Nov. 11-13, 1991, to clarify the extent to which studies of natural analogues can assist the Yucca Mountain site characterization (SC) project. This document is to provide guidance and recommendations to DOE for the implementation of natural analogue studies in the SC program. Performance assessment, integrity of engineered barriers, and communication to the public and the scientific community are stressed. The reference design being developed by Babcock ampersand Wilcox Fuel Company are reviewed. Guidelines for selecting natural analogues are given. Quality assurance is discussed. Recommendations are given for developing an effective natural analogue program within the SC program

  20. Conformational solution studies of the anti-microbial temporin A retro-analogues by using NMR spectroscopy.

    Science.gov (United States)

    Kamysz, Wojciech; Mickiewicz, Beata; Greber, Katarzyna; Rodziewicz-Motowidło, Sylwia

    2007-05-01

    Temporin A (TA) is a small, basic and highly hydrophobic peptide, isolated from the skin of the European red frog, Rana temporaria. The TA (FLPLIGRVLSGIL-NH2) displays a broad spectrum of anti-microbial activity against Gram-positive bacteria and fungi Candida albicans. In this study we investigate the solution structure of two TA retro-analogues, (6-1)(7-13)-TA (GILPLFRVLSGIL-NH2) and retro-TA (LIGSLVRGILPLF-NH2) by using nuclear magnetic resonance (NMR). The 3D solution structure of the analogues was established by using inter-proton distances and vicinal coupling constants in the Simulated Annealing (SA) calculations (XPLOR program). The NMR conformational studies show the existence of the helical structure in the middle part of the (6-1)(7-13)-TA peptide and an unordered structure of the retro-TA analogue under the D3-TFE/H2O (3:7, v/v) conditions. Our investigations have shown that the hydrophobic cluster at N-terminus with the Pro amino acid residue in position 3 or 4, the helical structure and the amphipathic character of the peptide are responsible for the anti-microbial activity of the TA analogues. Copyright (c) 2007 European Peptide Society and John Wiley & Sons, Ltd.

  1. Genie in a blotter: A comparative study of LSD and LSD analogues' effects and user profile.

    Science.gov (United States)

    Coney, Leigh D; Maier, Larissa J; Ferris, Jason A; Winstock, Adam R; Barratt, Monica J

    2017-05-01

    This study aimed to describe self-reported patterns of use and effects of lysergic acid diethylamide (LSD) analogues (AL-LAD, 1P-LSD, and ETH-LAD) and the characteristics of those who use them. An anonymous self-selected online survey of people who use drugs (Global Drug Survey 2016; N = 96,894), which measured perceived drug effects of LSD and its analogues. Most LSD analogue users (91%) had also tried LSD. The proportion of U.K. and U.S. respondents reporting LSD analogue use in the last 12 months was higher than for LSD only. LSD analogue users described the effects as psychedelic (93%), over half (55%) obtained it online, and almost all (99%) reported an oral route of administration. The modal duration (8 hr) and time to peak (2 hr) of LSD analogues were not significantly different from LSD. Ratings for pleasurable high, strength of effect, comedown, urge to use more drugs, value for money, and risk of harm following use were significantly lower for LSD analogues compared with LSD. LSD analogues were reported as similar in time to peak and duration as LSD but weaker in strength, pleasurable high, and comedown. Future studies should seek to replicate these findings with chemical confirmation and dose measurement. Copyright © 2017 John Wiley & Sons, Ltd.

  2. 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

  3. 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

  4. Synthesis and formulation studies of griseofulvin analogues with improved solubility and metabolic stability

    DEFF Research Database (Denmark)

    Petersen, Asger Bjørn; Andersen, Nikolaj Sten; Konotop, Gleb

    2017-01-01

    potency in vitro. Analogue 2 was also shown to retard tumor growth through inhibition of centrosomal clustering in murine xenograft models of colon cancer and multiple myeloma. However, similar to griseofulvin, compound 2 exhibited poor metabolic stability and aqueous solubility. In order to improve...... the poor pharmacokinetic properties, 11 griseofulvin analogues were synthesized and evaluated for biological activity and physiological stabilities including SGF, plasma, and metabolic stability. Finally, the most promising compounds were investigated in respect to thermodynamic solubility and formulation...... studies. The 2'-benzylamine analogue 10 proved to be the most promising compound with low μM in vitro anticancer potency, a 200-fold increase in PBS solubility over compound 2, and with improved metabolic stability. Furthermore, this analogue proved compatible with formulations suitable for both oral...

  5. Synthesis and formulation studies of griseofulvin analogues with improved solubility and metabolic stability.

    Science.gov (United States)

    Petersen, Asger B; Andersen, Nikolaj S; Konotop, Gleb; Hanafiah, Nur Hafzan Md; Raab, Marc S; Krämer, Alwin; Clausen, Mads H

    2017-04-21

    Griseofulvin (1) is an important antifungal agent that has recently received attention due to its antiproliferative activity in mammalian cancer cells. Comprehensive SAR studies have led to the identification of 2'-benzyloxy griseofulvin 2, a more potent analogue with low micromolar anticancer potency in vitro. Analogue 2 was also shown to retard tumor growth through inhibition of centrosomal clustering in murine xenograft models of colon cancer and multiple myeloma. However, similar to griseofulvin, compound 2 exhibited poor metabolic stability and aqueous solubility. In order to improve the poor pharmacokinetic properties, 11 griseofulvin analogues were synthesized and evaluated for biological activity and physiological stabilities including SGF, plasma, and metabolic stability. Finally, the most promising compounds were investigated in respect to thermodynamic solubility and formulation studies. The 2'-benzylamine analogue 10 proved to be the most promising compound with low μM in vitro anticancer potency, a 200-fold increase in PBS solubility over compound 2, and with improved metabolic stability. Furthermore, this analogue proved compatible with formulations suitable for both oral and intravenous administration. Finally, 2'-benzylamine analogue 10 was confirmed to induce G2/M cell cycle arrest in vitro. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Experimental and Theoretical Studies of the Structures and Interactions of Vancomycin Antibiotics with Cell Wall Analogues

    International Nuclear Information System (INIS)

    Yang, Zhibo; Vorpagel, Erich R.; Laskin, Julia

    2008-01-01

    Surface-induced dissociation (SID) of the singly protonated complex of vancomycin antibiotic with cell wall peptide analogue (N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala) was studied using a 6 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS) specially configured for SID experiments. The binding energy between the vancomycin and the peptide was obtained from the RRKM modeling of the time- and energy resolved fragmentation efficiency curves (TFECs) of the precursor ion and its fragments. Electronic structure calculations of the geometries, proton affinities and binding energies were performed for several model systems including vancomycin (V), vancomycin aglycon (VA), N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala, and non-covalent complexes of VA with N-acetyl-D-Ala-D-Ala and N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala at the B3LYP/6-31G(d) level of theory. Comparison between the experimental and computational results suggests that the most probable structure of the complex observed in our experiments corresponds to the neutral peptide bound to the vancomycin protonated at the secondary amino group of the N-methyl-leucine residue. The experimental binding energy of 30.9 ± 1.8 kcal/mol is in good agreement with the binding energy of 29.3 ± 2.5 kcal/mol calculated for the model system representing the preferred structure of the complex

  7. Natural analogue study on Tono sandstone-type uranium deposit in Japan

    International Nuclear Information System (INIS)

    Seo, T.; Ochiai, Y.; Takeda, S.; Nakatsuka, N.

    1989-01-01

    The Tertiary Tono sandstone-type uranium deposit is recognized as a potentially useful analogue for the geological isolation of radioactive wastes in Japan. The study of this natural analogue is being carried out to acquire information about the geochemical processes that relate to the containment and migration of uranium series nuclides over geologic time. There is no significant migration for uranium for the samples investigated as the result of radioactive disequilibrium study. The hydrogeochemical study suggests that the groundwater in the ore horizons is very stagnant and reducing

  8. Synthesis and Neurotrophic Activity Studies of Illicium Sesquiterpene Natural Product Analogues.

    Science.gov (United States)

    Richers, Johannes; Pöthig, Alexander; Herdtweck, Eberhardt; Sippel, Claudia; Hausch, Felix; Tiefenbacher, Konrad

    2017-03-02

    Neurotrophic natural products hold potential as privileged structures for the development of therapeutic agents against neurodegeneration. However, only a few studies have been conducted to investigate a common pharmacophoric motif and structure-activity relationships (SARs). Here, an investigation of structurally more simple analogues of neurotrophic sesquiterpenes of the illicium family is presented. A concise synthetic route enables preparation of the carbon framework of (±)-Merrilactone A and (±)-Anislactone A/B on a gram scale. This has allowed access to a series of structural analogues by modification of the core structure, including variation of oxidation levels and alteration of functional groups. In total, 15 derivatives of the natural products have been synthesized and tested for their neurite outgrowth activities. Our studies indicate that the promising biological activity can be retained by structurally simpler natural product analogues, which are accessible by a straightforward synthetic route. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. QSAR Studies of 6-Amino Uracil Base Analogues: A Thymidine Phosphorylase Inhibitor in Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Surya Prakash B. N. Gupta

    2008-01-01

    Full Text Available A novel series of 6-amino uracil base analogue were synthesized. QSAR study was used to relate the selective nonsubstrate inhibitory activity of 6-amino uracil base analogue with various physicochemical descriptors. Stepwise multiple regression analysis was performed to find out the correlation between various physicochemical descriptors and biological activity of the compounds by using Openstat 2 version 6.5.1 and valstat statistical software. Out of the several equations developed, the best equation having the highest significance was selected for further study. The equation is able to explain 60% of total variance and are more than 95% significant as revealed by the F value.

  10. The interaction of new piroxicam analogues with lipid bilayers--a calorimetric and fluorescence spectroscopic study.

    Science.gov (United States)

    Maniewska, Jadwiga; Szczęśniak-Sięga, Berenika; Poła, Andrzej; Sroda-Pomianek, Kamila; Malinka, Wiesław; Michalak, Krystyna

    2014-01-01

    The purpose of the present paper was to assess the ability of new piroxicam analogues to interact with the lipid bilayers. The results of calorimetric and fluorescence spectroscopic experiments of two new synthesized analogues of piroxicam, named PR17 and PR18 on the phase behavior of phospholipid bilayers and fluorescence quenching of fluorescent probes (Laurdan and Prodan), which molecular location within membranes is known with certainty, are shown in present work. The presented results revealed that, depending on the details of chemical structure, the studied compounds penetrated the lipid bilayers.

  11. Conformational determination of potent antagonist analogues of oxytocin by nuclear magnetic resonance spectroscopy and molecular dynamics simulations

    Czech Academy of Sciences Publication Activity Database

    Kritsi, E.; Potamitis, C.; Zoumpoulakis, P.; Borovičková, Lenka; Slaninová, Jiřina; Assimomytis, N. L.; Magafa, V.; Cordopatis, P.

    2014-01-01

    Roč. 20, Suppl S1 (2014), S200-S201 ISSN 1075-2617. [European Peptide Symposium /33./. 31.08.2014-05.09.2014, Sofia ] Institutional support: RVO:61388963 Keywords : oxytocin analogues * antagonistic activity * NMR * molecular dynamics Subject RIV: CC - Organic Chemistry

  12. Organometallic nucleoside analogues with ferrocenyl linker groups: synthesis and cancer cell line studies.

    Science.gov (United States)

    Nguyen, Huy V; Sallustrau, Antoine; Balzarini, Jan; Bedford, Matthew R; Eden, John C; Georgousi, Niki; Hodges, Nikolas J; Kedge, Jonathan; Mehellou, Youcef; Tselepis, Chris; Tucker, James H R

    2014-07-10

    Examples of organometallic compounds as nucleoside analogues are rare within the field of medicinal bioorganometallic chemistry. We report on the synthesis and properties of two chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group. These so-called ferronucleosides show promising anticancer activity, with cytostatic studies on five different cancer cell lines indicating that both functional groups are required for optimal activity.

  13. Studies of natural analogues and geological systems. Their importance to performance assessment

    International Nuclear Information System (INIS)

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

    1992-04-01

    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 of the 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. The results of the study show that studies of natural analogues and natural geological systems have provided significant information regarding many issues of importance to repository performance. In several cases the evidence from natural analogues has demonstrated that processes assumed to take place in repositories actually occur in natural systems or under conditions similar to those predicted to prevail in a future repository. One example of such a process is coprecipitation of fission products and ferric oxyhydroxides as an analogue to corrosion products from a steel canister. In addition, the study of concentration gradients of uranium and other trace substances in the rock surrounding groundwater conduits confirm that matrix diffusion occurs in nature and that the diffusivities in the rock matrix measured in the laboratory are consistent with the observations in nature

  14. Reasoning by analogy: rational foundation of natural analogue studies. [Application to radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Petit, J.-C. (CEA Centre d' Etudes Nucleaires de Fontenay-aux Roses, (France). DRDD/SESD)

    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).

  15. Natural analogue study on engineered barriers for underground disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Araki, K.; Motegi, M.; Emoto, Y.; Kaji, Y.; Ikari, S.; Nada, T.; Watanabe, T.

    1989-01-01

    This is a report to develop the natural analogue methodology for the assessment of the life of the engineered barriers beyond the time period of normal experiments, 1000 years, for the disposal of low-level radioactive wastes with activity levels greater than those of wastes acceptable for shallow land burial in Japan. Geological and archeological events and objects available for the assessment of the possible life of each engineered barrier are surveyed. Taking heavy precipitation into account in Japan, a long-term, zero-release engineered barrier system using long-term durable materials based on the natural analogue events and objects is proposed along with the conventional type of water permeable engineered barrier system. The combination of the material quality and the environment that could be achieved within the repository is important for the long-term durability of the engineered barrier material. It is proposed that for the natural analogue study a physico-chemical methodology, which may be referred to as the physico-chemical natural history, is necessary to get parameters from the natural analogue events for the long-term assessment of the disposal system

  16. Natural analogue studies of engineered barrier materials at PNC Tokai, Japan

    International Nuclear Information System (INIS)

    Kamei, G.; Yusa, Y.; Yamagata, J.; Inoue, K.

    1991-01-01

    Long-term extrapolations concerning the safety of a nuclear waste repository cannot be satisfactorily made on the sole basis of short-term laboratory tests. 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. Our natural analogue studies for the assessment of long-term durability of engineered barrier materials are outlined. Materials of young age and with simple history are the most suitable for the studies as: 1) properties of the materials tend to deteriorate over the longer term; and 2) detailed quantitative data on the term and on the environmental conditions can be obtained. The framework of our studies includes: 1) clarification of alteration phenomena, 2) examination of the environmental conditions, and 3) support experiments. (author)

  17. Characterization of electronic structure and physicochemical properties of antiparasitic nifurtimox analogues: A theoretical study

    Science.gov (United States)

    Soriano-Correa, Catalina; Raya, A.; Esquivel, Rodolfo O.

    American trypanosomiasis, also known as Chagas' disease, is caused by Trypanosoma cruzi (T. cruzi). It is well known that trypanosomes, and particularly T. cruzi, are highly sensitive towards oxidative stress, i.e., to compounds than are able to produce free radicals. Generally, nifurtimox (NFX) and benznidazol are most effective in the acute phase of the disease; therefore, nitroheterocycles constitute good models to design other nitrocompounds with specific biological characteristics. Thus, we have performed an ab initio study at the Hartree-Fock and Density Functional Theory levels of theory of several NFX analogues recently synthesized, to characterize them by obtaining their electronic, structural, and physicochemical properties, which might be linked to the observed antichagasic activity. The antitrypanosomal activity scale previously reported for the NFX analogues studied in this work is in good agreement with our theoretical results, from which we can conclude that the activity seems to be related to the reactivity along with the acidity observed for the most active molecules.

  18. Synthesis, Crystal Structure and in vitro DNA Binding Studies of Combretastatin A-4 Analogue

    Directory of Open Access Journals (Sweden)

    Masood Ahmad Rizvi

    2015-12-01

    Full Text Available Synthesis of a novel Combretastatin A-4 analogue using Schiff’s reaction of benzil and 4-aminoantipyrine has been achieved under solvent free conditions. The structure of compound was examined spectroscopically and confirmed from single crystal diffraction studies. The synthesized Combretastatin A-4 analogue was investigated for its DNA binding ability as the plausible mechanism for its antitumor activity. The binding propensity of the synthesized compound with calf-thymus (CT DNA was monitored with absorption and emission spectrophotometric titrations. The calculations predict a binding constant of 7.24×104 for the complex of the synthesized compound with CT DNA which is comparable in magnitude to that of DNA binding of bactericidal drug enoxacin and typical intercalation indicator ethidium bromide (EB. Competitive binding studies of the synthesized compound with EB using fluorescence titration reveal that it displaces the DNA-bound EB and binds in intercalative mode which was further supported by circular dichroism (CD spectroscopy. The probable site and binding energy of the compound with DNA was further theoretically investigated by molecular docking studies. The significant DNA binding ability of the synthesized Combretastatin A4 analogue as revealed from this study could be related to the anticancer activity of the Combretastatin A4.

  19. Medical judgement analogue studies with applications to spaceflight crew medical officer.

    Science.gov (United States)

    McCarroll, Michele L; Ahmed, Rami A; Schwartz, Alan; Gothard, Michael David; Atkinson, Steven Scott; Hughes, Patrick; Brito, Jose Cepeda; Assad, Lori; Myers, Jerry; George, Richard L

    2017-10-01

    The National Aeronautics and Space Administration (NASA) developed plans for potential emergency conditions from the Exploration Medical Conditions List. In an effort to mitigate conditions on the Exploration Medical Conditions List, NASA implemented a crew medical officer (CMO) designation for eligible astronauts. This pilot study aims to add knowledge that could be used in the Integrated Medical Model. An analogue population was recruited for two categories: administrative physicians (AP) representing the physician CMOs and technical professionals (TP) representing the non-physician CMOs. Participants completed four medical simulations focused on abdominal pain: cholecystitis (CH) and renal colic (RC) and chest pain: cardiac ischaemia (STEMI; ST-segment elevation myocardial infarction) and pneumothorax (PX). The Medical Judgment Metric (MJM) was used to evaluate medical decision making. There were no significant differences between the AP and TP groups in age, gender, race, ethnicity, education and baseline heart rate. Significant differences were noted in MJM average rater scores in AP versus TP in CH: 13.0 (±2.25), 4.5 (±0.48), p=medical judgement between the two analogue groups of spaceflight CMOs. Future studies should incorporate the MJM in a larger analogue population study to assess the medical risk for spaceflight crewmembers.

  20. 31P nuclear magnetic resonance of phosphonic acid analogues of adenosine nucleotides as functions of pH and magnesium ion concentration

    International Nuclear Information System (INIS)

    Schliselfeld, L.H.; Burt, C.T.; Labotka, R.J.

    1982-01-01

    The 31 P NMR proton-decoupled spectra of α,β-methylene-ATP [Ap(CH 2 )pp], β,γ-methylene-ATP [App(CH 2 )p], and α,β-methylene-ADP [Ap(CH 2 )p] were measured as functions of pH and Mg 2+ concentration. Each ATP analogue yielded three resonances: two doublets and one doublet-of-a- doublet. Assignments of resonances were based upon spin-coupling multiplets, their coupling constant magnitudes (24-27 Hz for -P-O-P- and 4-10 Hz for -P-CH 2 -P-), and the magnitude of the chemical shift movement during proton titration or its direction of movement. All phosphonyl resonances are substantially downfield compared to phosphoryl resonances. The chemical shifts of terminal phosphonyl units moved upfield with increasing pH or rising Mg 2+ concentration. The chemical shifts of phosphonyl and phosphoryl anhydride plus ester units usually either moved downfield during proton titration and addition of Mg 2+ or remained constant. Accurate pK/sub a/' values were readily determined from chemical shift movements as a function of pH; 3.05 +/- 0.04 and 8.80 +/- 0.05 for App(CH 2 )p, 7.34 +/- 0.06 for Ap(CH 2 )pp, and 8.29 +/- 0.02 for AP(CH 2 )p. Addition of Mg 2+ or Tris produced an acidic shift of the alkaline pK/sub a/' values. Addition of Mg 2+ at pH 7.0 to the nucleotides caused large movements in the chemical shifts of their terminal two phosphorus atoms

  1. Structure-activity relationship studies on cholecystokinin: Analogues with partial agonist activity

    Energy Technology Data Exchange (ETDEWEB)

    Galas, M.C.; Lignon, M.F.; Rodriguez, M.; Mendre, C.; Fulcrand, P.; Laur, J.; Martinez, J. (Centre de Pharmacologie-Endocrinologie, Montpellier (France))

    1988-02-01

    In the present study, hepta- and octapeptide analogues of the C-terminal part of cholecystokinin, modified on the C-terminal phenylalanine residue, were synthesized. CCK analogues were prepared in which the peptide bond between aspartic acid and phenylalanine had or had not been modified and were lacking the C-terminal primary amide function. These CCK derivatives were able to cause full stimulation of amylase release from rat pancreatic acini but without a decrease in amylase release at supramaximal concentrations. There was a close relationship between the abilities of these derivatives to stimulate amylase release and their abilities to inhibit binding of {sup 125}I-BH-CCK-9 to CCK receptors on rat and guinea pig pancreatic acini. These CCK analogues were also able to recognize the guinea pig brain CCK receptors, some of them being particularly potent. The findings indicate that the aromatic ring of phenylalanine is important for the binding to brain and pancreatic CCK receptors, whereas the C-terminal primary amide function is not essential for the binding to pancreatic CCK receptors but is crucial for biological activity of rat pancreatic acini.

  2. The network to review natural analogue studies and their applications to repository safety assessment and public communication (NAnet)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, W.M.; Hooker, P.J. [ENVIROS Consulting ltd, 61, the Shore Leith, UK-0 EH6 6RA Edinburgh (United Kingdom)

    2004-07-01

    Analogue information can increase our conceptual understanding of long-term repository behaviour in support of post-closure performance assessment (PA), provide quantitative data for PA models and provide ways of communicating safety information to non-specialist audiences. These functions of analogue studies have, however, received too little attention in PA reports and safety cases. Many analogue studies have been undertaken in the last two decades costing tens of millions of euros, and these have covered a wide range of phenomena such as uranium ore deposition, natural fission reactors, natural nuclide migration, contaminant containment by clays and sediments, preservation of ancient fossil trees and buried artefacts etc. The different uses of analogues would be easier to manage if a single database of quality approved analogue information were to be created. NAnet, a Thematic Network within the 5. EURATOM FP is aiming to promote more considered applications of analogues in performance and safety assessments and in audience dialogue. NAnet intends critically to review a number of analogue studies in terms of their relevance and limitations to different repository concepts and environments and with regard to their applications in performance assessments, safety cases and communication. On the basis of these reviews, a simple digital database is being developed for the PA community which will allow PA modelers to make quicker and wider use of natural analogue information in performance and safety assessments. It is expected that some of these tools will help radioactive waste institutions to make better use of natural analogue information for communication with different audiences, including the public. (authors)

  3. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    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.

  4. SS-HORSE method for studying resonances

    Energy Technology Data Exchange (ETDEWEB)

    Blokhintsev, L. D. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Mazur, A. I.; Mazur, I. A., E-mail: 008043@pnu.edu.ru [Pacific National University (Russian Federation); Savin, D. A.; Shirokov, A. M. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2017-03-15

    A new method for analyzing resonance states based on the Harmonic-Oscillator Representation of Scattering Equations (HORSE) formalism and analytic properties of partial-wave scattering amplitudes is proposed. The method is tested by applying it to the model problem of neutral-particle scattering and can be used to study resonance states on the basis of microscopic calculations performed within various versions of the shell model.

  5. SS-HORSE method for studying resonances

    International Nuclear Information System (INIS)

    Blokhintsev, L. D.; Mazur, A. I.; Mazur, I. A.; Savin, D. A.; Shirokov, A. M.

    2017-01-01

    A new method for analyzing resonance states based on the Harmonic-Oscillator Representation of Scattering Equations (HORSE) formalism and analytic properties of partial-wave scattering amplitudes is proposed. The method is tested by applying it to the model problem of neutral-particle scattering and can be used to study resonance states on the basis of microscopic calculations performed within various versions of the shell model.

  6. THE USE OF PANAX GINSENG AND ITS ANALOGUES AMONG PHARMACY CUSTOMERS IN ESTONIA: A CROSS-SECTIONAL STUDY.

    Science.gov (United States)

    Volmer, Dasy; Raal, Ain; Kalle, Raivo; Sõukand, Renata

    2016-01-01

    The aim of the cross-sectional study was to evaluate the pattern of complementary self-treatment with P. ginseng and its analogues amongst pharmacy customers in Estonia. The study instrument consisted of multiple-choice items related to personal knowledge about and experience with the use of P. ginseng and its analogues. In total, 1233 customers participated in the study. Of study participants, 18.1% reported the use of P. ginseng and its analogues in their lives. P. ginseng preparations were used mostly according to the well- known indications (tiredness, weakness and decreased mental and physical capacity). Of P. ginseng users 44.3% reported positive treatment effects and 12.0% had experienced different side effects. With increase of age (p < 0.01) and at lower levels of education (p = 0.04), the use of ginseng or its analogues decreased. The better the users evaluated their health, the better they perceived the effect of P. ginseng preparations (p < 0.01). This study reported rather frequent use of P. ginseng and its analogues. P. ginseng could be seen in the treatment of conditions, where the use of local medicinal plants has not been established. Further research is needed to learn more about public knowledge and experiences about efficacy and safety of P. ginseng and its analogues.

  7. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  8. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    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.

  9. A Resonant Damping Study Using Piezoelectric Materials

    Science.gov (United States)

    Min, J. B.; Duffy, K. P.; Choi, B. B.; Morrison, C. R.; Jansen, R. H.; Provenza, A. J.

    2008-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue (HCF) problems requiring damping treatments to mitigate vibration levels. Based on the technical challenges and requirements learned from previous turbomachinery blade research, a feasibility study of resonant damping control using shunted piezoelectric patches with passive and active control techniques has been conducted on cantilever beam specimens. Test results for the passive damping circuit show that the optimum resistive shunt circuit reduces the third bending resonant vibration by almost 50%, and the optimum inductive circuit reduces the vibration by 90%. In a separate test, active control reduced vibration by approximately 98%.

  10. Synthesis and preliminary cytotoxicity study of a cephalosporin-CC-1065 analogue prodrug

    Directory of Open Access Journals (Sweden)

    Wang Hong

    2001-11-01

    Full Text Available Abstract Background Antibody-directed enzyme prodrug therapy (ADEPT is a promising new approach to deliver anticancer drugs selectively to tumor cells. In this approach, an enzyme is conjugated to a tumor-specific antibody. The antibody selectively localizes the enzyme to the tumor cell surface. Subsequent administration of a prodrug substrate of the enzyme leads to the enzyme-catalyzed release of the free drug at the tumor site. The free drug will destroy the tumor cells selectively, thus, reducing side effects. Results A CC-1065 analogue was conjugated to a cephalosporin affording prodrug 2. The prodrug and its corresponding free drug, 1, have IC50 values of 0.9 and 0.09 nM, respectively, against U937 leukemia cells in vitro. Conclusions For the first time, a prodrug comprised of a cephalosporin and a CC-1065 analogue has been synthesized. The preliminary in vitro studies show that the prodrug was 10-fold less toxic than the free drug. Prodrug 2 has the potential to be useful in cancer treatment using the ADEPT approach.

  11. Antimicrobial and conformational studies of the active and inactive analogues of the protegrin-1 peptide.

    Science.gov (United States)

    Rodziewicz-Motowidło, Sylwia; Mickiewicz, Beata; Greber, Katarzyna; Sikorska, Emilia; Szultka, Lukasz; Kamysz, Elzbieta; Kamysz, Wojciech

    2010-02-01

    The natural antimicrobial cationic peptide protegrin-1 displays a broad spectrum of antimicrobial activity and rapidly kills pathogens by interacting with their cell membrane. We investigated the structure-activity relationships of three protegrin-1 analogues: IB-367 (RGGLCYCRGRFCVCVGR-NH(2)), BM-1 (RGLCYCRGRFCVCVG-NH(2)) and BM-2 (RGLCYRPRFVCVG-NH(2)). Our antimicrobial and antifungal activity studies of these peptides showed that BM-1 was much more active than IB-367 against Gram-positive bacteria and fungi, whereas BM-2 was inactive. The BM-1 peptide showed fourfold reduced haemolysis relative to IB-367, an additional advantage of this peptide. In addition, BM-1 was about 15% cheaper than IB-367 to synthesize. The absence of two cysteine residues in the BM-2 sequence could be the main reason for its unstable conformation and antimicrobial inactivity. The solution structures of these peptides were determined in dimethyl sulphoxide using two-dimensional NMR and restrained molecular dynamics calculations. IB-367 and BM-1 formed short, antiparallel, beta-hairpin structures connected by a type II' beta-turn. The shorter, inactive BM-2 analogue exhibited major and minor conformations (predominantly unordered) in the NMR spectra and was much more flexible.

  12. Nuclear magnetic resonance studies of biological systems

    International Nuclear Information System (INIS)

    Antypas, W.G. Jr.

    1988-01-01

    The difference between intracellular and extracellular proton relaxation rates provides the basis for the determination of the mean hemoglobin concentration (MHC) in red blood cells. The observed water T 1 relaxation data from red blood cell samples under various conditions were fit to the complete equation for the time-dependent decay of magnetization for a two-compartment system including chemical exchange. The MHC for each sample was calculated from the hematocrit and the intracellular water fraction as determined by NMR. The binding of the phosphorylcholine (PC) analogue, 2-(trimethylphosphonio)-ethylphosphate (phosphoryl-phosphocholine, PPC) to the PC binding myeloma proteins TEPC-15, McPC 603, and MOPC 167 was studied by 31 P NMR

  13. Kinetic analysis of synthetic analogues of linear-epitope peptides of glycoprotein D of herpes simplex virus type 1 by surface plasmon resonance

    NARCIS (Netherlands)

    Lasonder, E; Schellekens, GA; Koedijk, DGAM; Damhof, RA; WellingWester, S; Feijlbrief, M; Scheffer, AJ; Welling, GW

    1996-01-01

    The interaction between mAb A16 and glycoprorein D (gD) of herpes simplex virus type 1 was analyzed by studying the kinetics of binding with a surface-plasmon-resonance biosensor. mAb A16 belongs to group VII antibodies, which recognize residues 11-19 of gD. In a previous study, three critical

  14. Watson-Crick Base Pairing, Electronic and Photophysical Properties of Triazole Modified Adenine Analogues: A Computational Study

    KAUST Repository

    Das, Shubhajit

    2015-09-17

    We employ first-principles Density Functional Theory (DFT) and time-dependent DFT (TDDFT) to elucidate structural, electronic and optical properties of a few recently reported triazole adenine nucleobase analogues. The results are compared against the findings obtained for both natural adenine nucleobase and available experimental data. The optical absorption of these adenine analogues are calculated both in gas-phase and in solvent (methanol) using Polarized Continuum Model (PCM). We find that all the analogues show a red-shifted absorption profile as compared to adenine. Our simulated emission spectra in solvent compare fairly well with experimentally observed results. We investigate base paring ability of these adenine analogues with thymine. The calculations on the intrinsic stability of these base pairs ascertain that all the adenine analogues form the hydrogen bonded Watson-Crick base pair with similar H-bonding energy as obtained for natural adenine-thymine base pair. In our study, we provide a microscopic origin of the low-energy absorption and emission peaks, observed experimentally.

  15. A phase II study of the vitamin D analogue Seocalcitol in patients with inoperable hepatocellular carcinoma

    DEFF Research Database (Denmark)

    Dalhoff, K; Dancey, J; Astrup, L

    2003-01-01

    Hepatocellular carcinoma (HCC) is a common malignant tumour, which has a poor prognosis. Surgical resection can be curative but most patients are inoperable and most chemotherapy agents have minimal activity in this disease. Seocalcitol, a vitamin D analogue, induces differentiation and inhibits...... growth in cancer cell lines and in vivo. The vitamin D receptor is expressed in hepatocytes and more abundantly in HCC cells. In total, 56 patients with inoperable advanced HCC were included in an uncontrolled study of oral Seocalcitol treatment for up to 1 year (with possible extension for responders......). The dose was titrated according to serum calcium levels. The treatment effect was evaluated by regular CT scans. Out of 33 patients evaluable for tumour response, two had complete response (CR), 12 stable disease and 19 progressive disease. The CRs appeared after 6 and 24 months of treatment, and lasted...

  16. Quantitative structure activity relationship (QSAR) studies on nitazoxanide-based analogues against Clostridium difficile In vitro.

    Science.gov (United States)

    Zhang, Han; Liu, Xiwang; Yang, Yajun; Li, Jianyong

    2016-09-01

    Quantitative structure activity relationship (QSAR) has been established between the various physiochemical parameters of a series of nitazoxanide-based analogues and its antibacterial activity against Clostridium difficile. Genetic function approximation (GFA) and comparative molecular field analysis (CoMFA) techniques were used to identify the descriptors that have influence on biological activity. The most influencing molecular descriptors identified in 2D-QSAR include spatial, topological, and electronic descriptors, while electrostatic and stereoscopic fields were the most influencing molecular descriptors identified in 3D-QSAR. Statistical qualities (r2, q2) indicated the significance and predictability of the developed models. The study indicated that antibacterial activity of Clostridium difficile can be improved by increasing molecular connectivity index, local charge surface index, sharp index and decreasing molecular flexibility index.

  17. Advancing Translational Space Research Through Biospecimen Sharing: Amplified Impact of Studies Utilizing Analogue Space Platforms

    Science.gov (United States)

    Staten, B.; Moyer, E.; Vizir, V.; Gompf, H.; Hoban-Higgins, T.; Lewis, L.; Ronca, A.; Fuller, C. A.

    2016-01-01

    Biospecimen Sharing Programs (BSPs) have been organized by NASA Ames Research Center since the 1960s with the goal of maximizing utilization and scientific return from rare, complex and costly spaceflight experiments. BSPs involve acquiring otherwise unused biological specimens from primary space research experiments for distribution to secondary experiments. Here we describe a collaboration leveraging Ames expertise in biospecimen sharing to magnify the scientific impact of research informing astronaut health funded by the NASA Human Research Program (HRP) Human Health Countermeasures (HHC) Element. The concept expands biospecimen sharing to one-off ground-based studies utilizing analogue space platforms (e.g., Hindlimb Unloading (HLU), Artificial Gravity) for rodent experiments, thereby significantly broadening the range of research opportunities with translational relevance for protecting human health in space and on Earth.

  18. Natural analogues of radionuclide migration: reconnaissance study of sites (May 1985-March 1986)

    International Nuclear Information System (INIS)

    Hooker, P.J.; Ball, T.K.; Basham, I.R.; Bloodworth, A.J.; Roberts, P.D.; Ivanovich, M.

    1986-01-01

    Research into natural analogues of radionuclide migration provide data for supporting computer codes that describe the processes of transport and retardation. Such models are appropriate to the far-fields of shallow and deep radioactive waste repositories. The objective of this research project was to define locations within the UK and abroad worthy of detailed investigation. Site investigations and evaluations were carried out at a number of UK localities. The main focus of this survey has been on uraniferous veins in places at near surface where transport of uranium into sediments has occurred. Several uranium rich mineralisations associated with granite margins were visited in Cornwall, Devon and along the Solway Firth coast in Scotland; the disused U mine at South Terras in Cornwall and the coastal site at Needle's Eye near Dalbeattie are confirmed as future study sites. Results to hand from the sediments of Loch Lomand warrant further measurements of iodine and bromine in fresh cores. (author)

  19. Biological activity of insect juvenile hormone analogues against the stable fly and toxicity studies in domestic animals.

    Science.gov (United States)

    Wright, J E; Smalley, H E

    1977-01-01

    The insect JHAs are effective inhibitors of adult stable fly development. Laboratory and field evaluation studies demonstrated that area application of the analogues to larval breeding sites was efficacious for stable fly control in cattle feed lots and in marine grasses. Analytical methods by quantification with gas chromatography with flame ionization detection was developed to measure residual properties as well as aging and leaching in fly breeding media. The analogues did not interfere with the oviposition and development of the endoparasites, M. raptor and S. endius. Toxicity studies against swine, hamsters, and sheep showed that when compounds of high purity were used that no toxic effects were observed in any of the species.

  20. Comparative study on the in vitro cytotoxicity of linear, dendritic, and hyperbranched polylysine analogues.

    Science.gov (United States)

    Kadlecova, Zuzana; Baldi, Lucia; Hacker, David; Wurm, Florian Maria; Klok, Harm-Anton

    2012-10-08

    Lysine-based polycations are widely used as nonviral carriers for gene delivery. This manuscript reports the results of a comparative study on the in vitro cytotoxicity of a library of three structural polylysine variants, namely, linear polylysine (LPL), dendritic polylysine (DPL), and hyperbranched polylysine (HBPL). The aim of this study was to identify possible effects of polymer molecular weight and architecture on both immediate and delayed cytotoxicity and also to provide a mechanistic understanding for possible differences. Acute cytotoxicities were evaluated using cell viability assays with CHO DG44 cells. At comparable molecular weights, the EC(50) values for the LPL analogues were ∼5-250 times higher as compared to the DPL and HBPL samples. For low molecular weight polycations, osmotic shock was found to be an important contributor to immediate cell death, whereas for the higher molecular weight analogues, direct cell membrane disruption was identified to play a role. Delayed cytotoxicity (≥3 h) was assessed by identifying several of the hallmark events that characterize apoptosis, including phosphatidyl serine translocation, mitochondrial membrane depolarization, cytoplasmic cytochrome C release, and caspase 3 activation. At comparable molecular weights, apoptosis was found to be more pronounced for DPL and HBPL as compared to LPL. This difference was ascribed to the fact that LPL is completely enzymatically degradable, in contrast to DPL and HBPL, which also contain ε-peptidic bonds and are only partially degradable. Because their toxicity profiles are similar, HBPL is an interesting (i.e., synthetically easily accessible and inexpensive) alternative to DPL for the nonviral delivery of DNA.

  1. Natural analogues: studies of geological processes relevant to radioactive waste disposal in deep geological repositories

    International Nuclear Information System (INIS)

    Russel, A.W.; Reijonen, H.M.; McKinley, I.G.

    2015-01-01

    The geological disposal of radioactive wastes is generally accepted to be the most practicable approach to handling the waste inventory built up from over 70 years accumulation of power production, research-medical-industrial and military wastes. Here, a brief overview of the approach to geological disposal is presented along with some information on repository design and the assessment of repository post-closure safety. One of the significant challenges for repository safety assessment is how to extrapolate the likely long-term (i.e. ten thousand to a million years) behaviour of the repository from the necessarily short term data from analytical laboratories and underground rock laboratories currently available. One approach, common to all fields of the geosciences, but also in such diverse fields as philosophy, biology, linguistics, law, etc., is to utilise the analogue argumentation methodology. For the specific case of radioactive waste management, the term 'natural analogue' has taken on a particular meaning associated with providing supporting arguments for a repository safety assessment. This approach is discussed here with a brief overview of how the study of natural (and, in particular, geological) systems can provide supporting information on the likely long-term evolution of a deep geological waste repository. The overall approach is discussed and some relevant examples are presented, including the use of uranium ore bodies to assess waste form stability, the investigation of native metals to define the longevity of waste containers and how natural clays can provide information on the stability of waste tunnel backfill material. (authors)

  2. Natural analogues: studies of geological processes relevant to radioactive waste disposal in deep geological repositories

    Energy Technology Data Exchange (ETDEWEB)

    Russel, A.W. [Bedrock Geosciences, Auenstein (Switzerland); Reijonen, H.M. [Saanio and Rickkola Oy, Helsinki (Finland); McKinley, I.G. [MCM Consulting, Baden-Daettwil (Switzerland)

    2015-06-15

    The geological disposal of radioactive wastes is generally accepted to be the most practicable approach to handling the waste inventory built up from over 70 years accumulation of power production, research-medical-industrial and military wastes. Here, a brief overview of the approach to geological disposal is presented along with some information on repository design and the assessment of repository post-closure safety. One of the significant challenges for repository safety assessment is how to extrapolate the likely long-term (i.e. ten thousand to a million years) behaviour of the repository from the necessarily short term data from analytical laboratories and underground rock laboratories currently available. One approach, common to all fields of the geosciences, but also in such diverse fields as philosophy, biology, linguistics, law, etc., is to utilise the analogue argumentation methodology. For the specific case of radioactive waste management, the term 'natural analogue' has taken on a particular meaning associated with providing supporting arguments for a repository safety assessment. This approach is discussed here with a brief overview of how the study of natural (and, in particular, geological) systems can provide supporting information on the likely long-term evolution of a deep geological waste repository. The overall approach is discussed and some relevant examples are presented, including the use of uranium ore bodies to assess waste form stability, the investigation of native metals to define the longevity of waste containers and how natural clays can provide information on the stability of waste tunnel backfill material. (authors)

  3. Nanodiamond graphitization: a magnetic resonance study

    International Nuclear Information System (INIS)

    Panich, A M; Shames, A I; Sergeev, N A; Olszewski, M; McDonough, J K; Mochalin, V N; Gogotsi, Y

    2013-01-01

    We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) study of the high-temperature nanodiamond-to-onion transformation. 1 H, 13 C NMR and EPR spectra of the initial nanodiamond samples and those annealed at 600, 700, 800 and 1800 ° C were measured. For the samples annealed at 600 to 800 ° C, our NMR data reveal the early stages of the surface modification, as well as a progressive increase in sp 2 carbon content with increased annealing temperature. Such quantitative experimental data were recorded for the first time. These findings correlate with EPR data on the sensitivity of the dangling bond EPR line width to air content, progressing with rising annealing temperature, that evidences consequent graphitization of the external layers of the diamond core. The sample annealed at 1800 ° C shows complete conversion of nanodiamond particles into carbon onions. (paper)

  4. 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...

  5. The interplay between subduction and lateral extrusion : A case study for the European Eastern Alps based on analogue models

    NARCIS (Netherlands)

    van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.; Cloetingh, S. A.P.L.

    2017-01-01

    A series of analogue experiments simulating intra-continental subduction contemporaneous with lateral extrusion of the upper plate are performed to study the interference between these two processes at crustal levels and in the lithospheric mantle. The models demonstrate that intra-continental

  6. The interpretation of glucose clamp studies of long-acting insulin analogues: from physiology to marketing and back

    NARCIS (Netherlands)

    Swinnen, S. G. H. A.; Holleman, F.; DeVries, J. H.

    2008-01-01

    Glucose clamp studies assessing the time-action profile of long-acting insulin analogues have reported conflicting results. In an attempt to reconcile the data, we organised an expert meeting of four leading European clamp groups, during which consensus was reached on some but not all points

  7. Martian Feeling: An Analogue Study to Simulate a Round-Trip to Mars using the International Space Station

    Science.gov (United States)

    Felix, C. V.; Gini, A.

    When talking about human space exploration, Mars missions are always present. It is clear that sooner or later, humanity will take this adventure. Arguably the most important aspect to consider for the success of such an endeavour is the human element. The safety of the crew throughout a Martian mission is a top priority for all space agencies. Therefore, such a mission should not take place until all the risks have been fully understood and mitigated. A mission to Mars presents unique human and technological challenges in terms of isolation, confinement, autonomy, reliance on mission control, communication delays and adaptation to different gravity levels. Analogue environments provide the safest way to simulate these conditions, mitigate the risks and evaluate the effects of long-term space travel on the crew. Martian Feeling is one of nine analogue studies, from the Mars Analogue Path (MAP) report [1], proposed by the TP Analogue group of ISU Masters class 2010. It is an integrated analogue study which simulates the psychological, physiological and operational conditions that an international, six-person, mixed gender crew would experience on a mission to Mars. Set both onboard the International Space Station (ISS) and on Earth, the Martian Feeling study will perform a ``dress rehearsal'' of a mission to Mars. The study proposes to test both human performance and operational procedures in a cost-effective manner. Since Low Earth Orbit (LEO) is more accessible than other space-based locations, an analogue studies in LEO would provide the required level of realism to a simulated transit mission to Mars. The sustained presence of microgravity and other elements of true spaceflight are features of LEO that are neither currently feasible nor possible to study in terrestrial analogue sites. International collaboration, economics, legal and ethical issues were considered when the study was proposed. As an example of international collaboration, the ISS would

  8. Deposition of latex colloids at rough mineral surfaces: an analogue study using nanopatterned surfaces.

    Science.gov (United States)

    Krishna Darbha, Gopala; Fischer, Cornelius; Michler, Alex; Luetzenkirchen, Johannes; Schäfer, Thorsten; Heberling, Frank; Schild, Dieter

    2012-04-24

    Deposition of latex colloids on a structured silicon surface was investigated. The surface with well-defined roughness and topography pattern served as an analogue for rough mineral surfaces with half-pores in the submicrometer size. The silicon topography consists of a regular pit pattern (pit diameter = 400 nm, pit spacing = 400 nm, pit depth = 100 nm). Effects of hydrodynamics and colloidal interactions in transport and deposition dynamics of a colloidal suspension were investigated in a parallel plate flow chamber. The experiments were conducted at pH ∼ 5.5 under both favorable and unfavorable adsorption conditions using carboxylate functionalized colloids to study the impact of surface topography on particle retention. Vertical scanning interferometry (VSI) was applied for both surface topography characterization and the quantification of colloidal retention over large fields of view. The influence of particle diameter variation (d = 0.3-2 μm) on retention of monodisperse as well as polydisperse suspensions was studied as a function of flow velocity. Despite electrostatically unfavorable conditions, at all flow velocities, an increased retention of colloids was observed at the rough surface compared to a smooth surface without surface pattern. The impact of surface roughness on retention was found to be more significant for smaller colloids (d = 0.3, 0.43 vs. 1, 2 μm). From smooth to rough surfaces, the deposition rate of 0.3 and 0.43 μm colloids increased by a factor of ∼2.7 compared to a factor of 1.2 or 1.8 for 1 and 2 μm colloids, respectively. For a substrate herein, with constant surface topography, the ratio between substrate roughness and radius of colloid, Rq/rc, determined the deposition efficiency. As Rq/rc increased, particle-substrate overall DLVO interaction energy decreased. Larger colloids (1 and 2 μm) beyond a critical velocity (7 × 10(-5) and 3 × 10(-6) m/s) (when drag force exceeds adhesion force) tend to detach from the surface

  9. How sedimentation affects rift segment interaction during oblique extension: a 4D analogue modelling study

    Science.gov (United States)

    Zwaan, Frank; Schreurs, Guido; Adam, Jürgen

    2017-04-01

    During the early stages of rifting, rift segments may form along non-continuous and/or offset pre-existing weaknesses. It is important to understand how these initial rift segments interact and connect to form a continuous rift system. Previous modelling of rift interaction structures has shown the dominant influence of oblique extension, promoting rift segment linkage (e.g. Zwaan et al., 2016) and eventual continent break-up (Brune et al., 2012). However, these studies did not incorporate sedimentation, which can have important implications for rift evolution (e.g. Bialas and Buck, 2009). Here we present a series of analogue model experiments investigating the influence of sedimentation on rift interaction structures under oblique extension conditions. Our set-up involves a base of compressed foam and plexiglass that forces distributed extension in the overlying analogue materials when the model sidewalls move apart. A sand layer simulates the brittle upper crust and a viscous sand/silicone mixture the ductile lower crust. One of the underlying base plates can move laterally allowing oblique extension. Right-stepping offset and disconnected lines of silicone (seeds) on top of the basal viscous serve as inherited structures since the strong sand cover is locally thinner. We apply syn-rift sediments by filling in the developing rift and transfer zone basins with sand at fixed time steps. Models are run either with sedimentation or without to allow comparison. The first results suggest that the gross structures are similar with or without sedimentation. As seen by Zwaan et al. (2016), dextral oblique extension promotes rift linkage because rift propagation aligns itself perpendicular to the extension direction. This causes the rift segments to grow towards each other and to establish a continuous rift structure. However, the structures within the rift segments show quite different behaviour when sedimentation is applied. The extra sediment loading in the rift basin

  10. Natural analogue study for interaction between alkaline groundwater and bentonite at Mangatarem region in the Philippines

    International Nuclear Information System (INIS)

    Tsukada, Y.; Fujita, K.; Nakabayashi, R.; Sato, T.; Yoneda, T.; Yamakawa, M.; Fujii, N.; Namiki, K.; Kasama, T.; Alexander, R.; Arcilla, C.; Pascua, C.

    2012-01-01

    Document available in extended abstract form only. Alteration of bentonite by alkaline leachate from cement/concrete in geological repositories for TRU radioactive waste is deleterious to bentonite performance as a buffer material. Although there have been many laboratory studies on high pH fluid-bentonite interaction for longer term understanding of the behavior of bentonites as buffer materials, different time scales between laboratory experiments and real disposal conditions impede its proper assessment. Thus, a natural analogue study can play an important role in (a) bridging the timescale gaps between laboratory experiments and real disposal conditions and (b) verifying the modeling studies of bentonite stability. Previous natural analogue studies on the cement-bentonite interaction are relatively few. Therefore, this study focuses on the process of serpentinization in ophiolitic rocks which resemble the process of leaching high pH ground waters from cement materials and report the results of study about alkaline water-bentonite interaction in Mangatarem, Philippines. In Mangatarem, in west central Luzon Island in the northern Philippines, there are bentonite quarries in the Aksitero Formation, which is part of the Zambales Ophiolite. Several alkaline hot springs derived from ongoing serpentinization of the ophiolite can be found in close proximity to the bentonite.Through a site characterization (including a foot survey, a series of boreholes and trench excavation in the Saile quarry in Mangatarem, the interface between the bentonite and the pillow lava of the upper ophiolite was confirmed, and chrysotile, a low temperature type of serpentine, was observed in the fault filling by XRD analysis. In the pillow lava, serpentine was also observed inside the fault that cut across both the bentonite and the pillow lava. From these facts, low temperature high pH fluids appears to have passed through the faults and came into contact with the bentonite. In order to

  11. Indenes and tetralenes analogues attenuates lipopolysaccharide-induced inflammation: An in-vitro and in-vivo study.

    Science.gov (United States)

    Mohanty, Shilpa; Gautam, Yashveer; Maurya, Anil Kumar; Negi, Arvind S; Prakash, Om; Khan, Feroz; Bawankule, Dnyaneshwar Umrao

    2016-02-05

    In an effort to evaluate novel pharmacological activity of 1-chloro-2-formyl indene and tetralene analogues possessing potential antitubercular and antistaphylococcal agents, we explored its anti-inflammatory potential against lipopolysaccharide(LPS)-induced inflammation using in-vitro and in-vivo bioassay. Synthesized analogues significantly inhibited the production and expression of pro-inflammatory cytokines against LPS-induced inflammation in macrophages isolated from mice. Among all the analogues, TAF-5 (1-Chloro-2-formyl-1-tetralene) exhibited most potent anti-inflammatory activity without any cytotoxic effect. We have further evaluated the therapeutic efficacy and safety of TAF-5 in in-vivo system using LPS-induced sepsis, a systemic inflammation model and acute oral toxicity respectively in mice. Oral administration of TAF-5 inhibited the pro-inflammatory cytokines in serum, attenuated the organs injuries and improved host survival in dose dependent manner. Acute oral toxicity study showed TAF-5 is non-toxic at higher dose in mice. These results suggest the suitability of indene and tetralene analogues as new chemical entities for further investigation towards the management of inflammation related diseases. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Phenylpropanoid glycoside analogues: enzymatic synthesis, antioxidant activity and theoretical study of their free radical scavenger mechanism.

    Directory of Open Access Journals (Sweden)

    Agustín López-Munguía

    Full Text Available Phenylpropanoid glycosides (PPGs are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w, several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%-35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B as a biocatalyst with 40%-60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH• method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET. The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols.

  13. Synthesis and antiangiogenic activity study of new hop chalcone Xanthohumol analogues.

    Science.gov (United States)

    Nuti, Elisa; Bassani, Barbara; Camodeca, Caterina; Rosalia, Lea; Cantelmo, AnnaRita; Gallo, Cristina; Baci, Denisa; Bruno, Antonino; Orlandini, Elisabetta; Nencetti, Susanna; Noonan, Douglas M; Albini, Adriana; Rossello, Armando

    2017-09-29

    Angiogenesis induction is a hallmark of cancer. Antiangiogenic properties of Xanthohumol (XN), a naturally occurring prenylated chalcone from hops, have been widely reported. Here we describe the synthesis and study the antiangiogenic activity in vitro of a series of XN derivatives, where different substituents on the B-ring of the chalcone scaffold were inserted. The new XN derivatives inhibited human umbilical-vein endothelial cell (HUVEC) proliferation, adhesion, migration, invasion and their ability to form capillary-like structures in vitro at 10 μM concentration. The preliminary results indicate that the phenolic OH group in R, present in natural XN, is not necessary for having antiangiogenic activity. In fact, the most effective compound from this series, 13, was characterized by a para-methoxy group in R and a fluorine atom in R 2 on B-ring. This study paves the way for future development of synthetic analogues of XN to be used as cancer angiopreventive and chemopreventive agents. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

    Science.gov (United States)

    López-Munguía, Agustín; Hernández-Romero, Yanet; Pedraza-Chaverri, José; Miranda-Molina, Alfonso; Regla, Ignacio; Martínez, Ana; Castillo, Edmundo

    2011-01-01

    Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols. PMID:21674039

  15. Cytotoxicity Study of Cyclopentapeptide Analogues of Marine Natural Product Galaxamide towards Human Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Jignesh Lunagariya

    2017-01-01

    Full Text Available Herein, we report the cytotoxicity of cyclopentapeptide analogues of marine natural product galaxamide towards breast carcinoma cells and the underlying mechanisms. We examined the effect of the novel galaxamide analogues on cancer cell proliferation by MTT assay and also further examined the most active compound for morphological changes using Hoechst33342 staining technique, induction of apoptosis, cell cycle phases, mitochondrial membrane potential (MMP, and reactive oxygen species (ROS generation using flow cytometry in human breast cancer MCF-7 cells in vitro. Galaxamide and its analogues effectively induced toxicity in human hepatocellular carcinoma HepG2, human breast carcinoma MCF-7, human epitheloid cervix carcinoma HeLa, and human breast carcinoma MB-MDA-231 cell lines. Amongst them, compound 3 exhibited excellent toxicity towards MCF-7 cells. This galaxamide analogue significantly induced apoptosis in a dose-dependent manner in MCF-7 cells involves cell cycle arrest in the G1 phase, a reduction of MMP, and a marked increase in generation of ROS. Particularly, compound 3 of galaxamide analogues might be a potential candidate for the treatment of breast cancer.

  16. Natural analogue study of long-term leaching behavior of vitrification glass

    International Nuclear Information System (INIS)

    Arai, Takashi; Yusa, Yasuhisa; Kamei; Gento

    1990-01-01

    In the research on the formation disposal of high level radioactive wastes, the evaluation of the leaching behavior of vitrification glass over ultralong term is one of the important themes. Therefore, the research on the phenomena of quality change in natural environment of volcanic glass, of which the chemical composition resembles well, was carried out (natural analogue study). Among the pyroclastic fall deposit in Fuji and Izu Oshima Volcanoes, the examples of the weathering change of quality of basaltic glass over several hundreds-several thousands years were selected, and on the spot survey, the analysis of groundwater, SEM observation, EPMA and so on were carried out. As the results, the following facts were found. According to the review of the literatures on ancient climate, the atmospheric temperature and precipitation in the past 3000 years were regarded as nearly the same as now. The products from the quality change were similar to the case of laboratory leaching experiment on vitrification glass. The measured ion concentration in groundwater agreed with the calculated values. (K.I.)

  17. Semi-rigid analogues of the calcium antagonist verapamil: A molecular modelling study

    Science.gov (United States)

    Romanelli, Maria Novella; Dei, Silvia; Scapecchi, Serena; Teodori, Elisabetta; Gualtieri, Fulvio; Budriesi, Roberta; Mannhold, Raimund

    1994-04-01

    In this work the rigid-analogue approach has been used to obtain information on the active conformation(s) of the calcium antagonist verapamil. A series of semi-rigid analogues of verapamil were synthesized and their biological activities evaluated on guinea-pig heart and aorta. These molecules were analysed by means of molecular modelling techniques. On the basis of the pharmacological profile and conformational analysis of these compounds, two different models for negative inotropic and negative chronotropic activity are proposed. The two actions seem to be due to conformations of the molecules which differ in the orientation of their phenylethylamino groups.

  18. Biostructural and pharmacological studies of bicyclic analogues of the 3-isoxazolol glutamate receptor agonist ibotenic acid

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Pickering, Darryl S; Greenwood, Jeremy R

    2010-01-01

    We describe an improved synthesis and detailed pharmacological characterization of the conformationally restricted analogue of the naturally occurring nonselective glutamate receptor agonist ibotenic acid (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-7-carboxylic acid (7-HPCA, 5......) at AMPA receptor subtypes. Compound 5 was shown to be a subtype-discriminating agonist at AMPA receptors with higher binding affinity and functional potency at GluA1/2 compared to GluA3/4, unlike the isomeric analogue (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-5-carboxylic acid (5-HPCA, 4...

  19. [Gastric magnetic resonance study (methods, semiotics)].

    Science.gov (United States)

    Stashuk, G A

    2003-01-01

    The paper shows the potentialities of gastric study by magnetic resonance imaging (MRI). The methodic aspects of gastric study have been worked out. The MRI-semiotics of the unchanged and tumor-affected wall of the stomach and techniques in examining patients with gastric cancer of various sites are described. Using the developed procedure, MRI was performed in 199 patients, including 154 patients with gastric pathology and 45 control individuals who had no altered gastric wall. Great emphasis is placed on the role of MRI in the diagnosis of endophytic (diffuse) gastric cancer that is of priority value in its morphological structure. MRI was found to play a role in the diagnosis of the spread of a tumorous process both along the walls of the stomach and to its adjacent anatomic structures.

  20. Gas geochemistry of natural analogues for the studies of geological CO2 sequestration

    International Nuclear Information System (INIS)

    Voltattorni, N.; Sciarra, A.; Caramanna, G.; Cinti, D.; Pizzino, L.; Quattrocchi, F.

    2009-01-01

    Geological sequestration of anthropogenic CO 2 appears to be a promising method for reducing the amount of greenhouse gases released to the atmosphere. Geochemical modelling of the storage capacity for CO 2 in saline aquifers, sandstones and/or carbonates should be based on natural analogues both in situ and in the laboratory. The main focus of this paper has been to study natural gas emissions representing extremely attractive surrogates for the study and prediction of the possible consequences of leakage from geological sequestration sites of anthropogenic CO 2 (i.e., the return to surface, potentially causing localised environmental problems). These include a comparison among three different Italian case histories: (i) the Solfatara crater (Phlegraean Fields caldera, southern Italy) is an ancient Roman spa. The area is characterised by intense and diffuse hydrothermal activity, testified by hot acidic mud pools, thermal springs and a large fumarolic field. Soil gas flux measurements show that the entire area discharges between 1200 and 1500 tons of CO 2 per day; (ii) the Panarea Island (Aeolian Islands, southern Italy) where a huge submarine volcanic-hydrothermal gas burst occurred in November, 2002. The submarine gas emissions chemically modified seawater causing a strong modification of the marine ecosystem. All of the collected gases are CO 2 -dominant (maximum value: 98.43 vol.%); (iii) the Tor Caldara area (Central Italy), located in a peripheral sector of the quiescent Alban Hills volcano, along the faults of the Ardea Basin transfer structure. The area is characterised by huge CO 2 degassing both from water and soil. Although the above mentioned areas do not represent a storage scenario, these sites do provide many opportunities to study near-surface processes and to test monitoring methodologies.

  1. Defining the selectivity of processes along the auxin response chain: a study using auxin analogues

    Czech Academy of Sciences Publication Activity Database

    Simon, Sibu; Kubeš, Martin; Baster, P.; Robert, S.; Dobrev, Petre; Friml, J.; Petrášek, Jan; Zažímalová, Eva

    2013-01-01

    Roč. 200, č. 4 (2013), s. 1034-1048 ISSN 0028-646X R&D Projects: GA ČR(CZ) GAP305/11/0797 Institutional research plan: CEZ:AV0Z50380511 Keywords : auxin analogues * auxin signalling * auxin transport Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.545, year: 2013

  2. Development of electrical analogue model for studying seepage flow under hydraulic structures - case study: Sukkur barrage

    International Nuclear Information System (INIS)

    Gabriel, H.F.; Umar, I.A.; Khan, G.D.

