WorldWideScience

Sample records for analogue resonance studies

  1. Status of natural analogue studies

    International Nuclear Information System (INIS)

    Sekine, Keiichi

    1994-03-01

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

  2. Isobaric analogue resonances in the 56Fe(rho,γ)57Co reaction

    International Nuclear Information System (INIS)

    Elkateb, M.S.

    1974-01-01

    The excitation function for the reaction 56 Fe(rho,γ) 57 Co has been measured from 1200-3000 KeV proton energy using enriched 56 Fe targets. The resonance strength, ωsub(γ), has been determined for the studied resonances. The absence of the isobaric analogue resonance corresponding to the ground state in 57 Fe is discussed as a result of the present study. A coulomb displacement energy for 57 Co- 57 Fe of 8876 +- 6 KeV is deduced from these measurements. (author)

  3. 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

  4. /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.

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

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1996-01-01

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

  6. 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

  7. 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

  8. 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

  9. 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

  10. Study of isobaric analogue states in 64Zn through proton capture by 63Cu

    International Nuclear Information System (INIS)

    Roy, A.; Iyengar, K.V.K.; Jhingan, M.L.

    1976-01-01

    The reaction 63 Cu(p,γ) 64 Zn has been studied in the proton energy range 1650-2750 keV using the Van de Graaff accelerator at B.A.R.C., Trombay. About 100 resonances were observed in the excitation function out of which the prominent ones at Esub(p)=1731, 1882, 2036, 2099, 2312, 2352, 2421 and 2479 keV have been identified as analogues of the ground and low-lying excited states of 64 Cu. The overall energy resolution was 2.5 keV. The Coulomb displacement energy for the isobaric pair 64 Cu- 64 Zn has been deduced to be 99.63 +- MeV. The spectra of γ-rays and their angular distributions have been obtained at resonances corresponding to the analogue of the ground and first four excited states of 64 Cu. The resonance strengths and the branching ratios for the γ-decay of the resonances has been presented. The M1 width of the γ-decay from resonance at 1751 keV to the ground state of 64 Zn, (0.20 +- 0.04)eV, is in excellent agreement with the value 0.19 eV deduced from the log ft value of 5.3 of the β decay of the parent analogue

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

    OpenAIRE

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

    2012-01-01

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

  12. 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.

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

    International Nuclear Information System (INIS)

    Petit, J.C.

    1986-06-01

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

  14. 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)

  15. Measurement of Isobaric Analogue Resonances of 47Ar with the Active-Target Time Projection Chamber

    Science.gov (United States)

    Bradt, Joshua William

    While the nuclear shell model accurately describes the structure of nuclei near stability, the structure of unstable, neutron-rich nuclei is still an area of active research. One region of interest is the set of nuclei near N=28. The shell model suggests that these nuclei should be approximately spherical due to the shell gap predicted by their magic number of neutrons; however, experiments have shown that the nuclei in this region rapidly become deformed as protons are removed from the spherical 48Ca. This makes 46Ar a particularly interesting system as it lies in a transition region between 48Ca and lighter isotones that are known to be deformed. An experiment was performed at the National Superconducting Cyclotron Laboratory (NSCL) to measure resonant proton scattering on 46Ar. The resonances observed in this reaction correspond to unbound levels in the 47K intermediate state nucleus which are isobaric analogues of states in the 47Ar nucleus. By measuring the spectroscopic factors of these states in 47Ar, we gain information about the single-particle structure of this system, which is directly related to the size of the N=28 shell gap. Four resonances were observed: one corresponding to the ground state in 47Ar, one corresponding its first excited 1/2- state, and two corresponding to 1/2+ states in either 47Ar or the intermediate state nucleus. However, only a limited amount of information about these states could be recovered due to the low experimental statistics and limited angular resolution caused by pileup rejection and the inability to accurately reconstruct the beam particle track. In addition to the nuclear physics motivations, this experiment served as the radioactive beam commissioning for the Active-Target Time Projection Chamber (AT-TPC). The AT-TPC is a new gas-filled charged particle detector built at the NSCL to measure low-energy radioactive beams from the ReA3 facility. Since the gas inside the detector serves as both the tracking medium and

  16. 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)

  17. 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

  18. Decomposition of dioxin analogues and ablation study for carbon nanotube

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko

    2002-01-01

    Two application studies associated with the free electron laser are presented separately, which are the titles of 'Decomposition of Dioxin Analogues' and 'Ablation Study for Carbon Nanotube'. The decomposition of dioxin analogues by infrared (IR) laser irradiation includes the thermal destruction and multiple-photon dissociation. It is important for us to choose the highly absorbable laser wavelength for the decomposition. The thermal decomposition takes place by the irradiation of the low IR laser power. Considering the model of thermal decomposition, it is proposed that adjacent water molecules assist the decomposition of dioxin analogues in addition to the thermal decomposition by the direct laser absorption. The laser ablation study is performed for the aim of a carbon nanotube synthesis. The vapor by the ablation is weakly ionized in the power of several-hundred megawatts. The plasma internal energy is kept over an 8.5 times longer than the vacuum. The cluster was produced from the weakly ionized gas in the enclosed gas, which is composed of the rough particles in the low power laser more than the high power which is composed of the fine particles. (J.P.N.)

  19. Proton capture resonance studies

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, G.E. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Bilpuch, E.G. [Duke University, Durham, North Carolina (United States) 27708]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Bybee, C.R. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Cox, J.M.; Fittje, L.M. [Tennessee Technological University, Cookeville, Tennessee (United States) 38505]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Labonte, M.A.; Moore, E.F.; Shriner, J.D. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Shriner, J.F. Jr. [Tennessee Technological University, Cookeville, Tennessee (United States) 38505]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Vavrina, G.A. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Wallace, P.M. [Duke University, Durham, North Carolina (United States) 27708]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708

    1997-02-01

    The fluctuation properties of quantum systems now are used as a signature of quantum chaos. The analyses require data of extremely high quality. The {sup 29}Si(p,{gamma}) reaction is being used to establish a complete level scheme of {sup 30}P to study chaos and isospin breaking in this nuclide. Determination of the angular momentum J, the parity {pi}, and the isospin T from resonance capture data is considered. Special emphasis is placed on the capture angular distributions and on a geometric description of these angular distributions. {copyright} {ital 1997 American Institute of Physics.}

  20. 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.

  1. 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

  2. Positron annihilation studies on nasicon analogues containing cation vacancies

    International Nuclear Information System (INIS)

    Sreeramalu, V.; Sreepad, H.R.; Chandrashekara, A.; Ravindrachary, V.; Gopal, S.

    1990-01-01

    Positron annihilation studies were carried out on the Nasicon analogue Na 2 (La, Al)Zr(PO 4 ) 3 compound for three different concentrations (2.2, 2.8 and 5.2 by wt.%) of ZrO 2 in the nutrient. Angular correlation study of annihilated photons reveals that the defect concentration is maximum for 2.8(wt.%) of ZrO 2 . Further, positron lifetime studies indicate that the positrons are trapped at cation vacancies. Application of a two state trapping model to this system made it possible to evaluate the lifetime of positrons in the Bloch state and of positrons trapped at cation vacancies. (author). 16 refs., 4 figs

  3. 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

  4. Resonance and web structure in discrete soliton systems: the two-dimensional Toda lattice and its fully discrete and ultra-discrete analogues

    International Nuclear Information System (INIS)

    Maruno, Ken-ichi; Biondini, Gino

    2004-01-01

    We present a class of solutions of the two-dimensional Toda lattice equation, its fully discrete analogue and its ultra-discrete limit. These solutions demonstrate the existence of soliton resonance and web-like structure in discrete integrable systems such as differential-difference equations, difference equations and cellular automata (ultra-discrete equations)

  5. 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.

  6. 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

  7. Emotions and Habitability study in Moon Mars Analogue.

    Science.gov (United States)

    Mertens, Alexandre; Lia Schlacht, Irene

    Euro Moon Mars mission have been conducted by students and field researchers in the Mars Desert Research Station (MDRS) a habitat installed by the Mars Society (MS) in the Utah desert. The campaign was supported by ILEWG International Lunar Exploration Working Group, ESTEC, NASA Ames, and partners. It investigated human aspects of isolation in a Mars analogue base. The project is in line with the ILEWG which coordinates several MDRS missions, and contributes to the preparation of future Mars sample return missions. The objective is to study and improve the habitat dynamics in a closed and small environment. Investigation cover different fields as emotional, sociological and psychological aspects and a food study but also habitability aspects. The study has been conducted by asking to the crew members to perform task and fill in questionnaires before, during and after the simulation. Video recovering, pictures and heart rate counting will also be used. One of the main study subject, conducted by Bernard Rimé, concerns the sharing of emotions in an isolated environ-e ment. Another is "Mars Habitability Experiment", which responsible is Irene Schlacht, will try to determine whether humans need variability of stimuli such as it happens in the natural environment -e.g. seasonal changing -to gain efficiency, reliability and well-being. This study have been conducted from February 19 to April 19 on two crews presenting different aspects that could lead to various behaviours. The first crew is made of people from different countries that don't know each other very well. On the opposite, the second crew members have the same cultural background -they come from the same country, university -and they know each other for at least six months. This allow studying how the extreme conditions of the isolation affect the crew efficiency, creativity and sanity according to its homogeneity. Report on the science and technical results, and implications for Earth-Mars comparative stud-ies

  8. 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

  9. Uranium series disequilibrium studies at the Broubster analogue site

    International Nuclear Information System (INIS)

    Longworth, G.; Ivanovich, M.; Wilkins, M.A.

    1990-11-01

    Uranium series measurements at a natural analogue site at Broubster, Caithness have been used to investigate radionuclide migration over periods ranging from several hundred to 10 6 years. The measured values for the uranium concentration and activity values 234 U/ 238 U and 230 Th/ 234 U indicate that the geochemical system is more complicated than that originally proposed of uranium dispersion and water transport into a peat bog. There appears to be little thorium mobility although there is evidence for an appreciable fraction of thorium on the colloidal phase. (author)

  10. Uranium series disequilibrium studies at the Broubster analogue site

    International Nuclear Information System (INIS)

    Longworth, G.; Ivanovich, M.; Wilkins, M.A.

    1989-09-01

    Uranium series measurements at a natural analogue site at Broubster, Caithness have been used to investigate radionuclide migration over a period of several hundred to 10 6 years. The measured values for the uranium concentration and activity ratios 234 U/ 238 U and 230 Th/ 234 U indicate that the geochemical system is more complicated than that originally proposed of uranium dispersion and water transport into a peat bog. There appears to be little thorium mobility although there is evidence for an appreciable fraction of thorium on the colloidal phases. (author)

  11. 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

    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...... 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...

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

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

  14. 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.

  15. Structure activity relationship study of curcumin analogues toward the amyloid-beta aggregation inhibitor.

    Science.gov (United States)

    Endo, Hitoshi; Nikaido, Yuri; Nakadate, Mamiko; Ise, Satomi; Konno, Hiroyuki

    2014-12-15

    Inhibition of the amyloid β aggregation process could possibly prevent the onset of Alzheimer's disease. In this article, we report a structure-activity relationship study of curcumin analogues for anti amyloid β aggregation activity. Compound 7, the ideal amyloid β aggregation inhibitor in vitro among synthesized curcumin analogues, has not only potent anti amyloid β aggregation effects, but also water solubility more than 160 times that of curcumin. In addition, new approaches to improve water solubility of curcumin-type compounds are proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 0+ analogue state in 118Sb from 117Sn(p,nγ) reaction

    International Nuclear Information System (INIS)

    Pal, J.; Dey, C.C.; Bose, S.; Sinha, B.K.; Chatterjee, M.B.; Mahapatra, D.P.

    1996-01-01

    The analogue of the 0 + ground state in 118 Sn has been observed in the compound nucleus 118 Sb through 117 Sn(p,nγ) 117 Sb reaction. The neutron decays of this analogue resonance have been studied from the deexciting γ-rays of the residual nucleus 117 Sb. From off resonance excitation functions, spin assignments have been made to states in 117 Sb, on the basis of Hauser-Feshbach formalism. The resonance parameters of the isobaric analogue resonance have been determined, including the total, proton and neutron decay widths. (orig.)

  18. Attributions about Perpetrators and Victims of Interpersonal Abuse: Results from an Analogue Study

    Science.gov (United States)

    Langhinrichsen-Rohling, Jennifer; Shlien-Dellinger, Rania K.; Huss, Matthew T.; Kramer, Vertrie L.

    2004-01-01

    This analogue study (written vignettes and videotapes) examines the influence of victim-perpetrator relationship (spouse or acquaintance), sex of perceiver, and type of abuse (psychological vs. physical) on attributions about victims and perpetrators of domestic abuse. College student participants (73 men, 108 women) were randomly assigned to…

  19. Field studies about radionuclide migration natural analogues and faults in clays

    International Nuclear Information System (INIS)

    Williams, G.M.; Hooker, P.J.; Brightman, M.A.

    1990-01-01

    This report puts together final reports of CEC contracts about the following topics: in situ determination of the effects of organics on the mobility of radionuclides in controlled conditions of groundwater flow (Drigg site); natural analogue studies of radionuclide migration (Loch Lomond, Broubster, Needle's Eye); faults in clays: their detection and characterization (Down Ampney site)

  20. 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

  1. 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).

  2. 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

  3. 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)

  4. Synthesis of isocryptolepine analogues and their structure-activity relationship studies as antiplasmodial and antiproliferative agents.

    Science.gov (United States)

    Aroonkit, Pasuk; Thongsornkleeb, Charnsak; Tummatorn, Jumreang; Krajangsri, Suppachai; Mungthin, Mathirut; Ruchirawat, Somsak

    2015-04-13

    Novel isocryptolepine analogues have been conveniently synthesized and evaluated for antimalarial and antiproliferative activities. We have found 3-fluoro-8-bromo-isocryptolepine (1n) to have the highest activities against chloroquine-resistant K1, chloroquine-sensitive 3D7, and chloroquine- and mefloquine-resistant SKF58 and SRIV35 strains. Several fluorine-substituted analogues (1b, 1n, and 1q) also showed excellent selectivities while maintaining good to excellent activities against all four Plasmodium falciparum strains. Additionally, antiproliferative properties of isocryptolepine derivatives against HepG2, HuCCA-1, MOLT-3 and A549 cancer cell lines are reported for the first time in this study. 2-Chloroisocryptolepine (1c) and benzo-fused-2-chloroisocryptolepine (1i) showed significant bioactivities whereas several novel fluorinated compounds and 2-chloro-8-bromoisocryptolepine (1f) displayed excellent selectivities. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  5. The effects of dissociation on information processing for analogue trauma and neutral stimuli: a laboratory study.