    2003-01-01

    For the solution of groundwater problem many types of models are used, but electrical analogue model is preferred due to its close response with its prototype hydrological system. This model is easy to construct and is reusable. In the model voltage is correlated to groundwater head electric current to flow and capacitance to groundwater storage. The analogy of the model is derived based on Kirchhoffs law and Finite difference form of Laplace equation. The network is consisting of square and rectangular meshes. Scaling factor for voltage and resistors are selected. All the equipment needed for assembling the model are prepared. Terminal strips and their connectivity are checked. Calculated resistors with accurate values after cutting and molding are inserted in the terminal strips and desired section is completed. A network of resistors in X and Z direction is used to represent the aquifer. Two stabilized power supply are used to provide the electrical potential. The worst condition is maintained by supplying the maximum head at upstream and dry condition at downstream. After the development of the model conclusion derived shows that the model are in a position to express the groundwater potential for seepage distribution under the floor with high degree of accuracy. Moreover there is a very good proportion between sample and the actual prototype in existence. The actual model when tested by model show very clear results for the sheet pile in relation to floor length to control seepage or uplift pressure caused. The existence design of Sukkur barrage and its overestimation and underestimation with reference to their sheet pile have been specifically determined. (author)

  3. Interaction of tachykinins with their receptors studied with cyclic analogues of substance P and neurokinin B

    Energy Technology Data Exchange (ETDEWEB)

    Ploux, O.; Lavielle, S.; Chassaing, G.; Julien, S.; Marquet, A.; D' Orleans-Juste, P.; Dion, S.; Regoli, D.; Beaujouan, J.C.; Bergstroem, L.

    1987-11-01

    The activities of two groups of cyclic agonists of substance P (SP) have been studied. The disulfide bridge constraints have been designed on the basis of conformational studies on SP and physalaemin indicating an ..cap alpha..-helical structure for the core of these two tachykinins (group I) and a folding of the C-terminal carboxamide towards the side chains of the glutamines 5 and 6 (group II). Only peptides simulating the ..cap alpha..-helix present substantial potencies. (Cys/sup 3,6/)SP is as active as SP in inhibiting /sup 125/I-labeled Bolton and Hunter SP-specific binding on rat brain synaptosomes and on dog carotid bioassay, two assays specific for the neurokinin 1 receptor. Moreover, (Cys/sup 3,6/)SP is a potent as neurokinin B in inhibiting /sup 125/I-labeled Bolton and Hunter eledoisin-specific binding on rat cortical synaptosomes as well as in stimulating rat portal vein, two tests specific for the neurokinin 3 receptor. Interestingly, in contrast to neurokinin B, (Cys/sup 3,6/)SP is a weak agonist of the neurokinin 2 receptor subtype, as evidenced by its binding potency in inhibiting /sup 3/H-labeled neurokinin A-specific binding on rat duodenum and in inducing the contractions of the rabbit pulmonary artery, a neurokinin 2-type bioassay. To increase the specificity of the cyclic analogue (Cys/sup 3,6/)SP positions 8 and 9 were modified. Collectively, these results suggest that the neurokinin 1 and neurokinin 3 tachykinin receptors may recognize a similar three-dimensional structure of the core of the tachykinins. Different orientations of the common C-terminal tripeptide may be related to the selectivity for the different receptor subtypes.

  4. Systematic study on nuclear resonant scattering

    International Nuclear Information System (INIS)

    Suarez, A.A.; Freitas, M.L.

    1974-01-01

    New resonant scattering effect of thermal neutron capture gamma rays from Ti and Fe on Sb, Cu, Se and Ce target were observed. These results together with those published by other authors are summarized and discussed in terms of a possible systematic search for new resonant scattering effects

  5. Hemifacial spasm. Study by magnetic resonance angiography

    International Nuclear Information System (INIS)

    Bittar, Miriam Salvadori; Staut, Claudio Cesar Vilela; Barbosa, Egberto Reis; Bacheschi, Luiz Alberto; Magalhaes, Alvaro Cebrian de Almeida

    1995-01-01

    Nine patients with idiopathic hemifacial spasm were evaluated with cranial magnetic resonance imaging and angiography. Alterations of the posterior fossa vasculature, possibly related to the facial nerve irritation, were found in 8 patients (88%). Magnetic resonance angiography is a noninvasive procedure and appears to be a sensitive method to evaluate hemifacial spasm etiology. (author)

  6. Novel Penicillin Analogues as Potential Antimicrobial Agents; Design, Synthesis and Docking Studies.

    Directory of Open Access Journals (Sweden)

    Zaman Ashraf

    Full Text Available A number of penicillin derivatives (4a-h were synthesized by the condensation of 6-amino penicillinic acid (6-APA with non-steroidal anti-inflammatory drugs as antimicrobial agents. In silico docking study of these analogues was performed against Penicillin Binding Protein (PDBID 1CEF using AutoDock Tools 1.5.6 in order to investigate the antimicrobial data on structural basis. Penicillin binding proteins function as either transpeptidases or carboxypeptidases and in few cases demonstrate transglycosylase activity in bacteria. The excellent antibacterial potential was depicted by compounds 4c and 4e against Escherichia coli, Staphylococcus epidermidus and Staphylococcus aureus compared to the standard amoxicillin. The most potent penicillin derivative 4e exhibited same activity as standard amoxicillin against S. aureus. In the enzyme inhibitory assay the compound 4e inhibited E. coli MurC with an IC50 value of 12.5 μM. The docking scores of these compounds 4c and 4e also verified their greater antibacterial potential. The results verified the importance of side chain functionalities along with the presence of central penam nucleus. The binding affinities calculated from docking results expressed in the form of binding energies ranges from -7.8 to -9.2kcal/mol. The carboxylic group of penam nucleus in all these compounds is responsible for strong binding with receptor protein with the bond length ranges from 3.4 to 4.4 Ǻ. The results of present work ratify that derivatives 4c and 4e may serve as a structural template for the design and development of potent antimicrobial agents.

  7. Contemporaneous ring fault activity and surface deformation at subsiding calderas studied using analogue experiments

    Science.gov (United States)

    Liu, Yuan-Kai; Ruch, Joël; Vasyura-Bathke, Hannes; Jónsson, Sigurjón

    2017-04-01

    Ground deformation analyses of several subsiding calderas have shown complex and overlapping deformation signals, with a broad deflation signal that affects the entire volcanic edifice and localized subsidence focused within the caldera. However, the relation between deep processes at subsiding calderas, including magmatic sources and faulting, and the observed surface deformation is still debated. Several recent examples of subsiding calderas in the Galápagos archipelago and at the Axial seamount in the Pacific Ocean indicate that ring fault activity plays an important role not only during caldera collapse, but also during initial stages of caldera subsidence. Nevertheless, ring fault activity has rarely been integrated into numerical models of subsiding calderas. Here we report on sandbox analogue experiments that we use to study the processes involved from an initial subsidence to a later collapse of calderas. The apparatus is composed of a subsiding half piston section connected to the bottom of a glass box and driven by a motor to control its subsidence. We analyze at the same time during the subsidence the 3D displacement at the model surface with a laser scanner and the 2D ring fault evolution on the side of the model (cross-section) with a side-view digital camera. We further use PIVLab, a time-resolved digital image correlation software tool, to extract strain and velocity fields at both the surface and in cross-section. This setup allows to track processes acting at depth and assess their relative importance as the collapse evolves. We further compare our results with the examples observed in nature as well as with numerical models that integrate ring faults.

  8. Synthetic Rock Analogue for Permeability Studies of Rock Salt with Mudstone

    Directory of Open Access Journals (Sweden)

    Hongwu Yin

    2017-09-01

    Full Text Available Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock salt is to develop a synthetic analogue to use as a permeability model. To address the permeability of a mudstone/salt layered and mixed rock mass in Jintan, Jiangsu Province, synthetic mixed and layered specimens using the mudstone and the salt were fabricated for permeability testing. Because of the gas “slippage effect”, test results are corrected by the Klinkenberg method, and the permeability of specimens is obtained by regression fitting. The results show that the permeability of synthetic pure rock salt is 6.9 × 10−20 m2, and its porosity is 3.8%. The permeability of synthetic mudstone rock is 2.97 × 10−18 m2, with a porosity 17.8%. These results are close to those obtained from intact natural specimens. We also find that with the same mudstone content, the permeability of mixed specimens is about 40% higher than for the layered specimens, and with an increase in the mudstone content, the Klinkenberg permeability increases for both types of specimens. The permeability and mudstone content have a strong exponential relationship. When the mudstone content is below 40%, the permeability increases only slightly with mudstone content, whereas above this threshold, the permeability increases rapidly with mudstone content. The results of the study are of use in the assessment of the tightness of natural gas storage facilities in mudstone-rich rock salt formations in China.

  9. Effects of sphingosine and sphingosine analogues on the free radical production by stimulated neutrophils: ESR and chemiluminescence studies

    Directory of Open Access Journals (Sweden)

    A. Mouithys-Mickalad

    1997-01-01

    Full Text Available Sphingolipids inhibit the activation of the neutrophil (PMN NADPH oxidase by protein kinase C pathway. By electron spin resonance spectroscopy (ESR and chemiluminescence (CL, we studied the effects of sphingosine (SPN and ceramide analogues on phorbol 12-myristate 13-acetate (PMA, 5 × 10-7M stimulated PMN (6 × 106 cells. By ESR with spin trapping (100 mM DMPO: 5,5-dimethyl-1-pyrroline-Noxide, we showed that SPN (5 to 8 × 10-6M, C2-ceramide (N-acetyl SPN and C6-ceramide (N-hexanoyl SPN at the final concentration of 2 × 10-5 and 2 × 10-4M inhibit the production of free radicals by stimulated PMN. The ESR spectrum of stimulated PMN was that of DMPO-superoxide anion spin adduct. Inhibition by 5 × 10-6M SPN was equivalent to that of 30 U/ml SOD. SPN (5 to 8 × 10-6M has no effect on in vitro systems generating superoxide anion (xanthine 50 mM/xanthine oxidase 110 mU/ml or hydroxyl radical (Fenton reaction: 88 mM H2O2, 0.01 mM Fe2+ and 0.01 mM EDTA. SPN and N-acetyl SPN also inhibited the CL of PMA stimulated PMN in a dose dependent manner (from 2 × 10-6 to 10-5M, but N-hexanoyl SPN was less active (from 2 × 10-5 to 2 × 10-4M. These effects were compared with those of known PMN inhibitors, superoxide dismutase, catalase and azide. SPN was a better inhibitor compared with these agents. The complete inhibition by SPN of ESR signal and CL of stimulated PMN confirms that this compound or one of its metabolites act at the level of NADPH-oxidase, the key enzyme responsible for production of oxygen-derived free radicals.

  10. Study of spin resonances in the accelerators with snakes

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1989-01-01

    Spin resonances in the circular accelerators with snakes are studied to understand the nature of snake resonances. We analyze the effect of snake configuration, and the snake superperiod on the resonance. Defining the critical resonance strength ε c as the maximum tolerable resonance strength without losing the beam polarization after passing through the resonance, we found that ε c is a sensitive function of the snake configuration, the snake superperiod at the first order snake resonance, the higher order snake resonance conditions and the spin matching condition. Under properly designed snake configuration, the critical resonance strength ε c is found to vary linearly with N S as left-angle ε c right-angle=(1/π)sin -1 (cos πν z | 1/2 )N S , where ν| z and N S are the betatron tune and the number of snakes respectively. We also study the effect of overlapping intrinsic and imperfection resonances. The imperfection resonance should be corrected to a magnitude of insignificance (e.g., ε≤0.1 for two snakes case) to maintain proper polarization

  11. Study of spin resonances in the accelerators with snakes

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1988-01-01

    Spin resonances in the circular accelerators with snakes are studied to understand the nature of snake resonances. We analyze the effect of snake configuration, and the snake superperiod on the resonance. Defining the critical resonance strength ε/sub c/ as the maximum tolerable resonance strength without losing the beam polarization after passing through the resonance, we found that ε/sub c/ is a sensitive function of the snake configuration, the snake superperiod at the first order snake resonance, the higher order snake resonance conditions and the spin matching condition. Under properly designed snake configuration, the critical resonance strength ε/sub c/ is found to vary linearly with N/sub S/ as = (1/π)sin/sup /minus/1/(cos πν/sub z//sup /1/2//)N/sub S/, where ν/sub z/ and N/sub S/ are the betatron tune and the number of snakes respectively. We also study the effect of overlapping intrinsic and imperfection resonances. The imperfection resonance should be corrected to a magnitude of insignificance (e.g., ε≤0.1 for two snakes case) to maintain proper polarization. 23 refs., 25 figs

  12. 18F-Fluoroacetate - A longer lived acetate analogue for oncology studies with PET

    International Nuclear Information System (INIS)

    Khezami, Arbia; Ulrich, Eva; Matthies, Alexander; Ezziddin, Samer; Bender, Hans; Biersack, Hans-Juergen; Guhlke, Stefan

    2004-01-01

    Full text: Aim: 18 F-Fluoroacetate ( 18 Fac) can be considered as a fluoro analogue of 11C-acetate. Thus it may also be useful for oncologic PET studies. Like acetate, fluoroacetate is a substrate of the citric acid cycle, however in contrast to acetate it is an inhibitor of the enzyme Aconitase and thus no further metabolization of fluoroacetate occurs. The aim of this study was the in-vivo evaluation of this tracer with respect to tumor uptake in prostate carcinoma bearing nude mice as well as biodistribution and kinetics. Methods: The synthesis of 18 F-fluoroacetate was performed by using benzyl bromoacetate as precursor. The fluorinated ester was separated by HPLC, followed by basic hydrolysis and purification by use of anion exchange SEP-Pak chromatography. The formulation was performed by rinsing with water and subsequent elution of 18 Fac with sterile PBS-buffer and final sterile filtration. For the biodistribution studies, 3 groups of nude mice were inoculated with the prostate carcinoma cell lines PC3, DU-145 and LnCAP. After tumor growth, the animals were injected with 37-370 KBq of 18 Fac and bio-distributions performed at different times post injection. Results: The rcy of the substitution step was usually > 90%. The HPLC separation of the fluorinated ester and the precursor was performed on a C-18 column. The high UV-absorbance of the benzyl ester allows the determination of the specific activity of the tracer which was always lower than detection limits. Further, the injected animals did not show any signs of intoxication. The biodistribution studies revealed a primary biliary excretion. Regardless which cell line was used, accumulation of 18 Fac in tumor sites was well visible by PET-CT. Tumor to blood ratios increased with time. Conclusion: The synthesis of 18 Fac is straight forward and high radiochemical yields are typically obtained. The high specific activity of 18 F-fluoride allows injections of 18 Fac far below toxic concentrations. In nude

  13. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  14. Integration of natural analogue studies within a national confidence-building programme

    Energy Technology Data Exchange (ETDEWEB)

    Tsuboya, T. [Radioactive Waste Management Funding and Research Centre (RWMC), No. 15 Mori Bldg., 2-8-10 Toranomon, Minato-ku, Tokyo 105-0001 (Japan)]. E-mail: tsuboya@rwmc.or.jp; McKinley, I.G. [National Cooperative for the Disposal of Radioactive Waste (Nagra), Hardstrasse 73, 5430 Wettingen (Switzerland)]. E-mail: ian.mackinley@nagra.ch

    2004-07-01

    It is now commonly recognised that public acceptance is one of the key factors influencing the feasibility of nuclear waste repositories - or indeed, any major industrial or technical developments. The general antipathy against anything 'radioactive' is further compounded by the difficulty of developing a simple, transparent safety case for a facility deep underground that clearly shows that there is no health risk at any time in the future. Natural analogues have great potential as communication tools within such a safety case. The analogue programme must, however, be embedded in an integrated communication strategy that identifies the key concerns of different critical groups and identifies the most appropriate way to address them. Some of the important characteristics of such a strategy include: demonstration of high levels of competence, openness and honesty of involved organisations (both regulators and implementers); ensuring consistency of policy, procedures and utilisation of technical arguments; recognition of the importance of reacting to feedback from all involved parties. (author)

  15. Computational study of radicals derived from hydroxyurea and its methylated analogues.

    OpenAIRE

    Vinkovic Vrcek, Ivana; Sakic, Davor; Vrcek, Valerije; Zipse, Hendrik; Birus, Mladen

    2012-01-01

    Structural and electronic properties and chemical fate of free radicals generated from hydroxyurea (HU) and its methylated analogues N-methylhydroxyurea (NMHU) and O-methylhydroxyurea (OMHU) are of utmost importance for their biological and pharmacological effects. In this work the cis/trans conformational processes, tautomerizations, and intramolecular hydrogen and methyl migrations in hydroxyurea-derived radicals have been considered. Potential energy profiles for these reactions have been ...

  16. Protolytic properties of polyamine wasp toxin analogues studied by 13C NMR spectroscopy

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Piazzi, Lorna; Olsen, Christian A

    2006-01-01

    Acid-base properties of the natural polyamine wasp toxin PhTX-433 (1) and seven synthetic analogues [PhTX-343 (2), PhTX-334 (3), PhTX-443 (4), PhTX-434 (5), PhTX-344 (6), PhTX-444 (7), and PhTX-333 (8)], each having four protolytic sites, were characterized by 13C NMR spectroscopy. Nonlinear, mul...

  17. Studies of Titan s aerosols analogues produced by radio frequency dischare

    Science.gov (United States)

    Szopa, C.; Cernogora, G.; Boufendi, L.; Correia, J. J.; Ausset, P.

    Titan s organic aerosols play a significant role in the physico-chemical mechanisms of the Titan s atmosphere and heat transfer on the Titan s surface. As a matter of fact, the increase of surface temperature due to the methane green house effect is reduced by the solar flux absorption due to the haze layers of Titan s atmosphere. The presented laboratory experiment is developed to produce analogues of Titan s aerosols. The photo chemistry of the N2-CH4 mixture representative of Titan s atmosphere is simulated by a low pressure Radio Frequency plasma discharge. In this plasma, solid particles are produced in the gas. They are maintained in levitation by electrostatic force and they grow in the gas, away from the reactor walls. This phenomena was first observed in Argon Silane RF plasmas used for micro-electronic component production. The aim of this paper is to present new results obtained in N2-CH4 RF plasma. In this plasma the gas mixture is injected continuously and pumped with a mechanical vacuum pump, in order to maintain the plasma in low pressure conditions. In the studied pressure range, the plasma is not in thermal equilibrium, i.e neutral gas remains at room temperature, when electrons have a mean energy of about 1eV. Solid particles produced into the plasma are ejected when their weight is too high to be balanced by electrostatic force. The collected particles are observed and analysed. We observe that their colour changes from clear brown to dark brown following the plasma conditions. In order to change the composition of solid particles, total pressure is adjusted from 0.2 mbar to 3 mbar, and the CH4 percentage up to 10%. Solid particles are also observed by Scanning Electron Microscopy (SEM). They present a regular spherical shape and a size dispersion with a mean diameter of 0.8 mm. Their composition is investigated by pyrolysis-Gas-Chromatography-Mass Spectrometry (pyr-GC-MS) and elementary analysis. In order to correlate the solid particles

  18. Study of Geological Analogues for Understanding the Radar Sounder Response of the RIME Targets

    Science.gov (United States)

    Thakur, S.; Bruzzone, L.

    2017-12-01

    Radar for Icy Moon Exploration (RIME), the radar sounder onboard the Jupiter Icy Moons Explorer (JUICE), is aimed at characterizing the ice shells of the Jovian moons - Ganymede, Europa and Callisto. RIME is optimized to operate at 9 MHz central frequency with bandwidth of 1 MHz and 2.7 MHz to achieve a penetration depth up to 9 km through ice. We have developed an approach to the definition of a database of simulated RIME radargrams by leveraging the data available from airborne and orbital radar sounder acquisitions over geological analogues of the expected icy moon features. These simulated radargrams are obtained by merging real radar sounder data with models of the subsurface of the Jupiter icy moons. They will be useful for geological interpretation of the RIME radargrams and for better predicting the performance of RIME. The database will also be useful in developing pre-processing and automatic feature extraction algorithms to support data analysis during the mission phase of RIME. Prior to the JUICE mission exploring the Jovian satellites with RIME, there exist radar sounders such as SHARAD (onboard MRO) and MARSIS (onboard MEX) probing Mars, the LRS (onboard SELENE) probing the Moon, and many airborne sounders probing the polar regions of Earth. Analogues have been identified in these places based on similarity in geo-morphological expression. Moreover, other analogues have been identified on the Earth for possible dedicated acquisition campaigns before the RIME operations. By assuming that the subsurface structure of the RIME targets is approximately represented in the analogue radargrams, the difference in composition is accounted for by imposing different dielectric and subsurface attenuation models. The RIME radargrams are simulated from the analogue radargrams using the radar equation and the RIME processing chain and accounting for different possible scenarios in terms of subsurface structure, dielectric properties and instrument parameters. For

  19. Transferred nuclear Overhauser effect analyses of membrane-bound enkephalin analogues by sup 1 H nuclear magnetic resonance: Correlation between activities and membrane-bound conformations

    Energy Technology Data Exchange (ETDEWEB)

    Milon, Alain; Miyazawa, Tatsuo; Higashijima, Tsutomu (Univ. of Tokyo (Japan))

    1990-01-09

    Leu-enkephalin, (D-Ala{sup 2})Leu-enkephalin, and (D-Ala{sup 2})Leu-enkephalinamide (agonists) and (L-Ala{sup 2})Leu-enkephalin (inactive analogue) bind to lipid bilayer consisting of phosphatidylcholine and phosphatidylserine. The conformations that these compounds assume, once bound to perdeuterated phospholipid bilayer, have been shown to be unique, as shown by the transferred nuclear Overhauser effect (TRNOE) of {sup 1}H NMR spectroscopy. In addition, their location in the bilayer was analyzed by TRNOE in the presence of spin-labeled phospholipids. These analyses showed a clear relationship between the activity and the peptide-membrane interaction. The three active peptides, when bound to membranes, adopt the same conformation, characterized by a type II{prime} {beta}-turn around Gly{sup 3}-Phe and a {gamma}-turn around Gly{sup 2} (or D-Ala{sup 2}). The inactive analogue, (L-Ala{sup 2})Leu-enkephalin, displayed a completely different TRNOE pattern corresponding to a different conformation in the membrane-bound state. The tyrosine residue of the active compounds is not inserted into the interior of membrane, but it is inserted into the bilayer for the L-Ala{sup 2} analogue. According to these results, (L-Ala{sup 2})Leu-enkephalin may be explained to be inactive because the mode of binding to the membranes is different from that of active compounds.

  20. Ring-fault activity at subsiding calderas studied from analogue experiments and numerical modeling

    Science.gov (United States)

    Liu, Y. K.; Ruch, J.; Vasyura-Bathke, H.; Jonsson, S.

    2017-12-01

    Several subsiding calderas, such as the ones in the Galápagos archipelago and the Axial seamount in the Pacific Ocean have shown a complex but similar ground deformation pattern, composed of a broad deflation signal affecting the entire volcanic edifice and of a localized subsidence signal focused within the caldera. However, it is still debated how deep processes at subsiding calderas, including magmatic pressure changes, source locations and ring-faulting, relate to this observed surface deformation pattern. We combine analogue sandbox experiments with numerical modeling to study processes involved from initial subsidence to later collapse of calderas. The sandbox apparatus is composed of a motor driven subsiding half-piston connected to the bottom of a glass box. During the experiments the observation is done by five digital cameras photographing from various perspectives. We use Photoscan, a photogrammetry software and PIVLab, a time-resolved digital image correlation tool, to retrieve time-series of digital elevation models and velocity fields from acquired photographs. This setup allows tracking the processes acting both at depth and at the surface, and to assess their relative importance as the subsidence evolves to a collapse. We also use the Boundary Element Method to build a numerical model of the experiment setup, which comprises contracting sill-like source in interaction with a ring-fault in elastic half-space. We then compare our results from these two approaches with the examples observed in nature. Our preliminary experimental and numerical results show that at the initial stage of magmatic withdrawal, when the ring-fault is not yet well formed, broad and smooth deflation dominates at the surface. As the withdrawal increases, narrower subsidence bowl develops accompanied by the upward propagation of the ring-faulting. This indicates that the broad deflation, affecting the entire volcano edifice, is primarily driven by the contraction of the

  1. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....

  2. Nucleotide Analogue-Related Proximal Renal Tubular Dysfunction during Long-Term Treatment of Chronic Hepatitis B: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Abhasnee Sobhonslidsuk

    2016-01-01

    Full Text Available Background. There have been few reports of nucleotide analogue-related renal tubular dysfunction (RTD in CHB patients. We assessed the prevalence and presentation of nucleotide analogue-related proximal RTD. Methods. A cross-sectional study was performed in CHB patients taking nucleotide analogues. Inclusion criteria were patients who were on adefovir or tenofovir as mono- or add-on therapy with lamivudine (LAM >1 year. Serum and urine were collected. Fractional excretion of phosphate (FEPO4, uric acid (FEUA, and potassium was calculated. Renal losses were defined based on the criteria: protein (24-hour urine protein >150 mg, glucose (glycosuria with normoglycemia, phosphate (FEPO4 >18%, uric acid (FEUA >15%, potassium (renal potassium losses with hypokalemia, and bicarbonate (normal gap acidosis. Subclinical and overt proximal RTD were defined when 2 and ≥3 criteria presented. Results. Ninety-two patients were enrolled. The mean duration of nucleotide analogue taking was 55.1±29.6 months. Proximal RTD was found in 24 (26.1% patients (subclinical 15 (16.3% and overt 9 (9.8%. The severity of RTD was associated with the duration of nucleotide analogue (P=0.01. Conclusions. The prevalence of proximal RTD in CHB patients taking nucleotide analogues was 26%. The severity of RTD was associated with the treatment duration. Comprehensive testing is necessary for early detecting nucleotide analogue-related nephrotoxicity.

  3. Eigenvalue study of a chaotic resonator

    Energy Technology Data Exchange (ETDEWEB)

    Banova, Todorka [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder (TEMF), Schlossgartenstrasse 8, D-64289 Darmstadt (Germany); Technische Universitaet Darmstadt, Graduate School of Computational Engineering, Dolivostrasse 15, D-64293 Darmstadt (Germany); Ackermann, Wolfgang; Weiland, Thomas [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder (TEMF), Schlossgartenstrasse 8, D-64289 Darmstadt (Germany)

    2013-07-01

    The field of quantum chaos comprises the study of the manifestations of classical chaos in the properties of the corresponding quantum systems. Within this work, we compute the eigenfrequencies that are needed for the level spacing analysis of a microwave resonator with chaotic characteristics. The major challenges posed by our work are: first, the ability of the approaches to tackle the large scale eigenvalue problem and second, the capability to extract many, i.e. order of thousands, eigenfrequencies for the considered cavity. The first proposed approach for an accurate eigenfrequency extraction takes into consideration the evaluated electric field computations in time domain of a superconducting cavity and by means of signal-processing techniques extracts the eigenfrequencies. The second approach is based on the finite element method with curvilinear elements, which transforms the continuous eigenvalue problem to a discrete generalized eigenvalue problem. Afterwards, the Lanczos algorithm is used for the solution of the generalized eigenvalue problem. In the poster, a summary of the applied algorithms, as well as, critical implementation details together with the simulation results are provided.

  4. Nuclear magnetic resonance studies of metabolic regulation

    International Nuclear Information System (INIS)

    Sillerud, L.O.; Han, C.H.; Whaley, T.W.

    1983-01-01

    Nuclear magnetic resonance (NMR) techniques for the detection of the metabolic transformations of biological compounds labeled with stable isotopes, particularly carbon-13 have been explored. We have studied adipose tissue in the intact rat, the exteriorized epididymal fat pad, and the isolated adipocyte. Triacylglycerol metabolism in adipose tissue is regulated by lipogenic factors (insulin, corticosterone, thyroxine, and growth hormone) and lipolytic factors (glucagon and catecholamines). The synthesis of triglyceride from 5.5 mM glucose was stimulated by about 4-fold by 10 nM insulin. Triglyceride synthesis from glucose in the presence of insulin occurred at a rate of 330 nmol/hr/10 6 cells. Since the NMR signals from free and esterified fatty acids and glycerol are distinct, we could directly measure the rate of hormone-stimulated lipolysis. Epinephrine (10 μM) gave a lipolytic rate of 0.30 μmol/hr/10 6 cells as monitored by free-glycerol appearance in the medium. 13 C NMR provides a superior method for the measurement of triglyceride metabolism since it directly measures the changes in the substrates and products in situ

  5. Ferromagnetic resonance study of Fe50Ag50 granular film

    International Nuclear Information System (INIS)

    Sarmiento, G.; Fdez-Gubieda, M.L.; Siruguri, V.; Lezama, L.; Orue, I.

    2007-01-01

    Fe 50 Ag 50 granular film, produced by the pulsed laser deposition technique, has been studied using ferromagnetic resonance (FMR) at temperatures ranging from 4 to 300K. Three different resonance modes are well observed in the whole temperature range. We have also studied the angular evolution of the resonance peaks at three different temperatures T=150, 250, 300K. The thermal and the angular evolution of the three resonance fields has been interpreted on the basis of the existence of different magnetic coupling between the Fe nanoparticles and a weakly magnetized interface

  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. 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

  8. Simulation study of resonant reflector for S-band BWO

    International Nuclear Information System (INIS)

    Choyal, Y; Parmar, Nidhi; Saini, Ajay Kumar; Chhotray, S K; Bhat, K S; Kumar, Lalit

    2012-01-01

    This paper presents the result of simulation studies of resonant reflector used for reflection of backward wave in relativistic BWO. The resonant reflector is modelled and analyzed by CST MWS for TM 01 . A TM 01 mode is fed at the output end of the BWO and signal is observed at the cathode end. Results show that 90 percent of the backward TM 01 wave is get reflected back by the locked TM 02 mode in the resonant reflector.

  9. Study of giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    The electrodisintegration cross section for 181 Ta, 208 Pb and 209 Bi was measured by counting the emitted neutrons, with incident electrons in the energy range 8-22 MeV. The data was analysed using the virtual photon method, in order to obtain a multipole decomposition and the intensities of Magnetic Dipole and Electric Quadrupole, isoscalar and isovector, in the Giant Resonance. The results obtained for the isovector Giant Quadrupole Resonance are compared with the measured photodisintegration cross section, using data from Saclay and Livermore. This comparision indicates that the photodisintegration data can be well explained assuming an isovector E2 Resonance located between 120 and 130 A -1/3 MeV, with an intensity of one isovector E2 sum. (author) [pt

  10. Resonant Auger studies of metallic systems

    International Nuclear Information System (INIS)

    Coulthard, I.; Antel, W. J. Jr.; Frigo, S. P.; Freeland, J. W.; Moore, J.; Calaway, W. S.; Pellin, M. J.; Mendelsohn, M.; Sham, T. K.; Naftel, S. J.

    2000-01-01

    Results of resonant Auger spectroscopy experimental are presented for Cu, Co, and oxidized Al. Sublifetime narrowing of Auger spectra and generation of sublifetime narrowed absorption spectra constructed from Auger yield measurements were observed. Resonant Auger yields are used to identify three chemical states of oxidized Al. Partial absorption yield spectra were derived giving detailed electronic information and thickness information for the various chemical states of the bulk metal, the passivating aluminum oxide layer, and the metal-oxide interface region. In addition, the total absorption yield spectrum for the oxidized Al sample was constructed from the partial yield data, supporting the consistency of our method. (c) 2000 American Vacuum Society

  11. Study of giant resonances with pions

    International Nuclear Information System (INIS)

    Baer, H.W.

    1984-01-01

    Recent results on giant resonances obtained with pion-inelastic scattering and with single- and double-charge-exchange scattering are reviewed. The states discussed are isobaric analog states, double-isobaric analog states, and isovector L = 0, 1, and 2 collective states. 36 references

  12. Theoretical study of the electron paramagnetic resonance ...

    Indian Academy of Sciences (India)

    Abstract. The electron paramagnetic resonance (EPR) parameters (the g factors, hy- perfine structure constants and the superhyperfine parameters) for the tetragonal Ir2+ centre in NaCl are theoretically investigated from the perturbation formulas of these parameters for a 5d7 ion in tetragonally elongated octahedra.

  13. Theoretical study of the electron paramagnetic resonance ...

    Indian Academy of Sciences (India)

    conveniently investigated by means of electron paramagnetic resonance (EPR). In ... ion Ir2+ can experience the Jahn–Teller effect by means of vibration interaction, ... Similarly, k. (and k ) are the orbital reduction factors arising from the anisotropic interactions of the orbital angular momentum operator. From the cluster ...

  14. Resonance raman studies of phenylcyclopropane radical cations

    NARCIS (Netherlands)

    Godbout, J.T.; Zuilhof, H.; Heim, G.; Gould, I.R.; Goodman, J.L.; Dinnocenzo, J.P.; Myers Kelley, A.

    2000-01-01

    Resonance Raman spectra of the radical cations of phenylcyclopropane and trans-1-phenyl-2-methylcyclopropane are reported. A near-UV pump pulse excites a photosensitizer which oxidizes the species of interest, and a visible probe pulse delayed by 35 ns obtains the spectrum of the radical ion. The

  15. Resonance Raman study of benzyl radical

    DEFF Research Database (Denmark)

    Langkilde, F.W.; Bajdor, K.; Wilbrandt, R.

    1992-01-01

    symmetric a1 modes. The remaining observed bands are tentatively assigned to fundamental modes of b1, a2, and b2 symmetry, and to overtones and combinations. The resonance Raman spectra are found to be quite different from previous fluorescence spectra of benzyl, and the origins of these differences...

  16. A Study on Measurement Variations in Resonant Characteristics of Electrostatically Actuated MEMS Resonators

    Directory of Open Access Journals (Sweden)

    Faisal Iqbal

    2018-04-01

    Full Text Available Microelectromechanical systems (MEMS resonators require fast, accurate, and cost-effective testing for mass production. Among the different test methods, frequency domain analysis is one of the easiest and fastest. This paper presents the measurement uncertainties in electrostatically actuated MEMS resonators, using frequency domain analysis. The influence of the applied driving force was studied to evaluate the measurement variations in resonant characteristics, such as the natural frequency and the quality factor of the resonator. To quantify the measurement results, measurement system analysis (MSA was performed using the analysis of variance (ANOVA method. The results demonstrate that the resonant frequency ( f r is mostly affected by systematic error. However, the quality (Q factor strongly depends on the applied driving force. To reduce the measurement variations in Q factor, experiments were carried out to study the influence of DC and/or AC driving voltages on the resonator. The results reveal that measurement uncertainties in the quality factor were high for a small electrostatic force.

  17. Resonance magnetic x-ray scattering study of erbium

    DEFF Research Database (Denmark)

    Sanyal, M.K.; Gibbs, D.; Bohr, J.

    1994-01-01

    The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...

  18. Dissolution studies of natural analogues spent fuel and U(VI)-Silicon phases of and oxidative alteration process

    International Nuclear Information System (INIS)

    Perez Morales, I.

    2000-01-01

    In order to understand the long-term behavior of the nuclear spent fuel in geological repository conditions, we have performed dissolution studies with natural analogues to UO 2 as well as with solid phases representatives of the oxidative alteration pathway of uranium dioxide, as observed in both natural environment and laboratory studies. In all cases, we have studied the influence of the bicarbonate concentration in the dissolution process, as a first approximation to the groundwater composition of a granitic environment, where carbonate is one of the most important complexing agents. As a natural analogue to the nuclear spent fuel some uraninite samples from the Oklo are deposit in Gabon, where chain fission reactions took place 2000 millions years ago, as well as a pitchblende sample from the mine Fe ore deposit, in Salamanca (spain) have been studied. The studies have been performed at 25 and 60 deg C and 60 deg C, and they have focussed on the determination of both the thermodynamic and the kinetic properties of the different samples studied, using batch and continuous experimental methodologies, respectively. (Author)

  19. An analogue study of the initial carryover effects of meditation, hypnosis, and relaxation using native college students.

    Science.gov (United States)

    Colby, F

    1991-06-01

    An analogue study involving two experiments was conducted to test the initial carryover effects of hypnosis, meditation, and relaxation upon self-reports of awareness. In the first experiment, concentrative meditators reported fewer nonsensorial events than controls. In the second experiment, concentrative meditators again reported fewer nonsensorial events, but covariate analysis and pretest/posttest comparisons revealed that it was the controls who had changed, increasing their nonsensorial reports. In addition, the relaxation group increased its reports of somatic awareness. Results were discussed in terms of the effects of performance demands and the possibility that meditation and hypnosis might be able to disinhibit awareness processes otherwise inhibited by normal daily routines.

  20. Contribution to the study of electron paramagnetic resonance and relaxation

    International Nuclear Information System (INIS)

    Theobald, Jean-Gerard

    1962-01-01

    This research thesis reports an experimental work which comprises the development of a very practical and very sensitive electron paramagnetic resonance spectrometer, and the use of this equipment for the study of irradiated substances and carbons. By studying electronic resonance signals by fast modulation of the magnetic field, the author studied phenomena of quick passage in electronic resonance, and showed that the study of these phenomena requires observation systems with a particularly large bandwidth. He reports the measurement of the line width of packs of spins of inhomogeneous lines by two different methods [fr

  1. Dielectric studies of fluids with reentrant resonators

    International Nuclear Information System (INIS)

    Goodwin, A.R.H.; Moldover, M.R.

    1993-01-01

    The authors have used a reentrant radio-frequency (rf) cavity as a resonator operating near 375 MHz to measure changes in the dielectric constant of fluids within it. The utility of these measurements was demonstrated by determining the dipole moment of 1,1,1,2,3,3-hexafluoropropane, a candidate replacement refrigerant (denoted R236ea) and by detecting the phase boundaries in the mixture [(1-x)C 2 H 6 + xCO 2 ], for the mole fraction x = 0.492. The densities of the coexisting phases of the mixture were determined using the Clausius-Mossotti relation which has errors on the order of 0.5% in this application. To test the accuracy of the present techniques, the rf resonator was calibrated with helium and then used to redetermine the molar polarizability A e of argon. The results were in excellent agreement with published values. The design of the reentrant resonator makes it suitable for use with corrosive fluids at temperature up to 400 degrees C

  2. RESONANCE

    Indian Academy of Sciences (India)

    maceutical, paper, food, dyes, petrochemi- cals, pigments, etc., to identify molecules, to monitor reaction products and so on. One of the most spectacular contributions of NMR has been in the development of magnetic resonance imaging (MRI), a method that has today revolutionized diagnosis and treatment of diseases in ...

  3. A Computational Study of Structure and Reactivity of N-Substitued-4-Piperidones Curcumin Analogues and Their Radical Anions

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes

    2016-12-01

    Full Text Available In this work, a computational study of a series of N-substitued-4-piperidones curcumin analogues is presented. The molecular structure of the neutral molecules and their radical anions, as well as their reactivity, are investigated. N-substituents include methyl and benzyl groups, while substituents on the aromatic rings cover electron-donor and electron-acceptor groups. Substitutions at the nitrogen atom do not significantly affect the geometry and frontier molecular orbitals (FMO energies of these molecules. On the other hand, substituents on the aromatic rings modify the distribution of FMO. In addition, they influence the capability of these molecules to attach an additional electron, which was studied through adiabatic (AEA and vertical electron affinities (VEA, as well as vertical detachment energy (VDE. To study electrophilic properties of these structures, local reactivity indices, such as Fukui (f+ and Parr (P+ functions, were calculated, and show the influence of the aromatic rings substituents on the reactivity of α,β-unsaturated ketones towards nucleophilic attack. This study has potential implications for the design of curcumin analogues based on a 4-piperidone core with desired reactivity.

  4. A {mu}SR study of the magnetism in Prussian Blue analogue photomagnets

    Energy Technology Data Exchange (ETDEWEB)

    Salman, Z. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)]. E-mail: zaher@triumf.ca; Parolin, T.J. [Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Chow, K.H. [Department of Physics, University of Alberta, Edmonton, AB, T6G 2J1 (Canada); Keeler, T.A. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Miller, R.I. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Wang, D. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Chakhalian, J. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, Stuttgart D-70569 (Germany); MacFarlane, W.A. [Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

    2006-03-31

    In this work we present longitudinal field {mu}SR results in the molecular magnetic Co-Fe Prussian Blue analogue Rb{sub 1-2x}Co{sub 1+x}[Fe(CN){sub 6}].zH{sub 2}O, with x{approx}0.17 which exhibits light induced magnetic ordering. We were unable to observe the effect of light with {mu}SR, but in the reportedly paramagnetic unilluminated state, we find evidence for glassy magnetic freezing. We compare these results to those obtained in the non-photosensitive magnet Co{sub 1.5}[Fe(CN){sub 6}], which is the stoichiometric limit of x=0.5.

  5. 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.)

  6. Chemoenzymatic preparation of germacrene analogues.

    Science.gov (United States)

    Cascón, Oscar; Touchet, Sabrina; Miller, David J; Gonzalez, Veronica; Faraldos, Juan A; Allemann, Rudolf K

    2012-10-09

    A small library of novel germacrenes was generated using a combination of two plant enzymes, germacrene A synthase, and D synthase and modified farnesyl diphosphate (FDP) analogues. This chemoenzymatic approach allows the preparation of potentially valuable volatiles for biological studies.

  7. Chemoenzymatic preparation of germacrene analogues

    OpenAIRE

    Cascón, Oscar; Touchet, Sabrina; Miller, David James; Gonzalez, Veronica; Faraldos, Juan A.; Allemann, Rudolf Konrad

    2012-01-01

    A small library of novel germacrenes was generated using a combination of two plant enzymes, germacrene A synthase, and D synthase and modified farnesyl diphosphate (FDP) analogues. This chemoenzymatic approach allows the preparation of potentially valuable volatiles for biological studies.

  8. Cerebral fat embolism: magnetic resonance study

    International Nuclear Information System (INIS)

    Guedea, A.; Barrena, R.; Guelbenzu, S.; Tejada, A.

    1998-01-01

    We report the case of 26-year-old man who presented clinical evidence of fat embolism following a traffic accident. Although computed tomography (CT) of the brain showed no abnormalities, magnetic resonance imaging (MRI) disclosed several scattered points of high intensity on T2-weighted and proton density (PD) images, with complete resolution of the lesions on follow-up scan. MRI is considered more sensitive than computed tomography in detecting these lesions, and may be useful for their diagnosis, correlating well with the clinical course. (Author) 10 refs

  9. Role of chelates in magnetic resonance imaging studies

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2009-01-01

    Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

  10. Ferromagnetic resonance studies of granular materials (abstract)

    Science.gov (United States)

    Rubinstein, Mark; Das, Badri; Chrisey, D. B.; Horwitz, J.; Koon, N. C.

    1994-05-01

    We have investigated the ferromagnetic resonance (FMR) spectra of several granular alloys displaying giant magnetoresistance (GMR). For this task, we have produced melt-spun ribbons of Fe5Co15Cu80 and Co20Cu80 by rapid quenching and thin films of Co80Cu20 by pulsed laser deposition. The salient feature of the FMR spectra is the increase of the resonance linewidth as a function of increasing annealing temperature. We have deconvoluted the FMR spectra to a single-domain powder pattern and a multidomain powder pattern. As a function of annealing temperature, the GMR of these samples attains a maximum value. Near the peak of the GMR curve, the FMR spectrum reveals that the ferromagnetic particles are half mono- and half multidomain. Since the maximum size of a single-domain particle is known, this enables us to estimate the spin diffusion length of the Cu conduction electrons. We have also demonstrated, theoretically and experimentally, that the appropriate demagnetizing field to apply to the ensemble of spherical magnetic particles that comprise our granular thin film is simply the field corresponding to the average magnetization.

  11. Hawai'i and Gale Crater: A Mars Analogue Study of Igneous, Sedimentary, Weathering, and Alteration Trends in Geochemistry

    Science.gov (United States)

    Berger, J. A.; Flemming, R. L.; Schmidt, M. E.; Gellert, R.; Morris, R. V.; Ming, D. W.

    2017-01-01

    Sedimentary rocks in Gale Crater on Mars indicate a varied provenance with a range of alteration and weathering [1, 2]. Geochemical trends identified in basaltic and alkalic sedimentary rocks by the Alpha Particle X-ray Spectrometer (APXS) on the Mars rover Curiosity represent a complex interplay of igneous, sedimentary, weathering, and alteration processes. Assessing the relative importance of these processes is challenging with unknown compositions for parent sediment sources and with the constraints provided by Curiosity's instruments. We therefore look to Mars analogues on Earth where higher-resolution analyses and geologic context can constrain interpretations of Gale Crater geochemical observations. We selected Maunakea (AKA Mauna Kea) and Kohala volcanoes, Hawai'i, for an analogue study because they are capped by post-shield transitional basalts and alkalic lavas (hawaiites, mugearites) with compositions similar to Gale Crater [1, 3]. Our aim was to characterize Hawaiian geochemical trends associated with igneous processes, sediment transport, weathering, and alteration. Here, we present initial results and discuss implications for selected trends observed by APXS in Gale Crater.

  12. Synthesis, antiproliferative, anti-tubulin activity, and docking study of new 1,2,4-triazoles as potential combretastatin analogues.

    Science.gov (United States)

    Mustafa, Muhamad; Abdelhamid, Dalia; Abdelhafez, ElShimaa M N; Ibrahim, Mahmoud A A; Gamal-Eldeen, Amira M; Aly, Omar M

    2017-12-01

    Combretastatin A4 (CA4) is a natural product characterized by a powerful inhibition of tubulin polymerization and a potential anticancer activity. However, therapeutic application of CA4 is substantially hindered due to geometric isomerization. In the current study, new cis-restricted Combretastatin A4 analogues containing 1,2,4-triazle in place of the olefinic bond were designed and synthesized. The synthesized compounds were evaluated for their in vitro antiproliferative activity in human hepatocellular carcinoma HepG2 and leukemia HL-60 cell lines using MTT assay. Moreover, fourteen compounds were selected and tested for their antiproliferative activity by the National Cancer Institute. Some of the tested compounds showed moderate activity against sixty cell lines. In vitro tubulin polymerization inhibitory activity was evaluated on HepG2 cells. The assay revealed that 6a showed a remarkable tubulin inhibition compared to CA4. Moreover, the cell cycle analysis revealed significant G2/M cell cycle arrest of the analogue 6c in HepG2 cells. Molecular docking combined with AMBER-based molecular mechanical minimization results showed several noncovalent interactions, including van der Waals and hydrogen-bonding with several amino acids within the colchicine binding site of β-subunit of tubulin. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. 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

  14. Analogue modelling of microcontinent formation: a case study from the Danakil Block, southern Red Sea

    Science.gov (United States)

    Molnar, Nicolas; Cruden, Alexander; Betts, Peter

    2017-04-01

    The kinematic evolution of the Danakil Block is well constrained but the processes responsible for the formation of an isolated continental segment around 13 Ma ago with an independent pole of rotation are still matter of debate. We performed three-dimensional analogue experiments of rotational continental extension containing a pre-existing linear weakness zones in the lithospheric mantle to investigate the formation of the Red Sea, including the Danakil Block. We imposed a rotational extensional boundary condition that simulates the progressive anticlockwise rotation of the Arabian Plate with respect to the Nubia Plate over the last 13-15 Ma and we simulated the presence of a narrow thermal anomaly related to the northward channelling of Afar plume by varying the viscosity of the model lithospheric mantle. The results from experiments containing a linear zone of weakness oriented at low angles with respect to the rift axis show that early stages of deformation are characterised by the development of two rift sub-parallel compartments that delimit an intra-rift block in the vicinity of the weak lithosphere boundary zone, which are analogous to the two rift branches that confine the Danakil Block in the southern Red Sea. The imposed rotational boundary condition creates a displacement gradient along the intra-rift block and prevents the nucleation of the early rift compartments to the north of the block, enhancing the formation of an independently rotating intra-rift segment. Comparison with geodetic data supports our modelling results, which are also in agreement with the "crank-arm" model of Sichler (1980. La biellette Danakile: un modèle pour l'évolution géodynamique de l'Afar. Bull. la Société Géologique Fr. 22, 925-933). Additional analogue models of i) orthogonal extension with an identical lithospheric mantle weakness and, ii) rotational extension with a homogeneous lithosphere (i.e., no lithospheric mantle weakness) show no evidence of developing

  15. Environment sensitive fluorescent analogue of biologically active oxazoles differentially recognizes human serum albumin and bovine serum albumin: Photophysical and molecular modeling studies

    Science.gov (United States)

    Maiti, Jyotirmay; Biswas, Suman; Chaudhuri, Ankur; Chakraborty, Sandipan; Chakraborty, Sibani; Das, Ranjan

    2017-03-01

    An environment sensitive fluorophore, 4-(5-(4-(dimethylamino)phenyl)oxazol-2-yl)benzoic acid (DMOBA), that closely mimics biologically active 2,5-disubstituited oxazoles has been designed to probe two homologous serum proteins, human serum albumin (HSA) and bovine serum albumin (BSA) by means of photophysical and molecular modeling studies. This fluorescent analogue exhibits solvent polarity sensitive fluorescence due to an intramolecular charge transfer in the excited state. In comparison to water, the steady state emission spectra of DMOBA in BSA is characterized by a greater blue shift ( 10 nm) and smaller Stokes' shift ( 5980 cm- 1) in BSA than HSA (Stokes'shift 6600 cm- 1), indicating less polar and more hydrophobic environment of the dye in the former than the latter. The dye-protein binding interactions are remarkably stronger for BSA than HSA which is evident from higher value of the association constant for the DMOBA-BSA complex (Ka 5.2 × 106 M- 1) than the DMOBA-HSA complex (Ka 1.0 × 106 M- 1). Fӧrster resonance energy transfer studies revealed remarkably less efficient energy transfer (8%) between the donor tryptophans in BSA and the acceptor DMOBA dye than that (30%) between the single tryptophan moiety in HSA and the dye, which is consistent with a much larger distance between the donor (tryptophan)-acceptor (dye) pair in BSA (34.5 Å) than HSA (25.4 Å). Site specific competitive binding assays have confirmed on the location of the dye in Sudlow's site II of BSA and in Sudlow's site I of HSA, respectively. Molecular modeling studies have shown that the fluorescent analogue is tightly packed in the binding site of BSA due to strong steric complementarity, where, binding of DMOBA to BSA is primarily dictated by the van der Waals and hydrogen bonding interactions. In contrast, in HSA the steric complementarity is less significant and binding is primarily guided by polar interactions and van der Waals interactions appear to be less significant in the

  16. High-Resolution Resonance Photoemission Study of CeNi

    International Nuclear Information System (INIS)

    Sekiyama, A.; Kadono, K.; Iwasaki, T.; Imada, S.; Kasai, S.; Suga, S.; Araki, S.; Onuki, Y.

    2003-01-01

    We have performed the high-resolution Ce 3d - 4f resonance photoemission study of a considerably hybridized CeNi with the Kondo temperature of ∼ 150 K. The tail of the Kondo-resonance peak is predominantly observed in the bulk Ce 4f photoemission spectra, where its spin-orbit partner is suppressed compared with the so far reported surface-sensitive Ce 4d-4f resonance spectrum. Our results show that the bulk 4f electronic states are essentially understood by the single impurity Anderson model. (author)

  17. Natural analogue study for low-and-intermediate level radioactive waste shallow burial disposal

    International Nuclear Information System (INIS)

    Gu Cunli; Fan Zhiwen; Huang Yawen; Cui Anxi; Liu Xiuzheng; Zhang Jinshen

    1995-01-01

    The paper makes a comparison of low-and-intermediate level radioactive waste shallow burial disposal with Chinese ancient tombs in respects of siting, engineering structures, design principle and construction procedures. Results showed that Chinese ancient tombs are very good analogue for low-and-intermediate level radioactive waste shallow burial disposal. Long-term preservation of ancient tombs and buried objects demonstrated that low-and-intermediate level radioactive waste shallow burial disposal would be safe if suitable sites were selected, reasonable engineering structures and good backfill materials were adopted, and scientific construction procedures were followed. The paper reports for the first time the testing results of certain ancient tomb backfill materials. The results indicated that the materials have so low a permeability as 1.5 x 10 -8 cm/s , and strong adsorption to radionuclides Co and Cs with the distribution coefficients of 1.4 x 10 4 mL/g and 2.1 x 10 4 mL/g, and the retardation factors of 4.4 x 10 4 and 7.7 x 10 4 respectively. Good performance of these materials is important assurance of long-term preservation of the ancient tombs. These materials may be considered to be used as backfill materials in low-and-intermediate level radioactive shallow burial disposal. (4 figs., 10 tabs.)

  18. Measuring satiety with pictures compared to visual analogue scales. An exploratory study.

    Science.gov (United States)

    Sadoul, Bastien C; Schuring, Ewoud A H; Symersky, Tomas; Mela, David J; Masclee, Ad A M; Peters, Harry P F

    2012-02-01

    Visual analogue scales (VAS) are a standard tool used to measure subjective appetite. To explore a potentially more intuitive and precise alternative, we developed a method based on pictures and assessed its performance characteristics vs. VAS. The objective was to compare the capacity of the two methods to discriminate appetite ratings between interventions. Both methods were applied within a previously published trial in which 16 healthy adults received standardised meals followed by three different ileal infusions in a balanced crossover design. At regular intervals volunteers indicated how many units of individually pictured food portions (for 10 different items) they would like to eat, and also scored six VAS. Methods were compared over different timeframes and assessed for their sensitivity to intervention effects. Pictures were more sensitive than VAS in differentiating intervention effects; however, further refinement and validation would be needed for pictures to become a standardised and accepted alternative to VAS for this type of research. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. 2'-C-Methyl analogues of selective adenosine receptor agonists: synthesis and binding studies.

    Science.gov (United States)

    Franchetti, P; Cappellacci, L; Marchetti, S; Trincavelli, L; Martini, C; Mazzoni, M R; Lucacchini, A; Grifantini, M

    1998-05-07

    2'-C-Methyl analogues of selective adenosine receptor agonists such as (R)-PIA, CPA, CCPA, NECA, and IB-MECA were synthesized in order to further investigate the subdomain that binds the ribose moiety. Binding affinities of these new compounds at A1 and A2A receptors in bovine brain membranes and at A3 in rat testis membranes were determined and compared. It was found that the 2'-C-methyl modification resulted in a decrease of the affinity, particularly at A2A and A3 receptors. When such modification was combined with N6-substitutions with groups which induce high potency and selectivity at A1 receptors, the high affinity was retained and the selectivity was increased. Thus, 2-chloro-2'-C-methyl-N6-cyclopentyladenosine (2'-Me-CCPA), which displayed a Ki value of 1.8 nM at A1 receptors, was selective for A1 vs A2A and A3 receptors by 2166- and 2777-fold, respectively, resulting in one of the most potent and A1-selective agonists so far known. In functional assay, this compound inhibited forskolin-stimulated adenylyl cyclase activity with an IC50 value of 13.1 nM, acting as a full agonist.

  20. Talking about depression: an analogue study of physician gender and communication style on patient disclosures.

    Science.gov (United States)

    Roter, Debra L; Erby, Lori H; Adams, Ann; Buckingham, Christopher D; Vail, Laura; Realpe, Alba; Larson, Susan; Hall, Judith A

    2014-09-01

    To disentangle the effects of physician gender and patient-centered communication style on patients' oral engagement in depression care. Physician gender, physician race and communication style (high patient-centered (HPC) and low patient-centered (LPC)) were manipulated and presented as videotaped actors within a computer simulated medical visit to assess effects on analogue patient (AP) verbal responsiveness and care ratings. 307 APs (56% female; 70% African American) were randomly assigned to conditions and instructed to verbally respond to depression-related questions and indicate willingness to continue care. Disclosures were coded using Roter Interaction Analysis System (RIAS). Both male and female APs talked more overall and conveyed more psychosocial and emotional talk to HPC gender discordant doctors (all p<.05). APs were more willing to continue treatment with gender-discordant HPC physicians (p<.05). No effects were evident in the LPC condition. Findings highlight a role for physician gender when considering active patient engagement in patient-centered depression care. This pattern suggests that there may be largely under-appreciated and consequential effects associated with patient expectations in regard to physician gender that these differ by patient gender. High patient-centeredness increases active patient engagement in depression care especially in gender discordant dyads. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Cobalamin analogues in humans: a study on maternal and cord blood.

    Directory of Open Access Journals (Sweden)

    Tore Forsingdal Hardlei

    Full Text Available 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 of CorA. METHODS: HC-CorA were quantified in paired samples of cord serum from newborns and serum from mothers (n = 69. RESULTS: The CorA-concentration was higher in cord serum (median = 380, range: 41-780 pmol/L than in serum from the mothers (median = 160, range: 64-330 pmol/L, (p<0.0001. HPLC-analysis showed CorA-peaks with retention times of 13.5, 14,5 and 16.5 min in samples from both the mother and cord serum. The peak with retention time 16.5 min constituted 24% (mother and 45% (cord serum of the total amount CorA, and eluted as does dicyanocobinamide. CONCLUSION: Our results support that CorA in the human body are derived from Cbl.

  2. Analogue computing methods

    CERN Document Server

    Welbourne, D

    1965-01-01

    Analogue Computing Methods presents the field of analogue computation and simulation in a compact and convenient form, providing an outline of models and analogues that have been produced to solve physical problems for the engineer and how to use and program the electronic analogue computer. This book consists of six chapters. The first chapter provides an introduction to analogue computation and discusses certain mathematical techniques. The electronic equipment of an analogue computer is covered in Chapter 2, while its use to solve simple problems, including the method of scaling is elaborat

  3. Natural analogue study of CO2 storage monitoring using probability statistics of CO2-rich groundwater chemistry

    Science.gov (United States)

    Kim, K. K.; Hamm, S. Y.; Kim, S. O.; Yun, S. T.

    2016-12-01

    For confronting global climate change, carbon capture and storage (CCS) is one of several very useful strategies as using capture of greenhouse gases like CO2 spewed from stacks and then isolation of the gases in underground geologic storage. CO2-rich groundwater could be produced by CO2 dissolution into fresh groundwater around a CO2 storage site. As consequence, natural analogue studies related to geologic storage provide insights into future geologic CO2 storage sites as well as can provide crucial information on the safety and security of geologic sequestration, the long-term impact of CO2 storage on the environment, and field operation and monitoring that could be implemented for geologic sequestration. In this study, we developed CO2 leakage monitoring method using probability density function (PDF) by characterizing naturally occurring CO2-rich groundwater. For the study, we used existing data of CO2-rich groundwaters in different geological regions (Gangwondo, Gyeongsangdo, and Choongchungdo provinces) in South Korea. Using PDF method and QI (quantitative index), we executed qualitative and quantitative comparisons among local areas and chemical constituents. Geochemical properties of groundwater with/without CO2 as the PDF forms proved that pH, EC, TDS, HCO3-, Ca2+, Mg2+, and SiO2 were effective monitoring parameters for carbonated groundwater in the case of CO2leakage from an underground storage site. KEY WORDS: CO2-rich groundwater, CO2 storage site, monitoring parameter, natural analogue, probability density function (PDF), QI_quantitative index Acknowledgement This study was supported by the "Basic Science Research Program through the National Research Foundation of Korea (NRF), which is funded by the Ministry of Education (NRF-2013R1A1A2058186)" and the "R&D Project on Environmental Management of Geologic CO2 Storage" from KEITI (Project number: 2014001810003).

  4. 1,2,4-Triazole and 1,3,4-oxadiazole analogues: Synthesis, MO studies, in silico molecular docking studies, antimalarial as DHFR inhibitor and antimicrobial activities.

    Science.gov (United States)

    Thakkar, Sampark S; Thakor, Parth; Doshi, Hiren; Ray, Arabinda

    2017-08-01

    1,2,4-Triazole and 1,3,4-oxadiazole analogues are of interest due to their potential activity against microbial and malarial infections. In search of suitable antimicrobial and antimalarial compounds, we report here the synthesis, characterization and biological activities of 1,2,4-triazole and 1,3,4-oxadiazole analogues (SS 1-SS 10). The molecules were characterized by IR, mass, 1 H NMR, 13 C NMR and elemental analysis. The in vitro antimicrobial activity was investigated against pathogenic strains, the results were explained with the help of DFT and PM6 molecular orbital calculations. In vitro cytotoxicity and genotoxicity of the molecules were studied against S. pombe cells. In vitro antimalarial activity was studied. The active compounds were further evaluated for enzyme inhibition efficacy against the receptor Pf-DHFR computationally as well as in vitro to prove their candidature as lead dihydrofolate reductase inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Sorption studies of uranium in sediment-groundwater systems from the natural analogue sites of Needle's Eye and Broubster

    International Nuclear Information System (INIS)

    Higgo, J.J.; Falck, W.E.; Hooker, P.J.

    1990-01-01

    This report describes the results of sorption experiments designed to provide essential data for migration modelling. Sorption of 233 U from natural ground-water onto peat from Broubster and silt from Needle's Eye was studied under atmospheric conditions and different pH regimes. The temperature was maintained at 10 0 C and, in the case of Needle's Eye silt, the kinetics of sorption were followed. The results were analyzed in conjunction with speciation modelling in an attempt to understand the sorption mechanisms and to extrapolate the findings to cover the range of conditions likely to be met in the field. This work is part of the CEC project Mirage - Second phase, research area 'Natural analogues'

  6. Radon in underground waters as a natural analogue to study the escape of CO2 in geological repositories.

    Science.gov (United States)

    Martín Sánchez, A; Ruano Sánchez, A B; de la Torre Pérez, J; Jurado Vargas, M

    2015-11-01

    Activity concentrations of dissolved (222)Rn and (226)Ra were measured in several underground aquifers, which are candidates for repositories or for the study of analogue natural escapes of CO2. The concentration of both radionuclides in water was determined using liquid scintillation counting. The values obtained for the (222)Rn concentrations varied from 0 to 150 Bq l(-1), while the levels of (226)Ra were in general very low. This indicates that (222)Rn is coming from the decay of the undissolved (226)Ra existing in the rocks and deep layers of the aquifers, being later transported by diffusion in water. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. An optimization study for radioiodination of a new synthesized benzamide derivative as an analogue tracer for malignant melanoma imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, Shaban A.; Aglan, Hany; Seddik, Usama [Atomic Energy Authority, Cairo (Egypt). Nuclear Research Center; EL-Kafrawy, Ahmed F. [Ain Shams Univ., Cairo (Egypt). Faculty of Science

    2017-03-01

    Iodobenzamides are reported to possess some affinity for melanoma. This study describes the synthesis of a new benzamide analogue, N-(2-diethylamino-ethyl)-4-(4-chloro-nicotinamido)-5-[{sup 125}I]iodo-2 -methoxybenz amide ([{sup 125}I]H4) designed to target melanoma. The synthesis was simply achieved in four steps. There were two PyCIU/DIPEA amide condensations and a transfer hydrogenation using an ammonium formate hydrogen donor. The radioiodination step was carried out with {sup 125}I via an electrophilic substitution reaction. The reaction conditions were optimized. The labeled compound was purified by HPLC. The maximum radiochemical yield was found to be 78% at a radiochemical purity of 98%. All compounds were characterized by MS and NMR techniques. The log P value for [{sup 125}I]H4 was found as 3.96±0.5.

  8. Magnetic Resonance Imaging Studies of Postpartum Depression: An Overview

    Directory of Open Access Journals (Sweden)

    Marco Fiorelli

    2015-01-01

    Full Text Available Postpartum depression is a frequent and disabling condition whose pathophysiology is still unclear. In recent years, the study of the neural correlates of mental disorders has been increasingly approached using magnetic resonance techniques. In this review we synthesize the results from studies on postpartum depression in the context of structural, functional, and spectroscopic magnetic resonance studies of major depression as a whole. Compared to the relative wealth of data available for major depression, magnetic resonance studies of postpartum depression are limited in number and design. A systematic literature search yielded only eleven studies conducted on about one hundred mothers with postpartum depression overall. Brain magnetic resonance findings in postpartum depression appear to replicate those obtained in major depression, with minor deviations that are not sufficient to delineate a distinct neurobiological profile for this condition, due to the small samples used and the lack of direct comparisons with subjects with major depression. However, it seems reasonable to expect that studies conducted in larger populations, and using a larger variety of brain magnetic resonance techniques than has been done so far, might allow for the identification of neuroimaging signatures for postpartum depression.

  9. Alligator Rivers Analogue project. Hydrogeological field studies. Final Report - Volume 5

    Energy Technology Data Exchange (ETDEWEB)

    Davis, S.N. [Univ of Arizona, Tucson, Arizona (United States). Dept of Hydrology and Water Resources; Marley, R.D. [D.B. Stephens and Associates Inc., Albuquerque, NM (United States); Norris, J.R. [Hydro Geo Chem Inc., Tucson, Arizona (United States)

    1992-12-31

    The hydrogeology of the Koongarra site was interpreted primarily from long-term hydrographs, water-level maps, water injection tests, aquifer pumping tests, logs of boreholes, and chemical analyses of groundwater samples. Data have been collected over a 21-year period starting with test-drilling in 1970. The first intensive period of hydrogeologic investigations was from 1978 through 1981 and was related to anticipated exploitation of uranium ore at Koongarra. The second period was from 1986 through 1991 and was related to the international Alligator Rivers Analogue Project under the direction of the Australian Nuclear Science and Technology Organisation. The conclusion which can be drawn from the chemical data is that water moving out of the No. 1 ore deposit is diluted rapidly with recharge from the surface as it migrates down the hydraulic gradient. Most of the groundwater outside of the ore deposit does not originate from the ore deposit, and flow models which assume unmodified stream tubes extending out of the ore deposit in a downgradient direction do not reflect the true system. Water in the ore deposit itself, must come from slow upward seepage through the fault zone. Owing to the fact that this water must be at least hundreds of years old, observed fluctuations of water levels in the deposit must reflect pressure head variations induced by seasonal recharge to the overlying surficial materials. Water level fluctuations do not signify a yearly displacement of water deep in the system. Water in the deeper part of the ore must be almost static compared to obvious rapid groundwater circulation in the area around PH88. Small changes in pH, temperature and specific electrical conductivity during aquifer tests indicate a complex hydraulic system which has a variable response to pumping as a function of time. Low concentration in tritium and Carbon-14 together with high concentrations of dissolved helium in the groundwaters all suggested strongly that semi static

  10. Resonant and Ground Experimental Study on the Microwave Plasma Thruster

    Science.gov (United States)

    Yang, Juan; He, Hongqing; Mao, Genwang; Qu, Kun; Tang, Jinlan; Han, Xianwei

    2002-01-01

    resonator, which reduces the energy loss arising from the heat conducting, the wall temperature almost have no limitation. The cavity is partitioned in two halves separated by a dialectic quartz plate. The propellant is swirl-injected tangentially in the nozzle side of the cavity (plasma chamber), which extends lifetime and working reliability of MPT. Compared, coaxial resonator has the characteristic of smaller structure, lighter weight, wider bandwidth of resonating frequency and more stable resonate state. microwave energy can heat propellant gas to produce thrust efficiently. According to the test method on the return loss of passive parts of microwave apparatus, this paper also makes experimental study on the resonating state of MPT cavity with scalar network analyzer operating under low signal. Purpose is to analyze its energy absorbing efficiency and resonant frequency band, research the matching of the cavity dimension, microwave coupling probe position and the isolate plate material within the cavity. The conclusion is helpful for the thruster design and improving the system efficiency. different propellant gases (Ar and He) have been fulfilled. The power, resonant pressure and mass flow rate have been measured and analyzed. Experiments show that MPT can start up reliably and work steadily. Keywords: microwave plasma thrustermicrowaveplasmaresonatorreturn loss

  11. 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.

  12. 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.

  13. Studies of magnetic resonance in anemia of hematies falciformes

    International Nuclear Information System (INIS)

    Lores Guevara, Manuel Arsenio; Balcom, Bruce John; Cabal Mirabal, Carlos

    2012-01-01

    Magnetic Resonance applications to the study of Sickle Cell Disease are analyzed using classical procedures and Unilateral Magnetic Resonance. Hemoglobin and whole blood samples were obtained from healthy individual and patients with Sickle Cell Anemia to be used as samples. Classical pulse sequence as spin echo and inversion recovery were used in the experimental studies, the STEPR method was used for EPR spectrometric determinations. The results show the possibility of NMR methods to follow the molecular process causing the disease and allows to present quantitative procedures to estimate the clinical state of the patients and the results of clinical options. We present the Unilateral Magnetic Resonance as a new method to study Sickle Cell disease considering its portability and new possibilities as new image method

  14. Nitenpyram analogues with 1,4-dihydropyridine fixed cis-configuration:synthesis,insecticidal activities and molecular docking studies

    Directory of Open Access Journals (Sweden)

    XUE Sijia

    2013-08-01

    Full Text Available A novel series of Nitenpyram analogues(Ia-Ij with 1,4-dihydropyridine fixed cis-configuration were designed and synthesized.Preliminary bioassays showed that most of them exhibited good insecticidal activities against Aphis medicagini and Brown rice planthopper at 500 mg/L and 100 mg/L.The analogue Ij afforded the best activity in vitro,that had 100% mortality at 4 mg/L against Brown rice planthopper and Aphis medicagin.In addition,the molecular docking simulations revealed that the structural uniqueness of these analogues may lead to a unique molecular recognition and binding mode,and the results explained the SARs observed in vitro, which shed light on the novel insecticidal mechanism of these novel nitenpyam analogues.

  15. The interpretation of glucose clamp studies of long-acting insulin analogues: from physiology to marketing and back.

    Science.gov (United States)

    Swinnen, S G H A; Holleman, F; DeVries, J H

    2008-10-01

    Glucose clamp studies assessing the time-action profile of long-acting insulin analogues have reported conflicting results. In an attempt to reconcile the data, we organised an expert meeting of four leading European clamp groups, during which consensus was reached on some but not all points discussed. In this paper, which reflects our personal views only, we aim to provide guidance for readers and reviewers on the interpretation of this type of clamp study and to clarify its inherent limitations.Glucose clamp studies are either performed manually or using an automated procedure, but differences in clamp methodology hardly seem a satisfactory explanation for the conflicting results. (Un)conscious investigator-related bias, especially during manual studies, cannot be ruled out, despite attempts at blinding the study insulin during the clamp.The duration of action of study insulins is influenced by many factors, such as glucose and insulin levels prior to injection, endogenous insulin secretion, insulin dose, definitions used for onset and end of action, and insulin sensitivity (which is influenced by the necessity of fasting during the clamp). These factors limit the translation of clamp study results into daily practice.Because of the inherent limitations of the glucose clamp technique and the lack of reproducibility of the outcomes, its results should be regarded as no more than an indication of the clinical action profile of long-acting insulin preparations.

  16. Resolution and Determination of the Absolute Configuration of a Twisted Bis-Lactam Analogue of Troger's Base: A Comparative Spectroscopic and Computational Study

    DEFF Research Database (Denmark)

    Rúnarsson, Ögmundur Vidar; Benkhäuser, Christian; Christensen, Niels Johan

    2015-01-01

    unambiguously confirming the results from the spectroscopic studies. We conclude that, for the Troger's base (TB) analogue (2), we may rank the reliability of the individual methods for AC determination as AXRD >> VCD > ECD, while the synergy of all three methods provides very strong confidence in the assigned...

  17. Study of isovector resonances with pion charge exchange

    International Nuclear Information System (INIS)

    Baer, H.W.; Bolton, R.; Bowman, J.D.

    1982-01-01

    Studies with the pion charge exchange reactions (π/sup +-/,π 0 ) at 164 MeV using the LAMPF π 0 spectrometer are yielding new results on the existence and systematic features of isovector resonances in nuclei. These experiments possess an unusually high signal/background ratio for isovector resonances of low-multipolarity. Results obtained to date are: (1) observation and angular disribution measurement of the giant dipole resonance in nuclei 12 C, 40 Ca, 90 Zr, and 120 Sn; and (2) observation and angular distribution measurements in the (π - ,π 0 ) reaction on 90 Zr and 120 Sn of large signals possessing the expected angular distribution shapes and magnitudes for the isovector monopole resonance. Excitation energies are near the hydrodynamical model values 170 A - /sup 1/3/ MeV. Differential cross sections are approximately 0.7 J 1 2 (qR) mb/sr. An overview of this experimental program, with emphasis on new results and how they correlate with existing knowledge on the isovector resonances, is presented

  18. Magnetic resonance spectroscopy and imaging for the study of fossils.

    Science.gov (United States)

    Giovannetti, Giulio; Guerrini, Andrea; Salvadori, Piero A

    2016-07-01

    Computed tomography (CT) has long been used for investigating palaeontological specimens, as it is a nondestructive technique which avoids the need to dissolve or ionize the fossil sample. However, magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) have recently gained ground as analytical tools for examination of palaeontological samples, by nondestructively providing information about the structure and composition of fossils. While MRI techniques are able to reveal the three-dimensional geometry of the trace fossil, MRS can provide information on the chemical composition of the samples. The multidimensional nature of MR (magnetic resonance) signals has potential to provide rich three-dimensional data on the palaeontological specimens and also to help in elucidating paleopathological and paleoecological questions. In this work the verified applications and the emerging uses of MRI and MRS in paleontology are reviewed, with particular attention to fossil spores, fossil plants, ambers, fossil invertebrates, and fossil vertebrate studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Magnetic resonance imaging study of corpus callosum

    African Journals Online (AJOL)

    2014-11-02

    Nov 2, 2014 ... depression,[4] antisocial personality disorder,[5] post-traumatic stress disorder,[6] autism[7] and attention deficit hyperactivity disorder.[8]. Rosenthal and Bigelow[9] first drew attention to an increased thickness of the CC in postmortem brains of schizophrenia patients. Later, in neuroimaging studies, CC size ...

  20. Anesthesia and critical-care delivery in weightlessness: A challenge for research in parabolic flight analogue space surgery studies

    Science.gov (United States)

    Ball, Chad G.; Keaney, Marilyn A.; Chun, Rosaleen; Groleau, Michelle; Tyssen, Michelle; Keyte, Jennifer; Broderick, Timothy J.; Kirkpatrick, Andrew W.

    2010-03-01

    BackgroundMultiple nations are actively pursuing manned exploration of space beyond low-earth orbit. The responsibility to improve surgical care for spaceflight is substantial. Although the use of parabolic flight as a terrestrial analogue to study surgery in weightlessness (0 g) is well described, minimal data is available to guide the appropriate delivery of anesthesia. After studying anesthetized pigs in a 0 g parabolic flight environment, our group developed a comprehensive protocol describing prolonged anesthesia in a parabolic flight analogue space surgery study (PFASSS). Novel challenges included a physically remote vivarium, prolonged (>10 h) anesthetic requirements, and the provision of veterinary operating room/intensive care unit (ICU) equivalency on-board an aircraft with physical dimensions of ethical approval, multiple ground laboratory sessions were conducted with combinations of anesthetic, pre-medication, and induction protocols on Yorkshire-cross specific pathogen-free (SPF) pigs. Several constant rate infusion (CRI) intravenous anesthetic combinations were tested. In each regimen, opioids were administered to ensure analgesia. Ventilation was supported mechanically with blended gradients of oxygen. The best performing terrestrial 1 g regime was flight tested in parabolic flight for its effectiveness in sustaining optimal and prolonged anesthesia, analgesia, and maintaining hemodynamic stability. Each flight day, a fully anesthetized, ventilated, and surgically instrumented pig was transported to the Flight Research Laboratory (FRL) in a temperature-controlled animal ambulance. A modular on-board surgical/ICU suite with appropriate anesthesia/ICU and surgical support capabilities was employed. ResultsThe mean duration of anesthesia (per flight day) was 10.28 h over four consecutive days. A barbiturate and ketamine-based CRI anesthetic regimen supplemented with narcotic analgesia by bolus administration offered the greatest prolonged hemodynamic

  1. Anatomical and magnetic resonance imaging study of the medial ...

    African Journals Online (AJOL)

    Sally Mahmood Mohamed Hussin Omar

    2015-07-10

    Jul 10, 2015 ... Anatomical and magnetic resonance imaging study of the medial collateral ligament of the ankle joint. Sally Mahmood Mohamed Hussin Omar a. , Fardos Ahmed El-Kalaa a. ,. El Sebai Farag Ali b. , Ali Ali Abd El-Karim c. , Nancy Mohamed El Sekily d,. * a Department of Anatomy and Embryology, Faculty of ...

  2. Resonant inelastic x-ray scattering studies of elementary excitations

    NARCIS (Netherlands)

    Ament, Lucas Johannes Peter (Luuk)

    2010-01-01

    Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

  3. Electron cyclotron resonance breakdown studies in a linear plasma ...

    Indian Academy of Sciences (India)

    Abstract. Electron cyclotron resonance (ECR) plasma breakdown is studied in a small linear cylindrical system with four different gases – hydrogen, helium, argon and nitrogen. Microwave power in the experimental system is delivered by a magnetron at 2.45 ± 0.02. GHz in TE10 mode and launched radially to have ...

  4. In vitro particulate analogue fluids for experimental studies of rheological and hemorheological behavior of glucose-rich RBC suspensions.

    Science.gov (United States)

    Pinho, Diana; Campo-Deaño, Laura; Lima, Rui; Pinho, Fernando T

    2017-09-01

    Suspensions of healthy and pathological red blood cells (RBC) flowing in microfluidic devices are frequently used to perform in vitro blood experiments for a better understanding of human microcirculation hemodynamic phenomena. This work reports the development of particulate viscoelastic analogue fluids able to mimic the rheological and hemorheological behavior of pathological RBC suspensions flowing in microfluidic systems. The pathological RBCs were obtained by an incubation of healthy RBCs at a high concentration of glucose, representing the pathological stage of hyperglycaemia in diabetic complications, and analyses of their deformability and aggregation were carried out. Overall, the developed in vitro analogue fluids were composed of a suspension of semi-rigid microbeads in a carrier viscoelastic fluid made of dextran 40 and xanthan gum. All suspensions of healthy and pathological RBCs, as well as their particulate analogue fluids, were extensively characterized in steady shear flow, as well as in small and large amplitude oscillatory shear flow. In addition, the well-known cell-free layer (CFL) phenomenon occurring in microchannels was investigated in detail to provide comparisons between healthy and pathological in vitro RBC suspensions and their corresponding analogue fluids at different volume concentrations (5% and 20%). The experimental results have shown a similar rheological behavior between the samples containing a suspension of pathological RBCs and the proposed analogue fluids. Moreover, this work shows that the particulate in vitro analogue fluids used have the ability to mimic well the CFL phenomenon occurring downstream of a microchannel contraction for pathological RBC suspensions. The proposed particulate fluids provide a more realistic behavior of the flow properties of suspended RBCs when compared with existing non-particulate blood analogues, and consequently, they are advantageous for detailed investigations of microcirculation.

  5. Study of giant multipole resonances in 40Ca

    International Nuclear Information System (INIS)

    Rost, H.

    1979-01-01

    In the present thesis giant resonance states in 40 Ca were studied by scattering of 104 MeV a particles on 40 Ca and by the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar. The scattered α-particles were measured at extreme forward angles (THETAsub(L) = 4 0 -16 0 C), because at forward angles the cross sections for the excitation of states with spin 0 and 1 strongly differ from those with higher spin. The aim of this experiment was first of all the study of the giant resonance region in 40 Ca on the contribution to 0 + or 1 - states. Beside the known electric giant quadrupole resonances at Esub(x) approx. equal to 18.5 MeV (25% EWSR) contributions of EO-strength at Esub(x) approx. equal to 21 MeV (6% EWSR) and indications to a (isoscalar) E1-strength at Esub(x) approx. equal to 14 MeV and Esub(x) approx. equal to 16 MeV were found. At the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar in the channels (p,p 0 ),(p,p 4 ), (p,αsub(o)), and (p,α 1 ) at incident energies at about 10 MeV (Esub(x)( 40 Ca) approx. equal to 18 MeV) resonant structures were observed. A scattering phase analysis performed for the elastic proton scattering didn't however yield quantitative results about the resonance parameter. An expansion of the cross sections by Legendre polynomials for the remaining reaction channel didn't allow a conclusion about the dominance of a certain L-value. The only indication to the connection of the observed resonant structures with the giant quadrupole resonance in 40 Ca is therefore the energetic position at about Esub(x) approx. equal to 18 MeV. Altogether the observed structures however were not very pronounced, so it can be concluded, that the excitation of the giant quadrupole resonance in 40 Ca by protons via the ground state of 39 K occurs not very strongly. (orig./HSI) [de

  6. Asymmetric Synthesis and Binding Study of New Long-Chain HPA-12 Analogues as Potent Ligands of the Ceramide Transfer Protein CERT.

    Science.gov (United States)

    Ďuriš, Andrej; Daïch, Adam; Santos, Cécile; Fleury, Laurence; Ausseil, Frédéric; Rodriguez, Frédéric; Ballereau, Stéphanie; Génisson, Yves; Berkeš, Dušan

    2016-05-04

    A series of 12 analogues of the Cer transfer protein (CERT) antagonist HPA-12 with long aliphatic chains were prepared as their (1R,3S)-syn and (1R,3R)-anti stereoisomers from pivotal chiral oxoamino acids. The enantioselective access to these intermediates as well as their ensuing transformation relied on a practical crystallization-induced asymmetric transformation (CIAT) process. Sonogashira coupling followed by triple bond reduction and thiophene ring hydrodesulfurization (HDS) into the corresponding alkane moieties was then implemented to complete the synthetic routes delivering the targeted HPA-12 analogues in concise 4- to 6-step reaction sequences. Ten compounds were evaluated regarding their ability to bind to the CERT START domain by using the recently developed time-resolved FRET-based homogeneous (HTR-FRET) binding assay. The introduction of a lipophilic appendage on the phenyl moiety led to an overall 10- to 1000-fold enhancement of the protein binding, with the highest effect being observed for a n-hexyl residue in the meta position. The importance of the phenyl ring for the activity was indicated by the reduced potency of the 3-deoxyphytoceramide aliphatic analogues. The 1,3-syn stereoisomers were systematically more potent than their 1,3-anti analogues. In silico studies were used to rationalized these trends, leading to a model of protein recognition coherent with the stronger binding of (1R,3S)-syn HPAs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Long term alteration of glass/iron systems in anoxic conditions: contribution of archaeological analogues to the study of mechanisms

    International Nuclear Information System (INIS)

    Michelin, A.

    2011-01-01

    The knowledge of glass alteration mechanisms arouses a great interest over the last decades, particularly in the nuclear field, since vitrification is used to stabilize high-level radioactive wastes in many countries. In the French concept, these nuclear glasses would be stored in geological repositories. This multi-barrier system (glass matrix, stainless steel container, low carbon steel over-container, geological barrier) must ensure the durable confinement of radionuclides. But laboratory experiments do not permit to predict directly the behaviour of these materials over typically a million-year timescale and the extrapolation of short-term laboratory data to long time periods remains problematic. Part of the validation of the predictive models relies on natural and archaeological analogues. Here, the analogues considered are vitreous slags produced as wastes by a blast furnace working during the 16. century in the iron making site of Glinet (Normandy, France). The choice of these specific artefacts is due to the presence of particular interface between corrosion products and glass matrix inside the blocks. Thus, they can help us to understand the influence of iron corrosion products from the steel containers on the glass alteration mechanisms and kinetics. A first part of this work concerns the characterization of the archaeological artefacts especially the interfacial area between glass and corrosion products inside cracks using micro and nano-beam techniques (μRaman spectroscopy, FEG-SEM, TEM, STXM...). This study has enabled to suggest an alteration process with different geochemical steps that leads to alteration profile observed. One of these steps is the precipitation of an iron silicate phase. In a second time, leaching experiments were set up on a synthetic glass of similar composition than the archaeological one to understand the first stages of alteration with and without iron. Two phenomena can be observed: silicon sorption and precipitation of iron

  8. Astrobiology through the ages of Mars: the study of terrestrial analogues to understand the habitability of Mars.

    Science.gov (United States)

    Fairén, Alberto G; Davila, Alfonso F; Lim, Darlene; Bramall, Nathan; Bonaccorsi, Rosalba; Zavaleta, Jhony; Uceda, Esther R; Stoker, Carol; Wierzchos, Jacek; Dohm, James M; Amils, Ricardo; Andersen, Dale; McKay, Christopher P

    2010-10-01

    Mars has undergone three main climatic stages throughout its geological history, beginning with a water-rich epoch, followed by a cold and semi-arid era, and transitioning into present-day arid and very cold desert conditions. These global climatic eras also represent three different stages of planetary habitability: an early, potentially habitable stage when the basic requisites for life as we know it were present (liquid water and energy); an intermediate extreme stage, when liquid solutions became scarce or very challenging for life; and the most recent stage during which conditions on the surface have been largely uninhabitable, except perhaps in some isolated niches. Our understanding of the evolution of Mars is now sufficient to assign specific terrestrial environments to each of these periods. Through the study of Mars terrestrial analogues, we have assessed and constrained the habitability conditions for each of these stages, the geochemistry of the surface, and the likelihood for the preservation of organic and inorganic biosignatures. The study of these analog environments provides important information to better understand past and current mission results as well as to support the design and selection of instruments and the planning for future exploratory missions to Mars.

  9. Investigating β-N-Methylamino-l-alanine Misincorporation in Human Cell Cultures: A Comparative Study with Known Amino Acid Analogues

    Directory of Open Access Journals (Sweden)

    Rianita van Onselen

    2017-12-01

    Full Text Available Misincorporation of β-N-methylamino-l-alanine (BMAA into proteins has been proposed to be a mechanism of toxicity to explain the role of BMAA in neurodegenerative disease development. However, studies have shown that all detectable BMAA can be removed from proteins by SDS-PAGE purification and that the toxicity of l-canavanine cannot be reproduced in prokaryotes or in a rat pheochromocytoma cell line, strongly indicating that the misincorporation hypothesis of BMAA should be re-investigated. The aim of this study was therefore to determine if BMAA misincorporates into proteins in cells of human origin with subsequent misincorporation-type toxicity. Almost complete loss of viability in response to exposure to l-4-fluorophenylalanine and l-m-tyrosine was observed in all of the cell lines, corresponding to a concentration-dependent increase of the analogues in protein extracts from exposed cells. In contrast, BMAA exposure resulted in slight toxicity in one of the cell lines but the observed toxicity was not the result of misincorporation of BMAA into proteins, as no BMAA was detected in any of the SDS-PAGE purified protein extracts that were obtained from the cells following BMAA exposure. The results show that BMAA is not misincorporated into human proteins and that misincorporation is not a valid mechanism of toxicity.

  10. C-glycosyl bond conformation in oxazofurin: crystallographic and computational studies of the oxazole analogue of tiazofurin.

    Science.gov (United States)

    Goldstein, B M; Li, H; Hallows, W H; Langs, D A; Franchetti, P; Cappellacci, L; Grifantini, M

    1994-05-27

    Oxazofurin is the inactive oxazole analogue of the C-glycosyl thiazole antitumor agent tiazofurin. Replacement of the thiazole sulfur in tiazofurin with the oxazole oxygen in oxazofurin produces conformational effects that are examined using crystallographic and computational methods. The crystal structure of oxazofurin contains six molecules in the asymmetric unit and has been refined to a standard R value of 6.8% for all data. The six oxazofurin conformers show an average C-glycosidic torsion angle of 70(9) degrees. This value is significantly higher than the average absolute C-glycosidic torsion angle of 24(10) degrees obtained from previous thiazole nucleoside structures. Previous studies suggest that, in tiazofurin, an electrostatic interaction between a positively charged thiazole sulfur and negatively charged furanose oxygen constrains the C-glycosidic torsion angle to a relatively small value. Ab initio molecular orbital studies presented here suggest that the higher C-glycosidic angles observed in the oxazofurin structures result from a repulsive interaction between negatively charged oxazole and furanose oxygens. Thus, it is likely that differences in activity between oxazo- and tiazofurin are either (1) due directly to differences in electronic properties between the thiazole and oxazole rings or (2) due to the variation in C-glycosidic bond conformation resulting from the alteration in the charge distribution of the heterocycle.

  11. The International intraval project. Phase 1, case 7. The Pocos de Caldas natural analogue: studies of redox front movement

    International Nuclear Information System (INIS)

    Chapman, N.

    1992-01-01

    The study of natural analogues is an important means of validating models of the geochemical processes affecting radionuclide behaviour. This test case, which is one aspect taken from the much broader geochemical studies carried out in the Pocos de Caldas Project, concerns the nature and behaviour of redox fronts, such as might be generated in the near-field of a spent-fuel repository. A redox front is potentially important in terms of the movements and speciation of certain radionuclides close to the waste package. The natural redox fronts in Osamu Utsumi uranium mine display many of the features which may occur in a repository, and influence the movement of natural series radionuclides, and other elements, through the rock/groundwater system. This report, describes the geological, hydrogeological and geochemical nature of the site, and of the redox fronts. Emphasis is placed on the mineralogy of the fronts, and the concentration profiles of various elements across them. The project involved a number of different modelling approaches which attempted to describe the generation and movement of the fronts through the rock. These included mass balance, reaction-diffusion models, fissure flow models, thermodynamic models, and kinetic models. 21 refs., 36 figs., 1 tab

  12. Glycemic control with insulin glargine plus insulin glulisine versus premixed insulin analogues in real-world practices: a cost-effectiveness study with a randomized pragmatic trial design.

    Science.gov (United States)

    Levin, Philip A; Zhang, Quanwu; Mersey, James H; Lee, Francis Y; Bromberger, Lee A; Bhushan, Madhu; Bhushan, Rajat

    2011-07-01

    Cost can be an important consideration, along with safety and efficacy, in deciding the most appropriate treatment for patients with type 2 diabetes. Both basal-bolus and premixed insulin analogue regimens are widely used in clinical practice; however, limited information is available regarding cost-effectiveness. The goal of this study was to compare glycemic control, cost-effectiveness, and quality of life effects of insulin glargine plus insulin glulisine (glargine/glulisine) versus premixed insulin analogues in real-world clinical practice. Adults with type 2 diabetes (glycosylated hemoglobin [HbA(1c)] ≥7.0%) at 3 US endocrinology centers were randomly assigned to receive either glargine/glulisine or premixed insulin analogues and continued treatment following the centers' usual practice. HbA(1c), weight, insulin dose, concomitant oral antidiabetic drug (OAD) usage, and hypoglycemia were evaluated at baseline and 3, 6, and 9 months. Medication costs, including costs for all insulin or OAD regimens, were estimated using published wholesale acquisition costs. A total of 197 patients were randomized to receive glargine/glulisine therapy (n = 106) or premixed analogue therapy (n = 91). Overall, the mean age was 56 years, the mean duration of diabetes was 13 years, with a mean HbA(1c) of 9.25% and mean BMI of 35.8 kg/m(2) at baseline. Patients randomized to receive glargine/glulisine had a greater mean HbA(1c) reduction from baseline (-2.3%) than patients receiving a premixed analogue regimen (-1.7%). Adjusted mean follow-up HbA(1c) was 6.9% versus 7.5%, respectively (difference, -0.59%; P < 0.01). The glargine/glulisine group also used a lower mean number of OADs (0.86 vs 1.14; difference, -0.28; P = 0.04) but had a higher weight (240 vs 235 lb; difference, 4.55 lb; P = 0.03) than the premixed analogue group at follow-up. There were no significant differences in daily insulin dose and rates of hypoglycemia. Overall medication costs per 1.0% reduction in HbA(1c

  13. Synthesis and study of effects of new 4-chloro – amodiaquine analogues against two resistant and sensitive forms to chloroquine Plasmodium Falciparum, in vitro

    Directory of Open Access Journals (Sweden)

    afra Khosravi

    2009-03-01

    Full Text Available Background: Resistance to chloroquine (CQ in Plasmodium falciparum malaria has become a major health concern of the developing countries.This resistance has prompted a re-examination of the pharmacology of alternative antimalarials that may be effective against resistant strains. Amodiaquine (AQ is a 4-aminoquinoline antimalarial which is effective against many chloroquine-resistant strains of P. falciparum. However, clinical use of AQ has been severely restricted because of associations with hepatotoxicity and agranulocytosis. The aim of this study was to examine the effects of replacing the 4’OH function of amodiaquine with either chlorine or fluorine. Materials and Methods: A successful four-step synthesis of a new series of 4-chloro analogues has been designed and applied to the synthesis of an array of 10 analogues. Malaria parasites were maintained in continuous culture using the method of Jensen and Trager. Cultures were grown in flasks containing human erythrocytes (2-5% with parasitemia in the range of 1% to 10% suspended in RPMI 1640 medium supplemented with 25 mM HEPES and 32 mM NaHCO3, and 10% human serum (complete medium. Cultures were gassed with a mixture of 3% O2, 6% CO2 and 91% N2 and were kept in a 30 degree temperature. Results: It is apparent that several analogues had very potent antimalarial activity against both strains of the parasite. In particular 5b, 5c and 5i were not only active in the single nanomolar range, but they also displayed little cross-resistance. Against the sensitive HB3 strain, these analogues were superior to chloroquine and slightly more potent than amodiaquine. Activity was reduced when the side-chain was large (eg. dibutyl analogue and pyridine analogues, 5g and 5j respectively. Discussion: In a four - step Process, 10 different chloro - amodiaquine were synthesized which showed (in vitro Promising effects against chloroquine resistant strains of Plasmodium falciparum. It is clear that the 4

  14. RESONANCE

    Indian Academy of Sciences (India)

    rest of his career, except for the war years 1940-46 spent at the Institute for Advanced Study at Princeton. The 1945 Physics Nobel Prize was awarded to Pauli 'for the ... tribute, no less a person than Niels Bohr wrote: "At the same time as the anecdotes about his personality grew into a veritable legend, he more and more ...

  15. RESONANCE

    Indian Academy of Sciences (India)

    The wasp in question is Nasonia vitripennis and the study under consider- ation is by Dobson and Tanouye of the University of California at Berkeley. Nasonia vitripennis is a parasitoid wasp that is distributed throughout the world. Female wasps lay eggs in the pupae of flies that breed in carcasses and in bird nests. Like all.

  16. 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

  17. Treatment of experimental allergic encephalomyelitis (EAE) by a rationally designed cyclic analogue of myelin basic protein (MBP) epitope 72-85.

    Science.gov (United States)

    Tselios, T; Daliani, I; Deraos, S; Thymianou, S; Matsoukas, E; Troganis, A; Gerothanassis, I; Mouzaki, A; Mavromoustakos, T; Probert, L; Matsoukas, J

    2000-12-18

    In this report the rational design, synthesis and pharmacological properties of an amide-linked cyclic antagonist analogue of the guinea pig myelin basic protein epitope MBP(72-85) are described. Design of the potent cyclic analogue was based on 2D NOESY nuclear magnetic resonance and molecular dynamics studies carried out in the linear antagonist Ala81MBP(72-85). The cyclic antagonist completely prevented the induction of experimental allergic/autoimmune encephalomyelitis when coinjected with linear and cyclic agonist analogues MBP(72-85) and cyclo(2-9)MBP(72-85).

  18. Sleep in a Gymnasium: A Study to Examine the Psychophysiological and Environmental Conditions in Shelter-Analogue Settings

    Directory of Open Access Journals (Sweden)

    Koh Mizuno

    2016-11-01

    Full Text Available We aimed to examine sleep in shelter-analogue settings to determine the sleep and environmental conditions in evacuation shelters. A summer social/educational event was conducted in an elementary school, wherein children and their parents (n = 109 spent one night in the school gymnasium; a total of 15 children and 7 adults completed the study. Data were recording using wrist actigraphy and questionnaires, from two days before the event to two days after the event. During the night in the gymnasium, sleep initiation in the children was found to be significantly delayed, whereas adults did not show any significant change in actigraphic sleep parameters. Although 57% of adults complained of stiffness of the floor, only 7% of children had the same complaint. The nocturnal noise recorded at four locations in the gymnasium showed that the percentage of 1-min data epochs with a noise level >40 dB ranged from 53% to 74% during lights-out. The number of subjects that woke up during the night showed a similar pattern with the changes in the noise level. The changes in sleep might represent event-specific responses, such as to a noisy environment, and the different complaints between adults and children could be useful in shelter management.

  19. Anion Recognition by Pyrylium Cations and Thio-, Seleno- and Telluro- Analogues: A Combined Theoretical and Cambridge Structural Database Study

    Directory of Open Access Journals (Sweden)

    David Quiñonero

    2015-06-01

    Full Text Available Pyrylium salts are a very important class of organic molecules containing a trivalent oxygen atom in a six-membered aromatic ring. In this manuscript, we report a theoretical study of pyrylium salts and their thio-, seleno- and telluro- analogues by means of DFT calculations. For this purpose, unsubstituted 2,4,6-trimethyl and 2,4,6-triphenyl cations and anions with different morphologies were chosen (Cl–, NO3– and BF4–. The complexes were characterized by means of natural bond orbital and “atoms-in-molecules” theories, and the physical nature of the interactions has been analyzed by means of symmetry-adapted perturbation theory calculations. Our results indicate the presence of anion-π interactions and chalcogen bonds based on both σ- and π-hole interactions and the existence of very favorable σ-complexes, especially for unsubstituted cations. The electrostatic component is dominant in the interactions, although the induction contributions are important, particularly for chloride complexes. The geometrical features of the complexes have been compared with experimental data retrieved from the Cambridge Structural Database.

  20. Structural study of liposomes loaded with a GM3 lactone analogue for the targeting of tumor epitopes.

    Science.gov (United States)

    Ristori, Sandra; Di Cola, Emanuela; Lunghi, Carlotta; Richichi, Barbara; Nativi, Cristina

    2009-12-01

    Therapeutic vaccination with tumor antigens is a new approach in cancer treatment, which aims at inducing immune response while avoiding the side effects generally associated to many conventional therapies. To improve the efficacy of vaccines, suitable carriers may be used. Herein the insertion of a thioether analogue of GM3 lactone (SNeuAC-C14) into liposomes is reported. SNeuAC-C14 is a potential vaccine for the targeting of saccharide-based tumor epitopes. Different liposome formulations were designed to act as carriers and to generate recognition by tumor epitopes. The structural study of pure and loaded liposomes was carried out by synchrotron Small Angle X-ray Scattering and was complemented by Dynamic Light Scattering and Zeta potential measurements. This provided detailed information on relevant properties of the investigated host-guest structures and showed that the active unit of SNeuAC-C14, i.e. its spiro tricyclic moiety, was located in the polar head region of the liposome bilayer, which is an important requirement for recognition phenomena. Moreover, it was found that most of the SNeuAC-C14/liposome complexes were positively charged. The obtained results allow these systems to be considered as candidates to promote immunoresponse in tumor cells.

  1. Combining molecular docking and QSAR studies for modeling the anti-tyrosinase activity of aromatic heterocycle thiosemicarbazone analogues

    Science.gov (United States)

    Dong, Huanhuan; Liu, Jing; Liu, Xiaoru; Yu, Yanying; Cao, Shuwen

    2018-01-01

    A collection of thirty-six aromatic heterocycle thiosemicarbazone analogues presented a broad span of anti-tyrosinase activities were designed and obtained. A robust and reliable two-dimensional quantitative structure-activity relationship model, as evidenced by the high q2 and r2 values (0.848 and 0.893, respectively), was gained based on the analogues to predict the quantitative chemical-biological relationship and the new modifier direction. Inhibitory activities of the compounds were found to greatly depend on molecular shape and orbital energy. Substituents brought out large ovality and high highest-occupied molecular orbital energy values helped to improve the activity of these analogues. The molecular docking results provided visual evidence for QSAR analysis and inhibition mechanism. Based on these, two novel tyrosinase inhibitors O04 and O05 with predicted IC50 of 0.5384 and 0.8752 nM were designed and suggested for further research.

  2. Archaeological analogue studies for the prediction of long term corrosion on buried metals

    International Nuclear Information System (INIS)

    David, D.; Lemaitre, C.; Crusset, D.

    2003-01-01

    The prediction of the behaviour of metallic materials exposed to soil corrosion depends on many parameters. Any consideration of the effect of time, over long periods, can result only from a comparison with real cases of corrosion. It is the material-soil association which is the determining factor. This paper reports studies performed using modern techniques of materials science. The studies concern not only the characterisation of solid phase components, but corrosion products too and consequently it was also necessary to conduct electrochemical evaluations of corroded layer properties. (authors)

  3. A geostatistical model of facies-architecture and internal heterogeneity of Rotliegend-reservoirs developed from outcrop-analogues. Outcrop-analogue study Cutler Group (Utah/USA)

    Energy Technology Data Exchange (ETDEWEB)

    Irmen, A.

    2001-10-01

    The aim of this DGMK study was the collection of data that document the distribution of facies units within mixed fluvial/aeolian deposits. The Cutler Group of southeastern Utah was chosen as an outcrop analog since it contains all major lithofacies common within such deposits (aeolian dunes and interdunes, fluvial channel-films as well as lacustrine and Sabkha deposits). Because of the outstanding outcrop quality in this region, numerous detailed datasets could be collected, which allowed the visualization of size, distribution, and sedimentological inventory of the different facies in various ''paleogeographical'' maps and diagrams. A genetic model, which explains the presence of correlative horizons and cyclic patterns of deposition, could be developed. (orig.) [German] Zielsetzung dieses DGMK-Forschungsvorhabens war es, quantitative Daten zur Verteilung fazieller Einheiten innerhalb eines gemischt fluviatil/aeolischen Ablagerungsraums zu gewinnen. Die Cutler Group im Suedosten des amerikanischen Bundesstaates Utah wurde als Aufschlussanalog gewaehlt, in welchem die typischen Ablagerungen eines solchen Deposystems vorhanden sind (aeolische Duenen und -Interduenen, fluviatile Rinnenfuellungen, sowie lakustrine und Sabkha-Ablagerungen). Aufgrund der hervorragenden Aufschlusssituation konnten detaillierte Datensaetze gewonnen werden, welche die Darstellung von Groesse, bevorzugter Ausrichtung und Sedimentologie potentieller Heterogenitaetselemente entweder direkt als ''paleogeographische'' Karten, oder in statistischer Form ermoeglichten. Ein genetisches Modell erklaert die Zyklizitaet der Ablagerungen und die Anwesenheit von weitraeumig korrelierbaren Horizonten. (orig.)

  4. In Vitro Membrane Permeation Studies and in Vivo Antinociception of Glycosylated Dmt(1)-DALDA Analogues

    DEFF Research Database (Denmark)

    Ballet, Steven; Betti, Cecilia; Novoa, Alexandre

    2014-01-01

    In this study the μ opioid receptor (MOR) ligands DALDA (Tyr-d-Arg-Phe-Lys-NH2) and Dmt(1)-DALDA (Dmt-d-Arg-Phe-Lys-NH2, Dmt = 2',6'-dimethyltyrosine) were glycosylated at the N- or C-terminus. Subsequently, the modified peptides were subjected to in vitro and in vivo evaluation. In contrast to t...

  5. Medical Diagnostic Consultation concerning Mental Retardation: An Analogue Study of School Psychologists' Attitudes

    Science.gov (United States)

    Wodrich, David L.; Tarbox, Jennifer; Balles, John; Gorin, Joanna

    2010-01-01

    Recent research of relevance to school psychologists suggests that the cause, or etiology, of mental retardation can be established by medical diagnosticians in approximately one-half of cases. In the current study, 109 practicing school psychologists considered a hypothetical case of an elementary student with mental retardation and indicated…

  6. The role of metacognition and obsessive-compulsive symptoms in psychosis: an analogue study.

    Science.gov (United States)

    Hagen, Kristen; Solem, Stian; Opstad, Håvard Berg; Hansen, Bjarne; Hagen, Roger

    2017-06-29

    Several studies have indicated that obsessive-compulsive disorder (OCD) is a common comorbidity in patients with psychotic disorders, but there is sparse knowledge about the relationship between symptoms of OCD and psychotic symptoms. Metacognitions which guides thinking and coping is theorized to be a transdiagnostic component central for development and maintenance of psychological disorders, OCD and psychosis included. The aim of the study was therefore to explore how symptoms of OCD and metacognitions relate to symptoms of psychosis. Our main hypotheses were that metacognitions would be significantly related to all symptoms of psychological distress, and that there is considerable overlap between symptoms of psychosis and OCD. Community controls (N = 194) completed an internet survey measuring levels of paranoid ideation, predisposition to hallucinations, symptoms of OCD, depression, anxiety, and metacognitions. Correlations and hierarchical multiple linear regression analyses were used to unveil the relationship between symptoms and beliefs. Symptoms of OCD showed a strong positive correlation with symptoms of psychosis, and the relationships were still significant after controlling for symptoms of anxiety and depression. Metacognitions also showed strong positive correlations with all symptom measures. Metacognition and OCD-symptoms accounted for 53.8% of the variance in paranoid ideation and 43.8% of predisposition to hallucinations. There was a large overlap between symptoms of psychosis, OCD-symptoms, and metacognitions (30.2-37.3%). In general, the results suggest considerable overlap between paranoid ideation, predisposition to hallucinations, and OCD and metacognitive beliefs in a non-clinical sample. Further experimental- and clinical studies are needed in order to explore metacognitive models of OCD and psychosis.

  7. The use of messages in altering risky gambling behavior in college students: an experimental analogue study.

    Science.gov (United States)

    Jardin, Bianca; Wulfert, Edelgard

    2009-01-01

    This study examined the effects of messages on altering risky gambling behavior in college students. While playing a chance-based computerized game with play money, three groups of participants either viewed occasional accurate messages that correctly described the contingencies of the game, neutral messages unrelated to the contingencies, or no messages. Participants in the accurate message condition spent overall less money gambling, played fewer trials in the final phase of the game when all trials resulted in losses, and were more likely to quit the game while they still had money remaining in the bank. The findings suggest that "reminders" about the random nature of games and the overall negative rate of return might lead to more responsible gaming.

  8. In vitro study on potential pharmacological activity of curcumin analogues and their copper complexes.

    Science.gov (United States)

    Ferrari, Erika; Benassi, Rois; Saladini, Monica; Orteca, Giulia; Gazova, Zuzana; Siposova, Katarina

    2017-03-01

    Curcumin and its derivatives have attracted great interest in the prevention and treatment of Alzheimer's disease, thanks both to the ability to hinder the formation of amyloid-beta (Aβ) aggregates and the ability to bind Cu (II) ion. In this article, we explore the ability of curcumin derivatives of K2T series to affect amyloid Aβ 1-40 aggregation. These derivatives were obtained by introducing the t-butyl ester group through a methylenic spacer on the central carbon atom of the β-diketo moiety of curcumin frame. The studied curcuminoids were demonstrated to inhibit Aβ 1-40 fibrillization at substoichiometric concentrations with IC 50 value near that of curcumin. In addition, the antioxidant properties and DNA interaction of their Cu(II) complexes is evaluated. The structure of Cu(II)-K2T31 complex is also proposed on the basis of DFT calculation. © 2016 John Wiley & Sons A/S.

  9. Comparison of GLP-1 analogues versus sitagliptin in the management of type 2 diabetes: systematic review and meta-analysis of head-to-head studies.

    Directory of Open Access Journals (Sweden)

    Tiansheng Wang

    Full Text Available BACKGROUND: Incretin-based therapies which include glucagon-like peptide-1 (GLP-1 receptor agonists and dipeptidyl peptidase-4 (DPP-4 inhibitors are recommended by several practice guidelines as second-line agents for add-on therapy to metformin in patients with type 2 diabetes (T2DM who do not achieve glycemic control with metformin plus lifestyle interventions alone. The purpose of this study is to perform a systematic review with meta-analysis of existing head to head studies to compare the efficacy and safety of GLP-1 analogues with DPP-4 inhibitors. METHODS: We performed a systematic review and meta-analysis of head-to-head studies to compare GLP-1 analogues with DPP-4 inhibitors in the management of type 2 diabetes. A random effects model was selected to perform the meta-analyses, results were expressed as weighted mean differences for continuous outcomes and relative risks for dichotomous outcomes, both with 95% confidence intervals, and with I2 values and P values as markers of heterogeneity. RESULTS: Four head-to-head randomized controlled studies with 1755 patients were included. Compared to sitagliptin, GLP-1 analogues are more effective in reducing HbA1C (weight mean difference -0.41%, 95% CI -0.51 to -0.31 and body weight (weight mean difference -1.55 kg, 95% CI -1.98 to -1.12. Conversely, GLP-1 analogues are associated with a higher incidence of gastrointestinal adverse events compared to sitagliptin: nausea (relative risk 3.14, 95% CI 2.15 to 4.59, vomiting (relative risk 2.60, 95% CI 1.48 to 4.56, diarrhea (relative risk 1.82, 95% CI 1.24 to 2.69, and constipation (relative risk 2.50, 95% CI 1.33 to 4.70. CONCLUSIONS: The result of this meta-analysis demonstrates that compared to sitagliptin, GLP-1 analogues are more effective for glycemic control and weight loss, but have similar efficacy in reducing blood pressure and lipid parameters, however, GLP-1 analogues are associated with a higher incidence of gastrointestinal adverse

  10. Natural analogue study on backfill materials from ancient Chinese constructions for LILW disposal. Appendix 5: China (b)

    International Nuclear Information System (INIS)

    Cunli, G.; Zhiwen, F.; Xiuzhen, L.; Yawen, H.; Anxi, C.; Jinsheng, Z.

    2001-01-01

    Full text: The objective of this work was to contribute to the demonstration of the long term safety of low-and-intermediate level radioactive waste (LILW) disposal using information from a natural analogue study on ancient Chinese constructions. The work firstly compared LILW near surface disposal facilities with Chinese ancient tombs in respects of siting, engineering structures, design and construction procedures and indicates that they are both based upon multi-barrier principle. After extensive literature and field survey, three materials were collected from two Chinese ancient tombs and one ancient architectures for further laboratory study. The three materials were studied in laboratories from the point of view of radioactive waste disposal in near surface facilities to obtain information concerning their basic physical and chemical properties, engineering properties and radionuclide adsorption abilities. The results show that the two materials from the ancient tombs have low permeability and strong adsorption for 60 Co and 134 Cs. The saturated permeabilities of the two ancient materials are in the order of 10 -1 0 m/s and the distribution coefficients for the two radionuclides are all in the order of 10 1 m 3 /kg. The conclusion was that the then current LILW disposal option in near-surface would be effective for a long term period of time, and clay materials, as backfill materials for LILW near-surface disposal facilities would very effective in preventing water intrusion and retarding radionuclide release even over a long term of period. Overall the LILW disposal option was considered to be safe in long term. (author)

  11. VIS/NIR reflectance and fluorescence spectrometric studies of minerals, water, organics and biomarkers in MoonMars analogue samples

    Science.gov (United States)

    Vos, Heleen; Foing, Bernard; Kołodziejczyk, Agata; Vago, Jorge; Harasymczuk, Matt

    2017-04-01

    This study focuses on the detection and characterisation of elements, minerals, volatiles and organics using reflectance spectrometry. The goal is to create a calibration method to enable the use of spectrometers on analogue Moon/Mars missions and on a lander. For this study we use measurements that are done in the VIS and NIR spectrum, as well as fluorescence using different spectrometers. The first part of the study consists of measurements that are performed in a laboratory to create a calibration method. Different rock samples and soils are analysed and the reflectance and absorption of minerals, water, organics and biomarkers are measured. Also the influence of the grain size, light source and surroundings is being determined. An experiment on the reflectance spectra of plant growth in different soils is also done to determine the possibilities of detecting the presence of chlorophyll and other biomarkers, and to diagnose the growth and health of a plant. This analysis can result in a monitoring method for a Moon greenhouse, but also for general surface analysis. Using VIS and NIR spectrometry has a couple of advantages, one being the fact that measurements require no sample preparation, and also the small size of the spectrometer makes it an easy tool for different analyses on board space missions. However, VIS and NIR spectroscopy have detection limits which makes only certain characteristics detectable. Besides laboratory measurements, the different spectroscopy methods are tested during a field campaign in the Eifel, Germany. During this campaign we can determine the functionality of the spectrometer in the field and on a lander and the problems that can rise when a spectrometer is controlled from a distant or by a person who is not trained in using spectroscopy. These laboratory and field measurements can help in the scientific preparation for instruments on ExoMars rover, future MoonMars lander missions and for the MoonVillage.

  12. Synthesis and sar study of diarylpentanoid analogues as new anti-inflammatory agents.

    Science.gov (United States)

    Leong, Sze Wei; Faudzi, Siti Munirah Mohd; Abas, Faridah; Aluwi, Mohd Fadhlizil Fasihi Mohd; Rullah, Kamal; Wai, Lam Kok; Bahari, Mohd Nazri Abdul; Ahmad, Syahida; Tham, Chau Ling; Shaari, Khozirah; Lajis, Nordin H

    2014-10-09

    A series of ninety-seven diarylpentanoid derivatives were synthesized and evaluated for their anti-inflammatory activity through NO suppression assay using interferone gamma (IFN-γ)/lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Twelve compounds (9, 25, 28, 43, 63, 64, 81, 83, 84, 86, 88 and 97) exhibited greater or similar NO inhibitory activity in comparison with curcumin (14.7 ± 0.2 µM), notably compounds 88 and 97, which demonstrated the most significant NO suppression activity with IC50 values of 4.9 ± 0.3 µM and 9.6 ± 0.5 µM, respectively. A structure-activity relationship (SAR) study revealed that the presence of a hydroxyl group in both aromatic rings is critical for bioactivity of these molecules. With the exception of the polyphenolic derivatives, low electron density in ring-A and high electron density in ring-B are important for enhancing NO inhibition. Meanwhile, pharmacophore mapping showed that hydroxyl substituents at both meta- and para-positions of ring-B could be the marker for highly active diarylpentanoid derivatives.

  13. Synthesis and Sar Study of Diarylpentanoid Analogues as New Anti-Inflammatory Agents

    Directory of Open Access Journals (Sweden)

    Sze Wei Leong

    2014-10-01

    Full Text Available A series of ninety-seven diarylpentanoid derivatives were synthesized and evaluated for their anti-inflammatory activity through NO suppression assay using interferone gamma (IFN-γ/lipopolysaccharide (LPS-stimulated RAW264.7 macrophages. Twelve compounds (9, 25, 28, 43, 63, 64, 81, 83, 84, 86, 88 and 97 exhibited greater or similar NO inhibitory activity in comparison with curcumin (14.7 ± 0.2 µM, notably compounds 88 and 97, which demonstrated the most significant NO suppression activity with IC50 values of 4.9 ± 0.3 µM and 9.6 ± 0.5 µM, respectively. A structure–activity relationship (SAR study revealed that the presence of a hydroxyl group in both aromatic rings is critical for bioactivity of these molecules. With the exception of the polyphenolic derivatives, low electron density in ring-A and high electron density in ring-B are important for enhancing NO inhibition. Meanwhile, pharmacophore mapping showed that hydroxyl substituents at both meta- and para-positions of ring-B could be the marker for highly active diarylpentanoid derivatives.

  14. Interaction of chloroquine and its analogues with heme: An isothermal titration calorimetric study.

    Science.gov (United States)

    Bachhawat, K; Thomas, C J; Surolia, N; Surolia, A

    2000-10-05

    Quinoline-containing drugs such as chloroquine and quinine have had a long and successful history in antimalarial chemotherapy. Identification of ferriprotoporphyrin IX ([Fe(III)PPIX], haematin) as the drug receptors for these antimalarials called for investigations of the binding affinity, mode of interaction, and the conditions affecting the interaction. The parameters obtained are significant in recent times with the emergence of chloroquine resistant strains of the malaria parasites. This has underlined the need to unravel the molecular mechanism of their action so as to meet the requirement of an alternative to the existing antimalarial drugs. The isothermal titration calorimetric studies on the interaction of chloroquine with haematin lead us to propose an altered mode of binding. The initial recognition is ionic in nature mediated by the propionyl group of haematin with the quaternary nitrogen on CQ. This ionic interaction induces a conformational change, such as to favour binding of subsequent CQ molecules. On the contrary, conditions emulating the cytosolic environment (pH 7.4 and 150 mM salt) reveal the hydrophobic force to be the sole contributor driving the interaction. Interaction of a carefully selected panel of quinoline antimalarial drugs with monomeric ferriprotoporphyrin IX has also been investigated at pH 5.6 mimicking the acidic environment prevalent in the food vacuoles of parasite, the center of drug activity, which are consistent with their antimalarial activity. Copyright 2000 Academic Press.

  15. Natural analogue and microstructural studies in relation to radionuclide retardation by rock matrix diffusion in granite

    International Nuclear Information System (INIS)

    Montoto, M.; Rodriguez Rey, A.; Ruiz de Argandona, V.G.; Calleja, L.; Menendez, B.

    1992-01-01

    The possibility that radionuclide retardation by rock matrix diffusion will be limited in granitic rocks by geological factors is studied, as well as the possibility that diffusion will be confined to a narrow zone from water-conducting fractures. Petrophysical measurements, uranium series and geochemical analyses in the rock adjacent to fractures, have been performed to establish the extent of fracture-related microstructural changes that might influence the potential for diffusion and whether or not there is any record of diffusion of uranium, its daughters, or other elements. The results obtained from El Berrocal (Spain), Stripa (Sweden) and White-shell (Canada) granites, suggest that: (a) there is a zone adjacent to the fractures (generally less than 100 mm) where microstructural changes and enhanced uranium mobility exist; (b) the evidence for diffusion having taken place in the rock is confined largely to this zone. So, it appears that diffusivity determinations on rock collected away from the influence of fractures will not give representative data for diffusion modelling, in addition to the effect of distressing after removing rocks from depth. It is suggested that diffusion will be of limited effectiveness as a retardation mechanism in many granitic rocks, particularly in water movement confined to narrow channels where access by nuclides to the fracture walls is restricted. 51 refs., 56 figs., 9 tabs., 9 appendices

  16. 3D-QSAR study and design of 4-hydroxyamino α-pyranone carboxamide analogues as potential anti-HCV agents

    Science.gov (United States)

    Li, Wenlian; Xiao, Faqi; Zhou, Mingming; Jiang, Xuejin; Liu, Jun; Si, Hongzong; Xie, Meng; Ma, Xiuting; Duan, Yunbo; Zhai, Honglin

    2016-09-01

    The three dimensional-quantitative structure activity relationship (3D-QSAR) study was performed on a series of 4-hydroxyamino α-pyranone carboxamide analogues using comparative molecular similarity indices analysis (COMSIA). The purpose of the present study was to develop a satisfactory model providing a reliable prediction based on 4-hydroxyamino α-pyranone carboxamide analogues as anti-HCV (hepatitis C virus) inhibitors. The statistical results and the results of validation of this optimum COMSIA model were satisfactory. Furthermore, analysis of the contour maps helped to provide guidelines for finding structural requirement. Therefore, the satisfactory results from this study may provide useful guidelines for drug development of anti-HCV inhibitors.

  17. Natural glass analogues to alteration of nuclear waste glass: A review and recommendations for further study

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, W.F.

    1990-01-01

    The purpose of this report is to review previous work on the weathering of natural glasses; and to make recommendations for further work with respect to studying the alteration of natural glasses as it relates quantifying rates of dissolution. the first task was greatly simplified by the published papers of Jercinovic and Ewing (1987) and Byers, Jercinovic, and Ewing (1987). The second task is obviously the more difficult of the two and the author makes no claim of completeness in this regard. Glasses weather in the natural environment by reacting with aqueous solutions producing a rind of secondary solid phases. It had been proposed by some workers that the thickness of this rind is a function of the age of the glass and thus could be used to estimate glass dissolution rates. However, Jercinovic and Ewing (1987) point out that in general the rind thickness does not correlate with the age of the glass owing to the differences in time of contact with the solution compared to the actual age of the sample. It should be noted that the rate of glass dissolution is also a function of the composition of both the glass and the solution, and the temperature. Quantification of the effects of these parameters (as well as time of contact with the aqueous phase and flow rates) would thus permit a prediction of the consequences of glass-fluid interactions under varying environmental conditions. Defense high- level nuclear waste (DHLW), consisting primarily of liquid and sludge, will be encapsulated by and dispersed in a borosilicate glass before permanent storage in a HLW repository. This glass containing the DHLW serves to dilute the radionuclides and to retard their dispersion into the environment. 318 refs.

  18. Analogue Experimental Study of Debris Entrainment by Ice Growing into Supercooled Water

    Science.gov (United States)

    Spannuth, M.; Wettlaufer, J. S.

    2007-12-01

    Field studies have identified several processes by which glaciers and ice sheets can accumulate debris-rich basal ice. Although significant effort has gone into modeling these processes and the inferred effects on glacier dynamics, there is a dearth of laboratory investigations. In particular, in several field settings debris entrainment by frazil ice growing in glaciohydraulically supercooled water channels has been suggested as the source of the dirty basal ice. However, the physical mechanisms by which frazil ice actually traps the sediment and then incorporates it into the basal ice remain unclear. In order to clarify this process, we have frozen solutions of 140 nm-diameter silica spheres dispersed in water in a 400 micron-thick cell supercooled to between -2 and -6 C. The thinness of the cell results in an essentially two-dimensional ice fabric, thus allowing us to observe the particle distribution and movement during freezing and subsequent coarsening. During the nucleation and unstable growth of the ice we find that many particles segregate to the liquid interstices between ice dendrites. Over the next 10 seconds the inter-dendrite liquid freezes and some particles become trapped between dendrites while some are pushed ahead of the ice front. As the ice coarsens over several days, particles migrate through the ice due to temperature gradient regelation and move with the grain boundaries/veins/nodes, which evolve to accommodate the coarsening. While the physical conditions in our experiment do not correspond exactly to those of subglacial conduits, our observations of the microscopic dynamics of particles during the freezing and evolution of supercooled, sediment-laden water can help guide future experiments and provide insight into the ice and sediment textures observed in glacier basal ice.