    Science.gov (United States)

    Olsen, Shira A; Beck, J Gayle

    2012-01-01

    This study investigated the effects of high and low levels of dissociation on information processing for analogue trauma and neutral stimuli. Fifty-four undergraduate females who reported high and low levels of trait dissociation were presented with two films, one depicting traumatic events, the other containing neutral material. Participants completed a divided attention task (yielding a proxy measure of attention), as well as explicit memory (free-recall) and implicit memory (word-stem completion) tasks for both films. Results indicated that the high DES group showed less attention and had poorer recall for the analogue trauma stimuli, relative to the neutral stimuli and the low DES group. These findings suggest that high levels of trait dissociation are associated with reductions in attention and memory for analogue trauma stimuli, relative to neutral stimuli and relative to low trait dissociation. Implications for the role of cognitive factors in the etiology of negative post-trauma responses are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. 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)

  7. 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.

  8. Alpha resonant scattering for astrophysical reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  9. Alpha resonant scattering for astrophysical reaction studies

    International Nuclear Information System (INIS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-01-01

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of 7 Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the 7 Be(α,γ) reaction, and proposed a new cluster band in 11 C

  10. The effect of the pairing interaction on the energies of isobar analogue resonances in {sup 112-124}Sb and isospin admixture in {sup 100-124}Sn isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Babacan, Tahsin [Department of Physics, Celal Bayar University, Manisa (Turkey); Salamov, Djavad [Department of Physics, Anadolu University, Eskisehir (Turkey); Kuecuekbursa, Atalay [Department of Physics, Dumlupinar University, Kuetahya (Turkey); Babacan, Halil [Department of Physics, Celal Bayar University, Manisa (Turkey); Maras, Ismail [Department of Physics, Celal Bayar University, Manisa (Turkey); Aygoer, Hasan A [Department of Physics, Celal Bayar University, Manisa (Turkey); Uenal, Arslan [Department of Physics, Dumlupinar University, Kuetahya (Turkey)

    2004-06-01

    In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analogue resonances (IAR) in {sup 112-124}Sb isotopes and the isospin admixture in {sup 100-124}Sn isotopes is investigated within the framework of the proton-neutron quasi-particle random phase approximation (pnQRPA). The form of the interaction strength parameter is related to the shell-model potential by restoring the isotopic invariance of the nuclear part of the total Hamiltonian. In this respect, the isospin admixtures in the {sup 100-124}Sn isotopes are calculated, and the dependence of the differential cross section and the volume integral J{sub F} for the Sn({sup 3}He,t)Sb reactions at E({sup 3}He) =200 MeV occurring by the excitation of IAR on mass number A is examined. Our results show that the calculated value for the isospin mixing in the {sup 100}Sn isotope is in good agreement with Colo et al's estimates (4-5%), and the obtained values for the volume integral change within the error range of the value reported by Fujiwara et al (53 {+-} 5 MeV fm{sup 3}). Moreover, it is concluded that although the differential cross section of the isobar analogue resonance for the ({sup 3}He,t) reactions is not sensitive to pairing correlations between nucleons, a considerable effect on the isospin admixtures in N {approx} Z isotopes can be seen with the presence of these correlations.

  11. 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.

  12. 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.

  13. 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=<0.001; RC: 12.3 (±2.66), 4.8 (±0.94); STEMI: 12.1 (±3.33), 4.9 (±0.56); and PX: 13.5 (±2.53), 5.3 (±1.01), respectively. There could be a positive effect on crew health risk by having a physician CMO. The MJM demonstrated the ability to quantify 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.

  14. Dust grain resonant capture: A statistical study

    Science.gov (United States)

    Marzari, F.; Vanzani, V.; Weidenschilling, S. J.

    1993-01-01

    A statistical approach, based on a large number of simultaneous numerical integrations, is adopted to study the capture in external mean motion resonances with the Earth of micron size dust grains perturbed by solar radiation and wind forces. We explore the dependence of the resonant capture phenomenon on the initial eccentricity e(sub 0) and perihelion argument w(sub 0) of the dust particle orbit. The intensity of both the resonant and dissipative (Poynting-Robertson and wind drag) perturbations strongly depends on the eccentricity of the particle while the perihelion argument determines, for low inclination, the mutual geometrical configuration of the particle's orbit with respect to the Earth's orbit. We present results for three j:j+1 commensurabilities (2:3, 4:5 and 6:7) and also for particle sizes s = 15, 30 microns. This study extends our previous work on the long term orbital evolution of single dust particles trapped into resonances with the Earth.

  15. 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.

  16. Natural analogue studies of the role of colloids, natural organics and microorganisms on radionuclide transport

    International Nuclear Information System (INIS)

    McCarthy, J.F.

    1994-01-01

    Colloids may be important as a geochemical transport mechanism for radionuclides at geological repositories if they are (1) present in the groundwater, (2) stable with respect to both colloidal and chemical stabilities, (3) capable of adsorbing radionuclides, especially if the sorption is irreversible, and (4) mobile in the subsurface. The available evidence from natural analogue and other field studies relevant to these issues is reviewed, as is the potential role of mobile microorganisms (open-quotes biocolloidsclose quotes) on radionuclide migration. Studies have demonstrated that colloids are ubiquitous in groundwater, although colloid concentrations in deep, geochemically stable systems may be too low to affect radionuclide transport. However, even low colloid populations cannot be dismissed as a potential concern because colloids appear to be stable, and many radionuclides that adsorb to colloids are not readily desorbed over long periods. Field studies offer somewhat equivocal evidence concerning colloid mobility and cannot prove or disprove the significance of colloid transport in the far-field environment. Additional research is needed at new sites to properly represent a repository far-field. Performance assessment would benefit from natural analogue studies to examine colloid behavior at sites encompassing a suite of probable groundwater chemistries and that mimic the types of formations selected for radioactive waste repositories

  17. 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...

  18. Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity.

    Science.gov (United States)

    Haskell-Luevano, C; Sawyer, T K; Hendrata, S; North, C; Panahinia, L; Stum, M; Staples, D J; Castrucci, A M; Hadley, M F; Hruby, V J

    1996-01-01

    Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity: PEPTIDES 17(6) 995-1002, 1996.-Systematic analysis of fragment derivatives of the superpotent alpha-MSH analogue. Ac-Ser.Tyr-Ser-Nle4-Glu- His-DPhe7-Arg-Trp-Gly-Lys-Pro-Val-NH2(NDP-MSH), led to the discovery of tripeptide agonists possessing prolonged bioactivity in the frog skin assay. Of particular significance to this discovery was Ac-DPhe-Arg-DTrp-NH2, which was the most potent tripeptide in this series exhibiting sustained melanotropic activity. Different pharmacophore models appear to exist that are dependent on the substructure and stereochemistry of the MSH(6-9) "active site." The tripeptides Ac-DPhe-Arg-Trp-NH2, Ac-DPhe-Arg-DTrp-NH2, and Ac-DPhe-DArg-Trp-NH2 stereo-chemical combinations require only Phe7-Xaa8-Trp9, whereas Ac-DPhe-DArg-DTrp-NH2, Ac-Phe-Arg-DTrp-NH2, and Ac-Phe-Arg-Trp-NH2 additionally require His4 for minimal biological activity. Ac-DPhe-Arg-DTrp-NH2 represents a novel prototype lead for the development of MSH-based peptidomimetic agonists.

  19. Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide.

    Science.gov (United States)

    Coppola, Teresa; Varra, Michela; Oliviero, Giorgia; Galeone, Aldo; D'Isa, Giuliana; Mayol, Luciano; Morelli, Elena; Bucci, Maria-Rosaria; Vellecco, Valentina; Cirino, Giuseppe; Borbone, Nicola

    2008-09-01

    A new modified acyclic nucleoside, namely N(1)-(3-hydroxy-2-hydroxymethyl-2-methylpropyl)-thymidine, was synthesized and transformed into a building block useful for oligonucleotide (ON) automated synthesis. A series of modified thrombin binding aptamers (TBAs) in which the new acyclic nucleoside replaces, one at the time, the thymidine residues were then synthesized and characterized by UV, CD, MS, and (1)H NMR. The biological activity of the resulting TBAs was tested by Prothrombin Time assay (PT assay) and by purified fibrinogen clotting assay. From a structural point of view, nearly all the new TBA analogues show a similar behavior as the unmodified counterpart, being able to fold into a bimolecular or monomolecular quadruplex structure depending on the nature of monovalent cations (sodium or potassium) coordinated in the quadruplex core. From the comparison of structural and biological data, some important structure-activity relationships emerged, particularly when the modification involved the TT loops. In agreement with previous studies we found that the folding ability of TBA analogues is more affected by modifications involving positions 4 and 13, rather than positions 3 and 12. On the other hand, the highest anti-thrombin activities were detected for aptamers containing the modification at T13 or T12 positions, thus indicating that the effects produced by the introduction of the acyclic nucleoside on the biological activity are not tightly connected with structure stabilities. It is noteworthy that the modification at T7 produces an ON being more stable and active than the natural TBA.

  20. Natural analogue studies for the long-term safety of radioactive waste disposal. Lessons learned from the nature

    International Nuclear Information System (INIS)

    Yusa, Yasuhisa

    2002-01-01

    'Natural analogues' can be defined as the processes or materials analogous to those operating in the geological disposal system of radioactive waste. Natural analogue studies provide the only means by which long-term data can be obtained under the real natural conditions, and also the most convincing support to the long-term performance assessment of the geological disposal system. The framework of our natural analogue studies concerning the stability of the engineered barrier materials for geological disposal system of high-level radioactive waste is reviewed. One of the results is that the volcanic glass included in a clay bed did not alter during the past one million years. The Tono Uranium Deposits are studied as geochemical analogues of radioactive waste disposal in Japan. We conclude that although the deposits have been subjected to a variety of geological processes and events such as faulting, erosion and uplift/subsidence, the reducing condition has been maintained and uranium has not migrated for at least the past ten million years. Application and further development of the natural analogue studies are also discussed. (author)

  1. Uranium mineral - groundwater equilibrium at the Palmottu natural analogue study site, Finland

    International Nuclear Information System (INIS)

    Ahonen, L.; Ruskeeniemi, T.; Blomqvist, R.; Ervanne, H.; Jaakkola, T.

    1993-01-01

    The redox-potential, pH, chemical composition of fracture waters, and uraninite alteration associated with the Palmottu uranium mineralization (a natural analogue study site for radioactive waste disposal in southwestern Finland), have been studied. The data have been interpreted by means of thermodynamic calculations. The results indicate equilibrium between uraninite, ferric hydroxide and groundwater in the bedrock of the study site. Partially oxidized uraninite (UO 2 .33) and ferric hydroxide are in equilibrium with fresh, slightly acidic and oxidized water type, while primary uraninite is stable with deeper waters that have a higher pH and lower Eh. Measured Eh-pH values of groundwater cluster within a relatively narrow range indicating buffering by heterogenous redox-processes. A good consistency between measured Eh and analyzed uranium oxidation states was observed

  2. Natural decay series radionuclide studies at the Needle's Eye Natural Analogue Site, II, 1989-1991

    International Nuclear Information System (INIS)

    MacKenzie, A.B.; Whitton, A.M.; Shimmield, T.M.; Jemielita, R.A.; Scott, R.D.; Hooker, P.J.

    1991-12-01

    HMIP has a research programme investigating some naturally radioactive sites as geochemical analogues of radionuclide migration. The objective is to test thermodynamic databases and computer codes used for modelling radionuclide migration under environmental conditions. This report describes the study of transport and retardation processes affecting natural radionuclides, mainly uranium (U), in the vicinity of pitchblende veins in the cliff at Needle's Eye on the Solway Coast, SW Scotland. The natural decay series results from this study have been used to develop a well constrained geochemical model within which the codes can be tested. A conceptual geochemical model for the behaviour of U at the site was developed in stage I of the study; work in stage II is concerned with improving the information available on the U source term, groundwater chemistry, U aqueous phase specification, U retardation by fracture-lining minerals during fissure flow of groundwater, U-organic associations and loss of U from the site by stream drainage. (author)

  3. A study of tumour growth based on stoichiometric principles: a continuous model and its discrete analogue.

    Science.gov (United States)

    Saleem, M; Agrawal, Tanuja; Anees, Afzal

    2014-01-01

    In this paper, we consider a continuous mathematically tractable model and its discrete analogue for the tumour growth. The model formulation is based on stoichiometric principles considering tumour-immune cell interactions in potassium (K (+))-limited environment. Our both continuous and discrete models illustrate 'cancer immunoediting' as a dynamic process having all three phases namely elimination, equilibrium and escape. The stoichiometric principles introduced into the model allow us to study its dynamics with the variation in the total potassium in the surrounding of the tumour region. It is found that an increase in the total potassium may help the patient fight the disease for a longer period of time. This result seems to be in line with the protective role of the potassium against the risk of pancreatic cancer as has been reported by Bravi et al. [Dietary intake of selected micronutrients and risk of pancreatic cancer: An Italian case-control study, Ann. Oncol. 22 (2011), pp. 202-206].

  4. 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.

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

    KAUST Repository

    Das, Shubhajit; Samanta, Pralok Kumar; Pati, Swapan

    2015-01-01

    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.

  6. 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%.

  7. 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

  8. 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)

  9. 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.

  10. 18F-labelled N,N-dimethylamphetamine analogues for brain imaging studies

    International Nuclear Information System (INIS)

    Mathis, C.A.; Shulgin, A.T.; Yano, Y.; Sargent, T. III

    1986-01-01

    The radiochemical yields of nine N,N-dimethyl-2-(substituted phenyl)-isopropylamines (amphetamine analogues) were determined following reaction with [ 18 F]acetyl hypofluorite in a 0.1 M HCl solution at room temperature. The meta-dimethoxy substituted amphetamines gave the highest radiofluorination yields (24-32%, at EOB). Purification of the 18 F-labelled amphetamines was achieved in 10-20 min. 5- 18 F-2,4-Dimethoxy-N,N-dimethylamphetamine (5- 18 F-2,4-DNNA) was utilized to determine brain and lung uptake in rats. Positron emission tomography studies were conducted in a dog to determine the dynamic brain uptake and retention of this agent. The 5- 18 F-2,4-DNNA exhibited decreased initial uptake and more rapid loss of radioactivity in cerebral tissue compared to the iodinated homologue. (author)

  11. Magnetic resonance studies of solid polymers

    International Nuclear Information System (INIS)

    Lenk, R.

    1969-01-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [fr

  12. 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

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

    Science.gov (United States)

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

    2015-11-09

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

  14. 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)

  15. 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)

  16. 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...