  19. Pavlovian disgust conditioning as a model for contamination-based OCD: Evidence from an analogue study.

    Science.gov (United States)

    Armstrong, Thomas; Olatunji, Bunmi O

    2017-06-01

    Pavlovian fear conditioning provides a model for anxiety-related disorders, including obsessive-compulsive disorder (OCD). However, disgust is the predominant emotional response to contamination, which is a common theme in OCD. The present study sought to identify disgust conditioning abnormalities that may underlie excessive contamination concerns relevant to OCD. Individuals high and low in contamination concern (HCC, n = 32; LCC, n = 30) completed an associative learning task in which one neutral face (conditioned stimulus; CS+) was followed by a disgusting image (unconditioned stimulus; US) and another neutral face (CS-) was unreinforced. Following this acquisition procedure, there was an extinction procedure in which both CSs were presented unreinforced. The groups did not show significant differences in discriminant responding to the CSs following acquisition. However, following extinction, the HCC group reported less reduction in their expectancy of the US following the CS+, and also reported greater disgust to the CS+, compared to the LCC group. Increased disgust to the CS+ following both acquisition and extinction was correlated with increased symptoms of contamination-based OCD and increased disgust sensitivity. Additionally, disgust sensitivity mediated group differences in disgust responding to the CS+ at acquisition and extinction. Also, failure to adjust US expectancy in response to extinction partially mediated group differences in disgust to the CS+ following extinction. Together, these findings suggest that excessive contamination concerns observed in OCD may be related to difficulty inhibiting acquired disgust, possibly due to elevated disgust sensitivity that characterizes the disorder. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Natural glass analogues to alteration of nuclear waste glass: A review and recommendations for further study

    International Nuclear Information System (INIS)

    McKenzie, W.F.

    1990-01-01

    The purpose of this report is to review previous work on the weathering of natural glasses; and to make recommendations for further work with respect to studying the alteration of natural glasses as it relates quantifying rates of dissolution. the first task was greatly simplified by the published papers of Jercinovic and Ewing (1987) and Byers, Jercinovic, and Ewing (1987). The second task is obviously the more difficult of the two and the author makes no claim of completeness in this regard. Glasses weather in the natural environment by reacting with aqueous solutions producing a rind of secondary solid phases. It had been proposed by some workers that the thickness of this rind is a function of the age of the glass and thus could be used to estimate glass dissolution rates. However, Jercinovic and Ewing (1987) point out that in general the rind thickness does not correlate with the age of the glass owing to the differences in time of contact with the solution compared to the actual age of the sample. It should be noted that the rate of glass dissolution is also a function of the composition of both the glass and the solution, and the temperature. Quantification of the effects of these parameters (as well as time of contact with the aqueous phase and flow rates) would thus permit a prediction of the consequences of glass-fluid interactions under varying environmental conditions. Defense high- level nuclear waste (DHLW), consisting primarily of liquid and sludge, will be encapsulated by and dispersed in a borosilicate glass before permanent storage in a HLW repository. This glass containing the DHLW serves to dilute the radionuclides and to retard their dispersion into the environment. 318 refs

  1. Complexation and biodistribution study of 111In complexes of bifunctional phosphinic acid analogues of H4DOTA

    Czech Academy of Sciences Publication Activity Database

    Forsterová, Michaela; Zimová, Jana; Petrík, M.; Lázníček, M.; Lázníčková, A.; Hermann, P.; Melichar, František

    2007-01-01

    Roč. 2, č. 337 (2007), s. 34-34 ISSN 1619-7070 R&D Projects: GA AV ČR 1QS100480501 Institutional research plan: CEZ:AV0Z10480505 Keywords : bifunctional H4DOTA ligands * phosphinic acid analogues, * complexation of 111In Subject RIV: FR - Pharmacology ; Medidal Chemistry

  2. Collaborative Student Laboratory Exercise Using FT-IR Spectroscopy for the Kinetics Study of a Biotin Analogue

    Science.gov (United States)

    Leong, Jhaque; Ackroyd, Nathan C.; Ho, Karen

    2014-01-01

    The synthesis of N-methoxycarbonyl-2-imidazolidone, an analogue of biotin, was conducted by organic chemistry students and confirmed using FT-IR and H NMR. Spectroscopy students used FT-IR to measure the rate of hydrolysis of the product and determined the rate constant for the reaction using the integrated rate law. From the magnitude of the rate…

  3. Synthesis, biodistribution and PET studies in rats of F-18-Labeled bridgehead fluoromethyl analogues of WAY-100635

    NARCIS (Netherlands)

    Al Hussainy, Rana; Verbeek, Joost; van der Born, Dion; Molthoff, Carla; Booij, Jan; Herscheid, J. Koos D. M.

    2012-01-01

    Introduction: In vitro screening of fluoromethyl bridge-fused ring (BFR) analogues of WAY-100635 (5a, 5b and 5c) has shown a high binding affinity and a good selectivity for the 5-HT1A receptor. As these compounds were designed to provide PET ligands with high metabolic stability, they are now

  4. Experimental study of resonance fiber optic gyroscope employing a dual-ring resonator

    Science.gov (United States)

    Fan, Yue; Wang, Wei

    2016-09-01

    A dual-ring resonator which is available to alter the full width at half maximum (FWHM) without altering the free spectrum range (FSR) for practice applications is analyzed theoretically and set up in practice. The parameters of the dual-ring resonator have been optimized in simulation, the resonance depth and the dynamic range are enhanced. The prototype is set up with single mode fiber of 8 meter and two 95 : 5 couplers for open loop experiment. The FWHM of the dual-ring resonator is demonstrated less than 1.5MHz and the fineness is calculated to be 37 during the frequency sweeping experiment. The frequency locking experiment with demodulation curve method has been accomplished, and the locking time achieves less than 40ms. All these provide a basic reference for optimizing the resonance fiber optic gyro based on dual-ring resonator.

  5. Electron paramagnetic resonance study on irradiated green coffee

    International Nuclear Information System (INIS)

    Brasoveanu, Mirela; Nemtanu, Monica R.; Grecu, Maria Nicoleta

    2006-01-01

    Electron paramagnetic resonance (EPR) is a well-known method for its sensitivity and accuracy in irradiated food detection. Our goal is to analyse the irradiated green coffee by EPR. Arabica beans and grounded coffee was electron beam irradiated up to 40 kGy. The EPR spectra and time dependence of signals were studied. Results were analysed with respect to find a possibility to identify irradiated green coffee. (authors)

  6. The interplay between subduction and lateral extrusion: A case study for the European Eastern Alps based on analogue models

    Science.gov (United States)

    van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.; Cloetingh, S. A. P. L.

    2017-08-01

    A series of analogue experiments simulating intra-continental subduction contemporaneous with lateral extrusion of the upper plate are performed to study the interference between these two processes at crustal levels and in the lithospheric mantle. The models demonstrate that intra-continental subduction and coeval lateral extrusion of the upper plate are compatible processes leading to similar deformation structures within the extruding region as compared to the classical setup, lithosphere-scale indentation. Strong coupling across the subduction boundary allows for the transfer of stresses to the upper plate, where strain regimes are characterized by crustal thickening near a confined margin and dominated by lateral displacement of material near a weak lateral confinement. The strain regimes propagate laterally during ongoing convergence creating an area of overlap characterized by transpression. When subduction is oblique to the convergence direction, the upper plate is less deformed and as a consequence the amount of lateral extrusion decreases. In addition, strain is partitioned along the oblique plate boundary resulting in less subduction in expense of right lateral displacement close to the weak lateral confinement. Both oblique and orthogonal subduction models have a strong resemblance to lateral extrusion tectonics of the Eastern Alps (Europe), where subduction of the adjacent Adriatic plate beneath the Eastern Alps is debated. Our results imply that subduction of Adria is a valid mechanisms to induce extrusion-type deformation within the Eastern Alps lithosphere. Furthermore, our findings suggest that the Oligocene to Late Miocene structural evolution of the Eastern Alps reflects a phase of oblique subduction followed by a later stage of orthogonal subduction conform a Miocene shift in the plate motion of Adria. Oblique subduction also provides a viable mechanism to explain the rapid decrease in slab length of the Adriatic plate beneath the Eastern Alps

  7. Microbiological analysis at the Osamu Utsumi mine and Morro do Ferro analogue study sites, Pocos de Caldas, Brazil

    International Nuclear Information System (INIS)

    West, J.M.; Vialta, A.; McKinley, I.G.

    1990-01-01

    The Pocos de Caldas project is a wide-ranging natural analogue study focussed on a number of areas of concern in the performance assessment of the disposal of radioactive waste. Part of the work has involved characterising microbial populations and their influence in various processes. Core material and groundwaters have been sampled for microbiological content at various depths form boreholes at the Osamu Utsumi open pit uranium mine and Morro do Ferro Th/REE ore body. Microbes were found in all samples but numbers do not appear to be related to depth. Analyses of groundwaters gave higher numbers than with solid material and demonstrated the presence of sulphur cycle bacteria. These observations have been compared with predictions of a model used in performance assessment to calculate the maximum biomass/microbial activity based on constraints set by available nutrients and energy. The main conclusions of this analysis are: 1. Low microbial activities can be supported by the energy and nutrients supplied by alteration processes at or around the redox front. The maximum annual production of approximately equal to 0.01 - 0.1 g biomass (dry)/m 2 of redox front is in reasonable agreement with observed standing populations. 2. The presence of high concentrations of sulphate reducing bacteria around the redox front indicate a complex sulphur geochemistry which may be predominantly microbially catalysed and could explain the nodular form of pitchblende concretions and the presence of secondary pyrite. 3. There is little trace element mobilisation by organic byproducts and the main role of microbes in this system is to catalyse specific redox reactions. (au)

  8. Familial Essential Tremor Studied With Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Hernandez, A.; Salgado, P.; Gil, A.; Barrios, F. A.

    2003-09-01

    Functional Magnetic Resonance Imaging has become an important analytical tool to study neurodegenerative diseases. We applied the EPI-BOLD functional Magnetic Resonance Imaging technique to acquire functional images of patients with familial essential tremor (FET) disorder and healthy control volunteers, during a motor task activity. Functional and anatomic images were used to produce the brain activation maps of the patients and volunteers. These functional maps of the primary somatosensorial and motor cortexes of patients and control subjects were compared for functional differences per subject. The averaged functional brain images of eight of each case were acquired were, it can be clearly observed the differences in active zones. The results presented in this work show that there are differences in the functional maps during motor task activation between control subjects and FET patients suggesting a cerebral functional reorganization that can be mapped with BOLD-fMRI.

  9. A study of spinal cord tumors by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Gushiken, Isao; Nishihira, Takeshi; Nakasone, Tomohiro; Takara, Hiroaki; Oshiro, Yutaka; Oshiro, Takashi; Isa, Makoto; Kinjo, Yukio; Ibaraki, Kunio.

    1989-01-01

    We studied 17 cases of spinal cord tumors using magnetic resonance imaging. According to the intensity of image and histological feature of spinal cord tumors, we identified two groups in T2 weighted imaging. One was a hypointensity group showing cystic or vascular tumors, and the other was hyperintensity group of solid tumors. Preoperative images of swelling, narrowing, deviation of the spinal cord were remained after the operations. Grafted free fatty tissue for the prevention of adhesion was recognized well also after the operation. Postoperative imagings sometime showed pseudo-deviation of the spinal cord which was easy to be mistaken as the remains of tumors and narrowing of the spinal cord. In conclusion, the magnetic resonance imaging makes very early detection of spinal cord tumors possible, and it is valuable for a diagnosis of the spinal cord tumor associated with brain tumor. (author)

  10. Comparative study of the effect of BPA and its selected analogues on hemoglobin oxidation, morphological alterations and hemolytic changes in human erythrocytes.

    Science.gov (United States)

    Maćczak, Aneta; Bukowska, Bożena; Michałowicz, Jaromir

    2015-01-01

    Bisphenol A (BPA) has been shown to provoke many deleterious impacts on human health, and thus it is now successively substituted by BPA analogues, whose effects have been poorly investigated. Up to now, only one study has been realized to assess the effect of BPA on human erythrocytes, which showed its significant hemolytic and oxidative potential. Moreover, no study has been conducted to evaluate the effect of BPA analogues on red blood cells. The purpose of the present study was to compare the impact of BPA and its selected analogues such as bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) on hemolytic and morphological changes and hemoglobin oxidation (methemoglobin formation) of human erythrocytes. The erythrocytes were incubated with different bisphenols concentrations ranging from 0.5 to 500μg/ml for 1, 4 and 24h. The compounds examined caused hemolysis in human erythrocytes with BPAF exhibiting the strongest effect. All bisphenols examined caused methemoglobin formation with BPA inducing the strongest oxidative potential. Flow cytometry analysis showed that all bisphenols (excluding BPS) induced significant changes in erythrocytes size. Changes in red blood cells shape were conducted using phase contrast microscopy. It was noticed that BPA and BPAF induced echinocytosis, BPF caused stomatocytosis, while BPS did not provoke significant changes in shape of red blood cells. Generally, the results showed that BPS, which is the main substituent of bisphenol A in polymers and thermal paper production, exhibited significantly lower disturbance of erythrocyte functions than BPA. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Structure-activity relationships of β-hydroxyphosphonate nucleoside analogues as cytosolic 5'-nucleotidase II potential inhibitors: synthesis, in vitro evaluation and molecular modeling studies.

    Science.gov (United States)

    Meurillon, Maïa; Marton, Zsuzsanna; Hospital, Audrey; Jordheim, Lars Petter; Béjaud, Jérôme; Lionne, Corinne; Dumontet, Charles; Périgaud, Christian; Chaloin, Laurent; Peyrottes, Suzanne

    2014-04-22

    The cytosolic 5'-nucleotidase II (cN-II) has been proposed as an attractive molecular target for the development of novel drugs circumventing resistance to cytotoxic nucleoside analogues currently used for treating leukemia and other malignant hemopathies. In the present work, synthesis of β-hydroxyphosphonate nucleoside analogues incorporating modifications either on the sugar residue or the nucleobase, and their in vitro evaluation towards the purified enzyme were carried out in order to determine their potency towards the inhibition of cN-II. In addition to the biochemical investigations, molecular modeling studies revealed important structural features for binding affinities towards the target enzyme. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  12. Facies-architecture of fossil arid siliciclastic depositional systems as outcrop analogue for Rotliegend reservoirs. Literature study; Faziesarchitektur fossiler arid-klastischer Ablagerungsraeume als Rotliegend-Reservoiranalog. Literaturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Irmen, A.

    1999-08-01

    In this project a literature-based study was carried out in order to document the facies-architecture of siliciclastic sediments from arid environments and to investigate their suitability as outcrop-analogues for the strata of the Southern Permian Basin. The report resulting from this investigation presents possible analogues and case-studies. Three Formations (Flechtingen Sandstone, Corrie Sandstone and Cedar Mesa Sandstone of the Cutler Group) are especially well suited to serve as outcrop analogue for the 'Rotliegend' Sediments of the Southern Permian Basin. Possible analogues are documented at various scales, ranging from bed-scale to formation scale. Also, special attention was paid to general trends and what factors control them. To make a comparison of Formations from different settings possible, criteria were elaborated to qualify the relevant controlling factors. The catalog itself is preceded by a comprehensive preface, that introduces to the subject and points out the connection between the primary sediment fabric and its petrophysical properties. (orig.) [German] Im Rahmen dieses DGMK Forschungsvorhabens wurde eine Literaturstudie durchgefuehrt, welche die Faziesarchitektur fossiler arid-klastischer Sedimente darstellt und auf ihre Eignung als Rotliegend-Reservoiranalog untersucht. Die vorliegende Dokumentation stellt verschiedene moegliche Analoge und Fallbeispiele dar, wobei drei Abfolgen als besonders geeignet erscheinen. Es wurden Kriterien erarbeitet, die relevante Kontrollfaktoren qualifizieren, um einen Vergleich verschiedener arid-klastischer Sedimentationsraeume zu ermoeglichen. Die Bandbreite der Darstellung moeglicher Analoge umfasst das gesamte Spektrum vom Gefuegemassstab bis hin zu genetischen Einheiten und beleuchtet die jeweiligen Steuerungsfaktoren der Ablagerung. Der eigentlichen Dokumentation wurde eine umfassende Einleitung vorangestellt, welche in die Thematik einfuehrt und Zusammenhaenge zwischen primaerem

  13. Global profiling and rapid matching of natural products using diagnostic product ion network and in silico analogue database: Gastrodia elata as a case study.

    Science.gov (United States)

    Lai, Chang-Jiang-Sheng; Zha, Liangping; Liu, Da-Hui; Kang, Liping; Ma, Xiaojing; Zhan, Zhi-Lai; Nan, Tie-Gui; Yang, Jian; Li, Fajie; Yuan, Yuan; Huang, Lu-Qi

    2016-07-22

    Rapid discovery of novel compounds of a traditional herbal medicine is of vital significance for pharmaceutical industry and plant metabolic pathway analysis. However, discovery of unknown or trace natural products is an ongoing challenge. This study presents a universal targeted data-independent acquisition and mining strategy to globally profile and effectively match novel natural product analogues from an herbal extract. The famous medical plant Gastrodia elata was selected as an example. This strategy consists of three steps: (i) acquisition of accurate parent and adduct ions (PAIs) and the product ions data of all eluting compounds by untargeted full-scan MS(E) mode; (ii) rapid compound screening using diagnostic product ions (DPIs) network and in silico analogue database with SUMPRODUCT function to find novel candidates; and (iii) identification and isomerism discrimination of multiple types of compounds using ClogP and ions fragment behavior analyses. Using above data mining methods, a total of 152 compounds were characterized, and 70 were discovered for the first time, including series of phospholipids and novel gastroxyl derivatives. Furthermore, a number of gastronucleosides and phase II metabolites of gastrodin and parishins were discovered, including glutathionylated, cysteinylglycinated and cysteinated compounds, and phosphatidylserine analogues. This study extended the application of classical DPIs filter strategy and developed a structure-based screening approach with the potential for significant increase of efficiency for discovery and identification of trace novel natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Nitrenium ions and trivalent boron ligands as analogues of N-heterocyclic carbenes in olefin metathesis: a computational study.

    Science.gov (United States)

    Pazio, A; Woźniak, K; Grela, K; Trzaskowski, B

    2015-12-14

    We used the density functional theory to evaluate the suitability of nitrenium ions and trivalent boron ligands as analogues of N-heterocyclic carbenes in ruthenium-based metathesis catalysts. We demonstrate that these analogues induce only minor structural changes in Hoveyda-Grubbs-like precatalysts, but have major impact on precatalyst initiation. Nitrenium ion-modified precatalysts are characterized by a weak Ru-N bond resulting in a relatively strong Ru-O bond and large free energy barriers for initiation, making them good candidates for efficient latent Ru-based catalysts. On the other hand the trivalent boron ligand, bearing a formal -1 charge, binds strongly to the ruthenium ion, weakening the Ru-O bond and facilitating its dissociation, to promote fast reaction initiation. We show that the calculated bond dissociation energy of the Ru-C/N/B bond may serve as an accurate indicator of the Ru-O bond strength and the rate of metathesis initiation.

  15. Comparative study of purine and pyrimidine nucleoside analogues acting on the thymidylate kinases of Mycobacterium tuberculosis and of humans.

    OpenAIRE

    Pochet , Sylvie; Dugué , Laurence; Labesse , Gilles; Delepierre , Muriel; Munier-Lehmann , Hélène

    2003-01-01

    Thymidine monophosphate kinase (TMPK) from Mycobacterium tuberculosis (TMPKmt) is an attractive target for the design of specific inhibitors. This fact is the result of its key role in the thymidine pathway and of unique structural features in the active site observed by X-ray crystallography, especially in comparison to its human counterpart (TMPKh). Different 5-modified thymidine derivatives, as well as purine and pyrimidine analogues or C-nucleosides were tested on TMPKmt and TMPKh, and th...

  16. A Systematic ab initio Study of the Hydration of Selected Palladium Square-Planar Complexes. A Comparison with Platinum Analogues

    Czech Academy of Sciences Publication Activity Database

    Zeizinger, M.; Burda, J. V.; Šponer, Jiří; Kapsa, V.; Leszczynski, J.

    2001-01-01

    Roč. 105, č. 34 (2001), s. 8086-8092 ISSN 0305-4470 R&D Projects: GA AV ČR IAA4050702; GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4040901 Keywords : palladium square-planar complexes * platinum analogues * ab initio Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.542, year: 2001

  17. The influence of joint parameters on normal fault evolution and geometry: a parameter study using analogue modeling

    Science.gov (United States)

    Kettermann, Michael; von Hagke, Christoph; Urai, Janos L.

    2017-04-01

    Dilatant faults often form in rocks containing pre-existing joints, but the effects of joints on fault segment linkage and fracture connectivity is not well understood. Studying evolution of dilatancy and influence of fractures on fault development provides insights into geometry of fault zones in brittle rocks and will eventually allow for predicting their subsurface appearance. In an earlier study we recognized the effect of different angles between strike direction of vertical joints and a basement fault on the geometry of a developing fault zone. We now systematically extend the results by varying geometric joint parameters such as joint spacing and vertical extent of the joints and measuring fracture density and connectivity. A reproducibility study shows a small error-range for the measurements, allowing for a confident use of the experimental setup. Analogue models were carried out in a manually driven deformation box (30x28x20 cm) with a 60° dipping pre-defined basement fault and 4.5 cm of displacement. To produce open joints prior to faulting, sheets of paper were mounted in the box to a depth of 5 cm at a spacing of 2.5 cm. We varied the vertical extent of the joints from 5 to 50 mm. Powder was then sieved into the box, embedding the paper almost entirely (column height of 19 cm), and the paper was removed. During deformation we captured structural information by time-lapse photography that allows particle imaging velocimetry analyses (PIV) to detect localized deformation at every increment of displacement. Post-mortem photogrammetry preserves the final 3-dimensional structure of the fault zone. A counterintuitive result is that joint depth is of only minor importance for the evolution of the fault zone. Even very shallow joints form weak areas at which the fault starts to form and propagate. More important is joint spacing. Very large joint spacing leads to faults and secondary fractures that form subparallel to the basement fault. In contrast, small

  18. High-resolution mass spectrometry and hydrogen/deuterium exchange study of mitorubrin azaphilones and nitrogenized analogues.

    Science.gov (United States)

    Svilar, Ljubica; Stankov-Jovanovic, Vesna; Lesage, Denis; Dossmann, Héloïse; Tabet, Jean-Claude

    2012-08-01

    Azaphilones represent numerous groups of wild fungal secondary metabolites that exhibit exceptional tendency to bind to nitrogen atoms in various molecules, especially those containing the amine group. Nitrogenized analogues of mitorubrin azaphilones, natural secondary metabolites of Hypoxylon fragiforme fungus, have been detected in the fungal methanol extract in very low concentrations. Positive electrospray ionization interfaced with high-resolution mass spectrometry was applied for confirmation of the elemental composition of protonated species. Collision-induced dissociation (CID) experiments have been performed, and fragmentation mechanisms have been proposed. Additional information regarding both secondary metabolite analogue families has been reached by application of gas-phase proton/deuterium (H/D) exchanges performed in the collision cell of a triple quadrupole mass spectrometer. An incomplete H/D exchange with one proton less than expected was observed for both protonated mitorubrin azaphilones and their nitrogenized analogues. By means of the density functional theory, an appropriate explanation of this behavior was provided, and it revealed some information concerning gas-phase H/D exchange mechanism and protonation sites. Copyright © 2012 John Wiley & Sons, Ltd.

  19. Preliminaries toward studying resonant extraction from the Debuncher

    Energy Technology Data Exchange (ETDEWEB)

    Michelotti, Leo; Johnstone, John; /Fermilab

    2009-06-01

    A recent proposal to detect {mu} {yields} e direct conversion at Fermilab asks for slow extraction of protons from the antiproton source, specifically from the Debuncher. [1] A third-integer resonance originally was considered for this, partly because of the Debuncher's three-fold symmetry and partly because its operational horizontal tune, {nu}{sub x} {approx} 9.765, is already within 0.1 of {nu}{sub x} = 29/3. Using a half integer resonance, {nu}{sub x} = 19/2, though not part of the original proposal, has been suggested more recently because (a) Fermilab has had a good deal of experience with half-integer extraction from the Tevatron, the Main Injector and the erstwhile Main Ring, and (b) for reasons we shall examine later, it depopulates the entire bunch without an abort at the end. This memo presents considerations preliminary to studying both possibilities. It is meant only as a starting point for investigations to be carried out in the future. The working constraints and assumptions have oscillated between two extremes: (1) making minimal changes in the antiproton source to minimize cost and (2) building another machine in the same tunnel. In this memo we adopt an attitude aligned more toward the first. The assumed parameters are listed in Table 1. A few are not (easily) subject to change, such as those related to the beam's momentum and revolution frequency and the acceptance of the debuncher. Two resonance exemplars are presented in the next section, with an explanation of the analytic and semi-analytic calculations that can be done for each. Section 3 contains preliminary numerical work that was done to validate the exemplars within the context of extraction from the Debuncher. A final section contains a summary. Following the bibliography, appendices contain (a) a qualitative, conceptual discussion of extraction for the novice, (b) a telegraphic review of the perturbative incantations used to filter the exemplars as principal resonances of

  20. Preliminaries toward studying resonant extraction from the Debuncher

    International Nuclear Information System (INIS)

    Michelotti, Leo; Johnstone, John

    2009-01-01

    A recent proposal to detect μ → e direct conversion at Fermilab asks for slow extraction of protons from the antiproton source, specifically from the Debuncher. (1) A third-integer resonance originally was considered for this, partly because of the Debuncher's three-fold symmetry and partly because its operational horizontal tune, ν x ∼ 9.765, is already within 0.1 of ν x = 29/3. Using a half integer resonance, ν x = 19/2, though not part of the original proposal, has been suggested more recently because (a) Fermilab has had a good deal of experience with half-integer extraction from the Tevatron, the Main Injector and the erstwhile Main Ring, and (b) for reasons we shall examine later, it depopulates the entire bunch without an abort at the end. This memo presents considerations preliminary to studying both possibilities. It is meant only as a starting point for investigations to be carried out in the future. The working constraints and assumptions have oscillated between two extremes: (1) making minimal changes in the antiproton source to minimize cost and (2) building another machine in the same tunnel. In this memo we adopt an attitude aligned more toward the first. The assumed parameters are listed in Table 1. A few are not (easily) subject to change, such as those related to the beam's momentum and revolution frequency and the acceptance of the debuncher. Two resonance exemplars are presented in the next section, with an explanation of the analytic and semi-analytic calculations that can be done for each. Section 3 contains preliminary numerical work that was done to validate the exemplars within the context of extraction from the Debuncher. A final section contains a summary. Following the bibliography, appendices contain (a) a qualitative, conceptual discussion of extraction for the novice, (b) a telegraphic review of the perturbative incantations used to filter the exemplars as principal resonances of quadrupole, sextupole and octupole

  1. Shear localization in the shallow part of megathrusts: understanding active megathrusts trough the study of fossil analogues.

    Science.gov (United States)

    Cerchiari, Anna; MIttempergher, Silvia; Remitti, Francesca; Festa, Andrea

    2017-04-01

    The shallowest part of active megathrusts has an intriguing behaviour, characterized by the coexistence of coseismic slips and aseismic creep, slow slip events, low and very low frequency earthquakes. Origins and interplays of these phenomena are actually little known. In this respect, the study of exhumed shallow parts of fossil megathrusts is an advantageous approach in terms of accessibility, costs and resolution. The Sestola-Vidiciatico tectonic Unit in the Northern Apennines has been interpreted as a possible analogue of a shallow, hectometer scale megathrust shear zone, which accommodated subduction of the Adria plate under the Ligurian prism during early-middle Miocene by involving sediments from the seafloor to burial depth corresponding to 150° C maximum temperature. Performing detailed microstructural analysis on samples through optical, cathodoluminescence and scanning electron microscopy, we studied a 5 m thick fault zone marking the base of the SVU. Here, more or less competent marls make up a heterogeneous fault zone assemblage, with a strongly deformed tectonic fabric characterized by mesoscopic cleavage, boudinage, faults and low-angle thrusts coated by calcite veins. At the top of the shear zone, a sharp and continuous shear vein, 20 cm thick cuts all other structures. At the microscale, we identified a primary sedimentary layering, consisting of alternating fine and coarse marly or shaly laminae that are crosscut by "soft-sediment"-type deformation bands derived from the reorientation of mineral grains without fracturing. Parallel to the sedimentary laminae, oriented phyllosilicates define a pervasive foliation in clay-rich domains. More competent calcareous portions are strongly boudinaged and cut by calcite shear veins displaying crack-and-seal texture and locally implosion breccias. Multiple mutually crosscutting generations of extensional veins are recognizable, with dispersed orientations and complex relations with shear veins. Calcite veins

  2. Study of the maguemite-hematite transformation by magnetic resonance

    International Nuclear Information System (INIS)

    Portella, P.D.

    1979-08-01

    The conversion of γ-Fe 2 O 3 powders to α-Fe 2 O 3 has been studied with the magnetic resonance technique. The residual fraction of γ-Fe 2 O 3 was measured for several times and temperatures of isothermal treatments, in the range 450 0 C - 550 0 C. The transformation can be described by a first order Kinetic equation and the apparent activation energy is about 200 kJ/mol (48 kcal/mol). This value is independent of temperature and particle size. The experimental data suggest that the reaction is growth-controlled and nucleation occurs preferably at the particle surface. (Author) [pt

  3. Glucagon-like peptide-1 analogue therapy for psoriasis patients with obesity and type 2 diabetes: a prospective cohort study.

    LENUS (Irish Health Repository)

    Ahern, T

    2012-06-13

    Background  Diabetes and obesity are more prevalent amongst psoriasis patients as is disturbance of the innate immune system. GLP-1 analogue therapy considerably improves weight and glycaemic control in people with type 2 diabetes and its receptor is present on innate immune cells. Objective  We aimed to determine the effect of liraglutide, a GLP-1 analogue, on psoriasis severity. Methods  Before and after 10 weeks of liraglutide therapy (1.2 mg subcutaneously daily) we determined the psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI) in seven people with both psoriasis and diabetes (median age 48 years, median body mass index 48.2 kg\\/m(2) ). We also evaluated the immunomodulatory properties of liraglutide by measuring circulating lymphocyte subset numbers and monocyte cytokine production. Results  Liraglutide therapy decreased the median PASI from 4.8 to 3.0 (P = 0.03) and the median DLQI from 6.0 to 2.0 (P = 0.03). Weight and glycaemic control improved significantly. Circulating invariant natural killer T (iNKT) cells increased from 0.13% of T lymphocytes to 0.40% (P = 0.03). Liraglutide therapy also effected a non-significant 54% decrease in the proportion of circulating monocytes that produced tumour necrosis factor alpha (P = 0.07). Conclusion  GLP-1 analogue therapy improves psoriasis severity, increases circulating iNKT cell number and modulates monocyte cytokine secretion. These effects may result from improvements in weight and glycaemic control as well as from direct immune effects of GLP-1 receptor activation. Prospective controlled trials of GLP-1 therapies are warranted, across all weight groups, in psoriasis patients with and without type 2 diabetes.

  4. Nuclear quadrupole resonance applied for arsenic oxide study

    International Nuclear Information System (INIS)

    Correia, J.A.S.

    1991-04-01

    The objectives of this study are mounting a pulsed Nuclear Quadrupole Resonance (NQR) building a flow cryostat capable of varying the temperature continuously from 77 K to 340 K and using the spectrometer and the cryostat to study the polycrystalline arsenic oxide. The spin-lattice relaxation time (T 1 ), the spin-spin relaxation time (T 2 ) and the resonance frequency are obtained as a function of temperature. These data are obtained in 77 to 330 K interval. The relaxation times are obtained using the spin echo technique. The spin echo phenomenon is due to refocusing spins, when a 180 0 C pulse is applied after a 90 0 C pulse. The spin-lattice relaxation time is obtained using the plot of echo amplitude versus the repetition time. The spin-spin relaxation time is obtained using the plot of echo amplitude versus the separation between the 90 0 C - 180 0 C pulses. The theory developed by Bayer is used to explain the spin-lattice relaxation time and the frequency temperature dependence. The spin-spin relaxation time is discussed using the Bloch equations. (author)

  5. Studies of nucleon resonance structure in exclusive meson electroproduction

    International Nuclear Information System (INIS)

    Aznauryan, I.G.; Bashir, A.; Braun, V.M.

    2013-01-01

    Studies of the structure of excited baryons are key factors to the N* program at Jefferson Lab (JLab). Within the first year of data taking with the Hall B CLAS12 detector following the 12 GeV upgrade, a dedicated experiment will aim to extract the N* electrocouplings at high photon virtualities Q 2 . This experiment will allow exploration of the structure of N* resonances at the highest photon virtualities ever achieved, with a kinematic reach up to Q 2 = 12 GeV 2 . This high-Q 2 reach will make it possible to probe the excited nucleon structures at distance scales ranging from where effective degrees of freedom, such as constituent quarks, are dominant through the transition to where nearly massless bare-quark degrees of freedom are relevant. In this document, we present a detailed description of the physics that can be addressed through N* structure studies in exclusive meson electroproduction. The discussion includes recent advances in reaction theory for extracting N* electrocouplings from meson electroproduction off protons, along with Quantum Chromodynamics (QCD)-based approaches to the theoretical interpretation of these fundamental quantities. This program will afford access to the dynamics of the nonperturbative strong interaction responsible for resonance formation, and will be crucial in understanding the nature of confinement and dynamical chiral symmetry breaking in baryons, and how excited nucleons emerge from QCD. (author)

  6. Review: Magnetic Resonance Spectroscopy Studies of Pediatric Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Douglas G. Kondo

    2011-01-01

    Full Text Available Introduction. This paper focuses on the application of Magnetic Resonance Spectroscopy (MRS to the study of Major Depressive Disorder (MDD in children and adolescents. Method. A literature search using the National Institutes of Health's PubMed database was conducted to identify indexed peer-reviewed MRS studies in pediatric patients with MDD. Results. The literature search yielded 18 articles reporting original MRS data in pediatric MDD. Neurochemical alterations in Choline, Glutamate, and N-Acetyl Aspartate are associated with pediatric MDD, suggesting pathophysiologic continuity with adult MDD. Conclusions. The MRS literature in pediatric MDD is modest but growing. In studies that are methodologically comparable, the results have been consistent. Because it offers a noninvasive and repeatable measurement of relevant in vivo brain chemistry, MRS has the potential to provide insights into the pathophysiology of MDD as well as the mediators and moderators of treatment response.

  7. Partial volume effects in dynamic contrast magnetic resonance renal studies

    International Nuclear Information System (INIS)

    Gutierrez, D. Rodriguez; Wells, K.; Diaz Montesdeoca, O.; Moran Santana, A.; Mendichovszky, I.A.; Gordon, I.

    2010-01-01

    This is the first study of partial volume effect in quantifying renal function on dynamic contrast enhanced magnetic resonance imaging. Dynamic image data were acquired for a cohort of 10 healthy volunteers. Following respiratory motion correction, each voxel location was assigned a mixing vector representing the 'overspilling' contributions of each tissue due to the convolution action of the imaging system's point spread function. This was used to recover the true intensities associated with each constituent tissue. Thus, non-renal contributions from liver, spleen and other surrounding tissues could be eliminated from the observed time-intensity curves derived from a typical renal cortical region of interest. This analysis produced a change in the early slope of the renal curve, which subsequently resulted in an enhanced glomerular filtration rate estimate. This effect was consistently observed in a Rutland-Patlak analysis of the time-intensity data: the volunteer cohort produced a partial volume effect corrected mean enhancement of 36% in relative glomerular filtration rate with a mean improvement of 7% in r 2 fitting of the Rutland-Patlak model compared to the same analysis undertaken without partial volume effect correction. This analysis strongly supports the notion that dynamic contrast enhanced magnetic resonance imaging of kidneys is substantially affected by the partial volume effect, and that this is a significant obfuscating factor in subsequent glomerular filtration rate estimation.

  8. Partial volume effects in dynamic contrast magnetic resonance renal studies

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, D. Rodriguez, E-mail: drodriguez@biotronics3d.co [CVSSP, Faculty of Engineering and Physical Sciences, University of Surrey (United Kingdom); Wells, K., E-mail: k.wells@surrey.ac.u [CVSSP, Faculty of Engineering and Physical Sciences, University of Surrey (United Kingdom); Diaz Montesdeoca, O., E-mail: o.diaz.montesdeoca@gmail.co [EUITT, Universidad de Las Palmas de Gran Canaria (Spain); Moran Santana, A. [EUITT, Universidad de Las Palmas de Gran Canaria (Spain); Mendichovszky, I.A., E-mail: iosifm@hotmail.co [Radiology and Physics Unit, UCL Institute of Child Health, London WC1N 1EH (United Kingdom); Gordon, I., E-mail: i.gordon@ich.ucl.ac.u [Radiology and Physics Unit, UCL Institute of Child Health, London WC1N 1EH (United Kingdom)

    2010-08-15

    This is the first study of partial volume effect in quantifying renal function on dynamic contrast enhanced magnetic resonance imaging. Dynamic image data were acquired for a cohort of 10 healthy volunteers. Following respiratory motion correction, each voxel location was assigned a mixing vector representing the 'overspilling' contributions of each tissue due to the convolution action of the imaging system's point spread function. This was used to recover the true intensities associated with each constituent tissue. Thus, non-renal contributions from liver, spleen and other surrounding tissues could be eliminated from the observed time-intensity curves derived from a typical renal cortical region of interest. This analysis produced a change in the early slope of the renal curve, which subsequently resulted in an enhanced glomerular filtration rate estimate. This effect was consistently observed in a Rutland-Patlak analysis of the time-intensity data: the volunteer cohort produced a partial volume effect corrected mean enhancement of 36% in relative glomerular filtration rate with a mean improvement of 7% in r{sup 2} fitting of the Rutland-Patlak model compared to the same analysis undertaken without partial volume effect correction. This analysis strongly supports the notion that dynamic contrast enhanced magnetic resonance imaging of kidneys is substantially affected by the partial volume effect, and that this is a significant obfuscating factor in subsequent glomerular filtration rate estimation.

  9. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Barrall, Geoffrey Alden [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.

  10. Electron spin resonance intercomparison studies on irradiated foodstuffs

    International Nuclear Information System (INIS)

    Raffi, J.

    1992-01-01

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic studies using different fish species. The identification of pistachio nut shells is more complicated and further research is needed prior to the organization of a further intercomparison. Laboratories were able to distinguish between chicken bones irradiated in the range 1 to 3 KGy or 7 to 10 KGy although there was a partial overlap between the results from different laboratories

  11. Nuclear Magnetic Resonance Study of Nanoscale Ionic Materials

    KAUST Repository

    Oommen, Joanna Mary

    2010-08-13

    Nanoscale ionic materials (NIMs) are a new class of nanomaterials that exhibit interesting properties including negligible vapor pressures and tunable physical states, among others. In this study, we analyzed the temperature-wise performance of NIMs using nuclear magnetic resonance (NMR) spectroscopy. NIMs are relatively stable over a temperature range from 300 to 383 K, rendering them usable in high temperature applications. We confirmed the presence of covalent bonds between the SiO2 core and the sulfonate group and determined relative concentrations of aromatic and aliphatic hydrocarbons. These findings serve as first hand proof-of-concept for the usefulness of NMR analyses in further studies on the diffusive properties of NIMs. © 2010 The Electrochemical Society.

  12. Excited state properties of 2‧-hydroxychalcone analogues functionalized with a diene moiety studied by steady state and laser flash photolysis

    Science.gov (United States)

    Shinozaki, Yukino; Yamaji, Minoru; Arai, Tatsuo

    2018-01-01

    2‧-Hydroxychalcone (HC) analogues 1 and 2 having a diene part tethering the phenyl and naphthyl chromophores, respectively, were prepared, and their photochemical and photophysical properties were studied. Fluorescence from these compounds was absent in solution and the solid state. Based on the results obtained upon steady state and laser flash photolyses, compound 2 was found to be substantially stable on photoirradiation without undergoing intersystem crossing to the triplet state whereas compounds 1 showed transient absorption due to the triplet tautomer. The deactivation processes in the excited states were discussed by considering energetic reaction diagrams for the corresponding tautomers and isomers.

  13. Performance of the Visual Analogue Scale of Happiness and of the Cornell Scale for Depression in Dementia in the Tremembé Epidemiological Study, Brazil

    Directory of Open Access Journals (Sweden)

    Karolina G. César

    Full Text Available Depression is a major growing public health problem. Many population studies have found a significant relationship between depression and the presence of cognitive disorders. OBJECTIVE: To establish the correlation between the Visual Analogue Scale of Happiness and the Cornell Scale for Depression in Dementia in the population aged 60 years or over in the city of Tremembé, state of São Paulo, Brazil. METHODS: An epidemiological survey involving home visits was carried out in the city of Tremembé. The sample was randomly selected by drawing 20% of the population aged 60 years or older from each of the city's census sectors. In this single-phase study, the assessment included clinical history, physical and neurological examination, cognitive evaluation, and application of both the Cornell Scale and the Analogue Scale of Happiness for psychiatric symptoms. The presence of depressive symptoms was defined as scores greater than or equal to 8 points on the Cornell Scale. RESULTS: A total of 623 subjects were evaluated and of these 251 (40.3% had clinically significant depressive symptoms on the Cornell Scale, with a significant association with female gender (p<0.001 and with lower education (p=0.012. One hundred and thirty-six participants (21.8% chose the unhappiness faces, with a significant association with age (p<0.001, female gender (p=0.020 and low socioeconomic status (p=0.012. Although there was a statistically significant association on the correlation test, the correlation was not high (rho=0.47. CONCLUSION: The prevalence of depressive symptoms was high in this sample and the Visual Analogue Scale of Happiness and Cornell Scale for Depression in Dementia should not be used as similar alternatives for evaluating the presence of depressive symptoms, at least in populations with low educational level.

  14. 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

  15. Working Point and Resonance Studies at the CERN PS

    CERN Document Server

    Huschauer, A; Damerau, H; Freyermuth, P; Gilardoni, S S; Steerenberg, R; Vandorpe, B

    2013-01-01

    The increase of luminosity demanded by the High Luminosity LHC (HL-LHC) requires an increase of beam intensity, which might result in instabilities appearing at injection energy in the CERN PS. Transverse head-tail instabilities have already been observed on operational LHC beams and a stabilizing mechanism as an alternative to linear coupling is currently being studied. It consists of reducing the mode number of the transverse oscillation by changing linear chromaticity and in succession completely suppressing the instability by a transverse damper system with appropriate bandwidth. Therefore, a chromaticity correction scheme at low energy exploiting the intrinsic possibilities offered by special circuits mounted on top of the main magnet poles, the Pole Face Windings (PFW), has been examined. The presence of destructive betatron resonances, which restrict the choice of the injection working point and the maximum acceptable tune spread, forms an additional limitation for high-brightness and high-intensity be...

  16. Grey matter abnormalities in trichotillomania: morphometric magnetic resonance imaging study.

    Science.gov (United States)

    Chamberlain, Samuel R; Menzies, Lara A; Fineberg, Naomi A; Del Campo, Natalia; Suckling, John; Craig, Kevin; Müller, Ulrich; Robbins, Trevor W; Bullmore, Edward T; Sahakian, Barbara J

    2008-09-01

    Trichotillomania (repetitive hair-pulling) is an Axis I psychiatric disorder whose neurobiological basis is incompletely understood. Whole-brain trichotillomania neuroimaging studies are lacking. To investigate grey and white matter abnormalities over the whole brain in patients with trichotillomania. Eighteen patients with DSM-IV trichotillomania and 19 healthy controls undertook structural magnetic resonance imaging after providing written informed consent. Differences in grey and white matter were investigated using computational morphometry. Patients with trichotillomania showed increased grey matter densities in the left striatum, left amygdalo-hippocampal formation, and multiple (including cingulate, supplementary motor, and frontal) cortical regions bilaterally. Trichotillomania was associated with structural grey matter changes in neural circuitry implicated in habit learning, cognition and affect regulation. These findings inform animal models of the disorder and highlight key regions of interest for future translational research.

  17. Cavum septum pellucidum in schizophrenia. A magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Fukuzako, Tsuyoshi; Fukuzako, Hiroshi; Kodama, Satoshi; Hashiguchi, Tomo; Takigawa, Morikuni

    1996-01-01

    In order to determine if cavum septum pellucidum (CSP) is more prevalent in schizophrenic patients, we studied 72 Japanese patients who fulfilled the DSM-III-R criteria for schizophrenia and 41 normal controls. Sagittal, 1 mm thick magnetic resonance imaging slices of the entire cranium were obtained using a gradient-echo pulse sequence, and coronal and axial images were reconstructed for assessment. A CSP was observed in 34 patients (47.2%) and in 16 controls (38.0%). Although the CSP appeared to be more prevalent in schizophrenic patients, this difference was not statistically significant. However, schizophrenic patients with a history of long-term institutionalization had a higher incidence of CSP compared with patients who had not been admitted to hospital for more than 3 years (68.2 vs 38.0%). These results suggest that the CSP may be a pathophysiology that characterizes schizophrenic patients with poor prognoses. (author)

  18. Magnetic resonance imaging in schizophrenia: a morphometric study

    International Nuclear Information System (INIS)

    Castro, Claudio Campi de

    2001-01-01

    Thirty-three patients with chronic schizophrenia and 21 normal subjects were submitted to magnetic resonance imaging studies using a 1.5 T scanner. Axial and coronal T 2-weighted images were obtained. The volumes of the brain, intracranial, supratentorial, infratentorial and the total, ventricular and subarachnoid cerebrospinal fluid volumes were measured using semi-automated morphometric methods. The volumes of the amygdala-hippocampus complex, para hippocampal gyrus cortex, putamen, globus pallidus, temporal lobe, gray and white matter of temporal lobe were also measured. These volumes were normalized using the intracranial volume as reference. The most relevant findings observed were reduced brain volume and increased total, ventricular and subarachnoid cerebrospinal fluid volumes in patients with schizophrenia when compared to the controls. Patients with schizophrenia had also smaller amygdala-hippocampus complexes, temporal lobes and temporal lobe white matter than the controls, as well as increased putamen volumes. (author)

  19. Structural and conformational study of polysaccharides by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Bossennec, Veronique

    1989-01-01

    As some natural polysaccharides are involved in important biological processes, the use of nuclear magnetic resonance appears to be an adapted mean to determine their structure-activity relationship and is therefore the object of this research thesis. By using bi-dimensional proton-based NMR techniques, it is possible to identify minority saccharide units, to determine their conformation, and to identify units which they are bound to. The author reports the application of these methods to swine mucosa heparin, and to heparins displaying a high and low anticoagulant activity. The dermatan sulphate has also been studied, and the NMR analysis allowed some polymer structure irregularities to be identified. A molecular modelling of dermatan sulphate has been performed [fr

  20. Magnetic resonance studies of atomic hydrogen gas at low temperatures

    International Nuclear Information System (INIS)

    Hardy, W.N.; Morrow, M.; Jochemsen, R.; Statt, B.W.; Kubik, P.R.; Marsolais, R.M.; Berlinsky, A.J.; Landesman, A.

    1980-01-01

    Using a pulsed low temperature discharge in a closed cell containing H 2 and 4 He, we have been able to store a low density (approximately 10 12 atoms/cc) gas of atomic hydrogen for periods of order one hour in zero magnetic field and T=1 K. Pulsed magnetic resonance at the 1420 MHz hyperfine transition has been used to study a number of the properties of the gas, including the recombination rate H + H + 4 He→H 2 + 4 He, the hydrogen spin-exchange relaxation rates, the diffusion coefficient of H in 4 He gas and the pressure shift of the hyperfine frequency due to the 4 He buffer gas. Here we discuss the application of hyperfine frequency shifts as a probe of the H-He potential, and as a means for determining the binding energy of H on liquid helium

  1. A semiclassical study of optical potentials - potential resonances -

    International Nuclear Information System (INIS)

    Lee, S.Y.; Takigawa, N.; Marty, C.

    1977-01-01

    A semiclassical method is used to analyze resonances produced by complex potentials. The absorption plays a central role: when it is not too great, resonances manifest themselves by enhancement of cross sections near π. The reverse is not necessarily true, for instance the anomalous large angle scattering for α-Ca is due to a coherent superposition of many partial waves

  2. Mössbauer study of a tetrakis (pentafluorophenyl porphyrin iron (III chloride in comparison with the fluorine unsubstituted analogue

    Directory of Open Access Journals (Sweden)

    Kaczmarzyk Tomasz

    2015-03-01

    Full Text Available Mössbauer investigations, in association with density functional theory (DFT calculations, have been conducted for the molecular and electronic structures of iron (III [tetrakis (pentafluorophenyl] porphyrin chloride [(F20TPPFe:Cl], as a Fe(III-tetraphenylporphyrin complex containing chloride axial ligand and substituted hydrogen atoms by fluorine ones in the four phenyl rings, in comparison with its fluorine unsubstituted analogue [(TPPFe:Cl]. It was found that the parameters of Mössbauer spectra of both complexes are close to one another, and correspond to the high-spin state of Fe(III ions, but they show the different temperature dependence and the quadrupole doublets in Mössbauer spectra show different asymmetry at low temperatures. Results of DFT calculations are analyzed in the light of catalytic activity of the halogenated complex.

  3. Studying medical communication with video vignettes: a randomized study on how variations in video-vignette introduction format and camera focus influence analogue patients’ engagement

    Directory of Open Access Journals (Sweden)

    Leonie N. C. Visser

    2018-01-01

    Full Text Available Abstract Background Video vignettes are used to test the effects of physicians’ communication on patient outcomes. Methodological choices in video-vignette development may have far-stretching consequences for participants’ engagement with the video, and thus the ecological validity of this design. To supplement the scant evidence in this field, this study tested how variations in video-vignette introduction format and camera focus influence participants’ engagement with a video vignette showing a bad news consultation. Methods Introduction format (A = audiovisual vs. B = written and camera focus (1 = the physician only, 2 = the physician and the patient at neutral moments alternately, 3 = the physician and the patient at emotional moments alternately were varied in a randomized 2 × 3 between-subjects design. One hundred eighty-one students were randomly assigned to watch one of the six resulting video-vignette conditions as so-called analogue patients, i.e., they were instructed to imagine themselves being in the video patient’s situation. Four dimensions of self-reported engagement were assessed retrospectively. Emotional engagement was additionally measured by recording participants’ electrodermal and cardiovascular activity continuously while watching. Analyses of variance were used to test the effects of introduction format, camera focus and their interaction. Results The audiovisual introduction induced a stronger blood pressure response during watching the introduction (p = 0.048, η partial 2 $$ {\\eta}_{partial}^2 $$ = 0.05 and the consultation part of the vignette (p = 0.051, η partial 2 $$ {\\eta}_{partial}^2 $$ = 0.05, when compared to the written introduction. With respect to camera focus, results revealed that the variant focusing on the patient at emotional moments evoked a higher level of electrodermal activity (p = 0.003, η partial 2 $$ {\\eta}_{partial}^2 $$ = 0.06, when compared

  4. Studies of fracture network geometry of reservoir outcrop analogues from terrestrial lidar data: attempts to quantify spatial variations of fracture characteristics

    Science.gov (United States)

    Vsemirnova, E. A.; Jones, R. R.; McCaffrey, K. J. W.

    2012-04-01

    We describe studies analysing terrestrial lidar datasets of fracture systems from a range of reservoir analogues in clastic and carbonate lithologies that represent geological analogues of offshore hydrocarbon reservoirs for the UK continental shelf. As fracture networks (observed here from centimetre to kilometre scale) can significantly affect the permeability of a fractured reservoir, the definition of fracture network geometry at various scales has become an important goal of structural analysis. The main aim of the study has been to extend the investigation of fracture networks in order to quantify spatial variations in fracture parameters in a variety of lithologies. The datasets were pre-processed using RiSCAN PRO software, and then re-sampled and filtered to derive characteristics which are traditionally measured from outcrops, including size distributions, fracture spacing and clustering statistics. This type of analysis can significantly reduce the uncertainty associated with some field fracture network measurements. The digitised fracture networks datasets are then used to investigate various aspects of spatial heterogeneity. A series of fracture maps (joints and faults) were generated at different scales, and fracture trends were studied to test scale dependency of fracture orientations. Multiscale trend analysis was then applied to describe the trend structure of the fracture networks.

  5. Pro Free Will Priming Enhances "Risk-Taking" Behavior in the Iowa Gambling Task, but Not in the Balloon Analogue Risk Task: Two Independent Priming Studies.

    Science.gov (United States)

    Schrag, Yann; Tremea, Alessandro; Lagger, Cyril; Ohana, Noé; Mohr, Christine

    2016-01-01

    Studies indicated that people behave less responsibly after exposure to information containing deterministic statements as compared to free will statements or neutral statements. Thus, deterministic primes should lead to enhanced risk-taking behavior. We tested this prediction in two studies with healthy participants. In experiment 1, we tested 144 students (24 men) in the laboratory using the Iowa Gambling Task. In experiment 2, we tested 274 participants (104 men) online using the Balloon Analogue Risk Task. In the Iowa Gambling Task, the free will priming condition resulted in more risky decisions than both the deterministic and neutral priming conditions. We observed no priming effects on risk-taking behavior in the Balloon Analogue Risk Task. To explain these unpredicted findings, we consider the somatic marker hypothesis, a gain frequency approach as well as attention to gains and / or inattention to losses. In addition, we highlight the necessity to consider both pro free will and deterministic priming conditions in future studies. Importantly, our and previous results indicate that the effects of pro free will and deterministic priming do not oppose each other on a frequently assumed continuum.

  6. Study of lone working magnetic resonance technologists in Western Australia

    Directory of Open Access Journals (Sweden)

    Tracy Anne Dewland

    2013-12-01

    Full Text Available Objectives: It is recommended that magnetic resonance (MR technologists should not work alone due to potential occupational health risks although lone working is legally acceptable. The objective of this study was to investigate the current situation of lone working MR technologists in Western Australia (WA and any issue against the regulations. Materials and Methods: A questionnaire regarding the issues of occupational health of lone working MR technologists was developed based on relevant literature and distributed to WA MR technologists. Descriptive (percentage of frequency, mean and standard deviation and inferential statistics (Fisher's exact, Chi2 and t tests, and analysis of variance were used to analyze the responses of the yes/no, multiple choice and 5 pt scale questions from the returned questionnaires. Results: The questionnaire response rate was 65.6% (59/90. It was found that about half of the MR technologists (45.8%, 27/59 experienced lone working. The private magnetic resonance imaging (MRI centers were more likely to arrange technologists to work alone (p < 0.05. The respondents expressed positive views on issues of adequacy of training and arrangement, confidence and comfort towards lone working except immediate assistance for emergency (mean: 3. Factors of existence of MRI safety officer (p < 0.05 and nature of lone working (p < 0.001-0.05 affected MR technologists' concerns. Conclusions: Lone working of MR technologists is common in WA especially in private centers. The training and arrangement provided seem to be adequate for meeting the legal requirements. However, several areas should be improved by the workplaces including enhancement on immediate emergency assistance and concern relief.

  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. Brain Magnetic Resonance Elastography on Healthy Volunteers: A Safety Study

    International Nuclear Information System (INIS)

    Guang-Rui Liu; Pei-Yi Gao; Yan Lin; Jing Xue; Xiao-Chun Wang; Bin-Bin Sui; Li Ma; Zhi-Nong Xi; Qin Bai; Hao Shen

    2009-01-01

    Background: Magnetic resonance elastography (MRE) is a recently developed imaging technique that can directly visualize and quantitatively measure tissue elasticity. Purpose: To evaluate the safety of brain MRE on human subjects. Material and Methods: The study included 20 healthy volunteers. MRE sequence scan (drive signal not applied to external force actuator) and MRE study were separately performed on each volunteer at an interval of more than 24 hours. The heart rate and blood pressure of each volunteer were measured immediately before and after MRE sequence scan and MRE study. Electroencephalography (EEG) was also performed within 2 hours after each scan. The volunteers were asked about their experience of the two scans. Randomized-block analysis of variance (ANOVA) was used to analyze the data of blood pressure and heart rate. Paired t test was used to analyze the data of the two EEG examinations. The volunteers were followed up 1 week after the examination. Results: All procedures were performed on each volunteer, and no one complained of obvious discomfort. No related adverse events were reported during follow-up. There was no statistically significant difference in heart rate or blood pressure. There was a statistically significant difference (P<0.05) in EEG results in the right temporoparietal region. Increased power was found in the theta, delta, alpha, and beta2 bands. No brain injury was detected by the EEG examinations. Conclusion: Based on the study results, brain MRE examinations are safe to perform on human subjects

  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. Synthesis and evaluation of [{sup 123}I]labelled analogues of the partial inverse agonist Ro 15-4513 for the study of diazepam-insensitive benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, Andrew E-mail: akx@ansto.gov.au; Mardon, Karine; McPhee, Meredith; Mattner, Filomena; Dikic, Branko; Ridley, Damon

    1999-08-01

    The imidazobenzodiazepines ethyl 8-iodo-5,6 dihydro-5-methyl-6-oxo-4H-imidazo[1,5a][1,4] benzodiazepine-3-carboxylate 1 and tert-butyl 8-iodo-5,6 dihydro-5-methyl-6-oxo-4H-imidazo [1,5a][1,4] benzodiazepine-3-carboxylate 2 were prepared to study the diazepam-insensitive (DI) benzodiazepine receptor (BZR) subtype. The [{sup 123}I] analogues were prepared via iododestannylation reactions in radiochemical yields of 70-80% and a specific activity >2,500 Ci/mmol. The tert-butyl analogue [{sup 123}I]-2 exhibited nanomolar affinity for BZRs in homogenate membranes of rat cerebellum with K{sub d} values for the diazepam-sensitive (DS) and DI receptors of 3.18{+-}0.58 and 13.55{+-}2.72 nM, respectively. The B{sub max} for cerebellar DS and DI receptors were 1,276{+-}195 and 518{+-}26 fmol/mg protein, respectively.

  11. Infrared study of synthetic peptide analogues of the calcium-binding site III of troponin C: The role of helix F of an EF-hand motif.

    Science.gov (United States)

    Nara, Masayuki; Morii, Hisayuki; Tanokura, Masaru

    2013-05-01

    The EF-hand motif (helix-loop-helix) is a Ca(2+)-binding domain that is common among many intracellular Ca(2+)-binding proteins. We applied Fourier-transform infrared spectroscopy to study the synthetic peptide analogues of site III of rabbit skeletal muscle troponin C (helix E-loop-helix F). The 17-residue peptides corresponding to loop-helix F (DRDADGYIDAEELAEIF), where one residue is substituted by the D-type amino acid, were investigated to disturb the α-helical conformation of helix F systematically. These D-type-substituted peptides showed no band at about 1555 cm(-1) even in the Ca(2+)-loaded state although the native peptide (L-type only) showed a band at about 1555 cm(-1) in the Ca(2+)-loaded state, which is assigned to the side-chain COO(-) group of Glu at the 12th position, serving as the ligand for Ca(2+) in the bidentate coordination mode. Therefore, helix F is vital to the interaction between the Ca(2+) and the side-chain COO(-) group of Glu at the 12th position. Implications of the COO(-) antisymmetric stretch and the amide-I' of the synthetic peptide analogues of the Ca(2+)-binding sites are discussed. Copyright © 2012 Wiley Periodicals, Inc.

  12. The GLP-1 Analogue Exenatide Improves Hepatic and Muscle Insulin Sensitivity in Diabetic Rats: Tracer Studies in the Basal State and during Hyperinsulinemic-Euglycemic Clamp

    Directory of Open Access Journals (Sweden)

    Hui Wu

    2014-01-01

    Full Text Available Objective. Glucagon-like peptide-1 (GLP-1 analogues (e.g., exenatide increase insulin secretion in diabetes but less is known about their effects on glucose production or insulin-stimulated glucose uptake in peripheral tissues. Methods. Four groups of Sprague-Dawley rats were studied: nondiabetic (control, C; nondiabetic + exenatide (C + E; diabetic (D; diabetic + exenatide (D + E with diabetes induced by streptozotocin and high fat diet. Infusion of 3-3H-glucose and U-13C-glycerol was used to measure basal rates of appearance (Ra of glucose and glycerol and gluconeogenesis from glycerol (GNG. During hyperinsulinemic-euglycemic clamp, glucose uptake into gastrocnemius muscles was measured with 2-deoxy-D-14C-glucose. Results. In the diabetic rats, exenatide reduced the basal Ra of glucose (P<0.01 and glycerol (P<0.01 and GNG (P<0.001. During the clamp, Ra of glucose was also reduced, whereas the rate of disappearance of glucose increased and there was increased glucose uptake into muscle (P<0.01 during the clamp. In the nondiabetic rats, exenatide had no effect. Conclusion. In addition to its known effects on insulin secretion, administration of the GLP-1 analogue, exenatide, is associated with increased inhibition of gluconeogenesis and improved glucose uptake into muscle in diabetic rats, implying improved hepatic and peripheral insulin sensitivity.

  13. Metabolic effects of the iodothyronine functional analogue TRC150094 on the liver and skeletal muscle of high-fat diet fed overweight rats: an integrated proteomic study.

    Science.gov (United States)

    Silvestri, Elena; Glinni, Daniela; Cioffi, Federica; Moreno, Maria; Lombardi, Assunta; de Lange, Pieter; Senese, Rosalba; Ceccarelli, Michele; Salzano, Anna Maria; Scaloni, Andrea; Lanni, Antonia; Goglia, Fernando

    2012-07-06

    A novel functional iodothyronine analogue, TRC150094, which has a much lower potency toward thyroid hormone receptor (α1/β1) activation than triiodothyronine, has been shown to be effective at reducing adiposity in rats simultaneously receiving a high-fat diet (HFD). Here, by combining metabolic, functional and proteomic analysis, we studied how the hepatic and skeletal muscle phenotypes might respond to TRC150094 treatment in HFD-fed overweight rats. Drug treatment increased both the liver and skeletal muscle mitochondrial oxidative capacities without altering mitochondrial efficiency. Coherently, in terms of individual respiratory in-gel activity, blue-native analysis revealed an increased activity of complex V in the liver and of complexes II and V in tibialis muscle in TCR150094-treated animals. Subsequently, the identification of differentially expressed proteins and the analysis of their interrelations gave an integrated view of the phenotypic/metabolic adaptations occurring in the liver and muscle proteomes during drug treatment. TRC150094 significantly altered the expression of several proteins involved in key liver metabolic pathways, including amino acid and nitrogen metabolism, and fructose and mannose metabolism. The canonical pathways most strongly influenced by TRC150094 in tibialis muscle included glycolysis and gluconeogenesis, amino acid, fructose and mannose metabolism, and cell signaling. The phenotypic/metabolic influence of TRC150094 on the liver and skeletal muscle of HFD-fed overweight rats suggests the potential clinical application of this iodothyronine analogue in ameliorating metabolic risk parameters altered by diet regimens.

  14. Multiple sclerosis and anterograde axonal degeneration study by magnetic resonance

    International Nuclear Information System (INIS)

    Martinez Pardo, P.; Capdevila Cirera, A.; Sanz Marin, P.M.; Gili Planas, J.

    1993-01-01

    Multiple sclerosis (MS) is a disease of the central nervous system that affects specifically the myelin. Its diagnosis by imaging techniques is, since the development of magnetic resonance (MR), relatively simple, and its occasional association with anterograde axonal degeneration (WD) has been reported. In both disorders, there is a lengthening of the T1 and T2 relaxation times. In the present report, 76 patients with MS with less than 4 plaques in the typical periventricular position were studied retrospectively, resulting in a rate of association with anterograde axonal degeneration of 8%. We consider that in spite of their same behavior in MR,MS and WD, with moreover represent completely different pathologies, are perfectly differential by MR. The S-E images with longer repetition and echo times in the axial and coronal planes have proved to be those most sensitive for this differentiation. Given that MS is specific pathology of then myelin, the axonal damages in delayed until several plaques adjacent to an axon affect it. We consider that this, added to the restriction of our study group (less than 4 plaques), is the cause of the pow percentage of the MS-WD association in our study. (Author)

  15. Friction of polymer hydrogels studied by resonance shear measurements.

    Science.gov (United States)

    Ren, Huai-Yin; Mizukami, Masashi; Tanabe, Tadao; Furukawa, Hidemitsu; Kurihara, Kazue

    2015-08-21

    The friction between an elastomer and a hard surface typically has two contributors, i.e., the interfacial and deformation components. The friction of viscoelastic hydrogel materials has been extensively studied between planar gel and planar substrate surfaces from the viewpoint of an interfacial interaction. However, the geometry of the contact in practical applications is much more complex. The contribution of geometric and elastic deformation terms of a gel to friction could not be neglected. In this study, we used resonance shear measurements (RSMs) for characterizing the shear response of a glass sphere on a flat polymer hydrogel, a double network (DN) gel of 2-acrylamide-2-methylpropanesulfonic acid and N,N-dimethylacrylamide. The contact mechanics conformed to the Johnson-Kendall-Roberts theory. The observed resonance curves exhibited rather sharp peaks when the DN gel and the silica sphere were brought into contact, and their intensity and frequency increased with the increase in the normal load. We proposed a simple physical model of the shearing system, and the elastic (k2) and viscous (b2) parameters of the interface between a silica sphere and a flat DN gel were obtained. The friction force from elastic deformation and viscous dissipation terms was then estimated using the obtained parameters. It was revealed that the elastic parameter (k2) increased up to 1780 N m(-1) at a normal load of 524 mN, while the viscous parameter (b2) was zero or quite low (friction force between a flat DN gel and a silica sphere in air was dominated by the elastic term due to the local deformation by contact with the silica sphere. By adding water, the elastic parameter (k2) remained the same, while the viscous parameter (b2) slightly increased. However, the viscous term fviscous was still much smaller than felastic. To the best of our knowledge, this study was the first quantitative estimation of the contribution of the elastic deformation term to the friction in the case

  16. Electron paramagnetic resonance study of ternary Cu compounds ...

    Indian Academy of Sciences (India)

    , Argentina e-mail: santana@ufg.br. MS received 14 August 2013; revised 31 October 2013; accepted 5 November 2013. Abstract. We report here electron paramagnetic resonance (EPR) measurements at 9 and 34 GHz, and room temperature ...

  17. Magnetic Resonance Studies of Photosensitizers and Their Effect in Tumors

    Science.gov (United States)

    2003-08-01

    used increasingly to monitor metabolism and disease states in humans. Both magnetic resonance imaging and spectroscopy have evolved into sophisticated... disease states in humans. Both magnetic resonance imaging and spectroscopy have evolved into sophisticated diagnostic techniques. In addition to the...Antispermatogenic effect and chemical R.S.Gupta Pharmaceutical Biol. 2002 investigation of Opuntia dillenii A.Sharma 40,411-415 M.P. Dobhal 42 A

  18. Experimental study of the hydrothermal alteration of a chemical analogue of the French nuclear glass in a thermal gradient: characterization of newly formed phases and of matter transfers

    International Nuclear Information System (INIS)

    Poinssot, Christophe

    1994-01-01

    As the most dangerous radioactive wastes are to be stored in deep geological layers after having been packaged in barrels made of borosilicate glasses, this research report addresses the study of the alteration of such glasses through the study of a chemical analogue. In order to experimentally model phenomena involved within a storage, the studied glass has been submitted to different thermal gradients between 320 and 150 C and during 3 to 5 months. These gradients comply with those met about the parcels, and allows the spatial evolution of the waste parcel at a given moment, as well as the evolution in time (progressive cooling of wastes) to be simultaneously simulated. The different phases formed within the gradient have been studied and characterized by scanning electronic microscopy, semi-quantitative microanalysis, and X-ray micro-diffraction [fr

  19. Electron spin resonance study of radicals in irradiated polyethylene

    International Nuclear Information System (INIS)

    Fujimura, Takashi

    1979-02-01

    In order to elucidate radiation effect in polyethylene, the nature and behavior of radicals produced in polyethylene and the model compound of polyethylene irradiated at 77 0 K were studied by using electron spin resonance. The structure of radical pairs, which are composed of two radicals produced very closely each other, was investigated in drawn polyethylene and the single crystal of n-eicosane. The radical pairs of intrachain type and interchain type were found in polyethylene and n-eicosane respectively. It was suggested that these two types of radical pairs are the precursors of double bonds and crosslinks respectively. The thermal decay reactions of radicals themselves produced in irradiated polyethylene were investigated. It was made clear that the short range distances between two radicals play an important role in the decay reaction of alkyl radicals at low temperatures. The trapping regions of radicals were studied and it was clarified that allyl radicals, which are produced by the reaction of alkyl radicals with double bonds, are trapped both in the crystalline and non-crystalline regions. (author)

  20. The amygdala in schizophrenia: a trimodal magnetic resonance imaging study.

    Science.gov (United States)

    Kalus, Peter; Slotboom, Johannes; Gallinat, Jürgen; Wiest, Roland; Ozdoba, Christoph; Federspiel, Andrea; Strik, Werner K; Buri, Caroline; Schroth, Gerhard; Kiefer, Claus

    2005-03-03

    In schizophrenic psychoses, structural and functional alterations of the amygdala have been demonstrated by several neuroimaging studies. However, postmortem examinations on the brains of schizophrenics did not confirm the volume changes reported by volumetric magnetic resonance imaging (MRI) studies. In order to address these contradictory findings and to further elucidate the possibly underlying pathophysiological process of the amygdala, we employed a trimodal MRI design including high-resolution volumetry, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) in a sample of 14 schizophrenic patients and 14 matched controls. Three-dimensional MRI volumetry revealed a significant reduction of amygdala raw volumes in the patient group, while amygdala volumes normalized for intracranial volume did not differ between the two groups. The regional diffusional anisotropy of the amygdala, expressed as inter-voxel coherence (COH), showed a marked and significant reduction in schizophrenics. Assessment of qMTI parameters yielded significant group differences for the T2 time of the bound proton pool and the T1 time of the free proton pool, while the semi-quantitative magnetization transfer ratio (MTR) did not differ between the groups. The application of multimodal MRI protocols is diagnostically relevant for the differentiation between schizophrenic patients and controls and provides a new strategy for the detection and characterization of subtle structural alterations in defined regions of the living brain.

  1. Study of a possible S=+1 dynamically generated baryonic resonance

    International Nuclear Information System (INIS)

    Sarkar, S.; Oset, E.; Vaca, M.J.V.

    2005-01-01

    Starting from the lowest-order chiral Lagrangian for the interaction of the baryon decuplet with the octet of pseudoscalar mesons we find an attractive interaction in the ΔK channel with L=0 and I=1, while the interaction is repulsive for I=2. The attractive interaction leads to a pole in the second Riemann sheet of the complex plane and manifests itself in a large strength of the K scattering amplitude close to the ΔK threshold, which is not the case for I=2. However, we also make a study of uncertainties in the model and conclude that the existence of this pole depends sensitively upon the input used and can disappear within reasonable variations of the input parameters. We take advantage to study the stability of the other poles obtained for the 3/2 - dynamically generated resonances of the model and conclude that they are stable and not contingent to reasonable changes in the input of the theory

  2. Preliminary study of the antimicrobial activity of Mentha x villosa Hudson essential oil, rotundifolone and its analogues

    Directory of Open Access Journals (Sweden)

    Thúlio. A. Arruda

    Full Text Available Essential oils present antimicrobial activity against a variety of bacteria and yeasts, including species resistant to antibiotics and antifungicals. In this context, this work aims at the evaluation of the antimicrobial activity of the essential oil of Mentha x villosa Hudson ("hortelã da folha miúda", its major component (rotundifolone and four similar analogues of rotundifolone (limonene oxide, pulegone oxide, carvone epoxide and (+-pulegone against strain standards of Staphylococcus aureus ATCC 25923, E. coli ATCC 25922, Pseudomona aeruginosa ATCC 27853, Candida albicans ATCC 76645 and one strain of meticilin - resistant Staphylococcus aureus - MRSA (171c from human clinic. The method of the diffusion in plates with solid medium was used. The results showed that the oil of Mentha x villosa, rotundifolone, limonene oxide and (+-pulegone, are similar regarding the antimicrobial activity against the tested strains of S. aureus and C. albicans. All of the products present antimocrobial potential with antibacterial activity for S. aureus ATCC 25923 and antifungal activity for C. albicans ATCC 76645. None of the products presented antimicrobial activity for the strains of E. coli ATCC 25922 and P. aeruginosa ATCC 27853, representatives of the Gram negative bacteria.

  3. Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

    Science.gov (United States)

    Wysokiński, Rafał; Hernik, Katarzyna; Szostak, Roman; Michalska, Danuta

    2007-03-01

    Orotic acid (vitamin B 13) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C 5H 2N 2O 4)(NH 3) 2] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum-ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin.

  4. Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

    International Nuclear Information System (INIS)

    Wysokinski, Rafal; Hernik, Katarzyna; Szostak, Roman; Michalska, Danuta

    2007-01-01

    Orotic acid (vitamin B 13 ) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C 5 H 2 N 2 O 4 )(NH 3 ) 2 ] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum-ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin

  5. Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Wysokinski, Rafal; Hernik, Katarzyna [Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego 23, 50-370 Wroclaw (Poland); Szostak, Roman [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Michalska, Danuta [Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego 23, 50-370 Wroclaw (Poland)], E-mail: danuta.michalska@pwr.wroc.pl

    2007-03-06

    Orotic acid (vitamin B{sub 13}) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C{sub 5}H{sub 2}N{sub 2}O{sub 4})(NH{sub 3}){sub 2}] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum-ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin.

  6. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Saumen; Reed, Julian; Sage, Timothy; Branagan, Nicole C.; Petrik, Igor D.; Miner, Kyle D.; Hu, Michael Y.; Zhao, Jiyong; Alp, E. Ercan; Lu, Yi

    2015-10-05

    This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent twoelectron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a. clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction of a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. As a result, the outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.

  7. A Study of Standing Pressure Waves Within Open and Closed Acoustic Resonators

    Science.gov (United States)

    Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.

    2002-01-01

    The first section of the results presented herein was conducted on an axisymmetric resonator configured with open ventilation ports on either end of the resonator, but otherwise closed and free from obstruction. The remaining section presents the results of a similar resonator shape that was closed, but contained an axisymmetric blockage centrally located through the axis of the resonator. Ambient air was used as the working fluid. In each of the studies, the resonator was oscillated at the resonant frequency of the fluid contained within the cavity while the dynamic pressure, static pressure, and temperature of the fluid were recorded at both ends of the resonator. The baseline results showed a marked reduction in the amplitude of the dynamic pressure waveforms over previous studies due to the use of air instead of refrigerant as the working fluid. A sharp reduction in the amplitude of the acoustic pressure waves was expected and recorded when the configuration of the resonators was modified from closed to open. A change in the resonant frequency was recorded when blockages of differing geometries were used in the closed resonator, while acoustic pressure amplitudes varied little from baseline measurements.

  8. Novel nuclear magnetic resonance techniques for studying biological molecules

    International Nuclear Information System (INIS)

    Laws, David D.

    2000-01-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone (φ/ψ) dihedral angles by comparing experimentally determined 13 C a , chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

  9. 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.

  10. Comparison of long-term geochemical interactions at two natural CO2-analogues : Montmiral (Southeast Basin, France) and Messokampos (Florina Basin, Greece) case studies

    International Nuclear Information System (INIS)

    Gaus, I.; Le Guern, C.; Pauwels, H.; Pearce, J.; Shepherd, T.; Hatziyannis, G.; Metaxas, A.

    2005-01-01

    Carbon dioxide (CO 2 ) capture and storage is considered to be a viable strategy to reduce the amount of greenhouse gases released to the atmosphere. When assessing the feasibility of current or future CO 2 storage projects, mineral trapping within a reservoir is considered as a key mechanism for the permanent sequestration of CO 2 . There are many occurrences worldwide, where natural CO 2 has been trapped in geological reservoirs. These natural CO 2 analogues provide a unique opportunity to study the reactivity, due to CO 2 interactions, which occurred in the reservoirs over a geologic timeframe. Therefore, the study of analogous natural CO 2 -rich reservoirs, which act as long-term laboratories, are an important part of the assessment of the long-term geochemical effects of geological CO 2 storage. This paper referred to 2 natural CO 2 sites studied under the Natural Analogues for the Storage of CO2 in the Geological Environment (NASCENT) Project. The Montmiral reservoir in France's Southeast Basin is a high-temperature and high-pressure reservoir at great depth (100 degrees C and 36 MPa). The Messokampos reservoir in Greece's Florina Basin is a shallow, low temperature and low-pressure reservoir (25 degrees C and 0.5 MPa). Both are sandstone reservoirs, and feldspar alteration is the key interaction in both cases between dissolved CO 2 , the formation water and the reservoir rock. Both natural analogues were studied in detail petrographically and through geochemical modelling in order to characterize and explain the water-rock-gas interactions in the different geological contexts. The purpose was to assess the consequences of these interactions on CO 2 storage capacity and porosity of the host rock. It was concluded that the reservoir's temperature and pressure conditions determine the impact of CO 2 interactions, with elevated temperatures significantly increasing the reaction rates of mineral-trapping reactions. This is particularly significant when choosing

  11. Electron Paramagnetic Resonance studies of x-ray irradiated Nafion

    Science.gov (United States)

    Fragoso, Juan; Usher, Timothy

    2007-03-01

    Fuel cells promise a bright future as power sources for a variety of electronic equipment as well as more power demanding elements. Nafion (DuPont's trademark of a sulfonated tetrafluorethylene polymer modified from Teflon) is the heart of Proton Exchange Membrane Fuel Cells (PEMFCs) as well as Direct Methanol Fuel Cells (DMFCs). Fuel cells are used to power electronic equipment on spacecraft, satellites and unpiloted high altitude aircraft, where ionizing radiation can be a concern. Electron Paramagnetic Resonance (EPR) is a spectroscopic technique that is very sensitive to free radicals such as those produced by ionizing radiation therefore EPR can give us a window into the degradation of the Nafion membranes due to the ionizing radiation. Nafion samples were irradiated using a x-ray diffractometer with a copper target operating at 40kV and 55mA for at least 3hrs. X-Band EPR spectroscopy of the irradiated nafion reveals a peak at 3400G with a width of 10G, which decays over time, completely diminishing in a couple of weeks. Preliminary results from the polarization studies on the effects of ionizing radiation will also be presented.

  12. A magnetic resonance imaging study of double elevator palsy.

    Science.gov (United States)

    Cadera, W; Bloom, J N; Karlik, S; Viirre, E

    1997-06-01

    The pathophysiology of double elevator palsy is poorly understood. We assessed two patients with this condition using magnetic resonance imaging (MRI) to evaluate the appearance of the extraocular muscles. Cross-sectional study. Radiology department of a university-affiliated hospital in London, Ont. Two patients from a private ophthalmology practice who had undergone complete transpositions of the horizontal rectus muscles to treat hypotropia associated with double elevator palsy. MRI. A volume scanning technique was used to obtain maximum information about the muscles. Appearance of the extraocular muscles. In both patients MRI showed decreased volume of the superior rectus muscle on the affected side. The other rectus muscles were normal. This suggested either congenital hypoplasia or paresis of the involved superior rectus muscle. In addition, the full tendon transpositions of the medial and lateral recti did not appreciably change the middle and deep orbital pathways of the transposed horizontal rectus muscles. MRI may be a useful adjunct to saccadic velocity assessments in differentiating between primary inferior rectus restriction, primary superior rectus paresis and congenital supranuclear elevator deficiency.

  13. Studies of the giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    Experimental measurements of the eletrodisintegration cross section in 181 Ta, 208 Pb and 209 Bi nuclei are made in the Linear Accelerator of the IFUSP-Brazil. The cross section is obtained by the direct counting of the emitted neutrons, in an electron excitation energy range between 8 to 22 MeV. The experimental data are analysed throught the virtual photon method, with the aim of obtaining the isoscalar and isovectorial electric quadrupole giant resonance (E2GR) intensities, as well as the magnetic dipole intensity. For each studied nucleus the results obtained for the E2GR, isoscalar and isovectorial, are compared with the photodisintegration cross section measured by the Saclay and Livermore laboratories. From this comparison, it is observed that the photodisintegration cross sections are compatibles with the existence of an isovector E2GR, located between 120 to 130 A -1/3 Mev and which exhaust around 100% of the Energy-Weighted Sum rules (EWSR). (L.C.) [pt

  14. [Diagnosis. Radiological study. Ultrasound, computed tomography and magnetic resonance imaging].

    Science.gov (United States)

    Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente

    2014-01-01

    Because of its low cost, availability in primary care and ease of interpretation, simple X-ray should be the first-line imaging technique used by family physicians for the diagnosis and/or follow-up of patients with osteoarthritis. Nevertheless, this technique should only be used if there are sound indications and if the results will influence decision-making. Despite the increase of indications in patients with rheumatological disease, the role of ultrasound in patients with osteoarthritis continues to be limited. Computed tomography (CT) is of some -although limited- use in osteoarthritis, especially in the study of complex joints (such as the sacroiliac joint and facet joints). Magnetic resonance imaging (MRI) has represented a major advance in the evaluation of joint cartilage and subchondral bone in patients with osteoarthritis but, because of its high cost and diagnostic-prognostic yield, this technique should only be used in highly selected patients. The indications for ultrasound, CT and MRI in patients with osteoarthritis continue to be limited in primary care and often coincide with situations in which the patient may require hospital referral. Patient safety should be bourne in mind. Patients should be protected from excessive ionizing radiation due to unnecessary repeat X-rays or inadequate views or to requests for tests such as CT, when not indicated. Copyright © 2014 Elsevier España, S.L. All rights reserved.

  15. Study of nonlinear resonance effect in Paul trap.

    Science.gov (United States)

    Zhou, Xiaoyu; Xiong, Caiqiao; Zhang, Shuo; Zhang, Ning; Nie, Zongxiu

    2013-05-01

    In this article, we investigated the nonlinear resonance effect in the Paul trap with a superimposed hexapole field, which was assumed as a perturbation to the quadrupole field. On the basis of the Poincare-Lighthill-Kuo (PLK) perturbation method, ion motional equation, known as nonlinear Mathieu equation (NME) was expressed as the addition of approximation equations in terms of perturbation order. We discussed the frequency characteristics of ion axial-radial (z-r) coupled motion in the nonlinear field, derived the expressions of ion trajectories and nonlinear resonance conditions, and found that the mechanism of nonlinear resonance is similar to the normal resonance. The frequency spectrum of ion motion in nonlinear field includes not only the natural frequency series but also nonlinear introduced frequency series, which provide the driving force for the nonlinear resonance. The nonlinear field and the nonlinear effects are inevitable in practical ion trap experiments. Our method provides better understanding of these nonlinear effects and would be helpful for the instrumentation for ion trap mass spectrometers.

  16. Proton nuclear magnetic resonance studies on the variant-3 neurotoxin from Centruroides sculpturatus Ewing: Sequential assignment of resonances

    International Nuclear Information System (INIS)

    Nettesheim, D.G.; Klevit, R.E.; Drobny, G.; Watt, D.D.; Krishna, N.R.

    1989-01-01

    The authors report the sequential assignment of resonances to specific residues in the proton nuclear magnetic resonance spectrum of the variant-3 neurotoxin from the scorpion Centruroides sculpturatus Ewing (range southwestern U.S.A.). A combination of two-dimensional NMR experiments such as 2D-COSY, 2D-NOESY, and single- and double-RELAY coherence transfer spectroscopy has been employed on samples of the protein dissolved in D 2 O and in H 2 O for assignment purposes. These studies provide a basis for the determination of the solution-phase conformation of this protein and for undertaking detailed structure-function studies of these neurotoxins that modulate the flow of sodium current by binding to the sodium channels of excitable membranes

  17. Some double resonance and multiple quantum NMR studies in solids

    Energy Technology Data Exchange (ETDEWEB)

    Wemmer, D.E.

    1978-08-01

    The first section of this work presents the theory and experimental applications to analysis of molecular motion of chemical shielding lineshapes obtained with high resolution double resonance NMR techniques. Analysis of /sup 13/C powder lineshapes in hexamethylbenzene (HMB) and decamethylferrocene (DMFe) show that these molecules reorient in a jumping manner about the symmetry axis. Analysis of proton chemical shielding lineshapes of residual protons in heavy ice (D/sub 2/O) show that protons are exchanged among the tetrahedral positions of neighboring oxygen atoms, consistent with motion expected from defect migration. The second section describes the application of Fourier Transform Double Quantum NMR to measurement of chemical shielding of deuterium in powder samples. Studies of partially deuterated benzene and ferrocene give equal shielding anisotropies, ..delta..sigma = -6.5 ppM. Theoretical predictions and experimental measurements of dipolar couplings between deuterons using FTDQ NMR are presented. Crystals of BaClO/sub 3/.D/sub 2/O, ..cap alpha..,..beta.. d-2 HMB and ..cap alpha..,..beta..,..gamma.. d-3 HMB were studied, as were powders of d-2 HMB and anisic acid. The third section discusses general multiple quantum spectroscopy in dipolar coupled spin systems. Theoretical description is made for creation and detection of coherences between states without quantum number selection rules ..delta..m = +-1. Descriptions of techniques for partial selectivity of order in preparation and detection of multiple quantum coherences are made. The effects on selectivity and resolution of echo pulses during multiple quantum experiments are discussed. Experimental observation of coherences up to order 6 have been made in a sample of benzene dissolved in a liquid crystal. Experimental verifications of order selection and echo generation have been made.

  18. Some double resonance and multiple quantum NMR studies in solids

    International Nuclear Information System (INIS)

    Wemmer, D.E.

    1978-08-01

    The first section of this work presents the theory and experimental applications to analysis of molecular motion of chemical shielding lineshapes obtained with high resolution double resonance NMR techniques. Analysis of 13 C powder lineshapes in hexamethylbenzene (HMB) and decamethylferrocene (DMFe) show that these molecules reorient in a jumping manner about the symmetry axis. Analysis of proton chemical shielding lineshapes of residual protons in heavy ice (D 2 O) show that protons are exchanged among the tetrahedral positions of neighboring oxygen atoms, consistent with motion expected from defect migration. The second section describes the application of Fourier Transform Double Quantum NMR to measurement of chemical shielding of deuterium in powder samples. Studies of partially deuterated benzene and ferrocene give equal shielding anisotropies, Δsigma = -6.5 ppM. Theoretical predictions and experimental measurements of dipolar couplings between deuterons using FTDQ NMR are presented. Crystals of BaClO 3 .D 2 O, α,β d-2 HMB and α,β,γ d-3 HMB were studied, as were powders of d-2 HMB and anisic acid. The third section discusses general multiple quantum spectroscopy in dipolar coupled spin systems. Theoretical description is made for creation and detection of coherences between states without quantum number selection rules Δm = +-1. Descriptions of techniques for partial selectivity of order in preparation and detection of multiple quantum coherences are made. The effects on selectivity and resolution of echo pulses during multiple quantum experiments are discussed. Experimental observation of coherences up to order 6 have been made in a sample of benzene dissolved in a liquid crystal. Experimental verifications of order selection and echo generation have been made

  19. Unicuspid aortic valve disease: a magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A. [Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg (Germany); Djavidani, B.; Poschenrieder, F.; Feuerbach, S. [Inst. fuer Roentgendiagnostik, Universitaetsklinikum Regensburg (Germany); Schmid, C.; Kobuch, R. [Klinik und Poliklinik fuer Herz-, Thorax- und herznahe Gefaesschirurgie, Universitaetsklinikum Regensburg (Germany)

    2008-11-15

    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 {+-} 4.7 cm{sup 2} vs. 8.7 {+-} 2.3 cm{sup 2}, p < 0.01 and 4.6 {+-} 0.7 cm vs. 3.6 {+-} 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 {+-} 0.6 cm vs. 2.3 {+-} 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 {+-} 0.5 cm vs. 2.6 {+-} 0.3 cm, p < 0.05). (orig.)

  20. Does Balloon Kyphoplasty Deliver More Cement Safely into Osteoporotic Vertebrae with Compression Fractures Compared with Vertebroplasty? A Study in Vertebral Analogues

    Science.gov (United States)

    Abduljabbar, Fahad H.; Al-jurayyan, Abdulaziz; Alqahtani, Saad; Sardar, Zeeshan M.; Saluja, Rajeet Singh; Ouellet, Jean; Weber, Michael; Steffen, Thomas; Beckman, Lorne; Jarzem, Peter

    2015-01-01

    Study Design A biomechanical and radiographic study using vertebral analogues. Objectives Kyphoplasty and vertebroplasty are widely used techniques to alleviate pain in fractures secondary to osteoporosis. However, cement leakage toward vital structures like the spinal cord can be a major source of morbidity and even mortality. We define safe cement injection as the volume of the cement injected into a vertebra before the cement leakage occurs. Our objective is to compare the amount of cement that can be safely injected into an osteoporotic vertebra with simulated compression fracture using either vertebroplasty or balloon kyphoplasty techniques. Methods Forty artificial vertebral analogues made of polyurethane with osteoporotic cancellous matrix representing the L3 vertebrae were used for this study and were divided into four groups of 10 vertebrae each. The four groups tested were: low-viscosity cement injected using vertebroplasty, high-viscosity cement injected using vertebroplasty, low-viscosity cement injected using balloon kyphoplasty, and high-viscosity cement injected using balloon kyphoplasty. The procedures were performed under fluoroscopic guidance. The injection was stopped when the cement started protruding from the created vascular channel in the osteoporotic vertebral fracture model. The main outcome measured was the volume of the cement injected safely into a vertebra before leakage through the posterior vascular channel. Results The highest volume of the cement injected was in the vertebroplasty group using high-viscosity cement, which was almost twice the injected volume in the other three groups. One-way analysis of variance comparing the four groups showed a statistically significant difference (p osteoporotic vertebrae with compression fractures. PMID:26225279

  1. Light-free magnetic resonance force microscopy for studies of electron spin polarized systems

    International Nuclear Information System (INIS)

    Pelekhov, Denis V.; Selcu, Camelia; Banerjee, Palash; Chung Fong, Kin; Chris Hammel, P.; Bhaskaran, Harish; Schwab, Keith

    2005-01-01

    Magnetic resonance force microscopy is a scanned probe technique capable of three-dimensional magnetic resonance imaging. Its excellent sensitivity opens the possibility for magnetic resonance studies of spin accumulation resulting from the injection of spin polarized currents into a para-magnetic collector. The method is based on mechanical detection of magnetic resonance which requires low noise detection of cantilever displacement; so far, this has been accomplished using optical interferometry. This is undesirable for experiments on doped silicon, where the presence of light is known to enhance spin relaxation rates. We report a non-optical displacement detection scheme based on sensitive microwave capacitive readout

  2. Synthesis of iodine-123 labelled analogues of the partial agonist (S)-and (R)-bretazenil for the study of CNS benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, Andrew; Mattner, Filomena; McPhee, Meredith; Kassiou, Michael; Najdovski, Ljubco; Dikic, Branko [Australian Nuclear Science and Technology Organisation, Radiopharmaceutical Div., Menai, Sydney, NSW (Australia)

    1996-09-01

    The (S) and (R)-[{sup 123}I]iodinated analogues of the benzodiazepine receptor partial agonist bretazenil have been synthesized for study of the central benzodiazepine receptor using SPECT, (S)- and (R)-[{sup 123}I]iodobretazenil were prepared from the appropriate tin precursors by electrophilic iododestannylation with Na[{sup 123}I] in the presence of Chloramine-T. The products were purified by semi-preparative reverse-phase HPLC with radiochemical yields of 80% in a total synthesis time of 50 minutes. The specific activity was determined to be greater than 2500 Ci/mmol. The radiochemical and chemical purity assessed by radio-TLC and HPLC were found to be 98%. The enantiomeric purity of the (S) and (R) isomers were greater than 97% as assessed by analytical chiral HPLC analysis. (author).

  3. The type of GnRH analogue used during controlled ovarian stimulation influences early embryo developmental kinetics: a time-lapse study.

    Science.gov (United States)

    Muñoz, Manuel; Cruz, María; Humaidan, Peter; Garrido, Nicolás; Pérez-Cano, Inmaculada; Meseguer, Marcos

    2013-06-01

    To explore if the GnRH analogue used for controlled ovarian stimulation (COS) and the ovulation triggering factor (GnRH agonist + hCG triggering versus GnRH antagonist + GnRH agonist triggering) affect embryo development and kinetics. In a retrospective cohort study in the Instituto Valenciano de Infertilidad (IVI) Alicante and the Instituto Universitario-IVI Valencia, Spain, 2817 embryos deriving from 400 couples undergoing oocyte donation were analysed. After controlled ovarian stimulation and IVF/intracytoplamic sperm injection, the timing of embryonic cleavages was assessed by a video time-lapse system. The results were analysed using Student's t test for comparison of timings (hours) and Chi-squared test for comparison of proportions. A p-value we can suggest that the type of protocol used for controlled ovarian stimulation influences embryo kinetics of development but these variations are not reflected in embryo quality. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. Study on reactivity and protection of the alpha-hydroxyphosphonate moiety in 5'-nucleotide analogues: formation of the 3'-O-P-C(OH)-C4' internucleotide linkage.

    Science.gov (United States)

    Králíková, Sárka; Masojídková, Milena; Budĕsínský, Milos; Rosenberg, Ivan

    2003-03-01

    The recently described epimeric nucleosidyl-5'-C-phosphonates (alpha-hydroxyphosphonates) represent novel nucleotide analogues that can be incorporated into chimeric oligonucleotides by the phosphotriester condensation method. In order to prepare suitable protected monomer(s) we have studied condensation reaction between protected 2'-deoxythymidine and 2'-deoxythymidinyl-5'-C-phosphonate, both as model compounds, in dependence on the nature of the 5'-hydroxyl protecting group. We have found that the O-acetyl group is unstable in the presence of TPSCl or MSNT used as condensing agents for activation of the phosphorus moiety. This instability negatively influences the scope of the condensation process. On the other hand, introduction of the O-methoxycarbonyl group gave excellent results. The O-methoxycarbonyl group does not participate in the condensation process, and its quantitative introduction into the nucleotide analo gues is accomplished using a novel acylating agent, methoxycarbonyl tetrazole.

  5. Synthesis and Biological Evaluation of 7-Deoxy-Epothilone Analogues

    Directory of Open Access Journals (Sweden)

    Laura M. Woods

    2017-03-01

    Full Text Available The synthesis of two deoxygenated analogues of potent epothilones is reported in an effort to analyze the relative importance of molecular conformation and ligand–target interactions to biological activity. 7-deoxy-epothilone D and 7-deoxy-(S-14-methoxy-epothilone D were prepared through total synthesis and shown to maintain the conformational preferences of their biologically active parent congeners through computer modeling and nuclear magnetic resonance (NMR studies. The significant decrease in observed potency for each compound suggests that a hydrogen bond between the C7-hydroxyl group and the tubulin binding site plays a critical role in the energetics of binding in the epothilone class of polyketides.

  6. Chemical and isotopic composition of groundwaters and their seasonal variability at the OSAMU Utsumi mine and Morro do Ferro analogue study sites, Pocos de Caldas, Brazil

    International Nuclear Information System (INIS)

    Nordstrom, D.K.; Smellie, J.A.T.; Wolf, M.

    1990-01-01

    Groundwaters and a few surface waters were collected over a period of 3 years from two natural analogue sites near Pocos de Caldas, Brazil: the Osamu Utsumi uranium mine and the Morro do Ferro thorium/rare-earth deposit. These were analysed for major constituents, several trace elements, tritium, deuterium and 18 O, to provide hydrochemical data for the modelling objectives as defined within the natural analogue study programme. The groundwaters are K-Fe-SO 4 type, which classifies them as a highly unusual composition related to the weathering of a hydrothermally altered, mineralised complex of volcanic to sub-volcanic phonolites. A subset of selected constituents (Fe(II), Fe(total), SO 4 , pH, Eh, alkalinity, F and U) was monitored to gain detailed information on the seasonal variability. Seasonal patterns were only apparent from the very shallow groundwater data, but a trend of continuously increasing dissolved solids for the furthest down-gradient sampling point in deep groundwater indicates a growing plume of water affected by pyrite oxidation but without the residual acidity. Tritium and stable isotope measurements indicate that all groundwaters are of meteoric origin and are not affected significantly by evaporation or by water-rock interactions. Recharging groundwaters at both study site demonstrate infiltration of water of less than about 35 years in age, whereas deep groundwaters are below 1 TU (tritium unit) but still contain detectable tritium in most cases. These deeper groundwaters may be interpreted as being 35-60 or more years in age, resulting mainly from an admixture of younger with older groundwaters and/or indicating the influence of subsurface-produced tritium. (au)

  7. A study of nasal cavity volume by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tosa, Yasuyoshi (Showa Univ., Tokyo (Japan). School of Medicine)

    1992-04-01

    The nasal cavity volume in 69 healthy volunteers from 8 to 23 years old (17 males and 52 females) was studied using magnetic resonance imaging (MRI). Merits of MRI such as no radiation exposure, less artifact due to bone and air and measurement of intravascular blood flow; and demerits such as contraindication in users of heart pace-makers or magnetic clips, contraindication in people with claustrophobia and influence of environmental magnetic fields must be considered. A Magunetom M10 (Siemens), a superconduction device with 1.0 Tesla magnetic flux density was used. Enhanced patterns of T[sub 1], and pulse lines were photographed at 600 msec TR (repetition time) and 19 msec TE (echo time) using SE (spin echo) and short SE (spin echo), and 3 or 4 mm slices. Photographs were made of the piriform aperture, choana, superior-middle-inferior concha including the nasal meatus, the frontal sinus, maxillary sinus, cribriform plate, and upper surface of the palate. The line connecting the maximum depression point in the nasal root and the pontomedullary junction was selected by sagittal median section, because this corresponds well with the CM (canthomeatal) line which is useful in CT (computed tomography). The transverse section of the nasal cavity volume was traced by display console with an accessory MRI device and calculated by integration of the slice width. The increase of height and body weight neared a plateau at almost 16 years, whereas increase of nasal cavity volume continued until about 20 years. Pearson's coefficient of correlation and regression line were significant. There were no significant differences in these parameters between male and female groups. Comparatively strong correlation between nasal cavity volume, and age, height and body weight was statistically evident. (author).

  8. Basic studies on the human uterus by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Yasuzawa, Michio

    1990-01-01

    This study was designed to analyze characteristic features of the human uterus by using a 0.5 Tesla super-conducting magnet. Relative square ratios of the endometrium and the junctional zone to the uterine body were measured during menstrual cycle with a computed image analyser. Nine healthy volunteers aged 21 to 30 years underwent magnetic resonance imaging (MRI) in the proliferative, secretory, and menstrual phases. Relaxation times of the endometrium, junctional zone, and myometrium were determined. The relative ratio of the endometrium to the uterine body was 13.8% in the proliferative phase, 17.9% in the secretory phase, and 8.0% in the menstrual phase. The ratio of the junctional zone decreased from 26.6% in the proliferative phase to 23.4% in the secretory phase, and increased to 35.0% in the menstrual phase. Relaxation times of the endometrium and junctional zone were the shortest in the menstrual phase. For the myometrium, T 1 values showed the same tendency. T 2 values were the shortest in the proliferative phase. MRI was also performed in 39 patients with hydatidiform (one), myoma uteri (11), adenomyosis uteri (one), carcinoma of the uterine body (3), and carcinoma of the uterine cervix (23). Myoma nodule without degeneration appeared at low intensity, and had the shortest T 1 and T 2 values. Myoma uteri with degeneration had an increased intensity and larger T 1 and T 2 values. Adenomyosis uteri showed a diffuse low intensity with high intensity spots. Malignant lesions of both the uterine body and cervix showed a high intensity on T 2 -weighted image and similar T 1 and T 2 values. These T 1 and T 2 values were, however, shorter than tissue of unmarried normal women. MRI was considered useful for the observation of menstrual cyclic and quantitative change in the human physiologic uterus, as well as for the differentiation of malignant from benign uterine diseases. (N.K.)

  9. Bilingual brain organization: a functional magnetic resonance adaptation study.

    Science.gov (United States)

    Klein, Denise; Zatorre, Robert J; Chen, Jen-Kai; Milner, Brenda; Crane, Joelle; Belin, Pascal; Bouffard, Marc

    2006-05-15

    We used functional magnetic resonance adaptation (fMRA) to examine whether intra-voxel functional specificity may be present for first (L1)- and second (L2)-language processing. We examined within- and across-language adaptation for spoken words in English-French bilinguals who had acquired their L2 after the age of 4 years. Subjects listened to words presented binaurally through earphones. In two control conditions (one for each language), six identical words were presented to obtain maximal adaptation. The remaining six conditions each consisted of five words that were identical followed by a sixth word that differed. There were thus a total of eight experimental conditions: no-change (sixth word identical to first five); a change in meaning (different final word in L1); a change in language (final item translated into L2); a change in meaning and language (different final word in L2). The same four conditions were presented in L2. The study also included a silent baseline. At the neural level, within- and across-language word changes resulted in release from adaptation. This was true for separate analyses of L1 and L2. We saw no evidence for greater recovery from adaptation in across-language relative to within-language conditions. While many brain regions were common to L1 and L2, we did observe differences in adaptation for forward translation (L1 to L2) as compared to backward translation (L2 to L1). The results support the idea that, at the lexical level, the neural substrates for L1 and L2 in bilinguals are shared, but with some populations of neurons within these shared regions showing language-specific responses.

  10. RESPECT: Neutron resonance spin-echo spectrometer for extreme studies

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, R., E-mail: Robert.Georgii@frm2.tum.de [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Heinz Maier-Leibnitz Zentrum, Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); Kindervater, J. [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street Baltimore, MD 21218 (United States); Pfleiderer, C.; Böni, P. [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany)

    2016-11-21

    We propose the design of a REsonance SPin-echo spECtrometer for exTreme studies, RESPECT, that is ideally suited for the exploration of non-dispersive processes such as diffusion, crystallization, slow dynamics, tunneling processes, crystal electric field excitations, and spin fluctuations. It is a variant of the conventional neutron spin-echo technique (NSE) by (i) replacing the long precession coils by pairs of longitudinal neutron spin-echo coils combined with RF-spin flippers and (ii) by stabilizing the neutron polarization with small longitudinal guide fields that can in addition be used as field subtraction coils thus allowing to adjust the field integrals over a range of 8 orders of magnitude. Therefore, the dynamic range of RESPECT can in principle be varied over 8 orders of magnitude in time, if neutrons with the required energy are made available. Similarly as for existing NSE-spectrometers, spin echo times of up to approximately 1 μs can be reached if the divergence and the correction elements are properly adjusted. Thanks to the optional use of neutron guides and the fact that the currents for the correction coils are much smaller than in standard NSE, intensity gains of at least one order of magnitude are expected, making the concept of RESPECT also competitive for operation at medium flux neutron sources. RESPECT can also be operated in a MIEZE configuration allowing the investigation of relaxation processes in depolarizing environments as they occur when magnetic fields are applied at the sample position, i.e. for the investigation of the dynamics of flux lines in superconductors, magnetic fluctuations in ferromagnetic materials, and samples containing hydrogen.

  11. Magnetic resonance elastography in normal human brain: preliminary study

    International Nuclear Information System (INIS)

    Xu Lei; Gao Peiyi; Lin Yan; Han Jiancheng; Xi Zhinong; Shen Hao

    2007-01-01

    Objective: To study the application of magnetic resonance elastography (MRE) in the human brain. Methods: An external force actuator was developed. The actuator was fixed to the head coil. During MRE scan, one side of the actuator was attached to the volunteers' head. Low frequency oscillation was produced by the actuator and generated shear waves propagating into brain tissue. The pulse sequence of MRE was designed. A modified gradient echo sequence was developed with motion sensitizing gradient (MSG) imposed along X, Y or Z direction. Cyclic displacement within brain tissue induced by shear waves caused a measurable phase shift in the received MR signal. From the measured phase shift, the displacement at each voxel could be calculated, and the shear waves within the brain were directly imaged. By adjusting the phase offset, the dynamic propagation of shear waves in a wave cycle was obtained. Phase images were processed with local frequency estimation (LFE) technique to obtain the elasticity images. Shear waves at 100 Hz, 150 Hz, and 200 Hz were applied. Results: The phase images of MRE directly imaged the propagating shear waves within the brain. The direction of the propagation was from surface of the brain to the center. The wavelength of shear waves varied with the change of actuating frequency. The change of wavelength of shear waves in gray and white matter of the brain was identified. The wavelength of shear waves in gray matter was shorter than that in white matter. The elasticity image of the brain revealed that the shear modulus of the white matter was higher than that of gray matter. Conclusion: The phase images of MRE can directly visualize the propagation of shear waves in the brain tissue. The elasticity image of the brain can demonstrate the change of elasticity between gray and white matter. (authors)

  12. Novel nuclear magnetic resonance techniques for studying biological molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laws, David Douglas [Univ. of California, Berkeley, CA (United States)

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone (Φ/Ψ) dihedral angles by comparing experimentally determined 13Ca, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

  13. Study of the geometrical resonances of superconducting tunnel junctions

    DEFF Research Database (Denmark)

    Sørensen, O. Hoffmann; Finnegan, T.F.; Pedersen, Niels Falsig

    1973-01-01

    The resonant cavity structure of superconducting Sn-Sn-oxide-Sn tunnel junctions has been investigated via photon-assisted quasiparticle tunneling. We find that the temperature-dependent losses at 35 GHz are determined by the surface resistance of the Sn films for reduced temperatures between 0.5...

  14. Resonance Raman and optical dephasing study of tricarbocyanine dyes

    NARCIS (Netherlands)

    Ashworth, SH; Kummrow, A; Lenz, K

    Fluorescence lineshape analysis based on resonance Raman spectra of the dye HITCI was used to determine the details and magnitude of the vibrational part of the line broadening function, Forced light scattering (FLS) was applied to measure optical dephasing of HITCI in ethylene glycol, pumping at

  15. Studies of electron cyclotron resonance ion source plasma physics

    International Nuclear Information System (INIS)

    Tarvainen, O.

    2005-01-01

    This thesis consists of an introduction to the plasma physics of electron cyclotron resonance ion sources (ECRIS) and a review of the results obtained by the author and co-workers including discussion of related work by others. The thesis begins with a theoretical discussion dealing with plasma physics relevant for the production of highly charged ions in ECR ion source plasmas. This is followed by an overview of different techniques, such as gas mixing and double frequency heating, that can be used to improve the performance of this type of ion source. The experimental part of the work consists of studies related to ECRIS plasma physics. The effect of the gas mixing technique on the production efficiency of different ion beams was studied with both gaseous and solid materials. It was observed that gas mixing improves the confinement of the heavier element while the confinement of the lighter element is reduced. When the effect of gas mixing on MIVOC-plasmas was studied with several mixing gases it was observed that applying this technique can reduce the inevitable carbon contamination by a significant factor. In order to understand the different plasma processes taking place in ECRIS plasmas, a series of plasma potential and emittance measurements was carried out. An instrument, which can be used to measure the plasma potential in a single measurement without disturbing the plasma, was developed for this work. Studying the plasma potential of ECR ion sources is important not only because it helps to understand different plasma processes, but also because the information can be used as an input parameter for beam transport simulations and ion source extraction design. The experiments performed have revealed clear dependencies of the plasma potential on certain source parameters such as the amount of carbon contamination accumulated on the walls of the plasma chamber during a MIVOC-run. It was also observed that gas mixing affects not only the production efficiency

  16. 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)

  17. ACTINOMYCIN D ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

    acids, $g(b)-amino acids and/or longer chain $g(v)-amino acids, and a difunctional group which preferably is a cyclic entity, in particular, an aromatic or heteroaromatic entity acting as an intercalator group. Specific compounds and a library of such compounds may be prepared using conventional solid......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(a)-amino...

  18. Nuclear magnetic resonance. Present results and its application to renal pathology. Experimental study of hydronephrosis

    International Nuclear Information System (INIS)

    Bertrand, P.

    1987-01-01

    Results of proton nuclear magnetic resonance imaging and relaxation time measurement of experimental hydronephrosis in mice are presented. The study is preceded by a description of the physical principles underlying the phenomenon of nuclear magnetic resonance and of its biomedical applications and with a review of the clinical use of NMR imaging in renal pathology [fr

  19. Overtones of isoscalar giant resonances studied in direct particle decay measurements

    NARCIS (Netherlands)

    Hunyadi, M; van den Berg, AM; Csatlos, M; Csige, L; Davids, B; Garg, U; Gulyas, J; Harakeh, MN; de Huu, MA; Krasznahorkay, A; Sohler, D; Wortche, HJ

    The isoscalar giant dipole resonance (ISGDR), which is the lowest-energy overtone mode of the isoscalar giant resonances, has been studied in some medium-heavy and heavy nuclei in coincidence measurements. The observation of the direct nucleon decay channels significantly helped to enhance giant

  20. Study of $^{13}$Be through isobaric analog resonances in the Maya active target

    CERN Multimedia

    Riisager, K; Orr, N A; Jonson, B N G; Raabe, R; Fynbo, H O U; Nilsson, T

    We propose to perform an experiment with a $^{12}$Be beam and the Maya active target. We intend to study the ground state of $^{13}$Be through the population of its isobaric analog resonance in $^{13}$B. The resonance will be identified detecting its proton- and neutron-decay channels.

  1. Use of a radio-frequency resonance circuit in studies of alkali ionization in flames

    International Nuclear Information System (INIS)

    Borgers, A.J.

    1978-01-01

    The construction of a radio-frequency resonance system and its use in the study of alkali metal ionization in flames is described. The author re-determines the values of the alkali ionization rate constants for a CO flame with N 2 as diluent gas of known temperature using the RF resonance method. (Auth.)

  2. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1989-01-01

    Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances

  3. Isolation and structural identification of a novel minoxidil analogue in an illegal dietary supplement: triaminodil.

    Science.gov (United States)

    Lee, Ji Hyun; Park, Han Na; Park, Hyoung Joon; Kim, Nam Sook; Park, Sung-Kwan; Lee, Jongkook; Baek, Sun Young

    2018-01-01

    A new minoxidil analogue was detected in an illegal dietary supplement advertised as a hair-growth treatment. The analogue was identified using ultra-performance liquid chromatography (UPLC), high-resolution mass spectrometry (LC-HR-MS) and nuclear magnetic resonance (NMR) spectroscopy. The compound was structurally elucidated as a minoxidil analogue in which the piperidinyl group of minoxidil was replaced with a pyrrolidinyl group corresponding to a molecular formula of C 8 H 13 N 5 O. The new analogue has been named triaminodil. As this is the first report of the compound, there are no chemical, toxicology or pharmacological data available.

  4. Transaxial analogue tomography

    International Nuclear Information System (INIS)

    Duinker, S.; Geluk, R.J.; Mulder, H.

    1978-01-01

    After an introduction on computerized tomography (CT) scanners summarizing the various generations, the general outline of the concept of a transaxial tomography system is given, which is entirely based on analogue instead of digital techniques (AT system). In particular, the use of X-ray image-intensifier systems as a means of detecting the transmission profiles of the object in a so-called half-field detection method are discussed as well as various possibilities of detector scanning. It is further discussed how in a purely electronic way with the aid of a scan-converter, density profiles representative of parallel beams can be derived from the family of profiles as obtained from the fan-shaped beams in the actual experiment. A practical opto-electronic solution of the analogue spatial filtering problem is described as to how to process, on a real-time basis, parallel density profiles so that after back-projection tomographic images which are free from point-spreading effects will be obtained. Finally, after a brief indication of certain technical details for which corrective measures have to be worked out in the course of practical realization, the main relative advantages of AT scanners in comparison to CT scanners are enumerated. (Auth.)

  5. Electron spin resonance studies of gamma irradiated saccharides. Etudes par resonance paramagnetique electronique de saccharides soumis a un rayonnement gamma

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J.; Thiery, C.; Battesti, C.; Agnel, J.P.; Triolet, J.; Vincent, P. (CEA Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Physiologie Vegetale et Ecosystemes)

    1993-04-01

    The radiolysis mechanism of several saccharides was studied in order to understand the radiolysis mechanism of starches. Electron Spin Resonance first performed in powder state did not allow determination of the chemical structure of the induced radicals. The spin-trapping method combined with HPLC however, followed by ESR spectra analysis with the 'Voyons' simulation program was applied to the study of glucose, glucose oligomers and disaccharides. We were thus able to further our understanding of the radiolysis mechanism of starches. 2 tabs., 4 figs.

  6. A prospective randomised cross-over study of the effect of insulin analogues and human insulin on the frequency of severe hypoglycaemia in patients with type 1 diabetes and recurrent hypoglycaemia (the HypoAna trial: study rationale and design

    Directory of Open Access Journals (Sweden)

    Kristensen Peter

    2012-06-01

    Full Text Available Abstract Background Severe hypoglycaemia still represents a significant problem in insulin-treated diabetes. Most patients do not experience severe hypoglycaemia often. However, 20% of patients with type 1 diabetes experience recurrent severe hypoglycaemia corresponding to at least two episodes per year. The effect of insulin analogues on glycaemic control has been documented in large trials, while their effect on the frequency of severe hypoglycaemia is less clear, especially in patients with recurrent severe hypoglycaemia. The HypoAna Trial is designed to investigate whether short-acting and long-acting insulin analogues in comparison with human insulin are superior in reducing the occurrence of severe hypoglycaemic episodes in patients with recurrent hypoglycaemia. This paper reports the study design of the HypoAna Trial. Methods/design The study is a Danish two-year investigator-initiated, prospective, randomised, open, blinded endpoint (PROBE, multicentre, cross-over trial investigating the effect of insulin analogues versus human insulin on the frequency of severe hypoglycaemia in subjects with type 1 diabetes. Patients are randomised to treatment with basal-bolus therapy with insulin detemir / insulin aspart or human NPH insulin / human regular insulin in random order. The major inclusion criterion is history of two or more episodes of severe hypoglycaemia in the preceding year. Discussion In contrast to almost all other studies in this field the HypoAna Trial includes only patients with major problems with hypoglycaemia. The HypoAna Trial will elucidate whether basal-bolus regimen with short-acting and long-acting insulin analogues in comparison with human insulin are superior in reducing occurrence of severe hypoglycaemic episodes in hypoglycaemia prone patients with type 1 diabetes. http://www.clinicaltrials.gov: NCT00346996.

  7. Investigations of neutron-rich nuclei at the dripline through their analogue states : The cases of $^{10}$Li - $^{10}$Be (T=2) and $^{17}$C - $^{17}$N (T=5/2)

    CERN Multimedia

    2002-01-01

    We propose to study the elastic resonance scattering reactions $^{9}$Li+p and $^{16}$C+p to investigate the energies, spins and parities of the lowest T=2 states in $^{10}$Be and the T=5/2 states in $^{17}$N. These are analogue states of the ground states and first excited states in $^{10}$Li and $^{17}$C.

  8. Brain Biochemistry and Personality: A Magnetic Resonance Spectroscopy Study

    OpenAIRE

    Ryman, Sephira G.; Gasparovic, Chuck; Bedrick, Edward J.; Flores, Ranee A.; Marshall, Alison N.; Jung, Rex E.

    2011-01-01

    To investigate the biochemical correlates of normal personality we utilized proton magnetic resonance spectroscopy ((1)H-MRS). Our sample consisted of 60 subjects ranging in age from 18 to 32 (27 females). Personality was assessed with the NEO Five-Factor Inventory (NEO-FFI). We measured brain biochemistry within the precuneus, the cingulate cortex, and underlying white matter. We hypothesized that brain biochemistry within these regions would predict individual differences across major domai...

  9. Quick and dirty methods for studying black-hole resonances

    OpenAIRE

    Glampedakis, K.; Andersson, N.

    2003-01-01

    We discuss simple integration methods for the calculation of rotating black hole scattering resonances both in the complex frequency plane (quasinormal modes) and the complex angular momentum plane (Regge poles). Our numerical schemes are based on variations of "phase-amplitude" methods. In particular, we discuss the Pruefer transformation, where the original (frequency domain) Teukolsky wave equation is replaced by a pair of first-order non-linear equations governing the introduced phase fun...

  10. 'Quick and dirty' methods for studying black-hole resonances

    International Nuclear Information System (INIS)

    Glampedakis, Kostas; Andersson, Nils

    2003-01-01

    We discuss simple integration methods for the calculation of black-hole scattering resonances both in the complex frequency plane (quasinormal modes) and the complex angular momentum plane (Regge poles). Our numerical schemes are based on variations of 'phase-amplitude' methods. In particular, we discuss the Pruefer transformation, where the original (frequency domain) Teukolsky wave equation is replaced by a pair of first-order nonlinear equations governing the introduced phase functions. Numerical integration of these equations, performed along the real r * axis (where r * denotes the usual tortoise radial coordinate), or along rotated contours in the complex r * -plane, provides the required S-matrix element (the ratio of amplitudes of the outgoing and ingoing waves at infinity). Mueller's algorithm is then employed to conduct searches in the complex plane for the poles of this quantity (which are, by definition, the desired resonances). We have tested this method by verifying known results for Schwarzschild quasinormal modes and Regge poles, and provide new results for the Kerr black-hole problem. Results produced by our scheme prove to be accurate as long as the imaginary part of the resonance is not much larger than the real part. We also describe a new method for estimating the 'excitation coefficients' for quasinormal modes. The method is applied to scalar waves moving in the Kerr geometry, and the obtained results shed light on the long-lived quasinormal modes that exist for black holes rotating near the extreme Kerr limit

  11. Study of the nonlinearities in micromechanical clamped–clamped beam resonators using stroboscopic SEM

    International Nuclear Information System (INIS)

    Shao, L C; Wong, C L; Palaniapan, M

    2008-01-01

    This paper presents a comprehensive study of the nonlinearities in micromechanical clamped–clamped beam resonators using a stroboscopic scanning electron microscopy (SEM) technique. Stroboscopic SEM allows direct imaging and measurement of the resonator's momentary displacement, hence eliminating the uncertainties associated with the conventional characterization methods. Five different silicon-on-insulator (SOI) comb-drive clamped–clamped beam resonators with resonant frequencies ranging from 113 kHz to 239 kHz were designed, fabricated and tested to investigate how their nonlinearities are related to the device dimensions. Both the theoretical analysis and experimental results conclusively show that the critical vibration amplitude of the resonator is around 1% of the beam width in a vacuum and is relatively independent of the beam length. Furthermore, it is found that the maximum storable energy of the resonator can be significantly increased by increasing the beam width and/or reducing the beam length if there are no restrictions on these dimensions. On the other hand, if a specific resonant frequency needs to be maintained, the maximum storable energy can be improved by increasing both the beam width and length by the same factor. Such a study not only helps to reveal the intrinsic nonlinear properties of the micromechanical clamped–clamped beam resonators, but also provides useful design guidelines for engineers to optimize the overall device performance

  12. Micro - ring resonator with variety of gap width for acid rain sensing application: preliminary study

    Science.gov (United States)

    Mulyanti, B.; Ramza, H.; Pawinanto, R. E.; Rahman, J. A.; Ab-Rahman, M. S.; Putro, W. S.; Hasanah, L.; Pantjawati, A. B.

    2017-05-01

    The acid rain is an environmental disaster that it will be intimidates human life. The development micro-ring resonator sensor created from SOI (Silicon on insulator) and it used to detect acid rain index. In this study, the LUMERICAL software was used to simulate SOI material micro-ring resonator. The result shows the optimum values of fixed parameters from ring resonator have dependent variable in gap width. The layers under ring resonator with silicone (Si) and wafer layer of silicone material (Si) were added to seen three conditions of capability model. Model - 3 is an additional of bottom layer that gives the significant effect on the factor of quality. The optimum value is a peak value that given by the FSR calculation. FSR = 0, it means that is not shows the light propagation in the ring resonator and none of the light coming out on the bus - line.

  13. Progresses in the studies of adiabatic splitting of charged particle beams by crossing nonlinear resonances

    Directory of Open Access Journals (Sweden)

    A. Franchi

    2009-01-01

    Full Text Available The multiturn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by nonlinear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.

  14. GEANT4 simulation study of a gamma-ray detector for neutron resonance densitometry

    International Nuclear Information System (INIS)

    Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Takamine, Jun; Kureta, Masatoshi; Iimura, Hideki

    2013-01-01

    A design study of a gamma-ray detector for neutron resonance densitometry was made with GEANT4. The neutron resonance densitometry, combining neutron resonance transmission analysis and neutron resonance capture analysis, is a non-destructive technique to measure amounts of nuclear materials in melted fuels of the Fukushima Daiichi nuclear power plants. In order to effectively quantify impurities in the melted fuels via prompt gamma-ray measurements, a gamma-ray detector for the neutron resonance densitometry consists of cylindrical and well type LaBr 3 scintillators. The present simulation showed that the proposed gamma-ray detector suffices to clearly detect the gamma rays emitted by 10 B(n, αγ) reaction in a high environmental background due to 137 Cs radioactivity with its Compton edge suppressed at a considerably small level. (author)

  15. Study of lateral mode SOI-MEMS resonators for reduced anchor loss

    International Nuclear Information System (INIS)

    Lee, Joshua E-Y; Yan, Jize; Seshia, Ashwin A

    2011-01-01

    MEMS resonators fabricated in silicon-on-insulator (SOI) technology must be clamped to the substrate via anchoring stems connected either from within the resonator or through the sides, with the side-clamped solution often employed due to manufacturing constraints. This paper examines the effect of two types of commonly used side-clamped, anchoring-stem geometries on the quality factor of three different laterally-driven resonator topologies. This study employs an analytical framework which considers the relative distribution of strain energies between the resonating body and clamping stems. The ratios of the strain energies are computed using ANSYS FEA and used to provide an indicator of the expected anchor-limited quality factors. Three MEMS resonator topologies have been fabricated and characterized in moderate vacuum. The associated measured quality factors are compared against the computed strain energy ratios, and the trends are shown to agree well with the experimental data.