  17. Electrolytic analogue study of the effect of openings and surrounds of various permeabilities on the performance of field drainage pipes

    NARCIS (Netherlands)

    Dierickx, W.

    1980-01-01

    The effect of various openings and surrounds of various permeabilities on the performance of field drainage pipes was studied by means of an electrolytic analogue. The results obtained were compared with these of analytical solutions. Rather simple and sufficiently accurate solutions exist to

  18. 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

  19. 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

  20. Magnetic resonance studies of intercalation compounds

    International Nuclear Information System (INIS)

    Miller, G.R.

    1990-01-01

    During the last three or four years, nearly tow hundred papers have been published that used NMR or ESR spectroscopy to study compounds formed by the intercalation of molecules or ions into the van der Waals gap of a layered hast compound. The host lattices have ranged from the simple, such as graphite, to the complex, such as clay. In many cases, magnetic resonance techniques now enable one to obtain quite detailed information on even fairly complex intercalated species, on the nature of the changes in the host lattice accompanying intercalation, and on the nature of the interactions between the intercalant species and the host lattice. Magnetic resonance is used in conunction with many other techniques to obtain a fuller picture of these interesting systems, but this review will limit its focus to the use of NMR and ESR techniques. (author). 51 refs

  1. 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)

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Recent outputs of the Oklo (Gabon) natural analogue study to nuclear waste disposal

    International Nuclear Information System (INIS)

    Michaud, V.; Trotignon, L.; Louvat, D.

    2000-01-01

    In the past twenty five years, the natural nuclear reactors of Oklo have been the subject of numerous detailed studies. First investigated for the physical and neutron aspects of the nuclear reaction, they were then reconsidered because they provide a unique opportunity in the world to study the containment of actinides and fission products in a geological formation over a broad timescale (two billion years). Although the sites investigated do not represent a complete analogue of a repository system, many of the processes studied (mass transfer to the surface, transport, migration / retention), the spatial extent of these processes, and the timescales involved, are compatible with processes liable to occur during the lifespan of a repository for the deep geological disposal of spent nuclear fuel. A fresh program was therefore initiated as a European Commission project in 1990, entitled''Oklo as a natural analog for transfer processes in a radioactive waste repository'- phase 7, and then extended by a phase 2 entitled Oklo, Natural Analogue - Behavior of Nuclear Reaction Products in a Natural Environment''. Researches conducted in phase I served to determine the physical conditions of the operation of the natural reactor, reconstruct the geological history of the reactor environment, and decode the behavior of actinides as well as fission products in the surrounding geological formations. Phase N, which ended in June 1999, had three main objectives: i) to assess radionuclide migration and retention processes from the reactor zones to the geological environment, ii) to define the confinement properties and long-term behavior of geological materials; iii) to test models of processes related to radionuclide migration and retention, and eventually to provide suitable data and scenarios for performance assessment of nuclear waste disposal. This paper proposes a synthesis of the main outputs of the Oklo project to the performance assessment of nuclear waste disposal, the

  7. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  8. Smectite-zeolite envelope surrounding the Tsukiyoshi uranium deposit, central Japan. A natural analogue study

    International Nuclear Information System (INIS)

    Utada, Minoru

    2003-01-01

    The Tsukiyoshi uranium deposit in Gifu Prefecture is the largest one in Japan. It is embedded in lower part of the Mizunami Group of Miocene age. Relating to the existence of this uranium deposit, the constituent minerals in sediments were studied by XRD and SEM, using many drilling cores. The most abundant authigenic mineral is smectite. The amount of smectite increases generally from upper to lower horizons, and a highly smectitized zone is situated around the uranium deposit. Smectitization predominated in mafic glassy grains of sediments, which was probably formed in early burial diagenesis. Zeolites including clinoptilolite-heulandite, mordenite, analcime, chabazite and philipsite are secondly abundant authigenic minerals. They seem to have been formed at early to late diagenetic stages. Opaline silica is rather rare. Carbonate minerals, including calcite, dolomite, siderite and rhodocrosite are common. They may be formed by diagenesis as well. Gypsum and pyrite occur in upper horizons and lower horizons, respectively. In particular, a highly smectitized zone including pyrite probably played an important role for retarding the migration of uranium and as a result keeping the uranium deposit for past one million years. This smectite-zeolite envelope surrounding the Tsukiyoshi uranium deposit is regarded as a natural analogue of the buffer materials surrounding the high-level radioactive waste repository. (author)

  9. 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.)

  10. Lobatamide C: total synthesis, stereochemical assignment, preparation of simplified analogues, and V-ATPase inhibition studies.

    Science.gov (United States)

    Shen, Ruichao; Lin, Cheng Ting; Bowman, Emma Jean; Bowman, Barry J; Porco, John A

    2003-07-02

    The total synthesis and stereochemical assignment of the potent antitumor macrolide lobatamide C, as well as synthesis of simplified lobatamide analogues, is reported. Cu(I)-mediated enamide formation methodology has been developed to prepare the highly unsaturated enamide side chain of the natural product and analogues. A key fragment coupling employs base-mediated esterification of a beta-hydroxy acid and a salicylate cyanomethyl ester. Three additional stereoisomers of lobatamide C have been prepared using related synthetic routes. The stereochemistry at C8, C11, and C15 of lobatamide C was assigned by comparison of stereoisomers and X-ray analysis of a crystalline derivative. Synthetic lobatamide C, stereoisomers, and simplified analogues have been evaluated for inhibition of bovine chromaffin granule membrane V-ATPase. The salicylate phenol, enamide NH, and ortho-substitution of the salicylate ester have been shown to be important for V-ATPase inhibitory activity.

  11. Nitroglycerin enhances the propagation of cortical spreading depression: comparative studies with sumatriptan and novel kynurenic acid analogues

    Directory of Open Access Journals (Sweden)

    Knapp L

    2016-12-01

    Full Text Available Levente Knapp,1 Bence Szita,1 Kitti Kocsis,1,2 László Vécsei,2,3 József Toldi1,2 1Department of Physiology, Anatomy, and Neuroscience, University of Szeged, 2MTA-SZTE Neuroscience Research Group, 3Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Centre, University of Szeged, Szeged, Hungary Background: The complex pathophysiology of migraine is not yet clearly understood; therefore, experimental models are essential for the investigation of the processes related to migraine headache, which include cortical spreading depression (CSD and NO donor-induced neurovascular changes. Data on the assessment of drug efficacy in these models are often limited, which prompted us to investigate a novel combined migraine model in which an effective pharmacon could be more easily identified. Materials and methods: In vivo electrophysiological experiments were performed to investigate the effect of nitroglycerin (NTG on CSD induced by KCl application. In addition, sumatriptan and newly synthesized neuroactive substances (analogues of the neuromodulator kynurenic acid [KYNA] were also tested. Results: The basic parameters of CSDs were unchanged following NTG administration; however, propagation failure was decreased compared to the controls. Sumatriptan decreased the number of CSDs, whereas propagation failure was as minimal as in the NTG group. On the other hand, both of the KYNA analogues restored the ratio of propagation to the control level. Discussion: The ratio of propagation appeared to be the indicator of the effect of NTG. This is the first study providing direct evidence that NTG influences CSD; furthermore, we observed different effects of sumatriptan and KYNA analogues. Sumatriptan changed the generation of CSDs, whereas the analogues acted on the propagation of the waves. Our experimental design overlaps with a large spectrum of processes present in migraine pathophysiology, and it can be a useful experimental model

  12. 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...

  13. Gas geochemistry of natural analogues for the studies of geological CO{sub 2} sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Voltattorni, N., E-mail: nunzia.voltattorni@ingv.it [Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata no 605, 00143 Rome (Italy); Sciarra, A. [Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata no 605, 00143 Rome (Italy); Caramanna, G. [Earth Science Dep., University ' La Sapienza' , Piazzale A. Moro no 5, 00185 Rome (Italy); Cinti, D.; Pizzino, L.; Quattrocchi, F. [Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata no 605, 00143 Rome (Italy)

    2009-07-15

    Geological sequestration of anthropogenic CO{sub 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{sub 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{sub 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{sub 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{sub 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{sub 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.

  14. 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.

  15. Magnetic resonance spectroscopy studies in migraine

    Energy Technology Data Exchange (ETDEWEB)

    Montagna, P.; Cortelli, P.; Barbiroli, B. (Inst. of Medical Pathology, Univ. of Bologna (Italy))

    1994-06-01

    The authors describe the method of [sup 31]phosphorus magnetic resonance spectroscopy and review the results when it is applied to the study of brain and muscle energy metabolism in migraine subjects. Brain energy metabolism appears to be abnormal in all major subtypes of migraine when measured both during and between attacks. Impaired energy metabolism is also documented in skeletal muscle. It is suggested that migraine is associated with a generalized disorder of mitochondrial oxidative phosphorylation and that this may constitute a threshold for the triggering of migraine attacks. 47 refs., 10 figs., 3 tabs.

  16. Maltose neopentyl glycol-3 (MNG-3) analogues for membrane protein study

    DEFF Research Database (Denmark)

    Cho, Kyung Ho; Husri, Mohd; Amin, Anowarul

    2015-01-01

    characteristics is necessary to advance MP research. Maltose neopentyl glycol-3 (MNG-3) has contributed to >10 crystal structures including G-protein coupled receptors. Here, we prepared MNG-3 analogues and characterised their properties using selected MPs. Most MNGs were superior to a conventional detergent, n...

  17. 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

  18. 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...

  19. 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)

  20. Natural analogue study of uranium deposits in Japan with special reference to the Tono uranium deposit

    International Nuclear Information System (INIS)

    Komuro, Kosei; Sasao, Eiji

    2004-05-01

    In order to verify the safety assessment for geological disposal system of high-level radioactive waste, it is necessary to evaluate properly the stability of the disposal system under natural hydrogeological environment over long period of time (ten to hundred thousands years). For the safety assessment for that in the Japanese Islands, many geological processes inherent in the tectonically active Island-Arc system should be also taken into consideration in addition to those in stable continental environment. However, it is difficult because some processes such as earthquake seem to be accidental and some are periodic or gradual over our life scale. The uranium deposits in Japan are subjected to many geological processes inherent in the tectonically active Island-Arc system. The studies on long-term preservation of uranium deposits in Japan from a natural analogue viewpoint would be expected to provide useful information for the assessment in the Japanese Islands over long period of time. In order to understand the behavior of radionuclides under natural hydrogeological environment in Japanese Islands over long period of time, the uranium deposits in Japan, especially of the Tono uranium deposit was investigated from a natural analogue viewpoint under the course of joint research program by University of Tsukuba and Japan Nuclear Cycle Development Institute. Important conclusions obtained in the present study are summarized as follows: The migration behavior of the radionuclides in the granite area is mainly controlled by the stability of original minerals in oxic condition, being due to poor reducing agents such as organic matter and sulfide minerals. In the case of hydrothermal alteration, yttrialite and fergusonite were decomposed and thorogummite was formed at the altered part, whereas zircon and allanite have not been significantly altered. In the case of weathering, autunite and torbernite were formed, probably due to the high phosphorus weathering

  1. Teratology study of derivatives of tetramethylcyclopropyl amide analogues of valproic acid in mice.

    Science.gov (United States)

    Okada, Akinobu; Onishi, Yuko; Aoki, Yoshinobu; Yagen, Boris; Sobol, Eyal; Bialer, Meir; Fujiwara, Michio

    2006-06-01

    Although valproic acid (VPA) is used extensively for treating various kinds of epilepsies, it is well known that it causes neural tube and skeletal defects in both humans and animals. The amide and urea derivatives of the tetramethylcylcopropyl VPA analogue, N-methoxy-2,2,3,3-tetramethylcyclopropanecarboxamide (N-methoxy-TMCD) and 2,2,3,3-tetramethylcyclopropanecarbonylurea (TMC-urea), were synthesized and shown to have a more potent anticonvulsant activity than VPA. The objective of this study was to investigate the teratogenic effects of these compounds in NMRI mice. Pregnant NMRI mice were given a single subcutaneous injection of either VPA, N-methoxy-TMCD, or TMC-urea at 1.8 and 3.6 mmol/kg on gestation day (GD) 8. Cesarean section was performed on GD 18. First, the live fetuses were examined to detect any external malformations, then their skeletons were double-stained for bone and cartilage and subsequently examined. Significant increases in fetal losses and neural tube defects were observed with administration of VPA at 3.6 mmol/kg when compared to the vehicle control. In contrast, upon cesarean section, there were no significant differences between either N-methoxy-TMCD or TMC-urea and the control groups for any parameter. Skeletal examination revealed that a number of the abnormalities were induced by VPA dose-dependently at high rates of incidence. These abnormalities were mainly at the axial skeletal level. However, lower frequencies of skeletal abnormality were observed with N-methoxy-TMCD and TMC-urea than with VPA. In addition to their more potent antiepileptic activity, these findings clearly indicate that N-methoxy-TMCD and TMC-urea are distinctly less teratogenic than VPA in NMRI mice.

  2. 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.

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

    Science.gov (United States)

    Ashraf, Zaman; Bais, Abdul; Manir, Md Maniruzzaman; Niazi, Umar

    2015-01-01

    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.

  4. 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.

  5. The project De Caldas International Project: An example of a large-scale radwaste isolation natural analogue study

    International Nuclear Information System (INIS)

    Shea, M.

    1995-01-01

    The proper isolation of radioactive waste is one of today's most pressing environmental issues. Research is being carried out by many countries around the world in order to answer critical and perplexing questions regarding the safe disposal of radioactive waste. Natural analogue studies are an increasingly important facet of this international research effort. The Pocos de Caldas Project represents a major effort of the international technical and scientific community towards addressing one of modern civilization's most critical environmental issues - radioactive waste isolation

  6. 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.

  7. 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

  8. [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.

  9. A comparative study on the crystal structure of bicycle analogues to the natural phytotoxin helminthosporins

    Science.gov (United States)

    Barbosa, Luiz Cláudio de Almeida; Teixeira, Robson Ricardo; Nogueira, Leonardo Brandão; Maltha, Celia Regina Alvares; Doriguetto, Antônio Carlos; Martins, Felipe Terra

    2016-02-01

    Herein we described structural insights of a series of analogues to helminthosporin phytotoxins. The key reaction used to prepare the compounds corresponded to the [3 + 4] cycloaddition between the oxyallyl cation generated from 2,4-dibromopentan-3-one and different furans. Their structures were confirmed upon IR, NMR and X-ray diffraction analyses. While bicycles 7, 8 and 9 crystallize in the centrosymmetric monoclinic space group P21/c, compound 10 was solved in the noncentrosymmetric orthorhombic space group P212121. The solid materials obtained were shown to be racemic crystals (7, 8, 9) or racemic conglomerate (10). In all compounds, there is formation of a bicycle featured by fused tetrahydropyranone and 2,5-dihydrofuran rings. They adopt chair and envelope conformations, respectively. Crystal packing of all compounds is stabilized through C-H•••O contacts. Conformational aspects as well as similarities and differences among the crystal structures of the synthesized analogues are discussed.