  16. Adenosine deaminase converts purine riboside into an analogue of a reactive intermediate: a 13C NMR and kinetic study

    International Nuclear Information System (INIS)

    Kurz, L.C.; Frieden, C.

    1987-01-01

    The 13 C NMR spectra of [2- 13 C]- and [6- 13 C] purine ribosides have been obtained free in solution and bound to the active site of adenosine deaminase. The positions of the resonances of the bound ligand are shifted relative to those of the free ligand as follows: C-2, -3.7 ppm; C-6, -73.1 ppm. The binary complexes are in slow exchange with free purine riboside on the NMR time scale, and the dissociation rate constant is estimated to be 1.35 s -1 from the slow exchange broadening of the free signal. In aqueous solution, protonation of purine riboside at N-1 results in changes in 13 C chemical shift relative to those of the free base as follows: C-2, -4.9 ppm; C-6, -7.9 ppm. The changes in chemical shift that occur when purine riboside binds to the enzyme indicate that the hybridization of C-6 changes from sp 2 to sp 3 in the binary complex with formation of a new bond to oxygen or sulfur. A change in C-2 hybridization can be eliminated as can protonation at N-1 as the sole cause of the chemical shift changes. The kinetic constants for the adenosine deaminase catalyzed hydrolysis of 6-chloro- and 6-fluoropurine riboside have been compared, and the reactivity order implies that carbon-halogen bond breaking does not occur in the rate-determining step. These observations support a mechanism for the enzyme in which formation of a tetrahedral intermediate is the most difficult chemical step. Enzymic stabilization of this intermediate may be an important catalytic strategy used by the enzyme to lower the standard free energy of the preceding transition state

  17. Numerical study of heterogeneous mean temperature and shock wave in a resonator

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Takeru [Department of Mechanical Engineering, Osaka University, Suita 565-0871 (Japan)

    2015-10-28

    When a frequency of gas oscillation in an acoustic resonator is sufficiently close to one of resonant frequencies of the resonator, the amplitude of gas oscillation becomes large and hence the nonlinear effect manifests itself. Then, if the dissipation effects due to viscosity and thermal conductivity of the gas are sufficiently small, the gas oscillation may evolve into the acoustic shock wave, in the so-called consonant resonators. At the shock front, the kinetic energy of gas oscillation is converted into heat by the dissipation process inside the shock layer, and therefore the temperature of the gas in the resonator rises. Since the acoustic shock wave travels in the resonator repeatedly over and over again, the temperature rise becomes noticeable in due course of time even if the shock wave is weak. We numerically study the gas oscillation with shock wave in a resonator of square cross section by solving the initial and boundary value problem of the system of three-dimensional Navier-Stokes equations with a finite difference method. In this case, the heat conduction across the boundary layer on the wall of resonator causes a spatially heterogeneous distribution of mean (time-averaged) gas temperature.

  18. Automated Layout Generation of Analogue and Mixed-Signal ASIC's

    DEFF Research Database (Denmark)

    Bloch, Rene

    The research and development carried out in this Ph.D. study focusses on two key areas of the design flow for analogue and mixed-signal integrated circuit design, the mixed-signal floorplanning and the analogue layout generation.A novel approach to floorplanning is presented which provides true i...

  19. 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...

  20. 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...

  1. Longitudinal in vivo magnetic resonance imaging studies in experimental allergic encephalomyelitis: effect of a neurotrophic treatment on cortical lesion development

    International Nuclear Information System (INIS)

    Gispen, W.H.; Nicolay, K.; Verhaagen, J.; Muller, H.J.; Duckers, H.J.

    1997-01-01

    Proton magnetic resonance imaging enables non-invasive monitoring of lesion formation in multiple sclerosis and has an important role in assessing the potential effects of therapy. T2-weighted and short τ inversion recovery magnetic resonance imaging were used to assess the effect of a neurotrophic adrenocorticotrophic hormone 4-9 analogue [H-Met(O 2 )-Glu-His-Phe-d-Lys-Phe-OH] on the volume of lesions in the brains of rats suffering from chronic experimental allergic encephalomyelitis, an animal equivalent of multiple sclerosis. Lesion volume was monitored during a five-month period. Magnetic resonance imaging indicated that treatment with the adrenocorticotrophic hormone 4-9 analogue significantly reduced the lesion volume by 84 and 85% 10 and 20 weeks after lesion induction, respectively. Furthermore, peptide treatment significantly reduced chronic experimental allergic encephalomyelitis-related neurological symptoms during the chronic phase of the disease (week 3 until week 20 after lesion induction). Both functional and morphological recovery were considerably advanced by peptide treatment. Twenty weeks after lesion induction rats with chronic experimental allergic encephalomyelitis were killed for histological analysis, to correlate magnetic resonance imaging findings with morphological changes. The regions of abnormally high signal intensities on T2-weighted magnetic resonance images coincided with areas of demyelination and concomitant widespread inflammatory infiltration, oedema formation and enlarged ventricles.The improved neurological status and the 84% reduction in the lesion volume in the cerebrum of rats chronic experimental allergic encephalomyelitis point to the potential value of trophic peptides in the development of strategies for limiting the damage caused by central demyelinating lesions in syndromes such as multiple sclerosis. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Longitudinal in vivo magnetic resonance imaging studies in experimental allergic encephalomyelitis: effect of a neurotrophic treatment on cortical lesion development

    Energy Technology Data Exchange (ETDEWEB)

    Gispen, W.H. [Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Medical Faculty, Utrecht University Utrecht (Netherlands); Nicolay, K. [Department of in vivo NMR, Bijvoet Center, Utrecht University Utrecht (Netherlands); Verhaagen, J. [Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Medical Faculty, Utrecht University Utrecht (Netherlands); Muller, H.J. [Department of in vivo NMR, Bijvoet Center, Utrecht University Utrecht (Netherlands); Duckers, H.J. [Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Medical Faculty, Utrecht University Utrecht (Netherlands)

    1997-02-14

    Proton magnetic resonance imaging enables non-invasive monitoring of lesion formation in multiple sclerosis and has an important role in assessing the potential effects of therapy. T2-weighted and short {tau} inversion recovery magnetic resonance imaging were used to assess the effect of a neurotrophic adrenocorticotrophic hormone{sub 4-9} analogue [H-Met(O{sub 2})-Glu-His-Phe-d-Lys-Phe-OH] on the volume of lesions in the brains of rats suffering from chronic experimental allergic encephalomyelitis, an animal equivalent of multiple sclerosis. Lesion volume was monitored during a five-month period. Magnetic resonance imaging indicated that treatment with the adrenocorticotrophic hormone{sub 4-9} analogue significantly reduced the lesion volume by 84 and 85% 10 and 20 weeks after lesion induction, respectively. Furthermore, peptide treatment significantly reduced chronic experimental allergic encephalomyelitis-related neurological symptoms during the chronic phase of the disease (week 3 until week 20 after lesion induction). Both functional and morphological recovery were considerably advanced by peptide treatment. Twenty weeks after lesion induction rats with chronic experimental allergic encephalomyelitis were killed for histological analysis, to correlate magnetic resonance imaging findings with morphological changes. The regions of abnormally high signal intensities on T2-weighted magnetic resonance images coincided with areas of demyelination and concomitant widespread inflammatory infiltration, oedema formation and enlarged ventricles.The improved neurological status and the 84% reduction in the lesion volume in the cerebrum of rats chronic experimental allergic encephalomyelitis point to the potential value of trophic peptides in the development of strategies for limiting the damage caused by central demyelinating lesions in syndromes such as multiple sclerosis. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Does forming implementation intentions help people with mental health problems to achieve goals? A meta-analysis of experimental studies with clinical and analogue samples.

    Science.gov (United States)

    Toli, Agoro; Webb, Thomas L; Hardy, Gillian E

    2016-03-01

    People struggle to act on the goals that they set themselves, and this gap between intention and action is likely to be exacerbated by mental health problems. Evidence suggests that forming specific if-then plans (or 'implementation intentions') can promote goal attainment and a number of studies have applied such techniques in clinical contexts. However, to date, the extent to which planning can help people with mental health problems has not been systematically examined. The present review used meta-analysis to investigate the effect of if-then planning on goal attainment among people with a DSM-IV/ICD-10 diagnosis (i.e., clinical samples) or scores above a relevant cut-off on clinical measures (i.e., analogue samples). In total, 29 experimental studies, from 18 records, met the inclusion criteria. Excluding one outlying (very large) effect, forming implementation intentions had a large-sized effect on goal attainment (d+ = 0.99, k = 28, N = 1,636). Implementation intentions proved effective across different mental health problems and goals, and in studies with different methodological approaches. Taken together, the findings suggest that forming implementation intentions can be a useful strategy for helping people with mental health problems to achieve various goals and might be usefully integrated into existing treatment approaches. However, further studies are needed addressing a wider range of mental health problems. © 2015 The British Psychological Society.

  4. Bioceramic Resonance Effect on Meridian Channels: A Pilot Study.

    Science.gov (United States)

    Leung, Ting-Kai; Chan, Wing P; Tai, Chen-Jei; Cho, Ting-Pin; Yang, Jen-Chang; Lee, Po-Tsung

    2015-01-01

    Bioceramic is a kind of material which emits nonionizing radiation and luminescence, induced by visible light. Bioceramic also facilitates the breakup of large clusters of water molecules by weakening hydrogen bonds. Hydrogen bond weakening, which allows water molecules to act in diverse ways under different conditions, is one of the key mechanisms underlying the effects of Bioceramic on biophysical and physical-chemical processes. Herein, we used sound to amplify the effect of Bioceramic and further developed an experimental device for use in humans. Thirteen patients who suffered from various chronic and acute illnesses that severely affected their sleep patterns and life quality were enrolled in a trial of Bioceramic resonance (i.e., rhythmic 100-dB sound waves with frequency set at 10 Hz) applied to the skin surface of the anterior chest. According to preliminary data, a "Propagated Sensation along Meridians" (PSM) was experienced in all Bioceramic resonance-treated patients but not in any of the nine control patients. The device was believed to enhance microcirculation through a series of biomolecular and physiological processes and to subject the specific meridian channels of Traditional Chinese Medicine (TCM) to coherent vibration. This noninvasive technique may offer an alternative to needle acupuncture and other traditional medical practices with clinical benefits.

  5. Bioceramic Resonance Effect on Meridian Channels: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2015-01-01

    Full Text Available Bioceramic is a kind of material which emits nonionizing radiation and luminescence, induced by visible light. Bioceramic also facilitates the breakup of large clusters of water molecules by weakening hydrogen bonds. Hydrogen bond weakening, which allows water molecules to act in diverse ways under different conditions, is one of the key mechanisms underlying the effects of Bioceramic on biophysical and physical-chemical processes. Herein, we used sound to amplify the effect of Bioceramic and further developed an experimental device for use in humans. Thirteen patients who suffered from various chronic and acute illnesses that severely affected their sleep patterns and life quality were enrolled in a trial of Bioceramic resonance (i.e., rhythmic 100-dB sound waves with frequency set at 10 Hz applied to the skin surface of the anterior chest. According to preliminary data, a “Propagated Sensation along Meridians” (PSM was experienced in all Bioceramic resonance-treated patients but not in any of the nine control patients. The device was believed to enhance microcirculation through a series of biomolecular and physiological processes and to subject the specific meridian channels of Traditional Chinese Medicine (TCM to coherent vibration. This noninvasive technique may offer an alternative to needle acupuncture and other traditional medical practices with clinical benefits.

  6. A nuclear magnetic resonance and electron spin resonance study on the dynamics of pentacoordinated organophosphorus compounds

    International Nuclear Information System (INIS)

    Keijzer, A.E.H. de.

    1988-01-01

    In this thesis the role of the steric and electronic effects on the fundamental dynamic behaviour of pentacoordinated phosporus compounds is further elaborated. In chapter 2 a variable temperature 13 C NMR study, performed on a series of monocyclic oxyphosphoranes, is presented. The investigations were carried out to determine the influence of the conformational transmission effect on the barriers to pseudorotation in pentacoordinated phosphorus compounds. Chapter 3 also comprises a variable temperature 13 C NMR study on pentacoordinated phosphorus compounds. In this chapter, however, an additional high-resolution 1 H NMR study on the conformational equilibria around the P-O-C-C-O fragments is included. These studies were performed in order to determine whether the enhancement of the reorganization rates around phosphorus is brought about by accelerated pseudorotation or by the involvement of hexacoordinated zwitterionic phosphorus intermediates. In chapter 4, a 31 P NMR study on the solvolysis rate of several phosphinate esters is described. This study was performed in order to determine the influence of the conformational transmission effect on the solvolysis rate of phosphate esters. A number of phosphates is examined in which, during the course of the solvolysis reaction, the conformational transmission effect is bound to be present or absent respectively. Moreover, it is discussed in which way the concept of conformational transmission induced differences in solvolysis rates can be used as a probe to examine the reactions of biologically important phosphate esters. In chapters 5 and 6 ESR studies on the influence of steric and electronic factors on phosphoranyl formation in solution, and on the intramolecular electron transfer in phosphoranyl radicals are presented. (author). 121 refs.; 33 figs.; 17 figs

  7. Study of resonance production as a probe of heavy-ion collisions with the ALICE detector

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Hadronic resonances provide a rich set of measurements that can be used to study the properties of ultra-relativistic heavy-ion collisions. Measurements of resonances and long-lived particles provide information about the properties of the late hadronic phase due to the presence of scattering effects that can modify resonance yields. Resonances can also be used along with long-lived hadrons to study the various mechanisms that shape particle pT spectra, including in-medium energy loss, radial flow, and recombination. Measurements of resonances in pp and p-Pb collisions serve as baselines for measurements in heavy-ion collisions, provide input for tuning QCD-inspired event generators, and aid searches for collective behavior in small systems. I will present measurements of a wide variety of hadronic resonances, including some of the most recent results presented at the Quark Matter conference. By comparing measurements of resonances with different masses, lifetimes, and quark contents in pp, p-Pb, and Pb-Pb co...

  8. The Risk of Severe Hypoglycemia in Patients with Type 2 Diabetes Mellitus Starting Insulin Therapy with Premixed Insulin Analogues Taken Twice Daily: An Observational Study in Turkish Patients

    Directory of Open Access Journals (Sweden)

    Mustafa Sait Gönen

    2013-12-01

    Full Text Available Purpose: To assess the risk of severe hypoglycemia in Turkish patients with type 2 diabetes mellitus (T2DM starting insulin therapy with premixed insulin analogues alone or in combination with oral antihyperglycemic medications. Material and Method: Data from a subset of Turkish patients who participated in a 1-year, multinational, multicenter, prospective observational study were evaluated. Insulin treatment was initiated using commonly prescribed premixed regimens: insulin lispro mix 25 (25% insulin lispro, 75% insulin lispro protamine suspension or biphasic insulin aspart 30/70 (30% insulin aspart, 70% insulin aspart protamine suspension twice daily. Results: Of the 154 patients treated, 61 (39.6% were male with a mean age of 56 years and a T2DM duration of 8.9 years. Twelve patients (7.8% experienced ≥1 episode of severe hypoglycemia, but all recovered. The severe hypoglycemic rate was 0.14 episodes/patient-year. The mean glycated hemoglobin decreased by 2.7% (10.4% to 7.8% and fasting plasma glucose by 115.9 mg/dL (265.3 mg/dL to 157.6 mg/dL (p<0.0001. Self-monitored blood glucose (2-hour post morning meal decreased by 163.3 mg/dL (327.0 mg/dL to 216.2 mg/dL; p<0.0001. Self-monitored blood glucose level was low, particularly at the 2-hour post evening meal. Body mass index increased by 1.4 kg/m2, and total daily insulin dose by 4.2 IU. Discussion: In Turkish patients with T2DM, initiation of premixed insulin analogues during routine clinical care significantly improves glycemic control during the first year of treatment, but comes with a risk for severe hypoglycemia. Improvements in physician and patient education within the Turkish population regarding hypoglycemia management may be of benefit. Turk Jem 2013; 17: 83-8

  9. Surface plasmon enhanced interfacial electron transfer and resonance Raman, surface-enhanced resonance Raman studies of cytochrome C mutants

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Junwei [Iowa State Univ., Ames, IA (United States)

    1999-11-08

    Surface plasmon resonance was utilized to enhance the electron transfer at silver/solution interfaces. Photoelectrochemical reductions of nitrite, nitrate, and CO2 were studied on electrochemically roughened silver electrode surfaces. The dependence of the photocurrent on photon energy, applied potential and concentration of nitrite demonstrates that the photoelectrochemical reduction proceeds via photoemission process followed by the capture of hydrated electrons. The excitation of plasmon resonances in nanosized metal structures resulted in the enhancement of the photoemission process. In the case of photoelectrocatalytic reduction of CO2, large photoelectrocatalytic effect for the reduction of CO2 was observed in the presence of surface adsorbed methylviologen, which functions as a mediator for the photoexcited electron transfer from silver metal to CO2 in solution. Photoinduced reduction of microperoxidase-11 adsorbed on roughened silver electrode was also observed and attributed to the direct photoejection of free electrons of silver metal. Surface plasmon assisted electron transfer at nanostructured silver particle surfaces was further determined by EPR method.

  10. Study of 234U(n,f) Resonances Measured at the CERN n_TOF Facility

    CERN Document Server

    Leal-Cidoncha, E; Paradela, C; Tarrío, D; Leong, L S; Audouin, L; Tassan-Got, L; Praena, J; Berthier, B; Ferrant, L; Isaev, S; Le Naour, C; Stephan, C; Trubert, D; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Badurek, G; Baumann, P; Bečvář, F; Berthoumieux, E; Calviño, F; Calviani, M; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P.; Chepel, V; Chiaveri, E.; Colonna, N; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S.; Dillmann, I; Domingo-Pardo, C; Dridi, W; Eleftheriadis, C; Embid-Segura, M; Ferrari, A.; Ferreira-Marques, R; Fujii, K; Furman, W; Gonçalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A.; Igashira, M; Jericha, E; Kadi, Y.; Käppeler, F; Karadimos, D; Kerveno, M; Koehler, P; Kossionides, E; Krtička, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Oshima, M; Pancin, J; Papadopoulos, C; Pavlik, A; Pavlopoulos, P.; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Pretel, C; Quesada, J; Rauscher, T.; Reifarth, R; Rubbia, C.; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L.; Savvidis, I; Tagliente, G; Tain, J L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A.; Villamarin, D; Vincente, M C; Vlachoudis, V.; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2014-01-01

    We present the analysis of the resolved resonance region for the U-234(n,f) cross section data measured at the CERN n\\_TOF facility. The resonance parameters in the energy range from 1 eV to 1500 eV have been obtained with the SAMMY code by using as initial parameters for the fit the resonance parameters of the JENDL-3.3 evaluation. In addition, the statistical analysis has been accomplished, partly with the SAMDIST code, in order to study the level spacing and the Mehta-Dyson correlation.

  11. Brain biochemistry and personality: a magnetic resonance spectroscopy study.

    Science.gov (United States)

    Ryman, Sephira G; Gasparovic, Chuck; Bedrick, Edward J; Flores, Ranee A; Marshall, Alison N; Jung, Rex E

    2011-01-01

    To investigate the biochemical correlates of normal personality we utilized proton magnetic resonance spectroscopy ((1)H-MRS). Our sample consisted of 60 subjects ranging in age from 18 to 32 (27 females). Personality was assessed with the NEO Five-Factor Inventory (NEO-FFI). We measured brain biochemistry within the precuneus, the cingulate cortex, and underlying white matter. We hypothesized that brain biochemistry within these regions would predict individual differences across major domains of personality functioning. Biochemical models were fit for all personality domains including Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Our findings involved differing concentrations of Choline (Cho), Creatine (Cre), and N-acetylaspartate (NAA) in regions both within (i.e., posterior cingulate cortex) and white matter underlying (i.e., precuneus) the Default Mode Network (DMN). These results add to an emerging literature regarding personality neuroscience, and implicate biochemical integrity within the default mode network as constraining major personality domains within normal human subjects.

  12. Brain biochemistry and personality: a magnetic resonance spectroscopy study.

    Directory of Open Access Journals (Sweden)

    Sephira G Ryman

    Full Text Available To investigate the biochemical correlates of normal personality we utilized proton magnetic resonance spectroscopy ((1H-MRS. Our sample consisted of 60 subjects ranging in age from 18 to 32 (27 females. Personality was assessed with the NEO Five-Factor Inventory (NEO-FFI. We measured brain biochemistry within the precuneus, the cingulate cortex, and underlying white matter. We hypothesized that brain biochemistry within these regions would predict individual differences across major domains of personality functioning. Biochemical models were fit for all personality domains including Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Our findings involved differing concentrations of Choline (Cho, Creatine (Cre, and N-acetylaspartate (NAA in regions both within (i.e., posterior cingulate cortex and white matter underlying (i.e., precuneus the Default Mode Network (DMN. These results add to an emerging literature regarding personality neuroscience, and implicate biochemical integrity within the default mode network as constraining major personality domains within normal human subjects.

  13. Intramedullary cavernous hemangiomas, magnetic resonance studies in four patients

    International Nuclear Information System (INIS)

    Barrena, M.R.; Guelbenzu, S.; Garcia, S.; Bertrol, V.

    1998-01-01

    Intramedullary cavernous hemangiomas are vascular malformations that can be located throughout the entire central nervous system. They are more frequently found in brain than in spinal cord, where it is only possible to diagnose them by magnetic resonance (RM): We present four cases of intramedullary spinal cord cavernoma, three of which were located in the thoracic spine and one in cervical spine. Computed tomography was ineffective in their diagnosis. However, MR disclosed there presence of well-defined tumors producing a thickening of the spinal cord. The signal was heterogeneous in both T1 and T2-weighted images. There were low signal areas due to the presence of calcium and hemosiderin and high intensity signals provoked by methemoglobin within the lesions, which were scarcely enhanced by intravenous gadolinium administration. One of the lesions presented in the form of a large intramedullary hematoma. (Author) 8 refs

  14. The modulation of motor control by imitating non-biological motions: a study about motor resonance.

    Science.gov (United States)

    Miyawaki, Yu; Yamamoto, Taisei

    2018-01-01

    [Purpose] Sensorimotor experience modulates motor resonance, such as motor interference, which occurs when observing others' movements; however, it is unclear how motor resonance is modulated by intentionally imitating others' movements. This study examined the effects of imitation experience on subsequent motor resonance. [Subjects and Methods] Twenty-seven healthy participants performed horizontal arm movements while observing non-biological, incongruent (vertical) movements of a visual stimulus (triangle object) in pre- and post-test procedures. Thirteen participants in the imitation group imitated vertical movements (non-biological motion) of the triangle object between pre- and post-test procedures and fourteen participants in the non-imitation group observed that. [Results] Variance in the executed movements was measured as an index of motor resonance. Although there was no significant difference in the non-imitation group, there was a significantly smaller variance for post-test compared to pre-test in the imitation group. [Conclusion] Motor resonance was inhibited by intentionally imitating non-biological motions. Imitating movements different from one's own motor property might inhibit subsequent motor resonance. This finding might be applied to selectively using motor resonance as a form of rehabilitation.

  15. Theoretical study of platonic crystals with periodically structured N-beam resonators

    Science.gov (United States)

    Gao, Penglin; Climente, Alfonso; Sánchez-Dehesa, José; Wu, Linzhi

    2018-03-01

    A multiple scattering theory is applied to study the properties of flexural waves propagating in a plate with periodically structured N-beam resonators. Each resonator consists of a circular hole containing an inner disk connected to background plate with N rectangular beams. The Bloch theorem is employed to obtain the band structure of a two-dimensional lattice containing a single resonator per unit cell. Also, a numerical algorithm has been developed to get the transmittance through resonator slabs infinitely long in the direction perpendicular to the incident wave. For the numerical validation, a square lattice of 2-beam resonators has been comprehensively analyzed. Its band structure exhibits several flat bands, indicating the existence of local resonances embedded in the structure. Particularly, the one featured as the fundamental mode of the inner disk opens a bandgap at low frequencies. This mode has been fully described in terms of a simple spring-mass model. As a practical application of the results obtained, a homogenization approach has been employed to design a focusing lens for flexural waves, where the index gradient is obtained by adjusting the orientation of the resonators beams. Numerical experiments performed within the framework of a three-dimensional finite element method have been employed to discuss the accuracy of the models described here.

  16. The development of insomnia or the plasticity of good sleep? A preliminary study of acute changes in sleep and insomnia resulting from an analogue trauma.

    Science.gov (United States)

    Richardson, Cele; Gradisar, Michael; Pulford, Amanda

    2015-01-01

    The present preliminary study aimed to shed light on the mechanisms underlying the development of insomnia. An analogue stressor (i.e., trauma video) was used to prevent presleep cognitive de-arousal. Subsequent changes in nocturnal sleep and sleep-related attentional processing were examined. Thirty-four participants were randomly assigned to either a cognitive arousal (trauma video; age: M = 22.9, SD = 4.3, 6 male, 11 female) or control (pleasant video; age: M = 23.8, SD = 5.8, 7 male, 10 female) condition. Although no significant differences were found for presleep cognitive de-arousal (p = .39), the cognitive arousal group experienced a significant worsening in sleep latency (p = .048, partial η(2) = .12) and an increase in sleep-related attentional bias (p = .032, d = 0.51) following the manipulation. However, changes in sleep and attentional bias were not maintained. Vulnerability to stress did not significantly account for any change in attentional bias, arousal, or sleep. These findings challenge current conceptualizations of the development of insomnia, yet also supporting the notion that good sleep is a default state that protects individuals from sleep disturbance.

  17. Photon transfer in a system of coupled superconducting microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Muirhead, C. M., E-mail: c.m.muirhead@bham.ac.uk; Gunupudi, B.; Colclough, M. S. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2016-08-28

    A novel scheme is proposed for the study of energy transfer in a pair of coupled thin film superconducting microwave resonators. We show that the transfer could be achieved by modulating the kinetic inductance and that this has a number of advantages over earlier theoretical and experimental schemes, which use modulation of capacitance by vibrating nanobars or membranes. We show that the proposed scheme lends itself to the study of the classical analogues of Rabi and Landau-Zener-Stueckelberg oscillations and Landau-Zener transitions using experimentally achievable parameters. We consider a number of ways in which energy transfer (photon shuttle) between the two resonators could be achieved experimentally.

  18. 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...... of CorA. METHODS: HC-CorA were quantified in paired samples of cord serum from newborns and serum from mothers (n = 69). RESULTS: The CorA-concentration was higher in cord serum (median = 380, range: 41-780 pmol/L) than in serum from the mothers (median = 160, range: 64-330 pmol/L), (p...-analysis showed CorA-peaks with retention times of 13.5, 14,5 and 16.5 min in samples from both the mother and cord serum. The peak with retention time 16.5 min constituted 24% (mother) and 45% (cord serum) of the total amount CorA, and eluted as does dicyanocobinamide. CONCLUSION: Our results support that Cor...

  19. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method

    International Nuclear Information System (INIS)

    Huynh, V.D.

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths Γ γ from resonance to resonance, variation of Γ γ with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [fr

  20. Infrared Surface-Plasmon-Resonance -- a novel biophysical tool for studying living cell

    OpenAIRE

    Golosovsky, M.; Lirtsman, V.; Yashunsky, V.; Davidov, D.; Aroeti, B.

    2009-01-01

    We discuss the Surface-Plasmon-Resonance (SPR) technique based on Fourier -Transform - InfraRed (FTIR) spectrometry. We explore the potential of the infrared surface plasmon resonance technique for biological studies in aqueous solutions and compare it to the conventional surface plasmon technique operating in the visible range. We demonstrate that the sensitivity of the SPR technique in the infrared range is not lower and in fact is even higher. We show several examples of applying FTIR-SPR ...

  1. Synthesis of non-steroidal anti-inflammatory drug analogues for selective studies on the COX-II enzyme

    International Nuclear Information System (INIS)

    Fleming, S.A.; Ridges, M.D.; Jensen, A.W.

    1996-01-01

    Synthesis of the azido substituted non-steroidal anti-inflammatory drug 2-(2,6-dichloroanilino)phenylacetic acid and isotope labeling of this compound have been performed and are described. Initial evaluation of the binding ability and photoreactivity indicates that this compound has potential for photoaffinity labeling as well as enzyme selectivity studies. (author)

  2. Urocanic acid isomers are good hydroxyl radical scavengers: a comparative study with structural analogues and with uric acid

    NARCIS (Netherlands)

    Kammeyer, A.; Eggelte, T. A.; Bos, J. D.; Teunissen, M. B.

    1999-01-01

    UV-exposure of the epidermis leads to the isomerisation of trans-UCA into cis-UCA as well as to the generation of hydroxyl radicals. This study shows by means of the deoxyribose degradation test that UCA isomers are more powerful hydroxyl radical scavengers than the other 4-(5-)substituted imidazole

  3. Cancer risk among insulin users : comparing analogues with human insulin in the CARING five-country cohort study

    NARCIS (Netherlands)

    But, Anna; De Bruin, Marie L; Bazelier, Marloes T; Hjellvik, Vidar; Andersen, Morten; Auvinen, Anssi; Starup-Linde, Jakob; Schmidt, Marjanka K; Furu, Kari; de Vries, Frank; Karlstad, Øystein; Ekström, Nils; Haukka, Jari

    2017-01-01

    AIMS/HYPOTHESIS: The aim of this work was to investigate the relationship between use of certain insulins and risk for cancer, when addressing the limitations and biases involved in previous studies. METHODS: National Health Registries from Denmark (1996-2010), Finland (1996-2011), Norway

  4. Docking Based 3D-QSAR Study of Tricyclic Guanidine Analogues of Batzelladine K as anti-malarial agents

    Science.gov (United States)

    Ahmed, Nafees; Anwar, Sirajudheen; Thet Htar, Thet

    2017-06-01

    The Plasmodium falciparum Lactate Dehydrogenase enzyme (PfLDH) catalyzes inter-conversion of pyruvate to lactate during glycolysis producing the energy required for parasitic growth. The PfLDH has been studied as a potential molecular target for development of anti-malarial agents. In an attempt to find the potent inhibitor of PfLDH, we have used Discovery studio to perform molecular docking in the active binding pocket of PfLDH by CDOCKER, followed by three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of tricyclic guanidine batzelladine compounds, which were previously synthesized in our laboratory. Docking studies showed that there is a very strong correlation between in silico and in vitro results. Based on docking results, a highly predictive 3D-QSAR model was developed with q2 of 0.516. The model has predicted r2 of 0.91 showing that predicted IC50 values are in good agreement with experimental IC50 values. The results obtained from this study revealed the developed model can be used to design new anti-malarial compounds based on tricyclic guanidine derivatives and to predict activities of new inhibitors.

  5. Influence of GnRH analogue on body mass index in girls with precocious puberty: a prospective study

    Directory of Open Access Journals (Sweden)

    Heshmat Moaieri

    2014-06-01

    Conclusion: Gonadotropin-releasing hormone analog (GnRHa therapy in central precocious puberty (CPP is safe for BMI and increasing of BMI is not significant, long- term follow-up study is required to elucidate whether GnRHa treatment affects adult obesity. Using growth hormone concomitantly, the effect on increasing height is significant.

  6. Ferromagnetic-resonance studies of granular giant-magnetoresistive materials

    Science.gov (United States)

    Rubinstein, M.; Das, B. N.; Koon, N. C.; Chrisey, D. B.; Horwitz, J.

    1994-07-01

    Ferromagnetic resonance (FMR) can reveal important information on the size and shape of the ferromagnetic particles which are dispersed in granular giant magnetoresistive (GMR) materials. We have investigated the FMR spectra of three different types of granular GMR material, each with different properties: (1) melt-spun ribbons of Fe5Co15Cu80 and Co20Cu80, (2) thin films of Co20Cu80 produced by pulsed laser deposition, and (3) a granular multilayer film of [Cu(50 Å)/Fe(10 Å)]×50. We interpret the linewidth of these materials in as simple a manner as possible, as a ``powder pattern'' of noninteracting ferromagnetic particles. The linewidth of the melt-spun ribbons is caused by a completely random distribution of crystalline anisotropy axes. The linewidth of these samples is strongly dependent upon the annealing temperature: the linewidth of the as-spun sample is 2.5 kOe (appropriate for single-domain particles) while the linewidth of a melt-spun sample annealed at 900 °C for 15 min is 4.5 kOe (appropriate for larger, multidomain particles). The linewidth of the granular multilayer is attributed to a restricted distribution of shape anisotropies, as expected from a discontinuous multilayer, and is only 0.98 kOe when the applied magnetic field is in the plane of the film.

  7. Study of skin markers for magnetic resonance imaging examinations

    International Nuclear Information System (INIS)

    Takatsu, Yasuo; Umezaki, Yoshie; Miyati, Tosiaki; Yamamura, Kenichirou

    2013-01-01

    In magnetic resonance imaging (MRI), skin markers are used as a landmark in order to make plans for examinations. However, there isn't a lot of research about the material and shape of skin markers. The skin marker's essential elements are safety, good cost performance, high signal intensity for T 1 weighted image (T 1 WI) and T 2 weighted image (T 2 WI), and durable. In order to get a high signal-to-noise ratio (SNR) of T 1 WI and T 2 WI, baby oil, salad oil and olive oil were chosen, because these materials were easy to obtain and safe for the skin. The SNR of baby oil was the best. Baby oil was injected into the infusion tube, and the tube was solvent welded and cut by a heat sealer. In order to make ring shaped skin markers, both ends of the tube were stuck with adhesive tape. Three different diameters of markers were made (3, 5, 10 cmφ). Ring shaped skin markers were put on to surround the examination area, therefore, the edge of the examination area could be seen at every cross section. Using baby oil in the ring shaped infusion tube is simple, easy, and a highly useful skin marker. (author)

  8. Electron spin resonance studies of carbonates and phosphates

    International Nuclear Information System (INIS)

    Seletchi, Emilia Dana

    2005-01-01

    Electron Spin Resonance (ESR) is an absolute dating technique suitable for the Quaternary, which can be applied to a wide range of archaeological and geological materials. This method is mostly used to date such things as calcium carbonate in limestone, stalactites, stalagmites, mollusk shells, and corals. The results show that and are the most commonly present radiation-induced defects in bicarbonates. A new methodology for the provenance of ancient monuments and artifacts was developed by using a large number of marble spectrum parameters. The sextet, dominant in the spectra, other peaks due to lattice defects, and organic radicals have been used in the persistent effort to characterize marble quarries. In ESR dating and dosimetry we can measure the intensity of an ESR signal and its enhancement by artificial irradiation with the absorbed dose. ESR retrospective dosimetry has proven to be a very useful technique for dose assessment in past radiation accidents. Human exposure can be determined directly from the ESR signal of tooth enamel. The majority of radiation-induced radicals in tooth enamel are carbonate derived: CO 2 - ; CO 3 - ; CO - ; CO 3 3- , but radicals derived from phosphate and oxygen were also identified. (author)

  9. A theoretical study of a ZnO graphene analogue: adsorption on Ag(111) and hydrogen transport

    Energy Technology Data Exchange (ETDEWEB)

    Demiroglu, Ilker; Illas, Francesc; Bromley, Stefan T [Department de Quimica Fisica and Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona (UB), C/MartI i Franques 1, E-08028 Barcelona (Spain); Stradi, Daniele, E-mail: s.bromley@ub.edu [Departamento de Quimica, Universidad Autonoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid (Spain)

    2011-08-24

    A single sheet of zinc oxide (ZnO) based on the same flat two-dimensional (2D) hexagonal topology as graphene, but with alternating neighbouring Zn and O atoms in place of carbon atoms, is studied theoretically. Following experimental studies, the adsorption of 2D-ZnO with the Ag(111) surface is investigated using density functional theory, with and without a semi-empirical correction for dispersive interactions, and with classical interatomic potentials. The interaction of H atoms with the hexagonal Zn{sub 3}O{sub 3} rings of 2D-ZnO is given special attention where multi-centre bond formation is observed to significantly assist the transport of H atoms through the 2D-ZnO sheet.

  10. A theoretical study of a ZnO graphene analogue: adsorption on Ag(111) and hydrogen transport

    International Nuclear Information System (INIS)

    Demiroglu, Ilker; Illas, Francesc; Bromley, Stefan T; Stradi, Daniele

    2011-01-01

    A single sheet of zinc oxide (ZnO) based on the same flat two-dimensional (2D) hexagonal topology as graphene, but with alternating neighbouring Zn and O atoms in place of carbon atoms, is studied theoretically. Following experimental studies, the adsorption of 2D-ZnO with the Ag(111) surface is investigated using density functional theory, with and without a semi-empirical correction for dispersive interactions, and with classical interatomic potentials. The interaction of H atoms with the hexagonal Zn 3 O 3 rings of 2D-ZnO is given special attention where multi-centre bond formation is observed to significantly assist the transport of H atoms through the 2D-ZnO sheet.

  11. Ab initio studies on the electronic structure and properties of aluminum hydrides that are analogues of boron hydrides.

    Science.gov (United States)

    Srinivasu, K; Chandrakumar, K R S; Ghosh, Swapan K

    2010-11-25

    Although the boron hydrides are well-known in the literature, the aluminum hydride chemistry is limited to very few systems such as AlH(3), its dimer, and its polymeric form. In view of the recent experimental studies on the possible existence of the aluminum hydrides, herein, we have undertaken a systematic study on the electronic structure and properties of these aluminum hydrides. Under this, we have studied different classes of hydrides, viz., closo (Al(n)H(n+2)), nido (Al(n)H(n+4)), and arachno (Al(n)H(n+6)), similar to the boranes. All the aluminum hydrides are found to have exceptionally large highest-occupied molecular orbital-lowest-unoccupied molecular orbital gaps, low electron affinities, large ionization potentials and also large enthalpy and free energy of atomization. In addition, most of the structures are also found to have high symmetries. These exceptional properties can be indicative of the pronounced stability, and hence, it is expected that other aluminum hydride complexes can indeed be observed experimentally.

  12. Cancer risk among insulin users: comparing analogues with human insulin in the CARING five-country cohort study.

    Science.gov (United States)

    But, Anna; De Bruin, Marie L; Bazelier, Marloes T; Hjellvik, Vidar; Andersen, Morten; Auvinen, Anssi; Starup-Linde, Jakob; Schmidt, Marjanka K; Furu, Kari; de Vries, Frank; Karlstad, Øystein; Ekström, Nils; Haukka, Jari

    2017-09-01

    The aim of this work was to investigate the relationship between use of certain insulins and risk for cancer, when addressing the limitations and biases involved in previous studies. National Health Registries from Denmark (1996-2010), Finland (1996-2011), Norway (2005-2010) and Sweden (2007-2012) and the UK Clinical Practice Research Datalink database (1987-2013) were used to conduct a cohort study on new insulin users (N = 327,112). By using a common data model and semi-aggregate approach, we pooled individual-level records from five cohorts and applied Poisson regression models. For each of ten cancer sites studied, we estimated the rate ratios (RRs) by duration (≤0.5, 0.5-1, 1-2, 2-3, 3-4, 4-5, 5-6 and >6 years) of cumulative exposure to insulin glargine or insulin detemir relative to that of human insulin. A total of 21,390 cancer cases occurred during a mean follow-up of 4.6 years. No trend with cumulative treatment time for insulin glargine relative to human insulin was observed in risk for any of the ten studied cancer types. Of the 136 associations tested in the main analysis, only a few increased and decreased risks were found: among women, a higher risk was observed for colorectal (RR 1.54, 95% CI 1.06, 2.25) and endometrial cancer (RR 1.78, 95% CI 1.07, 2.94) for ≤0.5 years of treatment and for malignant melanoma for 2-3 years (RR 1.92, 95% CI 1.02, 3.61) and 4-5 years (RR 3.55, 95% CI 1.68, 7.47]); among men, a lower risk was observed for pancreatic cancer for 2-3 years (RR 0.34, 95% CI 0.17, 0.66) and for liver cancer for 3-4 years (RR 0.36, 95% CI 0.14, 0.94) and >6 years (RR 0.22, 95% CI 0.05, 0.92). Comparisons of insulin detemir with human insulin also showed no consistent differences. The present multi-country study found no evidence of consistent differences in risk for ten cancers for insulin glargine or insulin detemir use compared with human insulin, at follow-up exceeding 5 years.

  13. Long term corrosion of iron and non alloy or low alloy steels in clay soils. Physico-chemical characterisation and electrochemical study of archaeological analogues

    International Nuclear Information System (INIS)

    Pons, Emmanuelle

    2002-01-01

    Archaeological objects of Gallo-Roman and Merovingian time, and from a battlefield of World War 1, were studied to better understand long term corrosion phenomena of iron in clay soils. This study is part of the French national program about nuclear waste deep repository, conducted by the ANDRA (French national Agency for Radioactive Waste Management). Iron archaeological analogues make a valuable contribution to the specifying of containers for long lived and high level wastes (HLWs), because they provide access to the considered time scale. The experimental issue is divided into two major parts: - a physico-chemical characterisation of corrosion products, by Raman spectroscopy; - an electrochemical study of the behaviour of the different corrosion layers. Although the metallic material is different between ancient artefacts (ferrite) and 1914-1918 remains (hypo-eutectoid steels), the same stable phases are identified in their corrosion products: mainly iron oxides and oxi-hydroxides. From a macroscopic point of view, these products are staggered into two layers: an internal one, and an external one, which contains soil markers. Under the microscope, a complex composite structure appears. Goethite a-FeOOH, which was identified on each object, is frequently in contact with the metal core. The average corrosion rate in the burial environment, deduced from the layers thickness, highlights a significant slowdown of corrosion after the first burial time, about one century. The electrochemical study showed the predominant role of transport phenomena in the pores of corrosion layers. The behaviour of the metal - internal layer system is well explained by a model of porous electrode (De Levie theory). Despite its porosity, the internal layer is protective, as it leads to a significant decrease of the corrosion rate (about ten time). (author) [fr

  14. Effects of gender-related domain violations and sexual orientation on perceptions of male and female targets: an analogue study.

    Science.gov (United States)

    Blashill, Aaron J; Powlishta, Kimberly K

    2012-10-01

    The current study examined factors that influenced heterosexual male and female raters' evaluations of male and female targets who were gay or heterosexual, and who displayed varying gender roles (i.e., typical vs. atypical) in multiple domains (i.e., activities, traits, and appearance). Participants were 305 undergraduate students from a private, midwestern Jesuit institution who read vignettes describing one of 24 target types and then rated the target on possession of positive and negative characteristics, psychological adjustment, and on measures reflecting the participants' anticipated behavior toward or comfort with the target. Results showed that gender atypical appearance and activity attributes (but not traits) were viewed more negatively than their gender typical counterparts. It was also found that male participants in particular viewed gay male targets as less desirable than lesbian and heterosexual male targets. These findings suggest a nuanced approach for understanding sexual prejudice, which incorporates a complex relationship among sex, gender, sexual orientation, and domain of gendered attributes.

  15. Climate Change Impacts on the Stability of Small Tidal Inlets: A Numerical Modelling Study Using the Realistic Analogue Approach

    Directory of Open Access Journals (Sweden)

    Trang Minh Duong

    2012-09-01

    Full Text Available Tidal inlets are of great societal importance as they are often associated with ports and harbours, industry, tourism, recreation and prime waterfront real estate. Their behaviour is governed by the delicate balance of oceanic processes (tides, waves and mean sea level, and fluvial/estuarine processes (riverflow and heat fluxes, all of which can be significantly affected by climate change (CC processes. This study investigates the potential range of CC impacts on the stability (closed/open state and locational stability via the application of a sophisticated process based morphodynamic model (Delft3D to strategically selected schematized inlet morphologies and forcing conditions. Results show that, under worst case scenario conditions, the integrated effect of climate change driven increase in mean sea level, wave height and wave angle may significantly change inlet stability condition.

  16. Intubation after rapid sequence induction performed by non-medical personnel during space exploration missions: a simulation pilot study in a Mars analogue environment.

    Science.gov (United States)

    Komorowski, Matthieu; Fleming, Sarah

    2015-01-01

    The question of the safety of anaesthetic procedures performed by non anaesthetists or even by non physicians has long been debated. We explore here this question in the hypothetical context of an exploration mission to Mars. During future interplanetary space missions, the risk of medical conditions requiring surgery and anaesthetic techniques will be significant. On Earth, anaesthesia is generally performed by well accustomed personnel. During exploration missions, onboard medical expertise might be lacking, or the crew doctor could become ill or injured. Telemedical assistance will not be available. In these conditions and as a last resort, personnel with limited medical training may have to perform lifesaving procedures, which could include anaesthesia and surgery. The objective of this pilot study was to test the ability for unassisted personnel with no medical training to perform oro-tracheal intubation after a rapid sequence induction on a simulated deconditioned astronaut in a Mars analogue environment. The experiment made use of a hybrid simulation model, in which the injured astronaut was represented by a torso manikin, whose vital signs and hemodynamic status were emulated using a patient simulator software. Only assisted by an interactive computer tool (PowerPoint(®) presentation), five participants with no previous medical training completed a simplified induction of general anaesthesia with intubation. No major complication occurred during the simulated trials, namely no cardiac arrest, no hypoxia, no cardiovascular collapse and no failure to intubate. The study design was able to reproduce many of the constraints of a space exploration mission. Unassisted personnel with minimal medical training and familiarization with the equipment may be able to perform advanced medical care in a safe and efficient manner. Further studies integrating this protocol into a complete anaesthetic and surgical scenario will provide valuable input in designing health

  17. Comparative study of the antioxidant properties of monocarbonyl curcumin analogues C66 and B2BrBC in isoproteranol induced cardiac damage.

    Science.gov (United States)

    Hadzi-Petrushev, Nikola; Bogdanov, Jane; Krajoska, Jovanka; Ilievska, Jovana; Bogdanova-Popov, Biljana; Gjorgievska, Elizabeta; Mitrokhin, Vadim; Sopi, Ramadan; Gagov, Hristo; Kamkin, Andre; Mladenov, Mitko

    2018-03-15

    To test the antioxidant properties of the newly synthesized (2E,6E)-2,6-bis(2-bromobenzylidene)cyclohexanone (B2BrBC) in parallel with C66 in rats with cardiac hypertrophy. The protective effects of both C66 and B2BrBC against oxidative stress in rats with cardiac hypertrophy, was studied by evaluating the activity of antioxidant enzymes, the relationship between the ratio of the activities of the antioxidant enzymes R = SOD/(GPx + CAT) and levels of thiols and lipid peroxidation in the heart. In order to gain better understanding of the antioxidant properties of the studied compounds, computational methods were utilized. The properties of selected structurally related derivatives were obtained on optimized geometries for ground states, using semi-empirical PM3 quantum mechanical calculations. The ratio R shows disequilibrium in rats with induced hypertrophy (p antioxidant. The obtained results indicated that the antioxidant ability of B2BrBC is positively associated with the catalytic SOD and GPx activities expressed through preserved t-SH levels. It seems plausible that for a compound to exhibit antioxidant activity, as most of the 2,6-bis(benzylidene)cyclohexanones do, they should be good electron donors. Understanding the relationship between cardiac hypertrophy induced oxidative injuries and supporters of endogenous reparatory machinery will help in establishing the beneficial role of adequate antioxidant supplementation. In this study reliable data on the preventive effects of newly synthesized symmetric monocarbonyl curcumin analogue B2BrBC and its role in the prevention of oxidative injuries on three levels (enzymatic, protein and lipid), in the heart hypertrophic onset, were obtained. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Evaluation of cellular viability by quantitative autoradiographic study of myocardial uptake of a fatty acid analogue in isoproterenol-induced focal rat heart necrosis

    International Nuclear Information System (INIS)

    Humbert, T.; Luu-Duc, C.; Comet, M.; Demenge, P.

    1991-01-01

    Previous studies led us to hypothesize that a fatty acid analogue, 15-p-iodophenyl-β-methyl pentadecanoic acid (IMPPA or BMIPP), which is taken up but not quickly metabolized by heart cells, would be a more suitable tracer of cellular viability that 201 Tl. Biodistribution studies of 1- 14 C-IMPPA in conscious, freely moving rats showed that the concentration ratio of radioactivity in the heart with respect to the blood was about 8 for at least 60 min after intravenous administration, permitting its use as a putative tracer in these conscious, freely moving rats. Thereafter, the myocardial uptake of 14 C-IMPPA was studied in isoproterenol-treated rats (daily treatment for 10 days in order to induce cardiac hypertrophy and necrotic foci) with respect to control ones. Comparison of myocardial localizations by quantitative autoradiography of the uptake of 201 Tl and 14 C-IMPPA with that of triphenyltetrazolium chloride (TTC) staining enabled comparative evaluation of nutritional blood flow, localization and uptake of 14 C-IMPPA and necrotic foci size. Distributions of 14 C-IMPPA and 201 Tl in control rats' hearts were homogenous, like TTC staining. In infarcted hearts, areas of decreased 14 C-IMPPA uptake were nearly the same (100%±5%) as those unstained by TTC. These areas were larger than those showing a decrease in thallium uptake (about 70%±5% of the total scar size). Therefore, IMPPA seems to be a more accurate and sensitive indicator of necrosis localization compared with thallium. It may be a useful agent for assessment of myocardial viability by single photon emission tomography (SPET) imaging. (orig.)

  19. Shoulder Magnetic Resonance Arthrography: A Prospective Randomized Study of Anterior and Posterior Ultrasonography-Guided Contrast Injections

    International Nuclear Information System (INIS)

    Koivikko, M.P.; Mustonen, A.O.T.

    2008-01-01

    Background: Magnetic resonance (MR) arthrography is an accurate imaging method for internal shoulder derangements and rotator cuff pathologies. Both anterior and posterior contrast injection techniques, under palpatory, fluoroscopic, or ultrasonographic guidance have been described in the literature. However, clinical comparisons of the injection techniques remain few. Purpose: To compare the performance of anterior and posterior ultrasonography (US)-guided arthrography injections of the shoulder regarding patient discomfort and influence on diagnostic MR reading, and to illustrate the typical artifacts resulting from contrast leakage in the respective techniques. Material and Methods: 43 MR arthrographies were prospectively randomized into anterior and posterior US-guided contrast injections and performed by two radiologists, with the study of artifacts from contrast leakage. Pain from the injections was assessed by a survey utilizing a 100-mm visual analogue scale (VAS). Results: Of the 23 anterior injections, nine caused contrast artifacts in the subscapular tendon, and in three the leakage extended further anteriorly. Of the 20 posterior injections, 12 showed injection artifacts of the rotator cuff, extending outside the cuff in seven. Two of the anterior and none of the posterior artifacts compromised diagnostic quality. In posterior injections, the leakage regularly occurred at the caudal edge of the infraspinatus muscle and was easily distinguishable from rotator cuff tears. All patients completed the pain survey. Mean VAS scores were 25.0 (median 18, SD 22) for anterior, and 25.4 (median 16, SD 25) for posterior injections. The two radiologists achieved different mean VAS scores but closely agreed as to anterior and posterior VAS scores. Conclusion: Arthrography injections were fairly simple to perform under US guidance. Patient discomfort for anterior and posterior injections was equally minor. A tailored approach utilizing anterior or posterior injections

  20. Shoulder Magnetic Resonance Arthrography: A Prospective Randomized Study of Anterior and Posterior Ultrasonography-Guided Contrast Injections

    Energy Technology Data Exchange (ETDEWEB)

    Koivikko, M.P.; Mustonen, A.O.T. (Dept. of Radiology, Helsinki Univ. Central Hospital, Helsinki (Finland))

    2008-10-15

    Background: Magnetic resonance (MR) arthrography is an accurate imaging method for internal shoulder derangements and rotator cuff pathologies. Both anterior and posterior contrast injection techniques, under palpatory, fluoroscopic, or ultrasonographic guidance have been described in the literature. However, clinical comparisons of the injection techniques remain few. Purpose: To compare the performance of anterior and posterior ultrasonography (US)-guided arthrography injections of the shoulder regarding patient discomfort and influence on diagnostic MR reading, and to illustrate the typical artifacts resulting from contrast leakage in the respective techniques. Material and Methods: 43 MR arthrographies were prospectively randomized into anterior and posterior US-guided contrast injections and performed by two radiologists, with the study of artifacts from contrast leakage. Pain from the injections was assessed by a survey utilizing a 100-mm visual analogue scale (VAS). Results: Of the 23 anterior injections, nine caused contrast artifacts in the subscapular tendon, and in three the leakage extended further anteriorly. Of the 20 posterior injections, 12 showed injection artifacts of the rotator cuff, extending outside the cuff in seven. Two of the anterior and none of the posterior artifacts compromised diagnostic quality. In posterior injections, the leakage regularly occurred at the caudal edge of the infraspinatus muscle and was easily distinguishable from rotator cuff tears. All patients completed the pain survey. Mean VAS scores were 25.0 (median 18, SD 22) for anterior, and 25.4 (median 16, SD 25) for posterior injections. The two radiologists achieved different mean VAS scores but closely agreed as to anterior and posterior VAS scores. Conclusion: Arthrography injections were fairly simple to perform under US guidance. Patient discomfort for anterior and posterior injections was equally minor. A tailored approach utilizing anterior or posterior injections

  1. A Patient Specific Biomechanical Analysis of Custom Root Analogue Implant Designs on Alveolar Bone Stress: A Finite Element Study

    Directory of Open Access Journals (Sweden)

    David Anssari Moin

    2016-01-01

    Full Text Available Objectives. The aim of this study was to analyse by means of FEA the influence of 5 custom RAI designs on stress distribution of peri-implant bone and to evaluate the impact on microdisplacement for a specific patient case. Materials and Methods. A 3D surface model of a RAI for the upper right canine was constructed from the cone beam computed tomography data of one patient. Subsequently, five (targeted press-fit design modification FE models with five congruent bone models were designed: “Standard,” “Prism,” “Fins,” “Plug,” and “Bulbs,” respectively. Preprocessor software was applied to mesh the models. Two loads were applied: an oblique force (300 N and a vertical force (150 N. Analysis was performed to evaluate stress distributions and deformed contact separation at the peri-implant region. Results. The lowest von Mises stress levels were numerically observed for the Plug design. The lowest levels of contact separation were measured in the Fins model followed by the Bulbs design. Conclusions. Within the limitations of the applied methodology, adding targeted press-fit geometry to the RAI standard design will have a positive effect on stress distribution, lower concentration of bone stress, and will provide a better primary stability for this patient specific case.

  2. Study on the Antifibrotic Effects of Recombinant Shark Hepatical Stimulator Analogue (r-sHSA) in Vitro and in Vivo.

    Science.gov (United States)

    Wang, Ying; Zhang, Xiaoyuan; Yang, Yang; Yang, Xiaohong; Ye, Boping

    2015-08-18

    Hepatic fibrosis is an effusive wound healing process, characterized by an excessive deposition of extracellular matrix (ECM), as the consequence of chronic liver injury of any etiology. Current therapeutic repertoire for hepatic fibrosis is limited to withdrawal of the noxious agent, which is not always feasible. Hence, in this article, the antifibrotic effects and possible mechanisms of r-sHSA, a recombinant protein with hepatoprotection potential, were investigated. Using NIH/3T3 (mouse embro-fibroblast cell line), skin fibroblasts (human skin fibroblasts, SFBs) and HSC-T6 (rat hepatic stellate cell line), the in vitro effect of r-sHSA was evaluated by measuring the expression levels of alpha-1 Type I collagen (Col1A1) and α-smooth muscle actin (α-SMA). It turned out those fibrosis indicators were typically inhibited by r-sHSA, suggesting its capacity in HSCs inactivation. The antifibrotic activity of r-sHSA was further investigated in vivo on CCl4-induced hepatic fibrosis, in view of significant improvement of the biochemical and histological indicators. More specifically, CCl4-intoxication induced a significant increase in serological biomarkers, e.g., transaminase (AST, ALT), and alkaline phosphatase (ALP), as well as disturbed hepatic antioxidative status; most of the parameters were spontaneously ameliorated to a large extent by withdrawal of CCl4, although the fibrotic lesion was observed histologically. In contrast, r-sHSA treatment markedly eliminated fibrous deposits and restored architecture of the liver in a dose dependent manner, concomitantly with the phenomena of inflammation relief and HSCs deactivation. To sum up, these findings suggest a therapeutic potential for r-sHSA in hepatic fibrosis, though further studies are required.

  3. Study on the Antifibrotic Effects of Recombinant Shark Hepatical Stimulator Analogue (r-sHSA in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2015-08-01

    Full Text Available Hepatic fibrosis is an effusive wound healing process, characterized by an excessive deposition of extracellular matrix (ECM, as the consequence of chronic liver injury of any etiology. Current therapeutic repertoire for hepatic fibrosis is limited to withdrawal of the noxious agent, which is not always feasible. Hence, in this article, the antifibrotic effects and possible mechanisms of r-sHSA, a recombinant protein with hepatoprotection potential, were investigated. Using NIH/3T3 (mouse embro-fibroblast cell line, skin fibroblasts (human skin fibroblasts, SFBs and HSC-T6 (rat hepatic stellate cell line, the in vitro effect of r-sHSA was evaluated by measuring the expression levels of alpha-1 Type I collagen (Col1A1 and α-smooth muscle actin (α-SMA. It turned out those fibrosis indicators were typically inhibited by r-sHSA, suggesting its capacity in HSCs inactivation. The antifibrotic activity of r-sHSA was further investigated in vivo on CCl4-induced hepatic fibrosis, in view of significant improvement of the biochemical and histological indicators. More specifically, CCl4-intoxication induced a significant increase in serological biomarkers, e.g., transaminase (AST, ALT, and alkaline phosphatase (ALP, as well as disturbed hepatic antioxidative status; most of the parameters were spontaneously ameliorated to a large extent by withdrawal of CCl4, although the fibrotic lesion was observed histologically. In contrast, r-sHSA treatment markedly eliminated fibrous deposits and restored architecture of the liver in a dose dependent manner, concomitantly with the phenomena of inflammation relief and HSCs deactivation. To sum up, these findings suggest a therapeutic potential for r-sHSA in hepatic fibrosis, though further studies are required.

  4. Arginine-, D-arginine-vasopressin, and their inverso analogues in micellar and liposomic models of cell membrane: CD, NMR, and molecular dynamics studies

    Czech Academy of Sciences Publication Activity Database

    Lubecka, E. A.; Sikorska, E.; Sobolewski, D.; Prahl, A.; Slaninová, Jiřina; Ciarkowski, J.

    2015-01-01

    Roč. 44, č. 8 (2015), s. 727-743 ISSN 0175-7571 Institutional support: RVO:61388963 Keywords : antidiuretic agonists * anionic-zwitterionic micelles * liposomes * inverso analogues Subject RIV: CC - Organic Chemistry Impact factor: 1.444, year: 2015 http://link.springer.com/article/10.1007/s00249-015-1071-4/fulltext.html

  5. Resonant behavior of dielectric objects (electrostatic resonances).

    Science.gov (United States)

    Fredkin, D R; Mayergoyz, I D

    2003-12-19

    Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning.

  6. Resonance frequency of microbubbles in small blood vessels: a numerical study

    International Nuclear Information System (INIS)

    Sassaroli, E; Hynynen, K

    2005-01-01

    Microbubbles are currently used as ultrasound contrast agents. Their potential therapeutic applications are also under investigation. This work is designed to provide some insight into the mechanisms of energy absorption and deposition by a preformed gas bubble in the microvasculature to optimize its efficacy. In the linear regime, the most favourable condition for the transfer of energy from an ultrasonic field to a gas bubble occurs when the centre frequency of the ultrasonic field equals the resonance frequency of the bubble. The resonance frequency of gas microbubbles has been investigated up to now mainly in unbounded liquids; however when bubbles are confined in small regions, their resonance frequency is strongly affected by the surrounding boundaries. A parametric study on how the resonance frequency of microbubbles in blood vessels is affected by the bubble radius, vessel radius and the bubble position in the vessel is presented. The resonance frequency decreases below its free value with decreasing vessel radius for vessels smaller than 200-300 μm depending on the bubble size. This model suggests the possibility of using ultrasound in a range of frequencies that are, in general, lower than the ones used now for therapeutic and diagnostic applications of ultrasound (a few MHz). When microbubbles oscillate at their resonance frequency they absorb and therefore emit more energy. This energy may allow specific blood vessels to be targeted for both diagnostic and therapeutic applications of ultrasound

  7. Clinical study and the diagnosis in magnetic resonance imaging of renal scarring

    Energy Technology Data Exchange (ETDEWEB)

    Tsugaya, Masayuki; Hirao, Noriaki; Ohtaguro, Kazuo; Kato, Jiro.

    1989-04-01

    Twenty-nine kidneys of seventeen patients (nine boys and eight girls) with vesicoureteral reflux and repeated urinary tract infection were studied by magnetic resonance imaging for diagnosis of renal scarring and correlation between clinical data and the degree renal scarring. Renal scarring is classified into three types according to findings in magnetic resonance imaging. The degree of renal scarring are classified into five grades according to traditional grading of intravenous pyelogram. If a fine deformity of calyx is shown on intravenous pyelogram, magnetic resonance imaging demonstrates renal scarring. Magnetic resonance imaging without irradiation is exceedingly valuable for the diagnosis of renal scarring. The appearances of magnetic resonance imaging were supported by X-ray computed tomography. There is a substantial correlation between serum creatinine and the grades of renal scarring by magnetic resonance imaging. There is a substantial correlation between fever attacks and the grade of renal scarring, and there is a significant reverse correlation between the age of the onset of upper urinary tract infection and the grade of renal scarring. It is suggested that upper urinary tract infection is the most significant factor in scar formation. (author).

  8. Dynamic study of pelvic floor in patients with constipation: dynamic magnetic resonance vs defecography

    International Nuclear Information System (INIS)

    Gonzalez Vasquez, Carlos Mario; Pulgarin, Ricardo Luis German; Melo Arango, Catalina; Delgado de Bedout, Jorge Andres; Llano Serna, Juan Fernando; Restrepo Restrepo, Jose Ignacio

    2007-01-01

    Purpose: to compare the concordance between defecography and magnetic resonance in patients with constipation. Materials and methods: we did a prospective and descriptive assay to determine the concordance of a diagnostic test with 17 patients. The evaluation of the studies was double blind. Results: the 17 patients were females, age range 31 - 77 year the symptoms were present between 3 to 120 months. Anterior rectocele was the most common diagnosis (11 patients) and magnetic resonance had sensibility 100%, specificity 50%, positive predictive value 78, 57% and negative predictive value 100%. 7 patients had pelvic floor descent and magnetic resonance had sensibility 71.4%, specificity 20% positive predictive value 38.46% and negative predictive value 50%. Defecography found patients with enterocele and magnetic resonance had sensibility 0% and specificity 100 anismus was present in 2 patients and magnetic resonance didn't find them. Conclusion defecography is still the gold standard for patients with eonstipation. Magnetic resonance are a promise for those patients but has to improve

  9. A clinical study and the diagnosis in magnetic resonance imaging of renal scarring

    International Nuclear Information System (INIS)

    Tsugaya, Masayuki; Hirao, Noriaki; Ohtaguro, Kazuo; Kato, Jiro.

    1989-01-01

    Twenty-nine kidneys of seventeen patients (nine boys and eight girls) with vesicoureteral reflux and repeated urinary tract infection were studied by magnetic resonance imaging for diagnosis of renal scarring and correlation between clinical data and the degree renal scarring. Renal scarring is classified into three types according to findings in magnetic resonance imaging. The degree of renal scarring are classified into five grades according to traditional grading of intravenous pyelogram. If a fine deformity of calyx is shown on intravenous pyelogram, magnetic resonance imaging demonstrates renal scarring. Magnetic resonance imaging without irradiation is exceedingly valuable for the diagnosis of renal scarring. The appearances of magnetic resonance imaging were supported by X-ray computed tomography. There is a substantial correlation between serum creatinine and the grades of renal scarring by magnetic resonance imaging. There is a substantial correlation between fever attacks and the grade of renal scarring, and there is a significant reverse correlation between the age of the onset of upper urinary tract infection and the grade of renal scarring. It is suggested that upper urinary tract infection is the most significant factor in scar formation. (author)

  10. Real-world evidence for nucleoside/nucleotide analogues in a 5-year multicentre study of antiviral-naive chronic hepatitis B patients in China: 52-week results.

    Science.gov (United States)

    Jia, Jidong; Tang, Hong; Ning, Qin; Jiang, Jiaji; Dou, Xiaoguang; Zhang, Mingxiang; Zhang, Shuqin; Shang, Jia; Lu, Wei; Ye, Yinong; Wang, Xin; Li, Mingshu; Liu, Jie; Bo, Qingyan; Tan, Wenzhong

    2017-11-08

    In China, the clinical management of chronic hepatitis B (CHB) is complicated by the use of various nucleos(t)ide analogue (NUC) regimens in treatment-naïve patients, including NUCs with low genetic barriers to resistance, with/without add-on therapy and de novo NUC combinations. This longitudinal observational study therefore investigated the real-world clinical management and efficacy of NUC therapy in treatment-naïve CHB patients in China. Treatment-naïve CHB patients initiated on NUC therapy were enrolled from 63 hospitals in tier-2 Chinese cities. Demographic and treatment-specific data were collected, with the objective of reporting real-world treatment patterns and comparing the effectiveness of entecavir (ETV) treatment and lamivudine (LAM)-based treatment. We herein report the first-year data. 3,408 NUC-naïve patients were enrolled and treated with NUCs (53% ETV, 18% LAM-based, 29% other). Overall, 6.6% of patients modified their initial treatment, with ETV having lower rates of treatment modification than other major NUCs (P<0.05). At week 52, the virologic response rate was higher with ETV than with LAM-based treatment (77.0% versus 61.4%, P<0.0001). LAM-based treatment was associated with a higher probability of virologic breakthrough and genotypic resistance (21.4% and 19.6%, respectively) than ETV (1.6% and 0.1%, respectively) (P<0.0001). Treatment-related adverse events or serious adverse events were uncommon. In this nationwide observational study, more than 50% of patients with CHB in tier-2 city hospitals in China initially received ETV therapy. Consistent with clinical trial results, ETV was more effective than LAM-based treatments in a real-world setting, with treatment modification being relatively low in ETV-treated patients.

  11. Impact of a heteroatom in a structure-activity relationship study on analogues of phenyl glycidyl ether (PGE) from epoxy resin systems.

    Science.gov (United States)

    Niklasson, Ida B; Delaine, Tamara; Luthman, Kristina; Karlberg, Ann-Therese

    2011-04-18

    Epoxy resins are among the most common causes of occupational contact dermatitis. They are normally used in so-called epoxy resin systems (ERS). These commercial products are combinations of epoxy resins, curing agents, modifiers, and reactive diluents. The most frequently used resins are diglycidyl ethers based on bisphenol A (DGEBA) and bisphenol F (DGEBF). In this study, we have investigated the contact allergenic properties of a series of analogues to the reactive diluent phenyl glycidyl ether (PGE), all with similar basic structures but with varying heteroatoms or with no heteroatom present. The chemical reactivity of the compounds in the test series toward the hexapeptide H-Pro-His-Cys-Lys-Arg-Met-OH was investigated. All epoxides were shown to bind covalently to both cysteine and proline residues. The percent depletion of nonreacted peptide was also studied resulting in ca. 60% depletion when using either PGE, phenyl 2,3-epoxypropyl sulfide (2), or N-(2,3-epoxypropyl)aniline (3), and only 15% when using 1,2-epoxy-4-phenylbutane (4) at the same time point. The skin sensitization potencies of the epoxides using the murine local lymph node assay (LLNA) were evaluated in relation to the observed physicochemical and reactivity properties. To enable determination of statistical significance between structurally closely related compounds, a nonpooled LLNA was performed. It was found that all investigated compounds containing a heteroatom in the α-position to the epoxide were strong sensitizers, congruent with the reactivity data, indicating that the impact of a heteroatom is crucial for the sensitizing capacity for this type of epoxides.

  12. Snake resonances

    International Nuclear Information System (INIS)

    Tepikian, S.

    1988-01-01

    Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs

  13. Paramagnetic resonance study of nickel ions in hexagonal barium titanate

    Science.gov (United States)

    Böttcher, R.; Langhammer, H. T.; Müller, T.

    2011-03-01

    X-ray diffraction patterns and electron paramagnetic resonance (EPR) powder spectra (9 and 34 GHz) of BaTiO3 + 0.04 BaO + xNiO (0.001 Ni ions and their valence states as well as the development of the hexagonal phase (6H modification) of Ni-doped material with respect to doping level x and sintering temperature Ts. The 6H modification begins to occur at a nominal Ni concentration of between x = 0.005 and 0.01 and its percentage increases with increasing sintering temperature. Ni-doped BaTiO3 with x = 0.02 sintered at Ts = 1400 °C is completely hexagonal. In the 3C modification, present in as-sintered ceramics with low nominal Ni concentrations, only one type of Ni EPR spectrum was observed. By comparing its principal values of the g tensor with data of single-crystal measurements the clear assignment of this spectrum to Ni + ions is possible. Two different EPR spectra with orthorhombic g tensors are observed in the as-sintered samples with hexagonal crystal structure. These spectra were assigned to Ni3 + ions with the electron spin S = 1/2 (electron configuration 3d7, strong crystal field) substituted at Ti lattice sites corresponding to the different distorted octahedra of the hexagonal modification. Measurements of the concentration reveal that only 5% of the doping material is in the state Ni3 + . No EPR spectra of Ni2 + ions have been detected in either 3C or 6H modification in as-sintered ceramics. Therefore, we suppose that the main part of nickel is substituted as Ni4 + ions on Ti4 + lattice sites. After heat treatment of the samples in H2/Ar atmosphere a single-line spectrum with g = 2.21 ± 0.01 at room temperature has been observed which is assigned to metallic Ni or antiferromagnetically coupled Ni2 + ions in secondary phases segregated at grain boundaries or triple points.

  14. In Silico Screening and In Vitro Activity Measurement of Javamide Analogues as Potential p38 MAPK Inhibitors

    Directory of Open Access Journals (Sweden)

    Jae B. Park

    2017-12-01

    Full Text Available p38 Mitogen-activated protein kinase (p38 MAPK is a protein kinase critically involved in the progress of inflammation/stress-associated diseases. Our data suggested that javamide analogues may contain strong anti-inflammation activities, but there is little information about their effects on p38 MAPK. Therefore, in this paper, the effects of thirty javamide analogues on p38 MAPK were investigated using in silico screening and in vitro p38 MAPK assay methods. The javamide analogues were synthesized and their chemical structures were confirmed using nuclear magnetic resonance (NMR spectroscopic methods. Then, the javamide analogues were screened using an in silico modeling program. The screened analogues demonstrated a wide range of binding energy (ΔE; −20 to −39 and several analogues with ΔE; −34 to −39 showed strong binding affinity to p38 MAPK. In vitro p38 MAPK assay, the kinase was significantly inhibited by the analogues with great binding energy (ΔE; −34 to −39 and in silico scores (Avg. score; −27.5 to −29.3. Furthermore, the comparative analysis of both assays showed a positive correlation between the in silico scores and p38 MAPK inhibition. In fact, the javamide analogues with top five in silico scores (Avg. score; −27.5 to −29.3 were found to inhibit p38 MAPK by 27–31% (p < 0.05 better than those with less scores (ΔE < −27.0. Especially, javamide-II-O-ethyl ester with relatively high in silico score (Avg. score; −29.2 inhibited p38 MAPK (IC50 = 9.9 μM a little better than its methyl ester with best in silico score (Avg. score; −29.3. To support the ability to inhibit p38 MAPK, the treatment of javamide-II-ethyl and -methyl esters could suppress the production of IL-8 and MCP-1 protein significantly by 22–73% (p < 0.05 in the differentiated THP-1 cells, and the inhibition was slightly stronger by the ethyl ester than the methyl ester. Altogether, this study suggests that javamide-II-O-ethyl ester may

  15. Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

    International Nuclear Information System (INIS)

    Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

    1981-01-01

    Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

  16. State selective reactions of cosmic dust analogues at cryogenic temperatures

    International Nuclear Information System (INIS)

    Perry, James Samuel Anthony

    2001-01-01

    Molecular hydrogen (H 2 ) is the most abundant molecule in interstellar space. It is crucial for initiating all of the chemistry in the Interstellar Medium (ISM) and consequently plays an important role in star formation. However, the amount of H 2 believed to exist in the ISM cannot be accounted for by formation through gas-phase reactions alone. The current, widely accepted theory, is that H 2 forms on the surface of cosmic dust grains. These grains are thought to be composed of amorphous forms of carbon or silicates with temperatures of around 10 K. This thesis describes a new experiment that has been constructed to study H 2 formation on the surface of cosmic dust analogues and presents the initial experimental results. The experiment simulates, through ultra-high vacuum and the use of cryogenics, the conditions of the ISM where cosmic dust grains and H 2 molecules exist. During the experiment, a beam of atomic hydrogen is aimed at a cosmic dust analogue target. H 2 formed on the target's surface is ionised using a laser spectroscopy technique known as Resonance Enhanced Multiphoton lonisation (REMPI) and detected using time-of-flight mass spectrometry. The sensitivity of REMPI is such that H 2 molecules can be ionised in selective internal energy states. This allows the rovibrational populations of the H 2 molecules desorbing from the cosmic dust targets to be determined, providing information on the energy budget of the H 2 formation process in the ISM. Preliminary results from the experiment show that H 2 molecules formed on a diamond-like-carbon surface have a significant non-thermal population of excited vibrational and rotational energy states. (author)

  17. Ground water chemistry and geochemical modeling of water-rock interactions at the Osamu Utsumi mine and the Morro do Ferro analogue study sites, Poços de Caldas, Minas Gerais, Brazil

    Science.gov (United States)

    Nordstrom, D. Kirk; McNutt, R.H.; Puigdomenech, I.; Smellie, John A.T.; Wolf, M.

    1992-01-01

    Surface and ground waters, collected over a period of three years from the Osamu Utsumi uranium mine and the Morro do Ferro thorium/rare-earth element (Th/REE) deposits, were analyzed and interpreted to identify the major hydrogeochemical processes. These results provided information on the current geochemical evolution of ground waters for two study sites within the Poços de Caldas Natural Analogue Project.

  18. Coupled resonances allow studying the aging of adhesive contacts between a QCM surface and single, micrometer-sized particles.

    Science.gov (United States)

    Peschel, Astrid; Langhoff, Arne; Johannsmann, Diethelm

    2015-12-04

    Interparticle contacts and contacts between particles and surfaces are known to change over time. The contact area, the contact stiffness, and the contact strength usually increase as the contact ages. Contact aging is mostly driven by capillary forces, but also by plastic deformation. Making use of acoustic resonators, we have studied the stiffness of contacts between the surface of a quartz crystal microbalance (QCM) and individual, micrometer-sized particles adsorbed to the resonator surface. Studying single particles avoids ensemble-averaging. Central to the analysis is the coupled resonance, occurring when a surface-attached particle together with the link forms a resonator of its own. If the frequency of this second resonator comes close to one of the crystal's overtones, plots of shifts in resonance bandwidth versus overtone order display a resonance curve. This secondary resonance is caused by the coupling between the particle's resonance and the main resonance. One can read the frequency of the coupled resonance from this plot. Similarly, resonance curves are observed in plots of frequency and bandwidth versus time, if the contact stiffness varies smoothly with time. Because the coupled resonance is a characteristic feature, it is easily identified even in cases where frequency shifts of some other origin are superimposed onto the data. For the cases studied here, the links stiffened while they dried. Interestingly, the efficiency of coupling between the particle resonance and the main resonance decreased at the same time. This can be explained with an increase in the link's bending stiffness. The analysis highlights that a QCM experiment amounts to vibrational spectroscopy on surface-attached particles. Among the application examples is the adsorption and drying of a lycopodium spore. Clearly, the technique is also applicable to problems of bioadhesion.

  19. New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction

    International Nuclear Information System (INIS)

    Fernandes, P.

    2007-04-01

    This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B 2 liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B 2 phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation

  20. Trustworthiness and Influence: A Reexamination in an Extended Counseling Analogue.

    Science.gov (United States)

    Rothmeier, Rosemarie C.; Dixon, David N.

    1980-01-01

    The study demonstrated that: (1) interviewer trustworthiness can be manipulated in an analogue interview setting; and (2) interviewer trustworthiness is related to interpersonal influence in the interview setting. Findings follow a pattern of outcomes predicted by cognitive dissonance theory. (Author)

  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. Study of Intrinsic Dissipation Due to Thermoelastic Coupling in Gyroscope Resonators.

    Science.gov (United States)

    Li, Changlong; Gao, Shiqiao; Niu, Shaohua; Liu, Haipeng

    2016-09-07

    This paper presents analytical models, as well as numerical and experimental verification of intrinsic dissipation due to thermoelastic loss in tuning-fork resonator. The thermoelastic analytical governing equations are created for resonator vibrating at drive-mode and sense-mode, and thermoelastic vibration field quantities are deduced. Moreover, the theoretical values are verified that coincided well with finite element analysis (FEM) simulation results. Also, the comparison of vibration field quantities is made to investigate the effect of different conditions on resonator thermoelastic vibration behavior. The significant parameters of thermoelastic damping and quality factor are subsequently deduced to analyze the energy dissipation situation in the vibration process. Meanwhile, the corresponding conclusions from other studies are used to verify our theoretical model and numerical results. By comparing with the experimental quality factor, the numerical values are validated. The combination of the theoretical expressions, numerical results and experimental data leads to an important insight into the achievable quality factor value of tuning-fork resonator, namely, that the thermoelastic damping is the main loss mechanism in the micro-comb finger structure and the quality factor varies under different vibration modes. The results demonstrate that the critical geometry dimensions of tuning-fork resonator can be well designed with the assistance of this study.

  3. Study of Intrinsic Dissipation Due to Thermoelastic Coupling in Gyroscope Resonators

    Directory of Open Access Journals (Sweden)

    Changlong Li

    2016-09-01

    Full Text Available This paper presents analytical models, as well as numerical and experimental verification of intrinsic dissipation due to thermoelastic loss in tuning-fork resonator. The thermoelastic analytical governing equations are created for resonator vibrating at drive-mode and sense-mode, and thermoelastic vibration field quantities are deduced. Moreover, the theoretical values are verified that coincided well with finite element analysis (FEM simulation results. Also, the comparison of vibration field quantities is made to investigate the effect of different conditions on resonator thermoelastic vibration behavior. The significant parameters of thermoelastic damping and quality factor are subsequently deduced to analyze the energy dissipation situation in the vibration process. Meanwhile, the corresponding conclusions from other studies are used to verify our theoretical model and numerical results. By comparing with the experimental quality factor, the numerical values are validated. The combination of the theoretical expressions, numerical results and experimental data leads to an important insight into the achievable quality factor value of tuning-fork resonator, namely, that the thermoelastic damping is the main loss mechanism in the micro-comb finger structure and the quality factor varies under different vibration modes. The results demonstrate that the critical geometry dimensions of tuning-fork resonator can be well designed with the assistance of this study.

  4. Study of resonant processes in plasmonic nanostructures for sensor applications (Conference Presentation)

    Science.gov (United States)

    Pirunčík, Jiří; Kwiecien, Pavel; Fiala, Jan; Richter, Ivan

    2017-05-01

    This contribution is focused on the numerical studies of resonant processes in individual plasmonic nanostructures, with the attention particularly given to rectangular nanoparticles and concominant localized surface plasmon resonance processes. Relevant models for the description and anylysis of localized surface plasmon resonance are introduced, in particular: quasistatic approximation, Mie theory and in particular, a generalized (quasi)analytical approach for treating rectangularly shaped nanostructures. The parameters influencing resonant behavior of nanoparticles are analyzed with special interest in morphology and sensor applications. Results acquired with Lumerical FDTD Solutions software, using finite-difference time-domain simulation method, are shown and discussed. Simulations were mostly performed for selected nanostructures composed of finite rectangular nanowires with square cross-sections. Systematic analysis is made for single nanowires with varying length, parallel couple of nanowires with varying gap (cut -wires) and selected dolmen structures with varying gap between one nanowire transversely located with respect to parallel couple of nanowires (in both in-plane and -out-of-plane arrangements). The dependence of resonant peaks of cross-section spectral behavior (absorption, scattering, extinction) and their tunability via suitable structuring and morphology changes are primarily researched. These studies are then followed with an analysis of the effect of periodic arrangements. The results can be usable with respect to possible sensor applications.

  5. Post-operative Pain Analysis between Single Visit and Two Visit Root Canal Treatments using Visual Analogue Scale: An In Vivo Study

    Directory of Open Access Journals (Sweden)

    Kavita Tarale

    2013-01-01

    Full Text Available The purpose of this clinical study was to evaluate post-operative pain, after root canal therapy, performed in one appointment versus two appointment using calcium hydroxide intracanal medicament. Study design: In this in-vivo study, 60 patients requiring root canal therapy on permanent 1st molars were included. Patients were randomly divided into two experimental and one control group. Group1: One visit therapy (n=20 Group2: Two visit therapy with 1 week of calcium hydroxide dressing (n=20 Group3(Control: Two visit therapy with 1 week of sterile dry cotton pellet dressing (n=20 Materials and method : The standard protocol for all the patients included local anaesthesia, isolation & access cavity preparation, chemomechanical preparation with Rotary Protaper NiTi instruments, and irrigation with 3% sodium hypochlorite, 17% EDTA, 0.9%saline and 2% chlorhexidine. Teeth in group1 (n=20 were obturated on the same appointment using single cone technique (6% gutta percha points and AH Plus sealer. Teeth in group 2(n=20 and group 3(n=20 were given a dressing of calcium hydroxide and dry cotton pellet respectively for a week followed by double seal with Cavit G and IRM. These teeth were obturated on the 2nd appointment using same material and techniques as in group 1. Teeth in all three groups were restored with dual cure composite resin. A modified Visual Analogue Scale was used to measure preoperative pain and postoperative pain after 6, 12, 24 & 48hrs interval. Statistical analysis was performed using an independent-sample t test. There was no statistically significant difference between groups at any of the four postoperative intervals. There was no significant difference among all the three groups studied after 12, 24hrs & 48hrs. Conclusion : Within the limitations of this in vivo study, it may be concluded that Single Visit Endodontics provides excellent results, if care in diagnosis and proper case selection is given importance. Calcium hydroxide

  6. Evaluation of stereoisomers of 4-fluoroalkyl analogues of 3-quinuclidinyl benzilate in in vivo competition studies for the M1, M2, and M3 muscarinic receptor subtypes in brain

    International Nuclear Information System (INIS)

    Kiesewetter, Dale O.; Eckelman, William C.; Jaetae, Lee; Paik, Chang H.; Park, Seok G.

    1995-01-01

    To develop a subtype selective muscarinic acetylcholine receptor (mAChR) antagonist for PET, fluorine-19 labeled alkyl analogues of quinuclidinyl benzilate (QNB) were synthesized by stereoselective reactions. To investigate these analogues for tissue subtype specificity, in vivo competitive binding studies were performed in rat brain using (R)-3-quinuclidinyl (R)-4-[ 125 I]Iodobenzilate (IQNB). Five, fifty, or five-hundred nmol of the non-radioactive ligands were coinjected intravenously with 8 pmol of the radioligand. Cold (R,R)-IQNB blocked (R,R)-[ 125 I]IQNB in a dose-dependent manner, without showing regional specificity. For the (R,S)-fluoromethyl, -fluoroethyl, and -fluoropropyl derivatives, a higher percent blockade was seen at 5 and 50 nmol levels in M2 predominant tissues (medulla, pons, and cerebellum) than in M1 predominant tissues (cortex, striatum and hippocampus). The blockade pattern of the radioligand also correlated qualitatively with the percentage of M2 receptors in the region. The S-quinuclidinyl analogues showed M2 selectivity but less efficient blockade of the radioligand, indicating lower affinities. Radioligand bound to the medulla was inversely correlated to the M2 relative binding affinity of the fluoroalkyl analogues. These results indicate that the nonradioactive ligand blocks the radioligand based on the affinity of the nonradioactive ligand for a particular receptor subtype compared to the affinity of the radioligand for the same receptor subtype. Of the seven compounds evaluated, (R,S)-fluoromethyl-QNB appears to show the most selectivity for the M2 subtypes in competition studies in vivo

  7. The synthesis and pharmacology of ephedrine analogues

    OpenAIRE

    Mullen, Aidan J

    1991-01-01

    In this report we set out to extend recent studies on substituted PAC analogues produced by the fermentation of aromatic aldehydes with Saccharomyces cerevisiae. The medium selected contained glucose as a carbon source for the biotransformation, and sodium pyruvate as an inhibitor for alcohol dehydrogenase, the enzyme responsible for the conversion of the carbinol to a benzyl alcohol derivatives. An investigation of sodium cyanoborohydride for a selective reductive ami...

  8. Heterocyclic Analogues of Modafinil as Novel, Atypical Dopamine Transporter Inhibitors.

    Science.gov (United States)

    Kalaba, Predrag; Aher, Nilima Y; Ilić, Marija; Dragačević, Vladimir; Wieder, Marcus; Miklosi, Andras G; Zehl, Martin; Wackerlig, Judith; Roller, Alexander; Beryozkina, Tetyana; Radoman, Bojana; Saroja, Sivaprakasam R; Lindner, Wolfgang; Gonzalez, Eduardo Perez; Bakulev, Vasiliy; Leban, Johann Jakob; Sitte, Harald H; Urban, Ernst; Langer, Thierry; Lubec, Gert

    2017-11-22

    Modafinil is a wake promoting compound with high potential for cognitive enhancement. It is targeting the dopamine transporter (DAT) with moderate selectivity, thereby leading to reuptake inhibition and increased dopamine levels in the synaptic cleft. A series of modafinil analogues have been reported so far, but more target-specific analogues remain to be discovered. It was the aim of this study to synthesize and characterize such analogues and, indeed, a series of compounds were showing higher activities on the DAT and a higher selectivity toward DAT versus serotonin and norepinephrine transporters than modafinil. This was achieved by substituting the amide moiety by five- and six-membered aromatic heterocycles. In vitro studies indicated binding to the cocaine pocket on DAT, although molecular dynamics revealed binding different from that of cocaine. Moreover, no release of dopamine was observed, ruling out amphetamine-like effects. The absence of neurotoxicity of a representative analogue may encourage further preclinical studies of the above-mentioned compounds.

  9. Insulin analogues in pregnancy and specific congenital anomalies

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...... included 1286 foetuses of mothers using short-acting insulin analogues with 1089 references of mothers using human insulin and 768 foetuses of mothers using long-acting insulin analogues with 685 references of mothers using long-acting human insulin (Neutral Protamine Hagedorn). The congenital anomaly rate...... was 4.84% and 4.29% among the foetuses of mothers using lispro and aspart. For glargine and detemir, the congenital anomaly rate was 2.86% and 3.47%, respectively. No studies on the use of insulin glulisine and degludec in pregnancy were found. There was no statistically significant difference...

  10. Study on frequency characteristics of wireless power transmission system based on magnetic coupling resonance

    Science.gov (United States)

    Liang, L. H.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Yue, Z. K.; Cui, S.

    2017-11-01

    In order to study the frequency characteristics of the wireless energy transmission system based on the magnetic coupling resonance, a circuit model based on the magnetic coupling resonant wireless energy transmission system is established. The influence of the load on the frequency characteristics of the wireless power transmission system is analysed. The circuit coupling theory is used to derive the minimum load required to suppress frequency splitting. Simulation and experimental results verify that when the load size is lower than a certain value, the system will appear frequency splitting, increasing the load size can effectively suppress the frequency splitting phenomenon. The power regulation scheme of the wireless charging system based on magnetic coupling resonance is given. This study provides a theoretical basis for load selection and power regulation of wireless power transmission systems.

  11. Switching of transmission resonances in a two-channels coupler: A Boundary Wall Method scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, A. [Instituto de Física, Universidade Federal de Alagoas, 57072-970, Maceió-AL (Brazil); Zanetti, F.M. [Departamento de Física, Universidade Federal do Paraná, 81531-990, Curitiba-PR (Brazil); Lyra, M.L., E-mail: marcelo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970, Maceió-AL (Brazil)

    2016-10-15

    In this work, we study the transmission characteristics of a two-channels coupler model system using the Boundary Wall Method (BWM) to determine the solution of the corresponding scattering problem of an incident plane wave. We show that the BWM provides detailed information regarding the transmission resonances. In particular, we focus on the case of single channel input aiming to explore the energy switching performance of the coupler. We show that the coupler geometry can be tailored to allow for the first transmission resonances to be predominantly transmitted on specific output channels, an important characteristic for the realization of logical operations. - Highlights: • The switching performance of a coupled waveguide device is studied via the boundary wall method. • The method efficiently identifies all resonant transmission modes. • Energy switching is controlled and optimized as a function of the device geometry.

  12. Transmission-line resonators for the study of individual two-level tunneling systems

    Science.gov (United States)

    Brehm, Jan David; Bilmes, Alexander; Weiss, Georg; Ustinov, Alexey V.; Lisenfeld, Jürgen

    2017-09-01

    Parasitic two-level tunneling systems (TLS) emerge in amorphous dielectrics and constitute a serious nuisance for various microfabricated devices, where they act as a source of noise and decoherence. Here, we demonstrate a new test bed for the study of TLS in various materials which provides access to properties of individual TLS as well as their ensemble response. We terminate a superconducting transmission-line resonator with a capacitor that hosts TLS in its dielectric. By tuning TLS via applied mechanical strain, we observe the signatures of individual TLS strongly coupled to the resonator in its transmission characteristics and extract the coupling components of their dipole moments and energy relaxation rates. The strong and well-defined coupling to the TLS bath results in pronounced resonator frequency fluctuations and excess phase noise, through which we can study TLS ensemble effects such as spectral diffusion, and probe theoretical models of TLS interactions.

  13. A magnetic resonance study of 3d transition metals and thermal donors in silicon

    International Nuclear Information System (INIS)

    Wezep, D.A. van.

    1986-01-01

    This thesis describes a study of 3d-transition metal impurities in silicon (titanium and iron in particular) and a study of oxygen-related heat-treatment centers in silicon, both carried out mainly by magnetic resonances techniques like EPR and ENDOR. 119 refs.; 31 figs.; 14 tabs

  14. New alloferon analogues: synthesis and antiviral properties.

    Science.gov (United States)

    Kuczer, Mariola; Majewska, Anna; Zahorska, Renata

    2013-02-01

    We have extended our study on structure/activity relationship studies of insect peptide alloferon (H-His-Gly-Val-Ser-Gly-His-Gly-Gln-His-Gly-Val-His-Gly-OH) by evaluating the antiviral effects of new alloferon analogues. We synthesized 18 alloferon analogues: 12 peptides with sequences shortened from N- or C-terminus and 6 N-terminally modified analogues H-X(1)-Gly-Val-Ser-Gly-His-Gly-Gln-His-Gly-Val-His-Gly-OH, where X(1) = Phe (13), Tyr (14), Trp (15), Phg (16), Phe(p-Cl) (17), and Phe(p-OMe) (18). We found that most of the evaluated peptides inhibit the replication of Human Herpesviruses or Coxsackievirus B2 in Vero, HEp-2 and LLC-MK(2) cells. Our results indicate that the compound [3-13]-alloferon (1) exhibits the strongest antiviral activity (IC(50) = 38 μM) among the analyzed compound. Moreover, no cytotoxic activity against the investigated cell lines was observed for all studied peptides at concentration 165 μM or higher. © 2012 John Wiley & Sons A/S.

  15. 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.

  16. Somatostatin analogues for acute bleeding oesophageal varices

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C.; Hrobjartsson, A.

    2008-01-01

    BACKGROUND: Somatostatin and its derivatives are sometimes used for emergency treatment of bleeding oesophageal varices in patients with cirrhosis of the liver. OBJECTIVES: To study whether somatostatin or its analogues improve survival or reduce the need for blood transfusions in patients...... with bleeding oesophageal varices. SEARCH STRATEGY: PubMed and The Cochrane Library were searched (November 2007). Reference lists of publications, contacts with authors. SELECTION CRITERIA: All randomised trials comparing somatostatin or analogues with placebo or no treatment in patients suspected of acute...... or recent bleeding from oesophageal varices. DATA COLLECTION AND ANALYSIS: The outcome measures extracted were: mortality, blood transfusions, use of balloon tamponade, initial haemostasis and rebleeding. Intention-to-treat analyses including all randomised patients were conducted if possible; a random...

  17. Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance

    Science.gov (United States)

    Santavicca, Daniel F.; Adams, Jesse K.; Grant, Lierd E.; McCaughan, Adam N.; Berggren, Karl K.

    2016-06-01

    We study the microwave impedance of extremely high aspect ratio (length/width ≈ 5000) superconducting niobium nitride nanowires. The nanowires are fabricated in a compact meander geometry that is in series with the center conductor of a 50 Ω coplanar waveguide transmission line. The transmission coefficient of the sample is measured up to 20 GHz. At high frequency, a peak in the transmission coefficient is seen. Numerical simulations show that this is a half-wave resonance along the length of the nanowire, where the nanowire acts as a high impedance, slow wave transmission line. This resonance sets the upper frequency limit for these nanowires as inductive elements. Fitting simulations to the measured resonance enables a precise determination of the nanowire's complex sheet impedance at the resonance frequency. The real part is a measure of dissipation, while the imaginary part is dominated by kinetic inductance. We characterize the dependence of the sheet resistance and sheet inductance on both temperature and current and compare the results to recent theoretical predictions for disordered superconductors. These results can aid in the understanding of high frequency devices based on superconducting nanowires. They may also lead to the development of novel superconducting devices such as ultra-compact resonators and slow-wave structures.

  18. Psychosis and autism: magnetic resonance imaging study of brain anatomy.

    LENUS (Irish Health Repository)

    Toal, Fiona

    2009-05-01

    Autism-spectrum disorder is increasingly recognised, with recent studies estimating that 1% of children in South London are affected. However, the biology of comorbid mental health problems in people with autism-spectrum disorder is poorly understood.

  19. Organic Pollutants in Soils, as Studied by Nuclear Magnetic Resonance

    Science.gov (United States)

    1998-05-15

    fundamental behaviors of certain organic pollutants (e.g., benzene, CC1, trichloroethylene, ethylene glycol) when adsorbed in typical soils , as...represented in most of this study by the ’ following major soil components: humics (humic acid, fulvic acid, humin ), clays (montmorillonite, kaolinite...239.18 Designed using Perform Pro, WHS/DIOR, Oct 94 • • 2 2 NAY m^ FINAL TECHNICAL REPORT ORGANIC POLLUTANTS IN SOILS , AS STUDIED BY NUCLEAR

  20. Experimental Study on LTCC Glass-Ceramic Based Dual Segment Cylindrical Dielectric Resonator Antenna

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Gangwar

    2013-01-01

    Full Text Available The measured characteristics in C/X bands, including material properties of a dual segment cylindrical dielectric resonator antenna (CDRA fabricated from glass-ceramic material based on B2O3–La2O3–MgO glass and La(Mg0.5Ti0.5O3 ceramic, are reported. The sintering characteristic of the ceramic in presence of glass is determined from contact angle measurement and DTA. The return loss and input impedance versus frequency characteristics and radiation patterns of CDRA at its resonant frequency of 6.31 GHz are studied. The measured results for resonant frequency and return loss bandwidth of the CDRA are also compared with corresponding theoretical ones.

  1. NATO Advanced Study Institute on Giant Resonances in Atoms, Molecules, and Solids

    CERN Document Server

    Esteva, J; Karnatak, R

    1987-01-01

    Often, a new area of science grows at the confines between recognised subject divisions, drawing upon techniques and intellectual perspectives from a diversity of fields. Such growth can remain unnoticed at first, until a characteristic fami ly of effects, described by appropriate key words, has developed, at which point a distinct subject is born. Such is very much the case with atomic 'giant resonances'. For a start, their name itself was borrowed from the field of nuclear collective resonances. The energy range in which they occur, at the juncture of the extreme UV and the soft X-rays, remains to this day a meeting point of two different experimental techniques: the grating and the crystal spectrometer. The impetus of synchrotron spectroscopy also played a large part in developing novel methods, described by many acronyms, which are used to study 'giant resonances' today. Finally, although we have described them as 'atomic' to differentiate them from their counterparts in Nuclear Physics, their occurrence ...

  2. Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study

    Directory of Open Access Journals (Sweden)

    Solis S.E.

    2012-01-01

    Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.

  3. Studies of weak capture-gamma-ray resonances via coincidence techniques

    CERN Document Server

    Rowland, C; Champagne, A E; Dummer, A K; Fitzgerald, R; Harley, E C T; Mosher, J; Runkle, R

    2002-01-01

    A method for measuring weak capture-gamma-ray resonances via gamma gamma-coincidence counting techniques is described. The coincidence apparatus consisted of a large-volume germanium detector and an annular NaI(Tl) crystal. The setup was tested by measuring the weak E sub R =227 keV resonance in sup 2 sup 6 Mg(p,gamma) sup 2 sup 7 Al. Absolute germanium and NaI(Tl) counting efficiencies for a range of gamma-ray energies and for different detector-target geometries are presented. Studies of the gamma-ray background in our spectra are described. Compared to previous work, our method improves the detection sensitivity for weak capture-gamma-ray resonances by a factor of approx 100. The usefulness of the present technique for investigations of interest to nuclear astrophysics is discussed.

  4. Experimental and analytical study of highly tunable electrostatically actuated resonant beams

    KAUST Repository

    Hajjaj, Amal Z.

    2015-11-03

    We demonstrate theoretically and experimentally highly tunable clamped–clamped microbeam resonators actuated with electrostatic forces. Theoretically, the Galerkin procedure is used to solve for static deflection as well as the eigenvalue problem as a function of the dc voltage for different values of the ratio between the air gap and the thickness of the microbeam. We demonstrate theoretically and experimentally that the natural frequency of the microbeam can increase or decrease with the increase of the dc polarization voltage depending on the ratio between the air gap and the thickness. Hence, we show that unlike the classical softening effect of the dc voltage, by careful designs of the microbeams, the dc bias can be used to effectively increase the resonance frequencies by several factors. Experimental data are presented for two case studies of silicon beams showing the effective increase of their fundamental resonance frequencies by more than 50–80%. Excellent agreement is reported among the theoretical and experimental results.

  5. 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

  6. Nuclear gamma-resonance study of Co-Gd amorphous films

    International Nuclear Information System (INIS)

    Ivanov, O.A.; Kumejshin, V.F.; Vas'kovskij, V.O.; Laletin, E.V.

    1982-01-01

    The gamma-resonance method has been used to study X ray Co-Gd amorphous films of 18 at.% Cd, 76% Co, 6% Fe enriched with 57 Fe up to 4% obtained by cathode high-frequency sputtering. Spectra processing has been computerized by three different programs. Effective field distributions Hsub(eff) at 57 Fe nuclei are obtained. It is shown that at annealings up to 670 K gradual crystallization occurs under conservation of ''chemical disorder''. The Hsub(eff) temperature dependence at resonance nuclei as well as angles between the magnetization vector and a normal to the film after various thermal treatments are determined [ru

  7. A study of the optimum draft of multiple resonance power buoys for maximizing electric power production

    Directory of Open Access Journals (Sweden)

    Hyuck-Min Kweon

    2014-12-01

    Full Text Available To maximize electric power production using wave energy extractions from resonance power buoys, the maximum motion displacement spectra of the buoys can primarily be obtained under a given wave condition. In this study, wave spectra observed in shoaling water were formulated. Target resonance frequencies were established from the arithmetic means of modal frequency bands and the peak frequencies. The motion characteristics of the circular cylindrical power buoys with corresponding drafts were then calculated using numerical models without considering PTO damping force. Results showed that the heave motions of the power buoys in shoaling waters with insufficient drafts produced greater amplification effects than those in deep seas with sufficient drafts.

  8. Study of microwave components for an electron cyclotron resonance ...

    Indian Academy of Sciences (India)

    Instrum. 68: 4424–4426. Celona L, Ciavola G and Gammino S 1998 Study of microwave coupling ECR ion sources and microwave ion sources. Rev. Sci. Instrum. 69: 1113–1115. Celona L, Gammino S, Ciavola G, Chines F, Marletta S and Messina E 2000 Ionization of efficiency measurements with the microwave discharge ...

  9. Psychosis and autism: magnetic resonance imaging study of brain anatomy

    NARCIS (Netherlands)

    Toal, Fiona; Bloemen, Oswald J. N.; Deeley, Quinton; Tunstall, Nigel; Daly, Eileen M.; Page, Lisa; Brammer, Michael J.; Murphy, Kieran C.; Murphy, Declan G. M.

    2009-01-01

    BACKGROUND: Autism-spectrum disorder is increasingly recognised, with recent studies estimating that 1% of children in South London are affected. However, the biology of comorbid mental health problems in people with autism-spectrum disorder is poorly understood. AIMS: To investigate the brain

  10. Nuclear magnetic resonance study of interaction of ligands with Streptococcus faecium dihydrofolate reductase labeled with [#betta#-13C]tryptophan

    International Nuclear Information System (INIS)

    London, R.E.; Groff, J.P.; Cocco, L.; Blakley, R.L.

    1982-01-01

    Dihydrofolate reductase from Streptococcus faecium has been labeled with [#betta#- 13 C]tryptophan. We have determined changes occurring in the chemical shifts and line widths of the four resonances of the 13 C NMR spectrum of the labeled enzyme, due to its interaction with various ligands. These include the coenzyme, NPDPH and related nucleotides, folate and its polyglutamate derivatives, and many inhibitors including methotrexate and trimethoprim. In addition, paramagnetic relaxation effects produced by a bound spin-labeled analogue of 2'-phosphoadenosine-5'-diphosphoribose on the tryptophan C/sup #betta#/ carbons have been measured. Distances calculated from the relaxation data have been compared with corresponding distances in the crystallographic model of the NADPH-methotrexate ternary complex of Lactobacillus casei reductase. The paramagnetic relaxation data indicate that the two downfield resonances (1 and 2) correspond to tryptophans (W/sub A/ and W/sub B/) that are more remote from the catalytic site, and from the crystallographic model these are seen to be Trp-115 and Trp-160. The upfield resonances (3 and 4) that show broadening due to chemical exchange correspond to closer residues (W/sub C/ and W/sub D/), and these are identified with Trp-6 and Trp-22. However, the relaxation data do not permit specific assignments within the nearer and farther pairs. Although resonance 3, which is split due to chemical exchange, was formerly assigned to Trp-6, data obtained for the enzyme in the presence of various ligands are better interpreted if resonance 3 is assigned to Trp-22, which is located on a loop that joins elements of secondary structure and forms one side of the ligand-binding cavity

  11. Condensed matter analogues of cosmology

    Science.gov (United States)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    liveliest. A number of new experiments are reported here studying the dynamical evolution of domains and defects. Another phenomenon that played a key early role was the formation of vortices in the normal-to-superfluid transition in liquid helium-3. The complicated nature of the order parameter energy surface gives rise to a variety of intriguing effects. This too is still a vigorous field. Superconductivity is a special case because the symmetry that is broken is a gauge symmetry. This is also true in fundamental particle physics theories of relevance to cosmology, and for that reason experiments on superconductors are of particular interest to cosmologists. The situation in this case is more complicated because there are competing mechanisms of defect formation. Experiments in the field have not proved easy, either to perform or to interpret, but the papers in this collection show that good progress has been made of late. In recent years a new type of system has proved immensely fruitful, namely atomic Bose-Einstein or Fermi-gas condensates. Experiments on condensates with tunable parameters have in general provided broad support for the theory, and have also revealed a wide range of interesting and novel features, with intriguing possible analogues in cosmology (e.g. causal horizons and particle creation). The basic idea of the Kibble-Zurek mechanism has been shown to be relevant in this whole range of systems. But numerous complexities have also emerged, concerned for example with the role of inhomogeneity or the existence of composite defects. The field is still developing rapidly. Acknowledgments Finally, we would like to thank all the authors who have contributed to this issue, and the staff of Journal of Physics: Condensed Matter who have made it possible. Condensed matter analogues of cosmology contents Condensed matter analogues of cosmologyTom Kibble and Ajit Srivastava Symmetry breaking in nematic liquid crystals: analogy with cosmology and magnetismR Repnik, A

  12. Resonance Raman study on distorted symmetry of porphyrin in ...

    Indian Academy of Sciences (India)

    plants [32]. They form important chromphores in haeme protein, chlorophylls, cytochrome oxidase etc. Nickel ocatethyl porphyrin, Ni(OEP), plays a central role in studies of the molec- ular properties of porphyrins ..... may attain any one of these, viz., D4, D2d, C4h, C4h, D2h, C4, S4, D2, C2v, C2h,. C2, Cs, Ci and C1 distorted ...

  13. Electron spin resonance studies of some irradiated pharmaceuticals

    International Nuclear Information System (INIS)

    Gibella, M.; Crucq, A-S.; Tilquin, B.; Stocker, P.; Lesgards, G.; Raffi, J.

    2000-01-01

    Five antibiotics belonging to the cephalosporins and penicillins groups have been irradiated: anhydrous ampicilline acid, amoxicilline acid trihydrate, cefuroxime sodium salt, cloxacilline sodium salt monohydrate and ceftazidime pentahydrate. ESR studies have been carried out, showing the influence of irradiation and storage parameters on the nature and concentration of the free radicals trapped. These results may be used to detect an irradiation treatment on such pharmaceuticals. (author)

  14. Phase I study of OM-174, a lipid A analogue, with assessment of immunological response, in patients with refractory solid tumors

    International Nuclear Information System (INIS)

    Isambert, Nicolas; Bardou, Marc; Fumoleau, Pierre; Paul, Catherine; Ferrand, Christophe; Zanetta, Sylvie; Bauer, Jacques; Ragot, Kevin; Lizard, Gérard; Jeannin, Jean-François

    2013-01-01

    Lipids A, the lipophilic partial structure of lipopolysaccharides, induce regression of several tumor types in animal models. Rather than exerting direct cytotoxic effect, these compounds trigger the immune system which in turn stimulates secretion of cytokines, and activates the inducible nitric oxide synthase, as well as immune cell infiltration of tumors. OM-174 is an analogue of lipid A with dual action on Toll-like receptors 2 and 4. In an experimental model of peritoneal carcinomatosis induced in BDIX rats by intraperitoneal injection of syngeneic PROb colon cancer cells, it induced a complete regression of tumors. The present phase I trial was conducted to determine the maximum tolerated dose, the recommended phase II dose and biological response associated with OM-174 administered as intravenous infusion. Patients received OM-174 twice weekly for a total of 5, 10 or 15 injections of either 600, 800 or 1000 μg/m 2 . Blood samples for pharmacokinetic analysis and cytokine dosages were collected. NK cells activity and Toll-like receptors 4 polymorphism analysis were also performed. Seventeen patients were included. The highest dose administered was 1000 μg/m 2 repeated in 15 injections. The most common toxicities were a chills, fever, nausea/vomiting, diarrhea, fatigue and headache. No patient experienced haematological side effects. As no dose limiting toxicity was observed, despite a grade 3 respiratory complication, the maximal tolerated dose and recommended dose were not established. Three patients exhibited disease stabilization with a mean duration of 4 months. Pharmacokinetic profile of OM-174 was characterized by a low distribution volume and clearance. Analysis of TLR 4 polymorphysm showed that most (16/17) patients carried the wild type alleles. A progressive increase in NK cell number and activity was observed only in patients receiving 1000 μg/m 2 of OM-174. A peak of IL-8 and IL-10 concentrations were observed after each OM-174 injection. Peaks

  15. Synthesis, in vitro and in vivo small-animal SPECT evaluation of novel technetium labeled bile acid analogues to study (altered) hepatic transporter function

    International Nuclear Information System (INIS)

    Neyt, Sara; Vliegen, Maarten; Verreet, Bjorn; De Lombaerde, Stef; Braeckman, Kim; Vanhove, Christian; Huisman, Maarten Thomas; Dumolyn, Caroline; Kersemans, Ken; Hulpia, Fabian; Van Calenbergh, Serge; Mannens, Geert; De Vos, Filip

    2016-01-01

    Introduction: Hepatobiliary transport mechanisms are crucial for the excretion of substrate toxic compounds. Drugs can inhibit these transporters, which can lead to drug–drug interactions causing toxicity. Therefore, it is important to assess this early during the development of new drug candidates. The aim of the current study is the (radio)synthesis, in vitro and in vivo evaluation of a technetium labeled chenodeoxycholic and cholic acid analogue: [ 99m Tc]-DTPA-CDCA and [ 99m ]Tc-DTPA-CA, respectively, as biomarker for disturbed transporter functionality. Methods: [99mTc]-DTPA-CDCA([ 99m Tc]-3a) and [99mTc]-DTPA-CA ([ 99m Tc]-3b) were synthesized and evaluated in vitro and in vivo. Uptake of both tracers was investigated in NTCP, OCT1, OATP1B1, OATP1B3 transfected cell lines. K m and V max values were determined and compared to [ 99m Tc]-mebrofenin ([ 99m Tc]-MEB). Efflux was investigated by means of CTRL, MRP2 and BSEP transfected inside-out vesicles. Metabolite analysis was performed using pooled human liver S9. Wild type (n = 3) and rifampicin treated (n = 3) mice were intravenously injected with 37 MBq of tracer. After dynamic small-animal SPECT and short CT acquisitions, time–activity curves of heart, liver, gallbladder and intestines were obtained. Results: We demonstrated that OATP1B1 and OATP1B3 are the involved uptake transporters of both compounds. Both tracers show a higher affinity compared to [ 99m Tc]-MEB, but are in a similar range as endogenous bile acids for OATP1B1 and OATP1B3. [ 99m Tc]-3a shows higher affinities compared to [ 99m Tc]-3b. V max values were lower compared to [ 99m Tc]-MEB, but in the same range as endogenous bile acids. MRP2 was identified as efflux transporter. Less than 7% of both radiotracers was metabolized in the liver. In vitro results were confirmed by in vivo results. Uptake in the liver and efflux to gallbladder + intestines and urinary bladder of both tracers was observed. Transport was inhibited by rifampicin

  16. Evidence for resonant bonding in phase-change materials studied by IR spectroscopy

    Directory of Open Access Journals (Sweden)

    K. Shportko

    2017-04-01

    Full Text Available Phase-change materials (PCM attract attention due to their unique properties. This remarkable portfolio also makes them promising for applications in novel data storage devices. In this study, we discuss differences in the optical properties of PCM and non-PCM in the IR caused by presence or absence of resonant bonding.

  17. End organ damage in the metabolic syndrome and diabetes mellitus : biochemical and magnetic resonance imaging studies

    NARCIS (Netherlands)

    Tjeerdema, Nathanja

    2015-01-01

    The focus of this thesis was to evaluate biomarkers of cardiovascular end organ damage in the metabolic syndrome and diabetes mellitus. We performed cross-sectional studies with biochemical and magnetic resonance imaging (MRI) techniques. We have demonstrated that insulin resistance is a strong

  18. Defect-related internal dissipation in mechanical resonators and the study of coupled mechanical systems.

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, Thomas Aquinas; Czaplewski, David A.; Sullivan, John Patrick; Modine, Normand Arthur; Wendt, Joel Robert; Aslam, Dean (Michigan State University, Lansing, MI); Sepulveda-Alancastro, Nelson (University of Puerto Rico, Mayaguez, PR)

    2007-01-01

    Understanding internal dissipation in resonant mechanical systems at the micro- and nanoscale is of great technological and fundamental interest. Resonant mechanical systems are central to many sensor technologies, and microscale resonators form the basis of a variety of scanning probe microscopies. Furthermore, coupled resonant mechanical systems are of great utility for the study of complex dynamics in systems ranging from biology to electronics to photonics. In this work, we report the detailed experimental study of internal dissipation in micro- and nanomechanical oscillators fabricated from amorphous and crystalline diamond materials, atomistic modeling of dissipation in amorphous, defect-free, and defect-containing crystalline silicon, and experimental work on the properties of one-dimensional and two-dimensional coupled mechanical oscillator arrays. We have identified that internal dissipation in most micro- and nanoscale oscillators is limited by defect relaxation processes, with large differences in the nature of the defects as the local order of the material ranges from amorphous to crystalline. Atomistic simulations also showed a dominant role of defect relaxation processes in controlling internal dissipation. Our studies of one-dimensional and two-dimensional coupled oscillator arrays revealed that it is possible to create mechanical systems that should be ideal for the study of non-linear dynamics and localization.

  19. The Fontan circulation and the liver : A magnetic resonance diffusion-weighted imaging study

    NARCIS (Netherlands)

    Wolff, Djoeke; van Melle, Joost P.; Dijkstra, Hildebrand; Bartelds, Beatrijs; Willems, Tineke P.; Hillege, Hans; van den Berg, Aad P.; Ebels, Tjark; Sijens, Paul E.; Berger, Rolf M. F.

    2016-01-01

    Background: Patients with a Fontan circulation tend to develop liver fibrosis, liver cirrhosis and even hepatocellular carcinoma. The aim of this study is to use the magnetic resonance technique diffusing-weighted imaging (DWI) for detecting liver fibrosis/cirrhosis in Fontan patients and to

  20. Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

    1976-01-01

    The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

  1. The magnetic-resonance properties study of nanostructures for spintronics by FMR

    International Nuclear Information System (INIS)

    Kupriyanova, G; Zyubin, A; Astashonok, A; Orlova, A; Prokhorenko, E

    2011-01-01

    In this work we report the study of the magnetic-resonance properties such as magnetic anisotropy, magnetic damping, and interlayer exchange coupling between ferromagnetic layers separated by a nonmagnetic spacer by FMR to assess their applicability in a functional magnetic tunnel junction.

  2. Evaluation of relaxation time measurements by magnetic resonance imaging. A phantom study

    DEFF Research Database (Denmark)

    Kjaer, L; Thomsen, C; Henriksen, O

    1987-01-01

    Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different...

  3. Resonance Raman and quantum chemical studies of short polyene radical cations

    DEFF Research Database (Denmark)

    Keszthelyi, T.; Wilbrandt, R.; Bally, T.

    1997-01-01

    ,3,5-hexatriene have been studied. The radical cations were generated radiolytically in a glassy Freon matrix and investigated by optical absorption and resonance Raman spectroscopy. Ab initio and density functional molecular-orbital calculations have been carried out to predict equilibrium structures...

  4. [Abbreviations of special terms for presentation/paper titles in magnetic resonance study].

    Science.gov (United States)

    Komi, Masanori; Shiraishi, Junji

    2013-08-01

    A large number of abbreviations have been created for various special terms, and used in magnetic resonance (MR) study. However, the use of these abbreviations in the paper title has been restricted by the majority of societies and journals. In this study, we investigated the use of various abbreviations for special terms in MR study in order to clarify which abbreviation could be used in the paper title without spelling. We used two journals, Magnetic Resonance in Medicine (MRM) and Journal of Magnetic Resonance Imaging (JMRI) published by the International Society for Magnetic Resonance in Medicine (ISMRM), which has been considered to be the most advanced society for MR study in the world, as the reference standard for use of the abbreviations. Except for some basic abbreviations and specific abbreviations that were used on a long-term basis, the majority of abbreviations were used in the paper title with its full spelling in order to ensure generality. It is preferable that abbreviations not be used in the title of the or title of the paper.

  5. Quantitative and qualitative assessment of structural magnetic resonance imaging data in a two-center study

    NARCIS (Netherlands)

    Chalavi, Sima; Simmons, Andrew; Dijkstra, Hildebrand; Barker, Gareth J.; Reinders, A. A. T. Simone

    2012-01-01

    Background: Multi-center magnetic resonance imaging (MRI) studies present an opportunity to advance research by pooling data. However, brain measurements derived from MR-images are susceptible to differences in MR-sequence parameters. It is therefore necessary to determine whether there is an

  6. Glutamatergic Effects of Divalproex in Adolescents with Mania: A Proton Magnetic Resonance Spectroscopy Study

    Science.gov (United States)

    Strawn, Jeffrey R.; Patel, Nick C.; Chu, Wen-Jang; Lee, Jing-Huei; Adler, Caleb M.; Kim, Mi Jung; Bryan, Holly S.; Alfieri, David C.; Welge, Jeffrey A.; Blom, Thomas J.; Nandagopal, Jayasree J.; Strakowski, Stephen M.; DelBello, Melissa P.

    2012-01-01

    Objectives: This study used proton magnetic resonance spectroscopy ([superscript 1]H MRS) to evaluate the in vivo effects of extended-release divalproex sodium on the glutamatergic system in adolescents with bipolar disorder, and to identify baseline neurochemical predictors of clinical remission. Method: Adolescents with bipolar disorder who were…

  7. Nature of the pygmy dipole resonance in Ce-140 studied in (alpha, alpha 'gamma) experiments

    NARCIS (Netherlands)

    Savran, D.; Babilon, M.; van den Berg, A.M.; Harakeh, M.N.; Hasper, J.; Matic, A.; Wörtche, H.J.; Zilges, A.

    2006-01-01

    A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus Ce-140 in (alpha, alpha(')gamma) experiments at E-alpha=136 MeV. The technique of alpha-gamma coincidence experiments

  8. Interaction between adrenaline and dibenzo-18-crown-6: Electrochemical, nuclear magnetic resonance, and theoretical study

    Science.gov (United States)

    Yu, Zhang-Yu; Liu, Tao; Wang, Xue-Liang

    2014-12-01

    The interaction between adrenaline (Ad) and dibenzo-18-crown-6 (DB18C6) was studied by cyclic voltammetry, nuclear magnetic resonance spectroscopy, and the theoretical calculations, respectively. The results show that DB18C6 will affect the electron transfer properties of Ad. DB18C6 can form stable supramolecular complexes with Ad through ion-dipole and hydrogen bond interactions.

  9. 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.

  10. Computed tomography and magnetic resonance imaging study of uveal melanoma

    International Nuclear Information System (INIS)

    Xian Junfang; Wang Zhenchang; Yan Fei

    1998-01-01

    Purpose: To study CT and MRI findings of uveal melanoma and detect the most appropriate MRI scanning sequences. Materials and methods: A series of MRI scanning sequences were performed in 15 cases, and CT was performed in 11 cases. MRI and CT findings were compared with pathologic, operative and clinical findings. Results: Of 11 cases receiving CT scanning, 9 displayed iso-density masses with respect to extraocular muscles. The other two tumors were too small to be demonstrated. Fourteen cases of melanoma showed characteristic MR appearances with hyperintense signal with respect to the vitreous on T 1 -weighted images and hypointense with respect to the vitreous on T 2 -weighted images. One case of iris melanoma only 3 mm in height was not demonstrated on T 1 -weighted images, but was displayed hypointense signal on T 2 -weighted images. Eleven cases associated with retinal detachment showed high intensity signal on T 1 - and T 2 -weighted images and could not be distinguished from melanoma. Postcontrast T 1 -weighted images with fat suppression technique were found to be the most helpful in detecting and delineating small melanomas less than 5 mm as well as distinguishing them from retinal detachment. Conclusion: MRI was superior to ultrasound or CT. Collaborative diagnosis including clinical, ultrasonographic, CT and MRI examinations is the best for ocular melanoma

  11. Fourier transform nuclear magnetic resonance studies of 199Hg

    International Nuclear Information System (INIS)

    Krueger, H.; Lutz, O.; Nolle, A.; Schwenk, A.

    1975-01-01

    199 Hg Fourier Transform NMR studies of various solutions of diverse mercury salts in H 2 O and D 2 O or in the appropriate protonated and deuterated acids are reported for both Hg 2 ++ and Hg ++ . In the different solutions investigated the 199 Hg line positions depend on the concentration of the solution, on the solvents and their isotopic composition and on the temperature of the sample. A ratio of the Larmor frequency of 199 Hg and of 2 H in a Hg(NO 3 ) 2 solution in dilute DNO 3 is given. Using this ratio and the measured chemical shifts, a ratio of the Larmor frequencies of 199 Hg for infinite dilution relative to 2 H in pure D 2 O is given. From this a g 1 -factor for 199 Hg is derived and compared with the g 1 -factor of an optical pumping experiment. The resulting shielding constant is sigma (hydrated 199 Hg ++ versus 199 Hg atom) = -24.32(5) x 10 -4 . This yields an atomic reference scale for all measured NMR line shifts of mercury. (orig.) [de

  12. Localized surface plasmon resonance (LSPR) study of DNA hybridization at single nanoparticle transducers

    International Nuclear Information System (INIS)

    Schneider, T.; Jahr, N.; Jatschka, J.; Csaki, A.; Stranik, O.; Fritzsche, W.

    2013-01-01

    The effect of DNA–DNA interaction on the localized surface plasmon resonance of single 80 nm gold nanoparticles is studied. Therefore, both the attachment of the capture DNA strands at the particle surface and the sequence-specific DNA binding (hybridization) of analyte DNA to the immobilized capture DNA is subject of investigations. The influence of substrate attachment chemistry, the packing density of DNA as controlled by an assisting layer of smaller molecules, and the distance as increased by a linker on the LSPR efficiency is investigated. The resulting changes in signal can be related to a higher hybridization efficiency of the analyte DNA to the immobilized capture DNA. The subsequent attachment of additional DNA strands to this system is studied, which allows for a multiple step detection of binding and an elucidation of the resulting resonance shifts. The detection limit was determined for the utilized DNA system by incubation with various concentration of analyte DNA. Although the method allows for a marker-free detection, we show that additional markers such as 20 nm gold particle labels increase the signal and thereby the sensitivity significantly. The study of resonance shift for various DNA lengths revealed that the resonance shift per base is stronger for shorter DNA molecules (20 bases) as compared to longer ones (46 bases).

  13. 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

  14. PTH analogues and osteoporotic fractures

    NARCIS (Netherlands)

    Verhaar, H.J.; Lems, W.F.