  10. 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)

  11. Maltose Neopentyl Glycol-3 (MNG-3) Analogues for Membrane Protein Study

    OpenAIRE

    Cho, Kyung Ho; Husri, Mohd; Amin, Anowarul; Gotfryd, Kamil; Lee, Ho Jin; Go, Juyeon; Kim, Jin Woong; Loland, Claus J.; Guan, Lan; Byrne, Bernadette; Chae, Pil Seok

    2015-01-01

    Detergents are typically used to both extract membrane proteins (MPs) from the lipid bilayer and maintain them in solution. However, MPs encapsulated in detergent micelles are often prone to denaturation and aggregation. Thus, development of novel agents with enhanced stabilization characteristics is necessary to advance MP research. Maltose neopentyl glycol-3 (MNG-3) has contributed to >10 crystal structures including G-protein coupled receptors. Here we prepared MNG-3 analogues and characte...

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. Resonance Raman study of benzyl radical

    DEFF Research Database (Denmark)

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

    1992-01-01

    Time-resolved resonance Raman spectra are obtained of benzyl radicals created by laser flash photolysis of benzylchloride and diphenylacetone in solution. The spectra are obtained in resonance with the intense 2 2A2-1 B-2(2) transition of benzyl. The strong Raman bands are assigned to totally...... 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...

  20. 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......, multiparameter, simultaneous fit of all chemical shift data obtained from the NMR titration curves yielded macroscopic pKa values as well as intrinsic chemical shift data of all differently protonated macrospecies. Analyses of the chemical shift data demonstrated strong interactions between all four sites...

  1. 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....

  2. Maltose neopentyl glycol-3 (MNG-3) analogues for membrane protein study.

    Science.gov (United States)

    Cho, Kyung Ho; Husri, Mohd; Amin, Anowarul; Gotfryd, Kamil; Lee, Ho Jin; Go, Juyeon; Kim, Jin Woong; Loland, Claus J; Guan, Lan; Byrne, Bernadette; Chae, Pil Seok

    2015-05-07

    Detergents are typically used to both extract membrane proteins (MPs) from the lipid bilayers and maintain them in solution. However, MPs encapsulated in detergent micelles are often prone to denaturation and aggregation. Thus, the development of novel agents with enhanced stabilization characteristics is necessary to advance MP research. Maltose neopentyl glycol-3 (MNG-3) has contributed to >10 crystal structures including G-protein coupled receptors. Here, we prepared MNG-3 analogues and characterised their properties using selected MPs. Most MNGs were superior to a conventional detergent, n-dodecyl-β-D-maltopyranoside (DDM), in terms of membrane protein stabilization efficacy. Interestingly, optimal stabilization was achieved with different MNG-3 analogues depending on the target MP. The origin for such detergent specificity could be explained by a novel concept: compatibility between detergent hydrophobicity and MP tendency to denature and aggregate. This set of MNGs represents viable alternatives to currently available detergents for handling MPs, and can be also used as tools to estimate MP sensitivity to denaturation and aggregation.

  3. 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)

  4. 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.

  5. 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

  6. Nuclear magnetic resonance studies of lipoproteins

    International Nuclear Information System (INIS)

    Hamilton, J.A.; Morrisett, J.D.

    1986-01-01

    Several nuclei in lipoproteins are magnetically active and are thus potential NMR probes of lipoprotein structure. Table I lists the magnetic isotopes preset in the covalent structures of the molecular constituents of lipoproteins: lipids, proteins, and carbohydrates. Every type of nucleus that is part of the endogenous structure of these molecules has at least one magnetic isotope. Each magnetic nucleus represents an intrinsic and completely nonperturbing probe (when at the natural abundance level) of local molecular motion and magnetic environment. The NMR experiment itself is also nonperturbing and nondestructive. Table I also lists for each nucleus its nuclear spin, its natural isotopic abundance, its sensitivity, and its resonance frequency at two commonly employed magnetic in the low field range (21.14 kG or 2.11 Tesla) and the other in the high field range (47.0 kG or 4.70 Tesla). Of the nuclei listed in Table I, /sup 1/H, /sup 13/C, and /sup 31/P have been the primary ones studied in lipoproteins. The general advantages and disadvantages afforded by these and other nuclei as probes of lipoprotein structure are discussed. /sup 13/C NMR spectroscopy, the method which has had the most extensive application (and probably has the greatest future potential) to lipoproteins, is treated in greatest detail, but many of the principles described apply to other nuclei as well

  7. Nuclear magnetic resonance studies of lens transparency

    International Nuclear Information System (INIS)

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ( 31 P) NMR spectroscopy was used to measure the 31 P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. 1 H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T 1 and T 2 with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T 1 and T 2 at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T 1 or T 2 , consistent with the phase separation being a low-energy process. 1 H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T 1 relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine γ-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T 1 with increasing magnetic field

  8. Selective extractions in uranium migration studies - Findings from a natural analogue study at Palmottu

    International Nuclear Information System (INIS)

    Suksi, J.; Saarinen, L.

    1994-01-01

    The usefulness of chemical extractions in the study on uranium migration is considered in the light of the results compiled at Palmottu. Chemical extractions provide a method for evaluating the mass transfer of U and its retardation in geochemical cycling. The present detailed study provides more specific information on the in situ fixation of U on rock materials. The many observations made at Palmottu show the potential of the method to fill the gap in interpretations between the natural partitioning of U in rock and the distribution of artificial tracers determined by the short-term laboratory experiments. (orig.) (20 refs., 4 figs., 1 tab.)

  9. Deep-level defects in semiconductors: studies by magnetic resonance

    International Nuclear Information System (INIS)

    Ammerlaan, C.A.J.

    1983-01-01

    This work is divided into two parts. In the first one, the following topics are discussed: paramagnetic centers in semiconductors, principles of magnetic resonance, spin-Hamiltonian, g-tensor, hyperfine interaction, magnetic resonance spectrometer. In the second part it is dicussed defects studied by magnetic resonance including vacancy and divacancy in silicon, iron in silicon, nitrogen in diamond and antisite defects in III-V compounds. (A.C.A.S.) [pt

  10. 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.

  11. 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.

  12. Multichannel approach to studying scalar resonances

    International Nuclear Information System (INIS)

    Krupa, D.; Surovtsev, Yu.S.

    1995-11-01

    The multichannel approach to the investigation of resonances is given in order to determine their quantum chromodynamical nature. The formula for the analytic continuation of the N-channel S-matrix to the unphysical sheets of the Riemann surface is given, which is a solution of the N-channel problem in that it enables a prediction of the coupled-process amplitudes on the uniformization plane of the S-matrix. The resonance representations by pairs of complex-conjugate clusters of poles and zeros on the Riemann surface are discussed. The concept of standard clusters as model-independent characteristics of the resonance is developed. 32 refs, 5 figs, 4 tabs

  13. 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

  14. 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.)

  15. 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

  16. Study on Dynamic Alignment Technology of COIL Resonator

    International Nuclear Information System (INIS)

    Xiong, M D; Zou, X J; Guo, J H; Jia, S N; Zhang, Z B

    2006-01-01

    The performance of great power chemical oxygen-iodine laser (COIL) beam is decided mostly by resonator mirror maladjustment and environment vibration. To improve the performance of light beam, an auto-alignment device is used in COIL resonator, the device can keep COIL resonator collimating by adjusting the optical components of resonator. So the coupling model of COIL resonator is present. The multivariable self study fuzzy uncoupling arithmetic and six-dimensional micro drive technology are used to design a six-input-three-output uncoupling controller, resulting in the realization of the high precision dynamic alignment. The experiments indicate that the collimating range of this system is 8 mrad, precision is 5 urad and frequency response is 20Hz, which meet the demand of resonator alignment system

  17. Invariom based electron density studies on the C/Si analogues haloperidol/sila-haloperidol and venlafaxine/sila-venlafaxine.

    Science.gov (United States)

    Luger, Peter; Dittrich, Birger; Tacke, Reinhold

    2015-09-14

    The subjects of this study are the structures and electron densities of the carbon/silicon analogues haloperidol/sila-haloperidol (1a/1b) and venlafaxine/sila-venlafaxine (2a/2b). The parent carbon compounds 1a (an antipsychotic agent) and 2a (an antidepressant) are both in clinical use. For haloperidol/sila-haloperidol, three published structures were studied in more detail: the structures of haloperidol hydrochloride (1a·HCl), haloperidol hydropicrate (1a·HPic) and sila-haloperidol hydrochloride (1b·HCl). For venlafaxine/sila-venlafaxine, the published structures of venlafaxine (2a), venlafaxine hydrochloride (2a·HCl; as orthorhombic (2a·HCl-ortho) and monoclinic polymorph (2a·HCl-mono)) and sila-venlafaxine hydrochloride (2b·HCl) were investigated. Based on these structures, the molecular electron densities were reconstructed by using the invariom formalism. They were further analysed in terms of Bader's quantum theory of atoms in molecules, electrostatic potentials mapped onto electron density isosurfaces and Hirshfeld surfaces. These studies were performed with a special emphasis on the comparison of the corresponding carbon/silicon analogues.

  18. 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

  19. 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 ...

  20. Aspartame and Its Analogues

    Science.gov (United States)

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

    1981-04-01

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

  1. 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.

  2. 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

  3. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias).

    Science.gov (United States)

    Wood, Chris M; Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J

    2013-01-01

    The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L(-1) urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L(-1) with osmotic compensation by 175 mmol L(-1) mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L(-1)) to those of urea (175 mmol L(-1)), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  4. A perfusion study of the handling of urea and urea analogues by the gills of the dogfish shark (Squalus acanthias

    Directory of Open Access Journals (Sweden)

    Chris M. Wood

    2013-02-01

    Full Text Available The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L−1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L−1 with osmotic compensation by 175 mmol L−1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L−1 to those of urea (175 mmol L−1, urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.

  5. 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

  6. 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

  7. 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

  8. Breast cancer imaging using radiolabelled somatostatin analogues

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  9. 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.)

  10. Dillapiole as antileishmanial agent: discovery, cytotoxic activity and preliminary SAR studies of dillapiole analogues.

    Science.gov (United States)

    Parise-Filho, Roberto; Pasqualoto, Kerly Fernanda Mesquita; Magri, Fátima Maria Motter; Ferreira, Adilson Kleber; da Silva, Bárbara Athayde Vaz Galvão; Damião, Mariana Celestina Frojuello Costa Bernstorff; Tavares, Maurício Temotheo; Azevedo, Ricardo Alexandre; Auada, Aline Vivian Vatti; Polli, Michelle Carneiro; Brandt, Carlos Alberto

    2012-12-01

    In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structure-activity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC(50)  = 69.3 µM) and Leishmania brasiliensis (IC(50)  = 59.4 µM) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC(50)  = 99.9 µM for L. amazonensis and IC(50)  = 90.5 µM for L. braziliensis) and 3 (IC(50)  = 122.9 µM for L. amazonensis and IC(50)  = 109.8 µM for L. brasiliensis) were less active than dillapiole (1). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Comparative study of the interactions between bisphenol-A and its endocrine disrupting analogues with bovine serum albumin using multi-spectroscopic and molecular docking studies.

    Science.gov (United States)

    Ikhlas, Shoeb; Usman, Afia; Ahmad, Masood

    2018-04-24

    Interaction studies of bisphenol analogues; biphenol-A (BPA), bisphenol-B (BPB), and bisphenol-F (BPF) with bovine serum albumin (BSA) were performed using multi-spectroscopic and molecular docking studies at the protein level. The mechanism of binding of bisphenols with BSA was dynamic in nature. SDS refolding experiments demonstrated no stabilization of BSA structure denatured by BPB, however, BSA denatured by BPA and BPF was found to get stabilized. Also, CD spectra and molecular docking studies revealed that BPB bound more strongly and induced more conformational changes in BSA in comparison to BPA. Hence, this study throws light on the replacement of BPA by its analogues and whether the replacement is associated with a possible risk, raising a doubt that perhaps BPB is not a good substitute of BPA.

  12. 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...

  13. 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).

  14. 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

  15. Studies of ATM Kinase Activity Using Engineered ATM Sensitive to ATP Analogues (ATM-AS).

    Science.gov (United States)

    Enari, Masato; Matsushima-Hibiya, Yuko; Miyazaki, Makoto; Otomo, Ryo

    2017-01-01

    Ataxia-telangiectasia mutated (ATM) protein is a member of the phosphatidylinositol 3-phosphate kinase (PI3-K)-related protein kinase (PIKK) family and is implicated in the initiation of signaling pathways following DNA double strand breaks (DSBs) elicited by exposure to ionizing irradiation (IR) or radiomimetic compounds. Loss of function of the ATM gene product results in the human genetic disorder ataxia-telangiectasia (A-T) characterized by neurodegeneration, immunodeficiency, genomic instability, and cancer predisposition. In response to DSBs, ATM is activated and phosphorylates Ser/Thr-Gln (S/T-Q) sequences on numerous proteins participating in DNA-damage responses. Among these proteins, phosphorylation of the tumor suppressor p53 at Ser15 is known as a target for ATM, which leads to the dissociation of MDM2, an E3 ubiquitin ligase, from p53 to prevent MDM2-dependent p53 degradation. Ser46 on p53 is phosphorylated in response to DSBs and contributes to the preferential transactivation of pro-apoptotic genes, such as p53AIP1, Noxa, and PUMA, to prevent tumor formation. Our group have shown that not only ATM preferentially phosphorylates S/T-Q sequences, but also Ser46, which is a noncanonical site with an S-P sequence for ATM. Ser46 on p53 is directly phosphorylated by ATM in a p53 conformation-dependent manner using the ATP analogue-accepting ATM mutant (ATM-AS) system. This protocol summarizes an approach to identify direct numerous targets for ATM kinase and is used to elucidate ATM signaling pathways in the DNA damage responses.

  16. Geochemical behaviour of uranium in sedimentary formations: insights from a natural analogue study - 16340

    International Nuclear Information System (INIS)

    Noseck, Ulrich; Brasser, Thomas; Havlova, Vaclava; Cervinka, Radek; Suksi, Juhani

    2009-01-01

    Groundwater data from the natural analogue site Ruprechtov have been evaluated with special emphasis on the uranium behaviour in the so-called uranium-rich clay/lignite horizon. In this horizon in-situ Eh-values in the range of -160 to -280 mV seem to be determined by the SO 4 2- /HS - couple. Under these conditions U(IV) is expected to be the preferential redox state in solution. However, on-site measurements in groundwater from the clay/lignite horizon show only a fraction of about 20 % occurring in the reduced state U(IV). Thermodynamic calculations reveal that the high CO 2 partial pressure in the clay/lignite horizon can stabilise hexavalent uranium, which explains the occurrence of U(VI). The calculations also indicate that the low uranium concentrations in the range between 0.2 and 2.1 μg/l are controlled by amorphous UO 2 and/or the U(IV) phosphate mineral ningyoite. This confirms the findings from previous work that the uranium (IV) mineral phases are long-term stable under the reducing conditions in the clay/lignite horizon without any signatures for uranium mobilisation. It supports the current knowledge of the geological development of the site and is also another important indication for the long-term stability of the sedimentary system itself, namely of the reducing geochemical conditions in the near-surface (30 m to 60 m deep) clay/lignite horizon. Further work with respect to the impact of changes in redox conditions on the uranium speciation is on the way. (authors)

  17. 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.

  18. 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'

  19. Synthesis of iodine-123 labelled analogues of imidazenil and ethyl-imidazenil for studying benzodiazepine receptors using SPECT

    International Nuclear Information System (INIS)

    Katsifis, A.; Mattner, F.; Dikic, B.; Najdovski, L.; Kassiou, M.

    1996-01-01

    The [ 123 I]iodinated analogues of the benzodiazepine receptor partial agonist imidazenil and N-ethyl imidazenil have been synthesised for the study of the central benzodiazepine receptor using SPECT. [ 123 I]Iodomidazenil and [ 123 I]N-ethyliodoimidazenil were prepared by nucleophilic bromine-iodine exchange in acetic acid at 150 o . The products were purified by semi-preparative reverse-phase HPLC with average radiochemical yields of 80% in a total synthesis time of 80 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%. Alternatively, iododestannylation reactions via the trimethyltin precursors with Na[ 123 I] in the presence of Chloramine-T or peracetic acid resulted in yields of only 20-25% with the bulk of activity being lost as volatile methyl [ 123 I]iodide. (author)

  20. 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.

  1. 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.

  2. Synthesis, anticancer activity and molecular docking studies on a series of heterocyclic trans-cyanocombretastatin analogues as antitubulin agents.

    Science.gov (United States)

    Penthala, Narsimha Reddy; Zong, Hongliang; Ketkar, Amit; Madadi, Nikhil Reddy; Janganati, Venumadav; Eoff, Robert L; Guzman, Monica L; Crooks, Peter A

    2015-03-06

    A series of heterocyclic combretastatin analogues have been synthesized and evaluated for their anticancer activity against a panel of 60 human cancer cell lines. The most potent compounds were two 3,4,5-trimethoxy phenyl analogues containing either an (Z)-indol-2-yl (8) or (Z)-benzo[b]furan-2-yl (12) moiety; these compounds exhibited GI50 values of Compounds 8, and 12 and two previously reported compounds in the same structural class, i.e. 29 and 31, also showed potent anti-leukemic activity against leukemia MV4-11 cell lines with LD50 values = 44 nM, 47 nM, 18 nM, and 180 nM, respectively. From the NCI anti-cancer screening results and the data from the in vitro toxicity screening on cultured AML cells, seven compounds: 8, 12, 21, 23, 25, 29 and 31 were screened for their in vitro inhibitory activity on tubulin polymerization in MV4-11 AML cells; at 50 nM, 8 and 29 inhibited polymerization of tubulin by >50%. The binding modes of the three most active compounds (8, 12 and 29) to tubulin were also investigated utilizing molecular docking studies. All three molecules were observed to bind in the same hydrophobic pocket at the interface of α- and β-tubulin that is occupied by colchicine, and were stabilized by van der Waals' interactions with surrounding tubulin residues. The results from the tubulin polymerization and molecular docking studies indicate that compounds 8 and 29 are the most potent anti-leukemic compounds in this structural class, and are considered lead compounds for further development as anti-leukemic drugs. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. 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)

    1993-12-31

    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

  4. 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

  5. A differential scanning calorimetric study of the effects of metal ions, substrate/product, substrate analogues and chaotropic anions on the thermal denaturation of yeast enolase 1.

    Science.gov (United States)

    Brewer, J M; Wampler, J E

    2001-03-14

    The thermal denaturation of yeast enolase 1 was studied by differential scanning calorimetry (DSC) under conditions of subunit association/dissociation, enzymatic activity or substrate binding without turnover and substrate analogue binding. Subunit association stabilizes the enzyme, that is, the enzyme dissociates before denaturing. The conformational change produced by conformational metal ion binding increases thermal stability by reducing subunit dissociation. 'Substrate' or analogue binding additionally stabilizes the enzyme, irrespective of whether turnover is occurring, perhaps in part by the same mechanism. More strongly bound metal ions also stabilize the enzyme more, which we interpret as consistent with metal ion loss before denaturation, though possibly the denaturation pathway is different in the absence of metal ion. We suggest that some of the stabilization by 'substrate' and analogue binding is owing to the closure of moveable polypeptide loops about the active site, producing a more 'closed' and hence thermostable conformation.

  6. 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.

  7. 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.

  8. Ferromagnetic resonance studies of lunar core stratigraphy

    Science.gov (United States)

    Housley, R. M.; Cirlin, E. H.; Goldberg, I. B.; Crowe, H.

    1976-01-01

    We first review the evidence which links the characteristic ferromagnetic resonance observed in lunar fines samples with agglutinatic glass produced primarily by micrometeorite impacts and present new results on Apollo 15, 16, and 17 breccias which support this link by showing that only regolith breccias contribute significantly to the characteristic FMR intensity. We then provide a calibration of the amount of Fe metal in the form of uniformly magnetized spheres required to give our observed FMR intensities and discuss the theoretical magnetic behavior to be expected of Fe spheres as a function of size. Finally, we present FMR results on samples from every 5 mm interval in the core segments 60003, 60009, and 70009. These results lead us to suggest: (1) that secondary mixing may generally be extensive during regolith deposition so that buried regolith surfaces are hard to recognize or define; and (2) that local grinding of rocks and pebbles during deposition may lead to short scale fluctuations in grain size, composition, and apparent exposure age of samples.

  9. Harmony of computational quantum chemistry and experimental chemistry: Comprehensive DFT studies, microsynthesis, and characterization of mustard gas polysulfide analogues

    Science.gov (United States)

    Saeidian, Hamid; Faraz, Sajjad Mousavi; Mirjafary, Zohreh; Babri, Mehran

    2018-05-01

    After microsynthesis, structures of mustard gas polysulfide analogues were characterized using electron impact (EI) mass spectrometry. General EI fragmentation pathways for such compounds are proposed. The structure of sulfur mustard (HD) and its two other polysulfide analogues have been examined through B3LYP/6-311++G(2d, 2p) calculations. Geometrical analysis of HD shows that the calculated bond distances are satisfactorily comparable with experimental results. Calculated NMR chemical shifts for HD also were compared with experimental data, indicating good agreement both for 1H and 13C atoms. The vibrational frequencies of HD and polysulfide analogues have been precisely assigned. At the end, based on visual inspection of lowest unoccupied molecular orbitals and the relative difference in the total energies of their episulfonium ions, relative reactivity of HD and its polysulfide analogues were investigated.

  10. 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.

  11. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  12. 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.

  13. Experimental study on moonpool resonance of offshore floating structure

    Directory of Open Access Journals (Sweden)

    Seung-Ho Yang

    2013-06-01

    Full Text Available Offshore floating structures have so-called moonpool in the centre area for the purpose of drilling, installation of subsea structures, recovery of Remotely-Operated Vehicle (ROV and divers. However, this vertical opening has an effect on the operating performance of floating offshore structure in the vicinity of moonpool resonance frequency; piston mode and sloshing mode. Experimental study based on model test was carried out. Moonpool resonance of floating offshore structure on fixed condition and motion free condition were investigated. And, the effect of cofferdam which is representative inner structure inside moonpool was examined. Model test results showed that Molin's theoretical formula can predict moonpool resonance on fixed condition quite accurately. However, motion free condition has higher resonance frequency when it is compared with that of motion fixed. The installation of cofferdam moves resonance frequency to higher region and also generates secondary resonance at lower frequency. Furthermore, it was found that cofferdam was the cause of generating waves in the longitudinal direction when the vessel was in beam sea.

  14. Experimental study of resonance crossing with a Paul trap

    Directory of Open Access Journals (Sweden)

    H. Takeuchi

    2012-07-01

    Full Text Available The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands. Assuming a nonscaling fixed field alternating gradient accelerator composed of many identical FODO cells, we measure how much ion losses occur under diverse conditions. It is experimentally and numerically demonstrated that too slow resonance crossing leads to significant ion losses as expected. Particular attention must be paid to the linear coherent resonance excited at a quarter-integer tune. When the beam intensity is high, this type of linear stop band can seriously affect the beam quality even for rather fast resonance crossing. A scaling law is given of the emittance growth caused by the quarter-integer resonance crossing.

  15. Computational study of the activity, dynamics, energetics and conformations of insulin analogues using molecular dynamics simulations: Application to hyperinsulinemia and the critical residue B26

    Directory of Open Access Journals (Sweden)

    Anastasios Papaioannou

    2017-09-01

    Full Text Available Due to the increasing prevalence of diabetes, finding therapeutic analogues for insulin has become an urgent issue. While many experimental studies have been performed towards this end, they have limited scope to examine all aspects of the effect of a mutation. Computational studies can help to overcome these limitations, however, relatively few studies that focus on insulin analogues have been performed to date. Here, we present a comprehensive computational study of insulin analogues—three mutant insulins that have been identified with hyperinsulinemia and three mutations on the critical B26 residue that exhibit similar binding affinity to the insulin receptor—using molecular dynamics simulations with the aim of predicting how mutations of insulin affect its activity, dynamics, energetics and conformations. The time evolution of the conformers is studied in long simulations. The probability density function and potential of mean force calculations are performed on each insulin analogue to unravel the effect of mutations on the dynamics and energetics of insulin activation. Our conformational study can decrypt the key features and molecular mechanisms that are responsible for an enhanced or reduced activity of an insulin analogue. We find two key results: 1 hyperinsulinemia may be due to the drastically reduced activity (and binding affinity of the mutant insulins. 2 Y26BS and Y26BE are promising therapeutic candidates for insulin as they are more active than WT-insulin. The analysis in this work can be readily applied to any set of mutations on insulin to guide development of more effective therapeutic analogues.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Structure-activity relationship and mechanism of action studies of manzamine analogues for the control of neuroinflammation and cerebral infections.

    Science.gov (United States)

    Peng, Jiangnan; Kudrimoti, Sucheta; Prasanna, Sivaprakasam; Odde, Srinivas; Doerksen, Robert J; Pennaka, Hari K; Choo, Yeun-Mun; Rao, Karumanchi V; Tekwani, Babu L; Madgula, Vamsi; Khan, Shabana I; Wang, Bin; Mayer, Alejandro M S; Jacob, Melissa R; Tu, Lan Chun; Gertsch, Jürg; Hamann, Mark T

    2010-01-14

    Structure-activity relationship studies were carried out by chemical modification of manzamine A (1), 8-hydroxymanzamine A (2), manzamine F (14), and ircinal isolated from the sponge Acanthostrongylophora. The derived analogues were evaluated for antimalarial, antimicrobial, and antineuroinflammatory activities. Several modified products exhibited potent and improved in vitro antineuroinflammatory, antimicrobial, and antimalarial activity. 1 showed improved activity against malaria compared to chloroquine in both multi- and single-dose in vivo experiments. The significant antimalarial potential was revealed by a 100% cure rate of malaria in mice with one administration of 100 mg/kg of 1. The potent antineuroinflammatory activity of the manzamines will provide great benefit for the prevention and treatment of cerebral infections (e.g., Cryptococcus and Plasmodium). In addition, 1 was shown to permeate across the blood-brain barrier (BBB) in an in vitro model using a MDR-MDCK monolayer. Docking studies support that 2 binds to the ATP-noncompetitive pocket of glycogen synthesis kinase-3beta (GSK-3beta), which is a putative target of manzamines. On the basis of the results presented here, it will be possible to initiate rational drug design efforts around this natural product scaffold for the treatment of several different diseases.

  4. 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

  5. Subcutaneous insulin absorption explained by insulin's physicochemical properties. Evidence from absorption studies of soluble human insulin and insulin analogues in humans.

    Science.gov (United States)

    Kang, S; Brange, J; Burch, A; Vølund, A; Owens, D R

    1991-11-01

    To study the influence of molecular aggregation on rates of subcutaneous insulin absorption and to attempt to elucidate the mechanism of absorption of conventional soluble human insulin in humans. Seven healthy male volunteers aged 22-43 yr and not receiving any drugs comprised the study. This study consisted of a single-blind randomized comparison of equimolar dosages of 125I-labeled forms of soluble hexameric 2 Zn2+ human insulin and human insulin analogues with differing association states at pharmaceutical concentrations (AspB10, dimeric; AspB28, mixture of monomers and dimers; AspB9, GluB27, monomeric). After an overnight fast and a basal period of 1 h, 0.6 nmol/kg of either 125I-labeled human soluble insulin (Actrapid HM U-100) or 125I-labeled analogue was injected subcutaneously on 4 separate days 1 wk apart. Absorption was assessed by measurement of residual radioactivity at the injection site by external gamma-counting. The mean +/- SE initial fractional disappearance rates for the four preparations were 20.7 +/- 1.9 (hexameric soluble human insulin), 44.4 +/- 2.5 (dimeric analogue AspB10), 50.6 +/- 3.9 (analogue AspB28), and 67.4 +/- 7.4%/h (monomeric analogue AspB9, GluB27). Absorption of the dimeric analogue was significantly faster than that of hexameric human insulin (P less than 0.001); absorption of monomeric insulin analogue AspB9, GluB27 was significantly faster than that of dimeric analogue AspB10 (P less than 0.01). There was an inverse linear correlation between association state and the initial fractional disappearance rates (r = -0.98, P less than 0.02). Analysis of the disappearance data on a log linear scale showed that only the monomeric analogue had a monoexponential course throughout. Two phases in the rates of absorption were identified for the dimer and three for hexameric human insulin. The fractional disappearance rates (%/h) calculated by log linear regression analysis were monomer 73.3 +/- 6.8; dimer 44.4 +/- 2.5 from 0 to 2 h and

  6. Study of γ-irradiated lithographic polymers by electron spin resonance and electron nuclear double resonance

    International Nuclear Information System (INIS)

    Schlick, S.; Kevan, L.