    2010-01-01

    Importance of the field: At present there are two parathyroid hormone (PTH) analogues (PTH 1 34 and PTH 1 84) registered for the treatment of established osteoporosis in postmenopausal women (PTH 1 34 and PTH 1 84) and in men (PTH 1 34 only) who are at increased risk of having a fracture. Areas

  15. Chemopreventive properties of curcumin analogues ...

    African Journals Online (AJOL)

    Chemopreventive properties of curcumin analogues, hexagamavunone-0 and gamavutone-0, in rat colorectal cancer model. ... Histopathological analysis was performed using H & E staining and immunohistochemistry with antibodies against adenomatous polyposis coli (APC) and cyclooxygenase 2 (COX-2). Results: All ...

  16. Magnetic Resonance Studies of Proton Loss from Carotenoid Radical Cations

    Energy Technology Data Exchange (ETDEWEB)

    Kispert, Lowell D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Focsan, A Ligia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Konovalova, Tatyana A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lawrence, Jesse [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bowman, Michael K [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Molnar, Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deli, Jozsef [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-06-11

    Carotenoids, intrinsic components of reaction centers and pigment-protein complexes in photosynthetic membranes, play a photoprotective role and serve as a secondary electron donor. Before optimum use of carotenoids can be made in artificial photosynthetic systems, their robust nature in living materials requires extensive characterization of their electron transfer, radical trapping ability, stability, structure in and on various hosts, and photochemical behavior. Pulsed ENDOR and 2D-HYSCORE studies combined with DFT calculations reveal that photo-oxidation of natural zeaxanthin (I) and violaxanthin (II) on silica-alumina produces not only the carotenoid radical cations (Car•+) but also neutral radicals (#Car•) by proton loss from the methyl groups at positions 5 or 5', and possibly 9 or 9' and 13 or 13'. Notably, the proton loss favored in I at the 5 position by DFT calculations, is unfavorable in II due to the epoxide at the 5, 6 position. DFT calculations predict the isotropic methyl proton couplings of 8-10 MHz for Car•+ which agree with the ENDOR for carotenoid α-conjugated radical cations. Large α-proton hyperfine coupling constants (>10 MHz) determined from HYSCORE are assigned from the DFT calculations to neutral carotenoid radicals. Proton loss upon photolysis was also examined as a function of carotenoid polarity [Lycopene (III) versus 8'-apo-β-caroten-8'-al (IV)]; hydrogen bonding [Lutein (V) versus III]; host [silica-alumina versus MCM-41 molecular sieve]; and substituted metal in MCM-41. Loss of H+ from the 5(5'), 9(9') or 13(13') methyl positions has importance in photoprotection. Photoprotection involves nonphotochemical quenching (NPQ) in which 1Ch1* decays via energy transfer to the carotenoid which returns to the ground state by thermal dissipation; or via electron transfer to form a charge transfer state (I •+…Chl•-), lower in energy than 1Chl*. Formation of I •+ results in bond

  17. Magnetic Resonance Studies of Proton Loss from Carotenoid Radical Cations

    International Nuclear Information System (INIS)

    Kispert, Lowell D.; Focsan, A. Ligia; Konovalova, Tatyana A.; Lawrence, Jesse; Bowman, Michael K.; Dixon, David A.; Molnar, Peter; Deli, Jozsef

    2007-01-01

    Carotenoids, intrinsic components of reaction centers and pigment-protein complexes in photosynthetic membranes, play a photoprotective role and serve as a secondary electron donor. Before optimum use of carotenoids can be made in artificial photosynthetic systems, their robust nature in living materials requires extensive characterization of their electron transfer, radical trapping ability, stability, structure in and on various hosts, and photochemical behavior. Pulsed ENDOR and 2D-HYSCORE studies combined with DFT calculations reveal that photo-oxidation of natural zeaxanthin (I) and violaxanthin (II) on silica-alumina produces not only the carotenoid radical cations (Car ·+ ) but also neutral radicals ((number s ign)Car · ) by proton loss from the methyl groups at positions 5 or 5(prime), and possibly 9 or 9(prime) and 13 or 13(prime). Notably, the proton loss favored in I at the 5 position by DFT calculations, is unfavorable in II due to the epoxide at the 5, 6 position. DFT calculations predict the isotropic methyl proton couplings of 8-10 MHz for Car # center d ot# + which agree with the ENDOR for carotenoid π-conjugated radical cations. Large α-proton hyperfine coupling constants (>10 MHz) determined from HYSCORE are assigned from the DFT calculations to neutral carotenoid radicals. Proton loss upon photolysis was also examined as a function of carotenoid polarity (Lycopene (III) versus 8(prime)-apo-β-caroten-8(prime)-al (IV)); hydrogen bonding (Lutein (V) versus III); host (silica-alumina versus MCM-41 molecular sieve); and substituted metal in MCM-41. Loss of H + from the 5(5(prime)), 9(9(prime)) or 13(13(prime)) methyl positions has importance in photoprotection. Photoprotection involves nonphotochemical quenching (NPQ) in which 1 Ch1* decays via energy transfer to the carotenoid which returns to the ground state by thermal dissipation; or via electron transfer to form a charge transfer state (I # center d ot# + ...Chl # center d ot# - ), lower in

  18. Optically Detected Magnetic Resonance Studies on π-conjugated semiconductor systems

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Optically Detected Magnetic Resonance (ODMR) techniques were used to investigate the dynamics of excitons and charge carriers in π-conjugated organic semiconductors. Degradation behavior of the negative spin-1/2 electroluminescence-detected magnetic resonance (ELDMR) was observed in Alq3 devices. The increase in the resonance amplitude implies an increasing bipolaron formation during degradation, which might be the result of growth of charge traps in the device. The same behavior of the negative spin-1/2 ELDMR was observed in 2wt% Rubrene doped Tris(8-hydroxyquinolinato)aluminium (Alq3) devices. However, with increasing injection current, a positive spin-1/2 ELDMR, together with positive spin 1 triplet powder patterns at ΔmS=±1 and ΔmS=±2, emerges. Due to the similarities in the frequency dependences of single and double modulated ELDMR and the photoluminescence-detected magnetic resonance (PLDMR) results in poly[2-methoxy-5-(2 -ethyl-hexyloxy)-1,4-phenyl ene vinylene] (MEH-PPV) films, the mechanism for this positive spin-1/2 ELDMR was assigned to enhanced triplet-polaron quenching under resonance conditions. The ELDMR in rubrene doped Alq3 devices provides a path to investigate charge distribution in the device under operational conditions. Combining the results of several devices with different carrier blocking properties and the results from transient EL, it was concluded trions not only exist near buffer layer but also exist in the electron transport layer. This TPQ model can also be used to explain the positive spin-1/2 PLDMR in poly(3-hexylthiophene) (P3HT) films at low temperature and in MEH-PPV films at various temperatures up to room temperature. Through quantitative analysis, TE-polaron quenching (TPQ) model is shown having the ability to explain most behaviors of the positive spin-1/2 resonance. Photocurrent detected magnetic resonance (PCDMR) studies on MEH-PPV devices revealed a novel transient resonance signal. The signal

  19. Electron Spin Resonance and optical absorption spectroscopic studies of manganese centers in aluminium lead borate glasses.

    Science.gov (United States)

    SivaRamaiah, G; LakshmanaRao, J

    2012-12-01

    Electron Spin Resonance (ESR) and optical absorption studies of 5Al(2)O(3)+75H(3)BO(3)+(20-x)PbO+xMnSO(4) (where x=0.5, 1,1.5 and 2 mol% of MnSO(4)) glasses at room temperature have been studied. The ESR spectrum of all the glasses exhibits resonance signals with effective isotropic g values at ≈2.0, 3.3 and 4.3. The ESR resonance signal at isotropic g≈2.0 has been attributed to Mn(2+) centers in an octahedral symmetry. The ESR resonance signals at isotropic g≈3.3 and 4.3 have been attributed to the rhombic symmetry of the Mn(2+) ions. The zero-field splitting parameter (zfs) has been calculated from the intensities of the allowed hyperfine lines. The optical absorption spectrum exhibits an intense band in the visible region and it has been attributed to (5)E(g)→(5)T(2g) transition of Mn(3+)centers in an octahedral environment. The optical band gap and the Urbach energies have been calculated from the ultraviolet absorption edges. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. The A1 chieve study - an observational non-interventional study of patients with type 2 diabetes mellitus initiating or switched to insulin analogue therapy: subgroup analysis of the Gulf population.

    Science.gov (United States)

    El-Naggar, N; Almansari, A; Khudada, K; Salman, S; Mariswamy, N; Abdelfattah, W; Hashim, F

    2013-02-01

    To evaluate the safety and effectiveness of insulin analogues (insulin aspart, insulin detemir and biphasic insulin aspart 30, alone or in combination) in type 2 diabetes mellitus (T2DM) patients in routine clinical practice in the Gulf as a subgroup of the A(1) chieve multi-national study. A total of 10,704 T2DM Gulf patients with uncontrolled T2DM on oral antidiabetics ± insulins other than insulin aspart, insulin detemir or biphasic insulin aspart 30, who initiated or switched to study insulins were included and followed up for 24 weeks in the context of the A(1) chieve study. Baseline HbA(1c) (± SD) was poor: 9.7 ± 1.7%. At Week 24, an improvement in HbA(1c) of -2.3 ± 1.6% was observed in the entire cohort, and -2.4 ± 1.5% and -2.1 ± 1.7% for insulin-naïve patients and prior insulin users respectively. Overall, rates of hypoglycaemia increased in those new to insulin therapy, whereas a reduction was observed in those switching from other insulins. A marginal reduction in body weight (-0.8 ± 4.4 kg) was noted in the entire cohort, whereas the overall lipid profile and systolic blood pressure (-6.2 ± 15.3 mmHg) improved. Initiating or switching to insulin analogues was well tolerated and resulted in significant improvements in glycaemic control in T2DM patients in the Gulf. © 2013 Blackwell Publishing Ltd.

  1. Thermally stimulated luminescence and electron paramagnetic resonance studies on uranium doped calcium phosphate

    CERN Document Server

    Natarajan, V; Veeraraghavan, R; Sastry, M D

    2003-01-01

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies on uranium doped calcium phosphate yielded mechanistic information on the observed glow peaks at 365, 410 and 450 K. TSL spectral studies of the glow peaks showed that UO sub 2 sup 2 sup + acts as the luminescent center. Electron paramagnetic resonance studies on gamma-irradiated samples revealed that the predominant radiation induced centers are H sup 0 , PO sub 4 sup 2 sup - , PO sub 3 sup 2 sup - and O sup - ion. Studies on the temperature dependence studies of the EPR spectra of samples annealed to different temperatures indicate the role of H sup 0 and PO sub 4 sup 2 sup - ions in the main glow peak at 410 K.

  2. Organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin on chalcones: Synthesis, NMR and single-crystal X-ray diffraction studies of novel warfarin analogues

    Science.gov (United States)

    Talhi, Oualid; Fernandes, José A.; Pinto, Diana C. G. A.; Almeida Paz, Filipe A.; Silva, Artur M. S.

    2015-08-01

    The synthesis of a new series of warfarin analogues by convenient organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin to chalcone derivatives is described. 1H NMR spectroscopy evidenced the presence of a predominant acyclic open-form together with the cyclic hemiketal tautomers of the resulting Michael adducts. The acyclic open-form has been unequivocally proved by single-crystal X-ray diffraction analysis. The use of the B ring ortho-hydroxychalcone synthons in this reaction has led to a diastereoselective synthesis of warfarin bicyclo[3.3.1]nonane ketal derivatives.

  3. Real time hybridization studies by resonant waveguide gratings using nanopattern imaging for Single Nucleotide Polymorphism detection

    KAUST Repository

    Bougot-Robin, Kristelle

    2013-12-20

    2D imaging of biochips is particularly interesting for multiplex biosensing. Resonant properties allow label-free detection using the change of refractive index at the chip surface. We demonstrate a new principle of Scanning Of Resonance on Chip by Imaging (SORCI) based on spatial profiles of nanopatterns of resonant waveguide gratings (RWGs) and its embodiment in a fluidic chip for real-time biological studies. This scheme allows multiplexing of the resonance itself by providing nanopattern sensing areas in a bioarray format. Through several chip designs we discuss resonance spatial profiles, dispersion and electric field distribution for optimal light-matter interaction with biological species of different sizes. Fluidic integration is carried out with a black anodized aluminum chamber, advantageous in term of mechanical stability, multiple uses of the chip, temperature control and low optical background. Real-time hybridization experiments are illustrated by SNP (Single Nucleotide Polymorphism) detection in gyrase A of E. coli K12, observed in evolution studies of resistance to the antibiotic ciprofloxacin. We choose a 100 base pairs (bp) DNA target (∼30 kDa) including the codon of interest and demonstrate the high specificity of our technique for probes and targets with close affinity constants. This work validates the safe applicability of our unique combination of RWGs and simple instrumentation for real-time biosensing with sensitivity in buffer solution of ∼10 pg/mm2. Paralleling the success of RWGs sensing for cells sensing, our work opens new avenues for a large number of biological studies. © 2013 Springer Science+Business Media.

  4. Localization of dexamethasone within dendritic core-multishell (CMS) nanoparticles and skin penetration properties studied by multi-frequency electron paramagnetic resonance (EPR) spectroscopy.

    Science.gov (United States)

    Saeidpour, S; Lohan, S B; Anske, M; Unbehauen, M; Fleige, E; Haag, R; Meinke, M C; Bittl, R; Teutloff, C

    2017-07-01

    The skin and especially the stratum corneum (SC) act as a barrier and protect epidermal cells and thus the whole body against xenobiotica of the external environment. Topical skin treatment requires an efficient drug delivery system (DDS). Polymer-based nanocarriers represent novel transport vehicles for dermal application of drugs. In this study dendritic core-multishell (CMS) nanoparticles were investigated as promising candidates. CMS nanoparticles were loaded with a drug (analogue) and were applied to penetration studies of skin. We determined by dual-frequency electron paramagnetic resonance (EPR) how dexamethasone (Dx) labelled with 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA) is associated with the CMS. The micro-environment of the drug loaded to CMS nanoparticles was investigated by pulsed high-field EPR at cryogenic temperature, making use of the fact that magnetic parameters (g-, A-matrices, and spin-lattice relaxation time) represent specific probes for the micro-environment. Additionally, the rotational correlation time of spin-labelled Dx was probed by continuous wave EPR at ambient temperature, which provides independent information on the drug environment. Furthermore, the penetration depth of Dx into the stratum corneum of porcine skin after different topical applications was investigated. The location of Dx in the CMS nanoparticles is revealed and the function of CMS as penetration enhancers for topical application is shown. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 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

  6. Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

    Science.gov (United States)

    Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

    2017-10-30

    Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

  7. A combined post-mortem magnetic resonance imaging and quantitative histological study of multiple sclerosis pathology

    Science.gov (United States)

    Kolasinski, James; Chance, Steven A.; DeLuca, Gabriele C.; Esiri, Margaret M.; Chang, Eun-Hyuk; Palace, Jacqueline A.; McNab, Jennifer A.; Jenkinson, Mark; Miller, Karla L.; Johansen-Berg, Heidi

    2012-01-01

    Multiple sclerosis is a chronic inflammatory neurological condition characterized by focal and diffuse neurodegeneration and demyelination throughout the central nervous system. Factors influencing the progression of pathology are poorly understood. One hypothesis is that anatomical connectivity influences the spread of neurodegeneration. This predicts that measures of neurodegeneration will correlate most strongly between interconnected structures. However, such patterns have been difficult to quantify through post-mortem neuropathology or in vivo scanning alone. In this study, we used the complementary approaches of whole brain post-mortem magnetic resonance imaging and quantitative histology to assess patterns of multiple sclerosis pathology. Two thalamo-cortical projection systems were considered based on their distinct neuroanatomy and their documented involvement in multiple sclerosis: lateral geniculate nucleus to primary visual cortex and mediodorsal nucleus of the thalamus to prefrontal cortex. Within the anatomically distinct thalamo-cortical projection systems, magnetic resonance imaging derived cortical thickness was correlated significantly with both a measure of myelination in the connected tract and a measure of connected thalamic nucleus cell density. Such correlations did not exist between these markers of neurodegeneration across different thalamo-cortical systems. Magnetic resonance imaging lesion analysis depicted clearly demarcated subcortical lesions impinging on the white matter tracts of interest; however, quantitation of the extent of lesion-tract overlap failed to demonstrate any appreciable association with the severity of markers of diffuse pathology within each thalamo-cortical projection system. Diffusion-weighted magnetic resonance imaging metrics in both white matter tracts were correlated significantly with a histologically derived measure of tract myelination. These data demonstrate for the first time the relevance of functional

  8. Optimization of dose and technique for magnetic resonance studies with an oral contrast agent

    International Nuclear Information System (INIS)

    Broglia, L.; Tortora, A.; Maccioni, F.; Arpesani, R.; Marcelli, G.; Ascarelli, A.; Rossi, P.

    1999-01-01

    The aim of the study was to optimize the dose, scan delay and sequences for use in magnetic resonance (MR) studies with an oral contrast agent (FerriSeltz, Bracco Spa, Milan, Italy) to obtain positive or negative contrast enhancement in the bowel lumen. Ferric ammonium citrate, being positive or negative contrast agent according to its dilution, permits to tailor the dose to optimize bowel lumen opacification [it

  9. Resonant X-ray Raman scattering on molecules: A benchmark study on HCl

    International Nuclear Information System (INIS)

    Carniato, Stephane; Taieb, Richard; Journel, Loic; Guillemin, Renaud; Stolte, Wayne C.; Lindle, Dennis W.; Gel'mukhanov, Faris; Simon, Marc

    2010-01-01

    Resonant X-ray Raman scattering is a powerful tool to study molecular dynamics and subtle chemical effects like the molecular field beyond vibrational and lifetime limitations. Using this technique in the tender X-ray region, gas phase HCl is studied as a benchmark molecule for other compounds like freons, which play an important role in physical-chemical properties of the ozone layer of atmosphere.

  10. Resonant X-ray Raman scattering on molecules: A benchmark study on HCl

    Energy Technology Data Exchange (ETDEWEB)

    Carniato, Stephane [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Taieb, Richard, E-mail: richard.taieb@upmc.f [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Journel, Loic; Guillemin, Renaud [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Stolte, Wayne C.; Lindle, Dennis W. [Department of Chemistry, University of Nevada, Las Vegas, NV 89154-4003 (United States); Gel' mukhanov, Faris [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Simon, Marc [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France)

    2010-08-15

    Resonant X-ray Raman scattering is a powerful tool to study molecular dynamics and subtle chemical effects like the molecular field beyond vibrational and lifetime limitations. Using this technique in the tender X-ray region, gas phase HCl is studied as a benchmark molecule for other compounds like freons, which play an important role in physical-chemical properties of the ozone layer of atmosphere.

  11. Preoperative Magnetic Resonance Imaging in Patients With Stage I Invasive Ductal Breast Cancer: A Prospective Randomized Study.

    Science.gov (United States)

    Brück, N; Koskivuo, I; Boström, P; Saunavaara, J; Aaltonen, R; Parkkola, R

    2018-03-01

    Preoperative magnetic resonance imaging has become an important complementary imaging technique in patients with breast cancer, providing additional information for preoperative local staging. Magnetic resonance imaging is recommended selectively in lobular breast cancer and in patients with dense breast tissue in the case when mammography and ultrasound fail to fully evaluate the lesion, but the routine use of magnetic resonance imaging in all patients with invasive ductal carcinoma is controversial. The purpose of this randomized study was to investigate the diagnostic value of preoperative magnetic resonance imaging and its impact on short-term surgical outcome in newly diagnosed unifocal stage I invasive ductal carcinoma. A total of 100 patients were randomized to either receive preoperative breast magnetic resonance imaging or to be scheduled directly to operation without magnetic resonance imaging on a 1:1 basis. There were 50 patients in both study arms. In 14 patients (28%), breast magnetic resonance imaging detected an additional finding and seven of them were found to be malignant. Six additional cancer foci were found in the ipsilateral breast and one in the contralateral breast. Magnetic resonance imaging findings caused a change in planned surgical management in 10 patients (20%). Mastectomy was performed in six patients (12%) in the magnetic resonance imaging group and in two patients (4%) in the control group ( p = 0.140). The breast reoperation rate was 14% in the magnetic resonance imaging group and 24% in the control group ( p = 0.202). The mean interval between referral and first surgical procedure was 34 days in the magnetic resonance imaging group and 21 days in the control group ( p magnetic resonance imaging may be beneficial for some patients with early-stage invasive ductal carcinoma, but its routine use is not recommended without specific indications.

  12. Study of nuclear reactions and analog isobar states in the system He{sup 8} + p for low energy with the help of MAYA active target; Etude de reactions et d'etats isobariques analogues dans le systeme {sup 8}He+p, a basse energie a l'aide de la cible active MAYA

    Energy Technology Data Exchange (ETDEWEB)

    Demonchy, Ch.E

    2003-12-01

    With the resent improvements in the field of exotics beams, and specially with the SPIRAL facility at GANIL, we were able to study He{sup 9} shell inversion already known for Be{sup 11} and Li{sup 10}, which are two members of the N=7 family. A new detector was developed and also the software tools for the data analysis. This detector is at the same time the target (active-target) and is called MAYA. The He{sup 9} was studied by determining the properties of its isobaric analogue states in Li{sup 9}. The characteristics of the IAS (isomeric analog state) states were determined by an analysis of the resonances in the elastic scattering cross section for He{sup 8} + p from 2 up to 3.9 MeV/n. A study of (p,d) and (p,t) reactions was done too, in this domain of energy. By comparing the experimental results with calculations, an assignation of spin and parity for two states in He{sup 9} was possible. (author)

  13. A NEW TOOL FOR THE STUDY OF RESONANCE IN CHEMICAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Francisco Torrens

    2014-03-01

    Full Text Available The objective of this study is to present a computer-based project, for which our program POLAR and our version of PAPID were written for the study of the subject of resonance in chemistry. Both algorithms allow a better didactic strategy and methodological adaptation for the study of molecular properties in chemical education. Teachers will find the options of POLAR and PAPID useful for demonstrations. It is still to be explored the methodological application of these computational programs enriching the present teaching techniques. Implementing new algorithms in learning situations is technically simple, but checking their usefulness in teaching practice is extraordinarily complex and requires a research that has hardly begun. The topic of resonance in chemistry represents an opportunity for the integration of teaching and research into the European Space for Higher Education.

  14. Optically Detected Magnetic Resonance and Thermal Activation Spectroscopy Study of Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang-Hwan [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    Organic electronic materials are a new class of emerging materials. Organic light emitting devices (OLEDs) are the most promising candidates for future flat panel display technologies. The photophysical characterization is the basic research step one must follow to understand this new class of materials and devices. The light emission properties are closely related to the transport properties of these materials. The objective of this dissertation is to probe the relation between transport and photophysical properties of organic semiconductors. The transport characteristics were evaluated by using thermally stimulated current and thermally stimulated luminescence techniques. The photoluminescence detected magnetic resonance and photoluminescence quantum yield studies provide valuable photophysical information on this class of materials. OLEDs are already in the market. However, detailed studies on the degradation mechanisms are still lacking. Since both optically detected magnetic resonance and thermal activation spectroscopy probe long-lived defect-related states in organic semiconductors, the combined study generates new insight on the OLED operation and degradation mechanisms.

  15. Optically Detected Magnetic Resonance and Thermal Activation Spectroscopy Study of Organic Semiconductors

    International Nuclear Information System (INIS)

    Chang-Hwan Kim

    2003-01-01

    Organic electronic materials are a new class of emerging materials. Organic light emitting devices (OLEDs) are the most promising candidates for future flat panel display technologies. The photophysical characterization is the basic research step one must follow to understand this new class of materials and devices. The light emission properties are closely related to the transport properties of these materials. The objective of this dissertation is to probe the relation between transport and photophysical properties of organic semiconductors. The transport characteristics were evaluated by using thermally stimulated current and thermally stimulated luminescence techniques. The photoluminescence detected magnetic resonance and photoluminescence quantum yield studies provide valuable photophysical information on this class of materials. OLEDs are already in the market. However, detailed studies on the degradation mechanisms are still lacking. Since both optically detected magnetic resonance and thermal activation spectroscopy probe long-lived defect-related states in organic semiconductors, the combined study generates new insight on the OLED operation and degradation mechanisms

  16. Electron spin resonance studies on reduction process of nitroxyl spin radicals used in molecular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dhas, M. Kumara; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com [Department of Physics, NMSSVN College, Nagamalai, Madurai-625019, Tamilnadu (India); Jawahar, A. [Department of Chemistry, NMSSVN College, Nagamalai, Madurai-625019, Tamilnadu (India)

    2014-04-24

    The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM {sup 14}N labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters such as signal intensity ratio, line width, g-value, hyperfine coupling constant and rotational correlation time were determined. The half life time was estimated for 1mM {sup 14}N labeled nitroxyl radicals in 1 mM concentration of ascorbic acid. The ESR study reveals that the TEMPONE has narrowest line width and fast tumbling motion compared with TEMPO and TEMPOL. From the results, TEMPONE has long half life time and high stability compared with TEMPO and TEMPOL radical. Therefore, this study reveals that the TEMPONE radical can act as a good redox sensitive spin probe for molecular imaging.

  17. Electron spin resonance studies on reduction process of nitroxyl spin radicals used in molecular imaging

    Science.gov (United States)

    Dhas, M. Kumara; Jawahar, A.; Benial, A. Milton Franklin

    2014-04-01

    The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM 14N labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters such as signal intensity ratio, line width, g-value, hyperfine coupling constant and rotational correlation time were determined. The half life time was estimated for 1mM 14N labeled nitroxyl radicals in 1 mM concentration of ascorbic acid. The ESR study reveals that the TEMPONE has narrowest line width and fast tumbling motion compared with TEMPO and TEMPOL. From the results, TEMPONE has long half life time and high stability compared with TEMPO and TEMPOL radical. Therefore, this study reveals that the TEMPONE radical can act as a good redox sensitive spin probe for molecular imaging.

  18. Studies on the resonant properties in the asymmetric dipole-array terahertz metamaterials

    Science.gov (United States)

    Chen, Wei; Zhou, Qingli; Li, Chenyu; Shi, Lan; Liu, Changxiang; Zhang, Cunlin

    2018-01-01

    Artificial metamaterials with appropriate design can exhibit unique electromagnetic phenomena which do not exist in natural materials. Some studies have shown that the method of breaking the geometric symmetry is capable to modify the electromagnetic response, such as the metamaterial induced transparency in the Fano resonators. In this work, by using the finite-difference time-domain method, we firstly simulate the process that terahertz wave interacts with double-bar structures, in which one bar length is fixed at 36 μm and the other bar length is set to be 12, 24, 36, 48, and 56 μm, respectively. The incident terahertz polarization is along the bar direction. Simulated results show when the variable bar length is less than 36 μm, there is only one obvious resonant dip in transmission spectrum. Meanwhile, with the decreased bar length, this dip frequency presents a slight blueshift. Additionally, by tuning the spacing vertical to bar direction between these two bars, it still exhibits one dip. This result indicates the short bar less than 36 μm does not play important role and the coupling between vertical bars is weak. However, when the variable bar length is larger than 36 μm there are two obvious Fano-shaped resonant dips. With the increased bar length, the low-frequency dip shows a remarkable redshift, while the high-frequency one is almost unchanged. By further tuning the bar spacing vertical to the bar direction, two dips always exist. This phenomenon implies that the coupling between horizontal bars is dominated in this process. Moreover, the metamaterial induced transparency window is found between two resonant dips. The appearance of the resonances is attributed to the excitation of trapped mode. Our obtained results indicate that such metamaterials with very simple configuration could also provide the potential application in the field of terahertz slow-light devices, amplitude and phase modulators.

  19. Somatostatin analogue scintigraphy in granulomatous diseases

    Energy Technology Data Exchange (ETDEWEB)

    Vanhagen, P.M. (Dept. of Internal Medicine 3, Dijkzigt Univ. Hospital, Rotterdam (Netherlands) Dept. of Immunology, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Krenning, E.P. (Dept. of Internal Medicine 3, Dijkzigt Univ. Hospital, Rotterdam (Netherlands) Dept. of Nuclear Medicine, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Reubi, J.C. (Inst. of Pathology, Bern Univ. (Switzerland)); Kwekkeboom, D.J. (Dept. of Nuclear Medicine, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Bakker, W.H. (Dept. of Nuclear Medicine, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Mulder, A.H. (Dept. of Pathology, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Laissue, I. (Inst. of Pathology, Bern Univ. (Switzerland)); Hoogstede, H.C. (Dept. of Chest Medicine, Dijkzigt Univ. Hospital, Rotterdam (Netherlands)); Lamberts, S.W.J. (Dept. of Internal Medicine 3, Dijkzigt Univ. Hospital, Rotterdam (Netherlands))

    1994-06-01

    In the present study 20 consecutive patients were investigated, 12 with sarcoidosis, one with both sarcoidosis and aspergillosis, four with tuberculosis and three with Wegener's granulomatosis. For in vivo SS-R imaging, total-body scintigraphy was performed 24 and 48 h after the administration of [sup 111]In-octreotide. Granuloma localizations could be visualized in all patients studied; additional sites were found in nine patients with sarcoidosis and in two patients with tuberculosis. In vitro autoradiography of fresh tissue biopsies, using the SS analogue [[sup 125]I-Tyr[sup 3

  20. Effect of the glucagon-like peptide-1 analogue liraglutide on coronary microvascular function in patients with type 2 diabetes – a randomized, single-blinded, cross-over pilot study

    DEFF Research Database (Denmark)

    Faber, Rebekka; Zander, Mette; Pena, Adam

    2015-01-01

    with either the GLP-1 analogue liraglutide or received no treatment for 10 weeks, in a randomized, single-blinded, cross-over setup with a 2 weeks wash-out period. The effect of liraglutide on coronary microcirculation was evaluated using non-invasive trans-thoracic Doppler-flow echocardiography during...... dipyridamole induced stress. Peripheral microvascular endothelial function was assessed by Endo-PAT2000®. Interventions were compared by two-sample t-test after ensuring no carry over effect. RESULTS: A total of 24 patients were included. Twenty patients completed the study (15 male; mean age 57 ± 9; mean BMI...

  1. Novel acetylcholine and carbamoylcholine analogues

    DEFF Research Database (Denmark)

    Hansen, Camilla Petrycer; Jensen, Anders Asbjørn; Christensen, Jeppe K.

    2008-01-01

    A series of carbamoylcholine and acetylcholine analogues were synthesized and characterized pharmacologically at neuronal nicotinic acetylcholine receptors (nAChRs). Several of the compounds displayed low nanomolar binding affinities to the alpha 4beta 2 nAChR and pronounced selectivity...... for this subtype over alpha 3beta 4, alpha 4beta 4, and alpha 7 nAChRs. The high nAChR activity of carbamoylcholine analogue 5d was found to reside in its R-enantiomer, a characteristic most likely true for all other compounds in the series. Interestingly, the pronounced alpha 4beta 2 selectivities exhibited...... by some of the compounds in the binding assays translated into functional selectivity. Compound 5a was a fairly potent partial alpha 4beta 2 nAChR agonist with negligible activities at the alpha 3beta 4 and alpha 7 subtypes, thus being one of the few truly functionally selective alpha 4beta 2 nACh...

  2. Inhibition of thermolysin by phosphonamidate transition-state analogues: measurement of 31P-15N bond lengths and chemical shifts in two enzyme-inhibitor complexes by solid-state nuclear magnetic resonance.

    Science.gov (United States)

    Copié, V; Kolbert, A C; Drewry, D H; Bartlett, P A; Oas, T G; Griffin, R G

    1990-10-02

    31P and 15N chemical shifts and 31P-15N bond lengths have been measured with solid-state NMR techniques in two inhibitors of thermolysin, carbobenzoxy-Glyp-L-Leu-L-Ala (ZGpLA) and carbobenzoxy-L-Phep-L-Leu-L-Ala (ZFpLA), both as free lithium salts and when bound to the enzyme. Binding of both inhibitors to thermolysin results in large changes in the 31P chemical shifts. These changes are more dramatic for the tighter binding inhibitor ZFpLA, where a approximately 20 ppm downfield movement of the 31P isotropic chemical shift (sigma iso) is observed. This shift is due to changes in the shift tensor elements sigma 11 and sigma 22, while sigma 33 remains essentially constant. We observed a similar pattern for ZGpLA, but only a approximately 5 ppm change occurs in sigma iso. The changes in the 15N chemical shifts for both inhibitors are small upon binding, amounting to downfield shifts of 2 and 4 ppm for ZGpLA and ZFpLA, respectively. This indicates that there are no changes in the protonation state of the 15N in either the ZFpLA- or the ZGpLA-thermolysin complex. NMR distance measurements yield a P-N bond length rP-N = 1.68 +/- 0.03 A for the tight binding inhibitor ZFpLA both in its free lithium salt form and in its thermolysin-ZFpLA complex, a distance that is much shorter than the 1.90-A distance reported by X-ray crystallography studies [Holden et al. (1987) Biochemistry 26, 8542-8553].(ABSTRACT TRUNCATED AT 250 WORDS)

  3. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F

    2003-01-01

    Scoring erosions on magnetic resonance imaging (MRI) is one method of estimating damage in patients with rheumatoid arthritis (RA), but it has limitations. The aim of this pilot study was to assess the feasibility and inter-reader reliability of computer assisted erosion volume estimation...... use without prior reader training and calibration. The optimal slice thickness was not determined...

  4. Substrate analogues for isoprenoid enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Stremler, K.E.

    1987-01-01

    Diphosphonate analogues of geranyl diphosphate, resistant to degradation by phosphatases, were found to be alternate substrates for the reaction with farnesyl diphosphate synthetase isolated from avian liver. The difluoromethane analogue was shown to be the better alternate substrate, in agreement with solvolysis results which indicate that the electronegativity of the difluoromethylene unit more closely approximates that of the normal bridging oxygen. The usefulness of the C/sub 10/ difluoro analogue, for detecting low levels of isoprenoid enzymes in the presence of high levels of phosphatase activity, was demonstrated with a cell-free preparation from lemon peel. A series of C/sub 5/ through C/sub 15/ homoallylic and allylic diphosphonates, as well as two 5'-nucleotide diphosphonates, was prepared in high overall yield using the activation-displacement sequence. Radiolabeled samples of several of the allylic diphosphonates were prepared with tritium located at C1. A series of geraniols, stereospecifically deuterated at C1, was prepared. The enantiomeric purities and absolute configurations were determined by derivatization as the mandelate esters for analysis by /sup 1/H NMR. The stereochemistry of the activation-displacement sequence was examined using C1-deuterated substrates.

  5. Structural and kinetic studies on native intermediates and an intermediate analogue in benzoylformate decarboxylase reveal a least motion mechanism with an unprecedented short-lived predecarboxylation intermediate.

    Science.gov (United States)

    Bruning, Marc; Berheide, Marco; Meyer, Danilo; Golbik, Ralph; Bartunik, Hans; Liese, Andreas; Tittmann, Kai

    2009-04-21

    The thiamin diphosphate- (ThDP-) dependent enzyme benzoylformate decarboxylase (BFDC) catalyzes the nonoxidative decarboxylation of benzoylformic acid to benzaldehyde and carbon dioxide. To date, no structural information for a cofactor-bound reaction intermediate in BFDC is available. For kinetic analysis, a chromophoric substrate analogue was employed that produces various absorbing intermediates during turnover but is a poor substrate with a 10(4)-fold compromised kcat. Here, we have analyzed the steady-state distribution of native intermediates by a combined chemical quench/1H NMR spectroscopic approach and estimated the net rate constants of elementary catalytic steps. At substrate saturation, carbonyl addition of the substrate to the cofactor (k' approximately 500 s-1 at 30 degrees C) and elimination of benzaldehyde (k' approximately 2.400 s-1) were found to be partially rate-determining for catalysis, whereas decarboxylation of the transient 2-mandelyl-ThDP intermediate is 1 order of magnitude faster with k' approximately 16.000 s-1, the largest rate constant of decarboxylation in any thiamin enzyme characterized so far. The X-ray structure of a predecarboxylation intermediate analogue was determined to 1.6 A after cocrystallization of BFDC from Pseudomonas putida with benzoylphosphonic acid methyl ester. In contrast to the free acid, for which irreversible phosphorylation of active center Ser26 was reported, the methyl ester forms a covalent adduct with ThDP with a similar configuration at C2alpha as observed for other thiamin enzymes. The C2-C2alpha bond of the intermediate analogue is out of plane by 7degrees, indicating strain. The phosphonate part of the adduct forms hydrogen bonds with Ser26 and His281, and the 1-OH group is held in place by interactions with His70 and the 4'-amino group of ThDP. The phenyl ring accommodates in a hydrophobic pocket formed by Phe464, Phe397, Leu109, and Leu403. A comparison with the previously determined structure of

  6. Solid state nuclear magnetic resonance studies of prion peptides and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Heller, Jonathan [Univ. of California, Berkeley, CA (United States)

    1997-08-01

    High-resolution structural studies using x-ray diffraction and solution nuclear magnetic resonance (NMR) are not feasible for proteins of low volubility and high tendency to aggregate. Solid state NMR (SSNMR) is in principle capable of providing structural information in such systems, however to do this efficiently and accurately, further SSNMR tools must be developed This dissertation describes the development of three new methods and their application to a biological system of interest, the priori protein (PrP).

  7. Gas phase ion/molecule reactions as studied by Fourier Transform Ion Cyclotron Resonance mass spectrometry

    International Nuclear Information System (INIS)

    Joergensen, S.I.

    1985-01-01

    The subject of this thesis is gas phase ion/molecule reactions as studied by Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry (chapter 2 contains a short description of this method). Three chapters are mainly concerned with mechanistic aspects of gas phase ion/molecule reactions. An equally important aspect of the thesis is the stability and reactivity of α-thio carbanions, dipole stabilized carbanions and homoenolate anions, dealt with in the other four chapters. (Auth.)

  8. High-pressure electron-resonance studies of electronic, magnetic, and structural phase transitions. Progress report

    International Nuclear Information System (INIS)

    Pifer, J.H.; Croft, M.C.

    1983-01-01

    Research is described in development of a high-pressure electron-resonance probe capable of operating down to 1.5 0 K temperatures. The apparatus has been used to measure the EPR of a sample of DPPH at room temperature and zero pressure. EPR has been used to measure valence field instabilities in alloy systems. Studies have been done on metal-insulator transitions at high pressure, and are briefly described

  9. Cognitive Modules Utilized for Narrative Comprehension in Children: A Functional Magnetic Resonance Imaging Study

    OpenAIRE

    Schmithorst, Vincent J.; Holland, Scott K.; Plante, Elena

    2005-01-01

    The ability to comprehend narratives constitutes an important component of human development and experience. The neural correlates of auditory narrative comprehension in children were investigated in a large-scale functional magnetic resonance imaging (fMRI) study involving 313 subjects ages 5–18. Using group Independent Component Analysis (ICA), bilateral task-related components were found comprising the primary auditory cortex, the mid-superior temporal gyrus, the hippocampus, the angular g...

  10. Luminescent and Optically Detected Magnetic Resonance Studies of CdS/PVA Nanocomposite

    Directory of Open Access Journals (Sweden)

    Galyna Yu. Rudko

    2017-02-01

    Full Text Available Abstract A series of solid nanocomposites containing CdS nanoparticles in polymeric matrix with varied conditions on the interface particle/polymer was fabricated and studied by photoluminescence (PL and optically detected magnetic resonance (ODMR methods. The results revealed interface-related features in both PL and ODMR spectra. The revealed paramagnetic centers are concluded to be involved in the processes of photo-excited carriers relaxation.

  11. Love-related changes in the brain: a resting-state functional magnetic resonance imaging study

    OpenAIRE

    Song, Hongwen; Zou, Zhiling; Kou, Juan; Liu, Yang; Yang, Lizhuang; Zilverstand, Anna; d?Oleire Uquillas, Federico; Zhang, Xiaochu

    2015-01-01

    Romantic love is a motivational state associated with a desire to enter or maintain a close relationship with a specific other person. Functional magnetic resonance imaging (fMRI) studies have found activation increases in brain regions involved in the processing of reward, motivation and emotion regulation, when romantic lovers view photographs of their partners. However, not much is known about whether romantic love affects the brain’s functional architecture during rest. In the present stu...

  12. Electron spin resonance study of the demagnetization fields of the ferromagnetic and paramagnetic films

    Directory of Open Access Journals (Sweden)

    I.I. Gimazov, Yu.I. Talanov

    2015-12-01

    Full Text Available The results of the electron spin resonance study of the La1-xCaxMnO3 manganite and the diphenyl-picrylhydrazyl thin films for the magnetic field parallel and perpendicular to plane of the films are presented. The temperature dependence of the demagnetizing field is obtained. The parameters of the Curie-Weiss law are estimated for the paramagnetic thin film.

  13. Complexation of fluoxetine hydrochloride with beta-cyclodextrin. A proton magnetic resonance study in aqueous solution.

    Science.gov (United States)

    Ali, Syed Mashhood; Asmat, Fahmeena; Maheshwari, Arti; Koketsu, Mamoru

    2005-05-01

    A proton magnetic resonance spectroscopic study in D2O of mixtures of fluoxetine hydrochloride (guest) with beta-cyclodextrin (host) revealed the existence of two different equilibria for 1:1 inclusion complexes in which -CF3 substituted ring of the guest is more tightly held by the host cavity. The structures of the two complexes have been proposed which are supported by 2DROESY spectral data. The dissociation constant was also determined.

  14. 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.)

  15. 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.)

  16. Synthesis and 2D-QSAR studies of neolignan-based diaryl-tetrahydrofuran and -furan analogues with remarkable activity against Trypanosoma cruzi and assessment of the trypanothione reductase activity.

    Science.gov (United States)

    Hartmann, Ana Paula; de Carvalho, Marcelo Rodrigues; Bernardes, Lilian Sibelle Campos; Moraes, Milena Hoehr de; de Melo, Eduardo Borges; Lopes, Carla Duque; Steindel, Mario; da Silva, João Santana; Carvalho, Ivone

    2017-11-10

    Two series of diaryl-tetrahydrofuran and -furan were synthesised and screened for anti-trypanosomal activity against trypomastigote and amastigote forms of Trypanosoma cruzi, the causative agent of Chagas disease. Based on evidence that modification of a natural product may result in a more effective drug than the natural product itself, and using known neolignan inhibitors veraguensin 1 and grandisin 2 as templates to synthesise simpler analogues, remarkable anti-trypanosomal activity and selectivity were found for 3,5-dimethoxylated diaryl-furan 5c and 2,4-dimethoxylated diaryl-tetrahydrofuran 4e analogues with EC 50 0.01 μM and EC 50 0.75 μM, respectively, the former being 260-fold more potent than veraguensin 1 and 150-fold better than benznidazole, the current available drugs for Chagas disease treatment. The ability of the most potent anti-trypanosomal compounds to penetrate LLC-MK2 cells infected with T. cruzi amastigotes parasite was tested, which revealed 4e and 5e analogues as the most effective, causing no damage to mammalian cells. In particular, the majority of the derivatives were non-toxic against mice spleen cells. 2D-QSAR studies show the rigid central core and the position of dimethoxy-aryl substituents dramatically affect the anti-trypanosomal activity. The mode of action of the most active anti-trypanosomal derivatives was investigated by exploring the anti-oxidant functions of Trypanothione reductase (TR). As a result, diarylfuran series displayed the strongest inhibition, highlighting compounds 5d-e (IC 50 19.2 and 17.7 μM) and 5f-g (IC 50 8.9 and 7.4 μM), respectively, with similar or 2-fold higher than the reference inhibitor clomipramine (IC 50 15.2 μM). Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Metabolite profile of cerebrospinal fluid in patients with spina bifida: a proton magnetic resonance spectroscopy study.

    Science.gov (United States)

    Pal, Kamalesh; Sharma, Uma; Gupta, D K; Pratap, Akshay; Jagannathan, N R

    2005-02-01

    The present study was carried out to assess the metabolic differences between cerebrospinal fluid samples of patients with spina bifida and age-matched control individuals. To study the metabolite profile of cerebrospinal fluid of patients with spina bifida using proton magnetic resonance spectroscopy, compare the levels of metabolites with controls, establish correlation of underlying neuronal dysfunction with metabolic changes in patients with spina bifida, and evaluate the potential use of this technique as an additional tool for diagnostic assessment. Combination of embryopathy, stretching, ischemia, compression, and trauma is responsible for cord dysfunction in spina bifida. Changes in neuronal metabolism leads to changes in the local milieu of cerebrospinal fluid in the cord. Change in metabolite profile of cerebrospinal fluid in spina bifida in terms of increase in products of anaerobic metabolism, nerve membrane integrity, and nerve ischemia has not yet been studied. Cerebrospinal fluid obtained from patients and control individuals were characterized using various one- and two-dimensional proton magnetic resonance spectroscopy techniques. Concentration of various metabolites was calculated using the area under the nuclear magnetic resonance peak. Statistically significantly higher levels of lactate, choline, glycerophosphocholine, acetate, and alanine in the cerebrospinal fluid of patients with spina bifida was observed compared with control individuals. Significantly higher levels of metabolites were observed in patients with spina bifida, representing a state of nerve ischemia, anaerobic metabolism, and disruption of neuronal membrane.

  18. Free Surface Waves And Interacting Bouncing Droplets: A Parametric Resonance Case Study

    KAUST Repository

    Borja, Francisco J.

    2013-07-01

    Parametric resonance is a particular type of resonance in which a parameter in a system changes with time. A particularly interesting case is when the parameter changes in a periodic way, which can lead to very intricate behavior. This di↵ers from periodic forcing in that solutions are not necessarily periodic. A system in which parametric resonance is realized is when a fluid bath is shaken periodically, which leads to an e↵ective time dependent gravitational force. This system will be used to study the onset of surface waves in a bath with non-uniform topography. A linear model for the surface waves is derived from the Euler equations in the limit of shallow waves, which includes the geometry of the bottom and surface tension. Experiments are performed to compare with the proposed model and good qualitative agreement is found. Another experiment which relies on a shaking fluid bath is that of bouncing fluid droplets. In the case of two droplets the shaking allows for a larger bouncing droplet to attract a smaller moving droplet in a way that creates a bound system. This bound system is studied and shows some analogous properties to quantum systems, so a quantum mechanical model for a two dimensional atom is studied, as well as a proposed model for the droplet-wave system in terms of equations of fluid mechanics.

  19. Incorporation of tryptophan analogues into the lantibiotic nisin.

    Science.gov (United States)

    Zhou, Liang; Shao, Jinfeng; Li, Qian; van Heel, Auke J; de Vries, Marcel P; Broos, Jaap; Kuipers, Oscar P

    2016-05-01

    Lantibiotics are posttranslationally modified peptides with efficient inhibitory activity against various Gram-positive bacteria. In addition to the original modifications, incorporation of non-canonical amino acids can render new properties and functions to lantibiotics. Nisin is the most studied lantibiotic and contains no tryptophan residues. In this study, a system was constructed to incorporate tryptophan analogues into nisin, which included the modification machinery (NisBTC) and the overexpression of tryptophanyl-tRNA synthetase (TrpRS). Tryptophan and three different tryptophan analogues (5-fluoroTrp (5FW), 5-hydroxyTrp (5HW) and 5-methylTrp (5MeW)) were successfully incorporated at four different positions of nisin (I1W, I4W, M17W and V32W). The incorporation efficiency of tryptophan analogues into mutants I1W, M17W and V32W was over 97 %, while the mutant I4W showed relatively low incorporation efficiency (69-93 %). The variants with 5FW showed relatively higher production yield, while 5MeW-containing variants showed the lowest yield. The dehydration efficiency of serines or threonines was affected by the tryptophan mutants of I4W and V32W. The affinity of the peptides for the cation-ion exchange and reverse phase chromatography columns was significantly reduced when 5HW was incorporated. The antimicrobial activity of IIW and its 5FW analogue both decreased two times compared to that of nisin, while that of its 5HW analogue decreased four times. The 5FW analogue of I4W also showed two times decreased activity than nisin. However, the mutant M17W and its 5HW analogue both showed 32 times reduced activity relative to that of nisin.

  20. 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

  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. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source.

    Science.gov (United States)

    Yang, Y; Sun, L T; Feng, Y C; Fang, X; Lu, W; Zhang, W H; Cao, Y; Zhang, X Z; Zhao, H W

    2014-08-01

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

  3. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

    International Nuclear Information System (INIS)

    Yang, Y.; Sun, L. T.; Feng, Y. C.; Fang, X.; Lu, W.; Zhang, W. H.; Cao, Y.; Zhang, X. Z.; Zhao, H. W.

    2014-01-01

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented

  4. Motor circuit computer model based on studies of functional Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    Garcia Ramo, Karla Batista; Rodriguez Rojas, Rafael; Carballo Barreda, Maylen

    2012-01-01

    The basal ganglia are a complex network of subcortical nuclei involved in motor control, sensorimotor integration, and cognitive processes. Their functioning and interaction with other cerebral structures remains as a subject of debate. The aim of the present work was to simulate the basal ganglia-thalamus-cortex circuitry interaction in motor program selection, supported by functional connectivity pattern obtained by functional nuclear magnetic resonance imaging. Determination of connections weights between neural populations by functional magnetic resonance imaging, contributed to a more realistic formulation of the model; and consequently to obtain similar results to clinical and experimental data. The network allowed to describe the participation of the basal ganglia in motor program selection and the changes in Parkinson disease. The simulation allowed to demonstrate that dopamine depletion above to 40 % leads to a loss of action selection capability, and to reflect the system adaptation ability to compensate dysfunction in Parkinson disease, coincident with experimental and clinical studies

  5. Non-conventional ordering studied by magnetic resonance in Fe-doped manganites

    International Nuclear Information System (INIS)

    Gutierrez, J.; Siruguri, V.; Barandiaran, J.M.; Pena, A.; Lezama, L.; Rojo, T.

    2006-01-01

    Coexistence of ferromagnetic (FM) and paramagnetic (PM) phases in La 0.7 Pb 0.3 (Mn 1-x Fe x )O 3 (0.1=< x=<0.3) manganites is studied by the electron spin resonance (ESR) technique. Doping with Fe gives rise to a progressive decrease both in the low-temperature magnetic moment and magnetic order temperature values. Obtained spectra show narrow resonance signals above Curie temperature that transform to asymmetric Dyson-like signals as temperature decreases. The evolution of line width with temperature shows minima that correlate directly with the obtained paramagnetic Curie temperatures. Analysis of spectra above and below magnetic order temperatures reveals features of complex PM to FM transitions and coexistence of both type of phases in a wide range of temperatures

  6. A simple strobe to study high-order harmonics and multifrequency oscillations in mechanical resonators

    International Nuclear Information System (INIS)

    Castellanos-Gomez, A

    2013-01-01

    A simple strobe setup with the potential to study higher-order eigenmodes and multifrequency oscillations in micromechanical resonators is described. It requires standard equipment, commonly found in many laboratories, and it can thus be employed for public demonstrations of mechanical resonances. Moreover, the work presented here can be used by undergraduate students and/or teachers to prepare practical work in laboratory courses at physics or engineering universities. The dynamics of a micromachined cantilever is analysed as an example. In fact, using our stroboscopic setup, the first and second flexural eigenmodes, as well as a multifrequency oscillation composed by a superposition of both modes, have been successfully filmed with a conventional optical microscope equipped with a digital camera. (paper)

  7. 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

  8. Clinical study on the primary stability of two dental implant systems with resonance frequency analysis.

    Science.gov (United States)

    Rabel, Annette; Köhler, Steffen Gerhard; Schmidt-Westhausen, Andrea Maria

    2007-09-01

    Primary stability has a major impact on the long-term success of dental implants. The aim of this study was to investigate the correlation of resonance frequency analysis (RFA) and insertion torque of self-tapping and non-self-tapping implants and their respective differences in primary stability. A group of 263 patients were treated with a total of 602 conically formed dental implants: 408 non-self-tapping Ankylos and 194 self-tapping Camlog. The maximum insertion torque during implant placement was recorded. Resonance frequency, measured as the implant stability quotient (ISQ), was assessed once immediately after insertion and twice 3 months later. Torque values of the non-self-tapping implants were significantly higher than those in the self-tapping group (p = 0.023). RFA did not show differences between the 2 groups (p = 0.956), but a correlation between ISQ values after implantation and 3 months after implant placement was measured (r = 0.712). Within the implant systems, no correlation between insertion torque and resonance frequency values could be determined (r = 0.305). Our study indicates that the ISQ values obtained from different implant systems are not comparable. The RFA does not appear suitable for the evaluation of implant stability when used as a single method. Higher insertion torque of the non-self-tapping implants appeared to confirm higher clinical primary stability.

  9. Self-consistent Study of Fast Particle Redistribution by Alfven Eigenmodes During Ion Cyclotron Resonance Heating

    International Nuclear Information System (INIS)

    Bergkvist, T.; Hellsten, T.; Johnson, T.

    2006-01-01

    Alfven eigenmodes (AEs) excited by fusion born α particles can degrade the heating efficiency of a burning plasma and throw out αs. To experimentally study the effects of excitation of AEs and the redistribution of the fast ions, ion cyclotron resonance heating (ICRH) is often used. The distribution function of thermonuclear αs in a reactor is expected to be isotropic and constantly renewed through DT reactions. The distribution function of cyclotron heated ions is strongly anisotropic, and the ICRH do not only renew the distribution function but also provide a strong decorrelation mechanism between the fast ions and the AE. Because of the sensitivity of the AE dynamics on the details of the distribution function, the location of the resonance surfaces in phase space and the extent of the overlapping resonant regions for different AEs, a self-consistent treatment of the AE excitation and the ICRH is necessary. Interactions of fast ions with AEs during ICRH has been implemented in the SELFO code. Simulations are in good agreement with the experimentally observer pitch-fork splitting and rapid damping of the AE as ICRH is turned off. The redistribution of fast ions have been studied in the presence of several driven AEs. (author)

  10. Development of new methods for the radioactive labelling of compounds useful in biology. Application to the study of digestive tract hormones and their analogues (gastrine, pentagastrine, cholecystokinine, pancreozymine, caeruleine, somatostatine)

    International Nuclear Information System (INIS)

    Girma, J.-P.

    1976-01-01

    To establish the kinetics of fixation on receptor sites, tissular distribution and metabolism of hormones, it is necessary to obtain high specific activity labelled hormones possessing biological activities identical with those of the originals. In this context two aims were pursued: hormonal peptide labelling at high specific radioactivity; research on the biological fate of the intermediate compounds involved in the preparations. This research was centred chiefly on gastrine, caeruleine, cholecystokinine and pentagastrine, structural analogues representing one of the two groups of digestive tract hormones (the gastrine family). After a brief review of present knowledge on the gastro-intestinal system; the hormones selected are situated in their biological context. Part two is devoted mainly to the study of iodine and tritium labelling of peptides and includes the adaptation of an existing method to the problem of gastrine labelling and the development of two new tritium-labelling methods, one specific to tryptophanyl residues and the other to tyrosyl residues. Finally the separation of modified hormones during the preparations offered the occasion to develop a study of the biological behavior of these analogues [fr

  11. In vivo study of experimental pneumococcal meningitis using magnetic resonance imaging

    DEFF Research Database (Denmark)

    Brandt, C.T.; Simonsen, H.; Liptrot, Matthew George

    2008-01-01

    Background: Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment...... (P water distribution, assessed by ADC, and categorization of brain 'perfusion' by cortex ΔSI(bolus) were subject to increased inter......-vivo with MRI. Increasing BBB-breakdown and ventricle size was observed in rats with meningitis whereas changes in brain water distribution were heterogeneous. MRI will be a valuable technique for future studies aiming at evaluating or optimizing adjunctive treatments. © 2008 Brandt et al; licensee Bio...

  12. Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, P.

    2017-04-15

    This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in {sup 193}Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO{sub 2} and in Ruddlesden-Popper (RP) phases of strontium iridates Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO{sub 2}, SrIrO{sub 3} and Sr{sub 2}IrO{sub 4} have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field

  13. Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

    International Nuclear Information System (INIS)

    Alexeev, P.

    2017-04-01

    This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in 193 Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO 2 and in Ruddlesden-Popper (RP) phases of strontium iridates Sr n+1 Ir n O 3n+1 (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO 2 , SrIrO 3 and Sr 2 IrO 4 have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field on Ir nucleus have been determined for

  14. Improved selectivity for Pb(II) by sulfur, selenium and tellurium analogues of 1,8-anthraquinone-18-crown-5: synthesis, spectroscopy, X-ray crystallography and computational studies.

    Science.gov (United States)

    Mariappan, Kadarkaraisamy; Alaparthi, Madhubabu; Hoffman, Mariah; Rama, Myriam Alcantar; Balasubramanian, Vinothini; John, Danielle M; Sykes, Andrew G

    2015-07-14

    We report here a series of heteroatom-substituted macrocycles containing an anthraquinone moiety as a fluorescent signaling unit and a cyclic polyheteroether chain as the receptor. Sulfur, selenium, and tellurium derivatives of 1,8-anthraquinone-18-crown-5 (1) were synthesized by reacting sodium sulfide (Na2S), sodium selenide (Na2Se) and sodium telluride (Na2Te) with 1,8-bis(2-bromoethylethyleneoxy)anthracene-9,10-dione in a 1 : 1 ratio. The optical properties of the new compounds are examined and the sulfur and selenium analogues produce an intense green emission enhancement upon association with Pb(II) in acetonitrile. Selectivity for Pb(II) is markedly improved as compared to the oxygen analogue 1 which was also competitive for Ca(II) ion. UV-Visible and luminescence titrations reveal that 2 and 3 form 1 : 1 complexes with Pb(II), confirmed by single-crystal X-ray studies where Pb(II) is complexed within the macrocycle through coordinate covalent bonds to neighboring carbonyl, ether and heteroether donor atoms. Cyclic voltammetry of 2-8 showed classical, irreversible oxidation potentials for sulfur, selenium and tellurium heteroethers in addition to two one-electron reductions for the anthraquinone carbonyl groups. DFT calculations were also conducted on 1, 2, 3, 6, 6 + Pb(II) and 6 + Mg(II) to determine the trend in energies of the HOMO and the LUMO levels along the series.

  15. Thermodynamic study of lanthanide(III) complexes with bifunctional monophosphinic acid analogues of H4dota and comparative kinetic study of yttrium(III) complexes

    Czech Academy of Sciences Publication Activity Database

    Försterová, M.; Svobodová, Ivona; Lubal, P.; Táborský, P.; Kotek, J.; Hermann, P.; Lukeš, I.

    -, č. 5 (2007), s. 535-549 ISSN 1477-9226 Institutional research plan: CEZ:AV0Z40310501 Keywords : dota analog * lanthanide(III) ions * thermodynamic study Subject RIV: BJ - Thermodynamics Impact factor: 3.212, year: 2007

  16. Study of resonant magnet exciting system for the 3 GeV proton synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Koseki, Shoichiro; Zhang, Fengqing; Watanabe, Yasuhiro; Tani, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Adachi, Toshikazu; Someya, Hirohiko [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2001-07-01

    Exciting system for magnets of the 3 GeV Proton synchrotron is under consideration. A resonant exciting system is studied, and two type of power supply are compared. One is a parallel supply that is used generally. Another is a modified series supply. Either of them uses IGBT sinusoidal converters. Capacity of the power converter of the series supply for bending magnets becomes 28.8 MVAp. This is lager more than twice compared with the parallel supply. In the other hand, the series supply has good control performance and flexibility. More study is necessary to decide finally. (author)

  17. Bipartite Medial Cuneiform: Case Report and Retrospective Review of 1000 Magnetic Resonance (MR Imaging Studies

    Directory of Open Access Journals (Sweden)

    Geraldine H. Chang

    2014-01-01

    Full Text Available Objective. To present a unique case report of a Lisfranc fracture in a patient with a bipartite medial cuneiform and to evaluate the prevalence of the bipartite medial cuneiform in a retrospective review of 1000 magnetic resonance (MR imaging studies of the foot. Materials and Methods. Case report followed by a retrospective review of 1000 MR imaging studies of the foot for the presence or absence of a bipartite medial cuneiform. Results. The incidence of the bipartite medial cuneiform is 0.1%. Conclusion. A bipartite medial cuneiform is a rare finding but one with both clinical and surgical implications.

  18. 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.

  19. 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....

  20. Incidental findings are frequent in young healthy individuals undergoing magnetic resonance imaging in brain research imaging studies

    DEFF Research Database (Denmark)

    Hartwigsen, Gesa; Siebner, Hartwig R; Deuschl, Günther

    2010-01-01

    There is an ongoing debate about how to handle incidental findings (IF) detected in healthy individuals who participate in research-driven magnetic resonance imaging (MRI) studies. There are currently no established guidelines regarding their management....