    1982-01-01

    The room temperature gamma irradiation degradation of the lithographic polymers, poly(methylmethacrylate) (PMMA), poly(methyl-α-chloroacrylate) (PMCA), poly(methyl-α-fluoroacrylate) (PMFA), and poly(methylacrylonitrile) (PMCN), have been studied by electron spin resonance and electron nuclear double resonance (ENDOR) to assess their molecular degradation processes of relevance to electron beam lithography. Two classes of radicals are found, chain radicals and chain scission radicals. PMMA and PMCA mainly form chain scission radicals consistent with degradation while for PMCN the resolution is poorer, and this is only probable. PMFA forms mainly chain radicals consistent with predominant crosslinking. The total radical yield is greatest in PMCA and PMCN. ENDOR is used to assess the compactness of the radiation degradation region for PMMA and PMCA and hence the potential resolution of the resist; this appears to be about the same for these methacrylate polymers

  7. Magnetic resonance studies of solid polymers; Etude des polymeres solides par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [French] Cette etude est une recherche bibliographique sur l'application de la resonance magnetique nucleaire (RMN) aux polymeres solides. Dans la premiere partie theorique on discute les elements de la theorie de RMN, necessaires pour l'etude des proprietes des polymeres solides: la methode des moments, la relaxation nucleaire et la distribution des temps de correlation. La deuxieme partie presente les resultats des experiences. (auteur)

  8. Basic investigation and analysis for preferred host rocks and natural analogue study area with reference to high level radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jeong Ryul; Park, J. K.; Hwang, D. H.; Lee, J. H.; Yun, H. S.; Kim, D. Y.; Park, H. S.; Koo, S. B.; Cho, J. D.; Kim, K. E. [Korea Inst. of Geology, Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    The purpose of this study is basic investigation and analysis for preferred host rocks and natural analogue study area to develope underground disposal technique of high level radioactive waste in future. The study has been done for the crystalline rocks(especially granitic rocks) with emphasis of abandoned metallic mines and uranium ore deposits, and for the geological structure study by using gravity and aeromagnetic data. 138 refs., 54 tabs., 130 figs. (author)

  9. 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

  10. Attachment Anxiety, Verbal Immediacy, and Blood Pressure: Results from a Laboratory-Analogue Study Following Marital Separation

    Science.gov (United States)

    Lee, Lauren A.; Sbarra, David A.; Mason, Ashley E.; Law, Rita W.

    2011-01-01

    Marital separation and divorce increase risk for all-cause morbidity and mortality. Using a laboratory analogue paradigm, the present study examined attachment anxiety, language use, and blood pressure (BP) reactivity among 119 (n = 43 men, 76 women) recently separated adults who were asked to mentally reflect on their relationship history and separation experience. We created a language use composite of verbal immediacy from participants’ stream-of-consciousness recordings about their separation experience as a behavioral index of attachment-related hyperactivation. Verbal immediacy moderated the association between attachment anxiety and BP at the beginning of a divorce-specific activation task. Participants reporting high attachment anxiety who discussed their separation in a first-person, present-oriented and highly engaged manner evidenced the highest levels of BP at the start of the divorce-specific task. Results provide a deeper understanding of the association between marital dissolution and health and suggest that verbal immediacy may be a useful behavioral index of hyperactivating coping strategies. PMID:21647240

  11. Integrated planning of laboratory, in-situ, modelling and natural analogue studies in the Swiss radioactive waste management programme

    International Nuclear Information System (INIS)

    McKinley, I.G.; Zuidema, P.

    2001-01-01

    After more than 25 years of development, the Swiss radioactive waste management programme has a well established disposal strategy supported by an integrated R and D infrastructure. The process of implementation of repository projects is constrained by political factors, but a dynamic R and D programme is strongly guided by periodic integrated performance assessments and includes: Experimental studies in conventional and ''hot'' laboratories; Projects in underground test facilities and field test sites; Model development verification and validation; Natural and archaeological analogue projects. R and D in the Swiss national programme focuses on filling remaining gaps in system understanding, enhancing confidence via validation and demonstration projects, system optimisation and maintaining state of the art technical capacity in key areas. Increasingly, such work is carried out in collaboration with partner national waste management organisations. In addition, The National Cooperative for the Disposal of Radioactive Waste (Nagra) provides support services to developing programmes - which allows Nagra to widen its range of experience while providing attractive access to a knowledge base accumulated at a cost of over 750 M CHF. (author)

  12. Attachment Anxiety, Verbal Immediacy, and Blood Pressure: Results from a Laboratory-Analogue Study Following Marital Separation.

    Science.gov (United States)

    Lee, Lauren A; Sbarra, David A; Mason, Ashley E; Law, Rita W

    2011-06-01

    Marital separation and divorce increase risk for all-cause morbidity and mortality. Using a laboratory analogue paradigm, the present study examined attachment anxiety, language use, and blood pressure (BP) reactivity among 119 (n = 43 men, 76 women) recently separated adults who were asked to mentally reflect on their relationship history and separation experience. We created a language use composite of verbal immediacy from participants' stream-of-consciousness recordings about their separation experience as a behavioral index of attachment-related hyperactivation. Verbal immediacy moderated the association between attachment anxiety and BP at the beginning of a divorce-specific activation task. Participants reporting high attachment anxiety who discussed their separation in a first-person, present-oriented and highly engaged manner evidenced the highest levels of BP at the start of the divorce-specific task. Results provide a deeper understanding of the association between marital dissolution and health and suggest that verbal immediacy may be a useful behavioral index of hyperactivating coping strategies.

  13. 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.

  14. Hydrogen atom abstraction of 3,5-disubstituted analogues of paracetamol by horseradish peroxidase and cytochrome P450

    NARCIS (Netherlands)

    Bessems, J.G.M.; Groot, M.J. de; Baede, E.J.; Koppele, J.M. te; Vermeulen, N.P.E.

    1998-01-01

    1. The formation of free radicals during enzyme catalysed oxidation of eight 3,5-disubstituted analogues of paracetamol (PAR) has been studied. A simple peroxidase system as well as cytochrome P450-containing systems were used. Radicals were detected by electron spin resonance (ESR) on incubation of

  15. Nuclear magnetic resonance studies at high pressures

    International Nuclear Information System (INIS)

    Jonas, J.

    1980-01-01

    Recent advances in the field of NMR spectroscopy at high pressure are reviewed. After a brief discussion of two novel experimental techniques, the main focus of this review is on several specific studies which illustrate the versatility and power of this high pressure field. Experimental aspects of NMR measurements at high pressure and high temperature and the techniques for the high resolution NMR spectroscopy at high pressure are discussed. An overview of NMR studies of the dynamic structure of simple polyatomic liquids and hydrogen bonded liquids is followed by a discussion of high resolution spectroscopy at high pressure. Examples of NMR studies of disordered organic solids and polymers conclude the review. (author)

  16. A functional magnetic resonance imaging study

    Indian Academy of Sciences (India)

    MADU

    systems and ultra fast imaging techniques, such as echo planar imaging (EPI ) ... is used to understand brain organization, assessing of neurological status, and ..... J C 1998 Functional MRI studies of motor recovery after stroke;. NeuroImage 7 ...

  17. Studies on inclusive meson resonance and particle production

    International Nuclear Information System (INIS)

    Saarikko, Heimo

    1978-01-01

    Production and decay of meson resonances are studied in medium energy meson-proton collisions. Strong evidence is found that hadronic collisions are dominated by resonance production. Especially the vector mesons have often large inclusive cross sections, typically of the order of few millibarns at the present energies. In all, a majority of pions and kaons appear to be decay products of resonances or other unstable particles. The detailed kinematics of the parent resonance's decays is found to play an important role in determining inclusive pion spectra. The squared transverse momentum distributions of hadrons heavier than the pion appear to have in common an exponential behaviour, with a universal slope for the esponential fall-off. The observed vector meson yields suggest that only a small fraction of the direct lepton production observed at large transverse momentum in nucleon-nucleon interactions is accounted for by the ''old'' vector mesons. An attempt has been made to separate out the central production and fragmentation components of the meson production. Both the central production and the fragmentation of the incoming meson are found to be important mechanisms in the non-strange meson production whereas the central production of strange meson resonances is rare at our energies. The ratios of the observed meson yields are found to be generally in good agreement with a simple quark-counting model. (author)

  18. 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

  19. CO2 Capture with Enzyme Synthetic Analogue

    Energy Technology Data Exchange (ETDEWEB)

    Cordatos, Harry

    2010-11-08

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

  20. 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.)

  1. 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...... of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior of the magnetic...

  2. Flow chemistry kinetic studies reveal reaction conditions for ready access to unsymmetrical trehalose analogues.

    Science.gov (United States)

    Patel, Mitul K; Davis, Benjamin G

    2010-10-07

    Monofunctionalization of trehalose, a widely-found symmetric plant disaccharide, was studied in a microreactor to give valuable kinetic insights that have allowed improvements in desymmetrization yields and the development of a reaction sequence for large scale monofunctionalizations that allow access to probes of trehalose's biological function.

  3. 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...

  4. Natural analogue study on trace element migration in geological formation at Horonobe area, Japan

    International Nuclear Information System (INIS)

    Iwatsuki, Teruki; Ishii, Eiichi; Mizuno, Takashi; Honda, T.

    2010-01-01

    Usefulness of natural analog to study radionuclide transport models for deep geological repositories for high-level and long lived radioactive wastes is widely recognized. As the groundwater flow in the Horonobe area, Hokkaido, Japan is known to be stationary with neutral pH value and of reductive nature for a long-term, the authors began natural analog study by observing atomic distribution of such trace elements as rare earths, uranium, and thorium in carbonate nodules and veins of uranium minerals from several selected faults (Wakkanai F., Ketoi F., etc) in the area with the use of XED, XRF, and ICP-MS. The results give important information as to the maintainability of the rocks for trace elements and help to provide confidence in the safety assessment in the long term. (S. Ohno)

  5. Astrobiology in the Field: Studying Mars by Analogue Expeditions on Earth

    Science.gov (United States)

    Conrad, Pamela G.

    2011-01-01

    We will present a strategy for how one prepares to engage in fieldwork on another planets by practicing in analogous environments on the Earth, including at Mono Lake. As an example, we will address the problem of how to study the habitability of an environment when you have no idea what kind of life might be there to exploit it. This will all be related to the upcoming launch of the Mars Science Laboratory to Mars in late November this year.

  6. GLP-1 analogues for neuroprotection after out-of-hospital cardiac arrest: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Wiberg, Sebastian; Hassager, Christian; Thomsen, Jakob Hartvig; Frydland, Martin; Høfsten, Dan Eik; Engstrøm, Thomas; Køber, Lars; Schmidt, Henrik; Møller, Jacob Eifer; Kjaergaard, Jesper

    2016-06-30

    Attenuating the neurological damage occurring after out-of-hospital cardiac arrest is an ongoing research effort. This dual-centre study investigates the neuroprotective effects of the glucagon-like-peptide-1 analogue Exenatide administered within 4 hours from the return of spontaneous circulation to comatose patients resuscitated from out-of-hospital cardiac arrest. This pilot study will randomize a total of 120 unconscious patients with sustained return of spontaneous circulation after out-of-hospital cardiac arrest undergoing targeted temperature management in a blinded one-to-one fashion to a 6-hour and 15-minute infusion of either Exenatide or placebo. Patients are eligible for inclusion if resuscitated from cardiac arrest with randomization from 20 minutes to 240 minutes after return of spontaneous circulation. The co-primary endpoint is feasibility, defined as the initiation of treatment within the inclusion window in more than 90 % of participants, and efficacy, defined as the area under the neuron-specific enolase curve from 0 to 72 hours after admission. Secondary endpoints include all-cause mortality at 30 days and Cerebral Performance Category as well as a modified Rankin Score at 180 days. The study has been approved by the Danish National Board of Health and the local Ethics Committee and is monitored by Good Clinical Practice units. The study is currently enrolling. This paper presents the methods and planned statistical analyses used in the GLP-1 trial and aims to minimize bias and data-driven reporting of results. 1) Danish National Board of Health, EudraCT 2013-004311-45. Registered on 25 March 2014. 2) Videnskabsetisk komité C, Region Hovedstaden, No. 45728. Registered on 29 January 2014. 3) Clinicaltrial.gov, NCT02442791 . Registered on 25 of January 2015.

  7. 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.

  8. Resonance Raman study on distorted symmetry of porphyrin in ...

    Indian Academy of Sciences (India)

    The resonance Raman (RR) spectra of nickel octaethyl porphyrin, Ni(OEP), ... Nickel ocatethyl porphyrin, Ni(OEP), plays a central role in studies of the molec- ..... [8] T Kitagawa and Y Ozaki, Structure and bonding (Springer-Verlag, Berlin, ... [10] R S Czernuszewicz, K A Macar, Li Xiao-Yuan, J R Kincaid and T G Spiro, J. Am.

  9. Non-resonant microwave absorption studies of superconducting ...

    Indian Academy of Sciences (India)

    Abstract. Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing 10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field Hc1 is ...

  10. Galaxies and Saturn's rings: Gravitational analogues of nonneutral plasmas

    International Nuclear Information System (INIS)

    Mark, J.W.K.

    1985-01-01

    Orbit and collective dynamics in disk galaxies and in Saturn's rings are gravitational analogues of those occurring in nonneutral plasmas. The interesting problems for such ''gravitational plasmas'' are analogous to single-disk studies of transverse dynamics in particle beams. Of particular interest are various orbit-resonances with spiral density and bending waves in these disks which are analogous to electrostatic waves in nonneutral beam plasmas. The background physics, terminology and results of astrophysical investigations in these fields are surveyed in this paper. 53 refs., 19 figs., 1 tab

  11. Synthesis and photodegradation studies of analogues of muscle relaxant 1,4-dihydropyridine compounds

    Directory of Open Access Journals (Sweden)

    Gündüz Miyase Gözde

    2017-09-01

    Full Text Available This paper describes the synthesis of 1,4-dihydropyridine compounds (DHPs endowed with good muscle relaxant activity and stability to light. Six new condensed DHPs were synthesized by the microwave irradiation method. A long-chain ester moiety [2-(methacryloyloxyethyl] and various substituents on the phenyl ring were demonstrated to affect the muscle relaxant activity occurring in isolated rabbit gastric fundus smooth muscle strips. Forced photodegradation conditions were applied to the molecules according to the ICH rules. The degradation profile of the drugs was monitored by spectrophotometry coupled with the multivariate curve resolution technique. Formation of the oxidized pyridine derivative was observed for all the studied DHPs, except for one compound, which showed very fast degradation and formation of a second photo-product. Pharmacological tests on the molecules showed a good muscle relaxing effect, with a mechanism similar to that of nifedipine, however, proving to be more stable to light.

  12. The Ruprechtov natural analogue site (Cz) study: mobile natural organic matter identification, characterisation and link to PA relevant processes - 16341

    International Nuclear Information System (INIS)

    Havlova, Vaclava; Cervinka, Radek; Noseck, Ulrich; Brasser, Thomas; Havel, Josef

    2009-01-01

    The Ruprechtov Natural Analogue (CZ) Programme has been focused on studying real system processes, relevant to performance assessment (PA) of sediment formations that can form the overburden of geological repository host rocks. The site has been extensively studied due to its geological constitution (granite - kaolin - clay - U mineralisation - organic matter). The presented study used Ruprechtov unique but well-described geological conditions in order to identify and characterise mobile organic matter (MOM) that can be easily released into groundwater and can influence PA relevant specie migration due to complexation/sorption reaction. The modem analytical method MALDI-TOF MS was used for characterisation. It was found that only a small fraction of sedimentary natural organic matter (NOM) from the site was easily releasable (max. 5%) as MOM, resulting in low organic substance concentration in natural groundwater. MOM amount released was decreasing with increasing NOM content. MALDI-TOF MS proved to be a useful tool to characterize organic substances, either natural ones or artificially released from natural organic matter samples. A noticeable fingerprint for all the MOM compounds analysed was found at MALDITOF MS spectra. This showed that MOM from the Ruprechtov site was in all cases composed of molecules with low molecular weight (under 1000 Da). As determined by the consequent geochemical analyses, despite groundwater reducing conditions MOM compounds would be mainly interacting with U(VI) in the groundwater, being present as more abundant U specie. Good correspondence of results enabled to consider the extracted humic acid HA 12/3 as a mobile organic matter fraction representative. (authors)

  13. 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)

  14. 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

  15. Benzothiazole analogues: Synthesis, characterization, MO calculations with PM6 and DFT, in silico studies and in vitro antimalarial as DHFR inhibitors and antimicrobial activities.

    Science.gov (United States)

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

    2017-10-15

    Benzothiazole analogues are of interest due to their potential activity against malarial and microbial infections. In search of suitable antimicrobial and antimalarial agents, we report here the synthesis, characterization and biological activities of benzothiazole analogues (J 1-J 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 J 1, J 2, J 3, J 5 and J 6 were further evaluated for enzyme inhibition efficacy against the receptor Pf-DHFR, computational and in vitro studies were carried out to examine their candidatures as lead dihydrofolate reductase inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Study of inelastic proton scattering at isobaric analog resonances

    International Nuclear Information System (INIS)

    Davis, S.L.

    1974-01-01

    Inelastic proton scattering at isobaric analog resonances (IAR's) was studied using the targets 138 Ba and 92 Mo. Differential cross sections and analyzing powers were measured at the 10.00, 10.63, 11.09, 11.45, and 11.70 MeV resonances in 138 Ba + p and at the 5.89, 6.09, and 6.55 MeV resonances in 92 Mo + p. In addition, a new measurement, the spin flip asymmetry, was developed. The experiment was performed by using a polarized beam to make spin flip measurements. Angular distributions for the spin flip probability and spin flip asymmetry were measured at all of the above energies except for the lowest three resonances in 138 Ba, where only the spin flip probability was measured. A DWBA code modified to include the coherent addition of resonance amplitudes was used to analyze the 138 Ba data. The partial widths extracted from this analysis were converted to expansion coefficients for parent states in 139 Ba. The coefficients were found to be in good agreement with unified model calculations. For 92 Mo, inelastic polarizations, deduced from the spin flip and spin flip asymmetry, were found to be large. Attempts using Hauser Feshbach theory to describe both the cross section and polarization data repeatedly failed for both the 6.55 and 5.87 MeV IAR's. This failure represents strong evidence that Hauser Feshbach theory is not valid when extended to describe scattering at an IAR. The 92 Mo data were analyzed using a reaction theory modified to include channel-channel correlations. This theory predicts that the enhanced compound scattering is identical to the resonance scattering. Good fits have been obtained with the use of this modified Hauser Feshbach theory. (U.S.)

  17. The use of swept-charge devices in planetary analogue X-ray fluorescence studies

    International Nuclear Information System (INIS)

    Walker, T E; Smith, D R

    2012-01-01

    The Chandrayaan-1 X-ray Spectrometer (C1XS) was launched onboard the Indian Space Research Organisation (ISRO) Chandrayaan-1 lunar mission in October 2008. The instrument consisted of 24 swept-charge device (SCD) silicon X-ray detectors providing a total collecting area of ∼ 24 cm 2 , corresponding to a 14° field of view (FWHM), with the ability to measure X-rays from 0.8–10 keV. One algorithm used to analyse the C1XS flight data was developed at Rutherford Appleton Laboratory (RAL) to convert the raw X-ray flux data into elemental ratios and abundances to make geological interpretations about the lunar surface. Laboratory X-ray fluorescence (XRF) data were used to validate the RAL algorithm, with previous studies investigating how the measured XRF flux varies with target surface characteristics including grain size and roughness. Evidence for a grain-size effect was observed in the data, the XRF line intensity generally decreasing with increasing sample grain size, dependent on the relative abundance of elemental components. This paper presents a subsequent study using more homogeneous samples made from mixtures of MgO, Al 2 O 3 and SiO 2 powders, all of grain size < 44 μm, across a broader range of mixture ratios and at a higher level of X-ray flux data in order to further validate the RAL algorithm. For the majority of the C1XS flight data analysed so far with the RAL algorithm, the corresponding lunar ground tracks have been generally basaltic, laboratory verification of the algorithm having been primarily conducted using basaltic lunar regolith simulant (JSC-1A) XRF data. This paper also presents results from tests on a terrestrial anorthosite sample, more relevant to the anorthositic lunar highlands, from where the remaining C1XS lunar dataset derives. The operation of the SCD, the XRF test facility, sample preparation and collected XRF spectra are discussed in this paper.

  18. 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

  19. 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.

  20. 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

  1. 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…

  2. 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

  3. Mineralogy, petrology and geochemistry of the Pocos de Caldas analogue study sites, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Waber, M.

    1991-01-01

    The thorium-rare-earth element deposit at Morro do Ferro is of supergene origin and was formed under lateritic weathering conditions. The ore body forms shallow NW-SE elongated argillaceous lenses that extend from the top of the hill downwards along its south-eastern slope. The deposit is capped by a stockwork of magnetite veins which have protected the underlying, highly argillaceous host rock from excessive erosion. The surrounding country rocks comprise a sequence of subvolcanic phonolite intrusions that have been strongly altered by hydrothermal and supergene processes. From petrological, mineralogical and geochemical studies and mass balance calculations, it is inferred that the highly weathered host rock was originally carbonatic in composition and was initially enhanced in thorium and rare-earth elements compared to the surrounding silicate rocks. Intrusion of the carbonatite produced fenitic alteration of the surrounding phonolites, consisting of an early potassic alteration followed by a vein-type Th-REE mineralization with associated fluorite, carbonate, pyrite and zircon. Subsequent lateritic weathering has completely destroyed the carbonatite, forming a residual supergene enrichment of Th and REEs. Initial weathering of the carbonatite leading to solutions enriched in carbonate and phosphate may have appreciably restricted the dissolution of the primary Th-REE phases. Strongly oxidic weathering has resulted in a fractionation between cerium and the other light rare-earth elements. Ce 3+ is oxidized to Ce 4+ and retained together with thorium by secondary mineral formation and adsorption on poorly crystalline iron- and aluminium-hydroxides. In contrast, the trivalent LREEs are retained to a lesser degree and are thus more available for secondary mineral formation and adsorption at greater depths down the weathering column. (author) figs., tabs., 60 refs

  4. 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.

  5. 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.

  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. Magnetic resonance study of maghemite-based magnetic fluid

    International Nuclear Information System (INIS)

    Figueiredo, L.C.; Lacava, B.M.; Skeff Neto, K.; Pelegrini, F.; Morais, P.C.

    2008-01-01

    This study reports on the magnetic resonance (MR) data (X-band experiment) of 10.2 nm average diameter maghemite nanoparticle in the temperature range of 100-230 K. Maghemite nanoparticles were suspended as low-pH ionic magnetic fluid containing 2.3x10 17 particles/cm 3 . The temperature dependence of both resonance linewidth and resonance field of the zero-field-cooled sample as well as the resonance field of the field-cooled sample (angular variation experiment) was analyzed using well-established methodology. Information regarding particle size, particle clusterization and surface magnetic anisotropy were obtained from the analysis of the MR data. The number of magnetic sites per particle from the MR data is in excellent agreement with the number provided by the transmission electron microscopy (TEM) data. The demagnetizing field value obtained from the MR data indicates cluster of particles containing on average 1.42 particles. The MR angular variation data suggest that magnetoelastic effect accounts for the non-linearity observed for the surface component of the magnetic anisotropy

  9. In vitro and In Silico Studies on Curcumin and Its Analogues as Dual Inhibitors for cyclooxygenase-1 (COX-1 and cyclooxygenase-2 (COX-2

    Directory of Open Access Journals (Sweden)

    Nunung Yuniarti

    2012-03-01

    Full Text Available Curcumin has been widely reported as an anti-inflammatory agent isolated from the plant Curcuma longa L. (turmeric. This anti-inflammatory activity was associated with the ability of this compound to inhibit the activity of both cyclooxygenase-1 (COX-1 and cyclooxygenase-2 (COX-2 in arachidonic acid metabolism. Dual COX-1 and COX-2 inhibitors are preferred to be employed in the therapy of chronic inflammatory diseases compared to selective inhibitors, since it was reported that the use of selective inhibitors led to severe adverse side effect. In the present study, in vitro and in silico assays on curcumin and its analogues as dual inhibitors for both COX-1 and COX-2 were performed. The results provide theoretical contribution in understanding the ligand-protein interactions at the molecular level to develop new curcumin analogues which possess better anti-inflammatory activity as well as to avoid unsolicited side effects.

  10. Nuclear magnetic resonance studies of epithelial metabolism and function

    International Nuclear Information System (INIS)

    Balaban, R.S.

    1982-01-01

    Nuclear magnetic resonance (NMR) is a noninvasive technique for studying cellular metabolism and function. In this review the general applications and advantages of NMR will be discussed with specific reference to epithelial tissues. Phosphorus NMR investigations have been performed on epithelial tissues in vivo and in vitro; however, other detectable nuclei have not been utilized to date. Several new applications of phosphorus NMR to epithelial tissues are also discussed, including studies on isolated renal tubules and sheet epithelia

  11. 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

  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 Sedimentgefuege und

  13. Analogue circuits simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mendo, C

    1988-09-01

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

  14. Nuclear resonance vibrational spectroscopic studies of iron-containing biomolecules

    International Nuclear Information System (INIS)

    Ohta, Takehiro; Seto, Makoto

    2014-01-01

    In this review, we report recent nuclear resonance vibrational spectroscopic (NRVS) studies of iron-containing biomolecules and their model complexes. The NRVS is synchrotron-based element-specific vibrational spectroscopic methods. Unlike Raman and infrared spectroscopy, the NRVS can investigate all iron motions without selection rules, which provide atomic level insights into the structure/reactivity correlation of biologically relevant iron complexes. (author)

  15. Optimization experiments on the study of giant resonance in nuclei

    International Nuclear Information System (INIS)

    Lyubarskij, G.Ya.; Savitskij, G.A.; Fartushnyj, V.A.; Khazhmuradov, M.A.; Levandovskij, S.P.

    1988-01-01

    Optimum choice of the target exposure to a beam in experiments on the study of giant resonances in nuclei is considered. Optimization is aimed at reducing mean square errors of defined formfactors. Four different optimization quality criteria - variances of four form factor experimental values are considered. Variances resulting form optimization are 1.5-2 times as less as variances in real experiment. The effect of experiment design optimization criterion on form factors determination errors is ascertained. 1 ref.; 3 tabs

  16. Study of resonances produced in Heavy Ion Collisions

    Science.gov (United States)

    Quattrocchi, L.; Acosta, L.; Auditore, L.; Cardella, G.; Chbihi, A.; De Filippo, E.; Favela, F.; Gnoffo, B.; Lanzalone, G.; Martel, I.; Martorana, N. S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Rizzo, F.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Veselsky, M.

    2018-05-01

    At Laboratori Nazionali del Sud of Catania an experiment has been carried out in order to investigate the correlations between particles produced in 12C+24Mg reaction at 35 AMeV incident energy. Two α correlation has been explored because provide information about temperature of 8Be nuclei produced in the reaction, while three α correaltion has been studied in order to evaluate the competition between sequential and direct decay mode of resonances produced in 12C quasi-projectiles.

  17. Structure-function studies of BPP-BrachyNH2 and synthetic analogues thereof with Angiotensin I-Converting Enzyme.

    Science.gov (United States)

    Arcanjo, Daniel D R; Vasconcelos, Andreanne G; Nascimento, Lucas A; Mafud, Ana Carolina; Plácido, Alexandra; Alves, Michel M M; Delerue-Matos, Cristina; Bemquerer, Marcelo P; Vale, Nuno; Gomes, Paula; Oliveira, Eduardo B; Lima, Francisco C A; Mascarenhas, Yvonne P; Carvalho, Fernando Aécio A; Simonsen, Ulf; Ramos, Ricardo M; Leite, José Roberto S A

    2017-10-20

    The vasoactive proline-rich oligopeptide termed BPP-BrachyNH 2 (H-WPPPKVSP-NH 2 ) induces in vitro inhibitory activity of angiotensin I-converting enzyme (ACE) in rat blood serum. In the present study, the removal of N-terminal tryptophan or C-terminal proline from BPP-BrachyNH 2 was investigated in order to predict which structural components are important or required for interaction with ACE. Furthermore, the toxicological profile was assessed by in silico prediction and in vitro MTT assay. Two BPP-BrachyNH 2 analogues (des-Trp 1 -BPP-BrachyNH 2 and des-Pro 8 -BPP-BrachyNH 2 ) were synthesized, and in vitro and in silico ACE inhibitory activity and toxicological profile were assessed. The des-Trp 1 -BPP-BrachyNH 2 and des-Pro 8 -BPP-BrachyNH 2 were respectively 3.2- and 29.5-fold less active than the BPP-BrachyNH 2 -induced ACE inhibitory activity. Molecular Dynamic and Molecular Mechanics Poisson-Boltzmann Surface Area simulations (MM-PBSA) demonstrated that the ACE/BBP-BrachyNH 2 complex showed lower binding and van der Wall energies than the ACE/des-Pro 8 -BPP-BrachyNH 2 complex, therefore having better stability. The removal of the N-terminal tryptophan increased the in silico predicted toxicological effects and cytotoxicity when compared with BPP-BrachyNH 2 or des-Pro 8 -BPP-BrachyNH 2 . Otherwise, des-Pro 8 -BPP-BrachyNH 2 was 190-fold less cytotoxic than BPP-BrachyNH 2 . Thus, the removal of C-terminal proline residue was able to markedly decrease both the BPP-BrachyNH 2 -induced ACE inhibitory and cytotoxic effects assessed by in vitro and in silico approaches. In conclusion, the aminoacid sequence of BPP-BrachyNH 2 is essential for its ACE inhibitory activity and associated with an acceptable toxicological profile. The perspective of the interactions of BPP-BrachyNH 2 with ACE found in the present study can be used for development of drugs with differential therapeutic profile than current ACE inhibitors. Copyright © 2017 Elsevier Masson SAS. All

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

    Energy Technology Data Exchange (ETDEWEB)

    Gushiken, Isao; Nishihira, Takeshi; Nakasone, Tomohiro [Ryukyu Univ., Nishihara, Okinawa (Japan). School of Medicine; Takara, Hiroaki; Oshiro, Yutaka; Oshiro, Takashi; Isa, Makoto; Kinjo, Yukio; Ibaraki, Kunio

    1989-10-01

    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).

  19. 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)

  20. A solid-state hybrid density functional theory study of Prussian blue analogues and related chlorides at pressure

    Energy Technology Data Exchange (ETDEWEB)

    Middlemiss, Derek S; Lawton, Lorreta M; Wilson, Chick C [Department of Chemistry and WestCHEM Research School, University Avenue, University of Glasgow, Glasgow G12 8QQ (United Kingdom)], E-mail: c.c.wilson@chem.gla.ac.uk

    2008-08-20

    The variations with pressure in the structural, electronic and magnetic properties of a series of Prussian blue analogues (PBAs) K{sup I}M{sup II}[Cr{sup III}(CN){sub 6}] (M = V{sup II}, Mn{sup II} and Ni{sup II}) and associated isomorphous chlorides K{sup I}M{sup II}Cr{sup III}Cl{sub 6} are investigated within a series of solid-state hybrid density functional calculations. The sensitivity of the computed properties to the choice of Hamiltonian is tested by application of functionals containing 35%, 65% and 100% admixtures of Fock exchange. Magnetic coupling constants (J) are obtained at a range of cell volumes (V), with fits of the Bloch relationship (J {proportional_to} V{sup -{epsilon}}, {epsilon} typically 3-4) yielding exponents {epsilon} in the ranges 5.16-6.34, 8.48-12.07 and 4.00-4.51 for the antiferromagnetic (AF) V{sup II}Cr{sup III}-, ferrimagnetic (FI) Mn{sup II}Cr{sup III}- and ferromagnetic (FO) Ni{sup II}Cr{sup III} PBAs, respectively; and 3.33-4.99, 1.86-3.09 and 1.65-3.28 for the AF V{sup II}Cr{sup III}-, FO Mn{sup II}Cr{sup III}- and FO Ni{sup II}Cr{sup III} chlorides, respectively. The Mn{sup II}Cr{sup III} PBA range encloses the high values {epsilon}{approx}9-10 obtained in a recent joint experimental and theoretical study, and it is suggested that this strong magnetostructural effect arises due to the presence of competing AF and FO interactions in this material. Estimates of the spin ordering temperatures derived from the combination of the 35%-functional couplings with a mean field approach are in good agreement with experiment in the V{sup II}Cr{sup III} and Ni{sup II}Cr{sup III} PBAs, but are too low in the Mn{sup II}Cr{sup III} system. The variations with pressure in the structural parameters, charges and spin moments are also detailed, the PBA and chloride energy-volume data yielding bulk moduli in the ranges 39-53 and 36-50 GPa, respectively. Finally, the energies governing CN{sup -} ligand isomerization are estimated and successfully

  1. 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.

  2. In utero eyeball development study by magnetic resonance imaging.

    Science.gov (United States)

    Brémond-Gignac, D S; Benali, K; Deplus, S; Cussenot, O; Ferkdadji, L; Elmaleh, M; Lassau, J P

    1997-01-01

    The aim of this study was to measure fetal ocular development and to determine a growth curve by means of measurements in utero. Fetal ocular development was recorded by analysis of the results of magnetic resonance imaging (MRI). An anatomic study allowed definition of the best contrasted MRI sequences for calculation of the ocular surface. Biometric analysis of the values of the ocular surface in the neuro-ocular plane in 35 fetuses allowed establishment of a linear model of ocular growth curve in utero. Evaluation of ocular development may allow the detection and confirmation of malformational ocular anomalies such as microphthalmia.

  3. 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

  4. 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.

  5. 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

  6. Impact of GnRH analogues on oocyte/embryo quality and embryo development in in vitro fertilization/intracytoplasmic sperm injection cycles: a case control study

    Directory of Open Access Journals (Sweden)

    Rigó János

    2009-09-01

    Full Text Available Abstract Background Despite the clinical outcomes of ovarian stimulation with either GnRH-agonist or GnRH-antagonist analogues for in vitro fertilization (IVF being well analysed, the effect of analogues on oocyte/embryo quality and embryo development is still not known in detail. The aim of this case-control study was to compare the efficacy of a multiple-dose GnRH antagonist protocol with that of the GnRH agonist long protocol with a view to oocyte and embryo quality, embryo development and IVF treatment outcome. Methods Between October 2001 and December 2008, 100 patients were stimulated with human menopausal gonadotrophin (HMG and GnRH antagonist in their first treatment cycle for IVF or intracytoplasmic sperm injection (ICSI. One hundred combined GnRH agonist + HMG (long protocol cycles were matched to the GnRH antagonist + HMG cycles by age, BMI, baseline FSH levels and by cause of infertility. We determined the number and quality of retrieved oocytes, the rate of early-cleavage embryos, the morphology and development of embryos, as well as clinical pregnancy rates. Statistical analysis was performed using Wilcoxon's matched pairs rank sum test and McNemar's chi-square test. P Results The rate of cytoplasmic abnormalities in retrieved oocytes was significantly higher with the use of GnRH antagonist than in GnRH agonist cycles (62.1% vs. 49.9%; P Conclusion Antagonist seemed to influence favourably some parameters of early embryo development dynamics, while other morphological parameters seemed not to be altered according to GnRH analogue used for ovarian stimulation in IVF cycles.

  7. Immediate, non-submerged, root-analogue direct laser metal sintering (DLMS) implants: a 1-year prospective study on 15 patients.

    Science.gov (United States)

    Mangano, Francesco Guido; De Franco, Michele; Caprioglio, Alberto; Macchi, Aldo; Piattelli, Adriano; Mangano, Carlo

    2014-07-01

    This study evaluated the 1-year survival and success rate of root-analogue direct laser metal sintering (DLMS) implants, placed into the extraction sockets of 15 patients. DLMS is a technology which allows solids with complex geometry to be fabricated by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model; the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer-by-layer, the desired object. Cone-beam computed tomography (CBCT) acquisition and 3D image conversion, combined with the DLMS process, allow the fabrication of custom-made, root-analogue implants (RAIs). CBCT images of 15 non-restorable premolars (eight maxilla; seven mandible) were acquired and transformed into 3D models: from these, custom-made, root-analogue DLMS implants with integral abutment were fabricated. Immediately after tooth extraction, the RAIs were placed in the sockets and restored with a single crown. One year after implant placement, clinical and radiographic parameters were assessed: success criteria included absence of pain, suppuration, and exudation; absence of implant mobility and absence of continuous peri-implant radiolucency; distance between the implant shoulder and the first visible bone-to-implant contact <1.5 mm from initial surgery; and absence of prosthetic complications. At the 1-year follow-up, no implants were lost, for a survival rate of 100 %. All implants were stable, with no signs of infection. The good conditions of the peri-implant tissues were confirmed by the radiographic examination, with a mean DIB of 0.7 mm (±0.2). The possibility of fabricating custom-made, RAI DLMS implants opens new interesting horizons for immediate placement of dental implants.

  8. 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)

  9. 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)

  10. ACTINOMYCIN D ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

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

  11. 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...

  12. Excitation of the Roper resonance and study of higher baryon resonances

    International Nuclear Information System (INIS)

    Morsch, H.P.; Forschungszentrum Juelich GmbH

    1992-01-01

    The region of the P 11 resonance N(1440) is investigated in inelastic α-scattering on hydrogen using alpha-particles from Saturne with a beam momentum of 7 GeV/c. In the missing mass spectra of the scattered α-particles two effects are observed, excitation of the projectile, preferentially excited to the Δ-resonance, and excitation of the Roper resonance. The large differential cross sections indicate a structure of a compression mode. From this the compressibility of the nucleon K N may be extracted. The Roper resonance excitation corresponds to a surface mode which may be related to an oscillation of the meson cloud. The other monopole mode which corresponds to a vibration of the valence quarks should lie at about 800 MeV of excitation or above. This is the region of the P 11 (1710 MeV) resonance. Therefore experiments are important to measure the monopole strength in this energy region. Another interesting aspect is the scalar polarizability which can be extracted from inelastic dipole excitations (squeezing modes) as excitation energies above 500 MeV

  13. Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

    Directory of Open Access Journals (Sweden)

    Nelson L. Brock

    2013-05-01

    Full Text Available Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP via competing pathways releasing either methanethiol (MeSH or dimethyl sulfide (DMS. Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextraction coupled to GC–MS. Feeding experiments with [2H6]DMSP resulted in the incorporation of a deuterium label into MeSH and DMS. Knockout of relevant genes from the known DMSP demethylation pathway to MeSH showed in both species a residual production of [2H3]MeSH, suggesting that a second demethylation pathway is active. The role of DMSP degradation pathways for MeSH and DMS formation was further investigated by using the synthetic analogue DMTeP as a probe in feeding experiments with the wild-type strain and knockout mutants. Feeding of DMTeP to the R. pomeroyi knockout mutant resulted in a diminished, but not abolished production of demethylation pathway products. These results further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO42−, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable sulfur source for the MeSH volatiles, whereas incorporation of labeling from sulfate was not observed. Moreover, the utilization of selenite and selenate salts by marine alphaproteobacteria for the production of methylated selenium volatiles was explored and resulted in the production of numerous methaneselenol-derived volatiles via reduction and methylation. The pathway of selenate/selenite reduction, however, proved to be strictly separated from sulfate reduction.

  14. 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.

  15. 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.

  16. High-resolution nuclear magnetic resonance studies of proteins.

    Science.gov (United States)

    Jonas, Jiri

    2002-03-25

    The combination of advanced high-resolution nuclear magnetic resonance (NMR) techniques with high-pressure capability represents a powerful experimental tool in studies of protein folding. This review is organized as follows: after a general introduction of high-pressure, high-resolution NMR spectroscopy of proteins, the experimental part deals with instrumentation. The main section of the review is devoted to NMR studies of reversible pressure unfolding of proteins with special emphasis on pressure-assisted cold denaturation and the detection of folding intermediates. Recent studies investigating local perturbations in proteins and the experiments following the effects of point mutations on pressure stability of proteins are also discussed. Ribonuclease A, lysozyme, ubiquitin, apomyoglobin, alpha-lactalbumin and troponin C were the model proteins investigated.

  17. New possibilities for using laser polarimetry technology to study electron paramagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, E V; Zapasskii, V S

    1982-01-01

    Optical methods of recording electron paramagnetic resonance which arose in the early 50's as applied to the problem of recording the magnetic resonance of excited atoms is at the present time widely used in studying the electron paramagnetic resonance of the ground and excited states of free atoms and paramagnetic centers in condensed media. At the present time attention is devoted to the additional possibilities of optical methods of electron paramagnetic resonance which are realized using laser sources.

  18. Resonant beam behavior studies in the Proton Storage Ring

    Directory of Open Access Journals (Sweden)

    S. Cousineau

    2003-07-01

    Full Text Available We present studies of space-charge-induced beam profile broadening at high intensities in the Proton Storage Ring (PSR at Los Alamos National Laboratory. We investigate the profile broadening through detailed particle-in-cell simulations of several experiments and obtain results in good agreement with the measurements. We interpret these results within the framework of coherent resonance theory. With increasing intensity, our simulations show strong evidence for the presence of a quadrupole-mode resonance of the beam envelope with the lattice in the vertical plane. Specifically, we observe incoherent tunes crossing integer values, and large amplitude, nearly periodic envelope oscillations. At the highest operating intensities, we observe a continuing relaxation of the beam through space charge forces leading to emittance growth. The increase of emittance commences when the beam parameters encounter an envelope stop band. Once the stop band is reached, the emittance growth balances the intensity increase to maintain the beam near the stop band edge. Additionally, we investigate the potential benefit of a stop band correction to the high intensity PSR beam.

  19. Experimental REMPI [Resonance Enhanced Multiphoton Ionization] studies of small molecules

    International Nuclear Information System (INIS)

    Dehmer, J.L.; Dehmer, P.M.; Pratt, S.T.; O'Halloran, M.A.; Tomkins, F.S.

    1986-01-01

    Resonance Enhanced Multiphoton Ionization (REMPI) utilizes tunable dye lasers to ionize an atom or molecule by first preparing an excited state by multiphoton absorption and then ionizing that state before it can decay. This process is highly selective with respect to both the initial and resonant intermediate states of the target, and it can be extremely sensitive. In addition, the products of the REMPI process can be detected as needed by analyzing the resulting electrons, ions, fluorescence, or by additional REMPI. This points to a number of exciting opportunities for both basic and applied science. On the applied side, REMPI has great potential as an ultrasensitive, highly selective detector for trace, reactive, or transient species. On the basic side, REMPI affords an unprecedented means of exploring excited state physics and chemistry at the quantum-state-specific level. We shall give an overview together with examples of current studies of excited molecular states to illustrate the principles of and prospects for REMPI. 27 refs., 3 figs

  20. 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

  1. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    International Nuclear Information System (INIS)

    Barrall, G.A.; Lawrence Berkeley Lab., CA

    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

  2. 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

  3. 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

  4. Electron spin resonance intercomparison studies on irradiated foodstuffs

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (FR)

    1992-07-01

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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)

  10. 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

  11. 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

  12. Study of biological fluids by nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Kriat, M.; Vion-Dury, J.; Confort-Gouny, S.; Sciaky, M.; Cozzone, P.J.

    1991-01-01

    The use of nuclear magnetic resonance (NMR) spectroscopy in the study of biofluids is rapidly developing and might soon constitute a new major medical application of this technique which benefits from technological and methodological progress such as higher magnetic fields, new probe design, solvent suppression sequences and advanced data processing routines. In this overview, the clinical and pharmacological impact of this new approach is examined, with emphasis on the NMR spectroscopy of plasma, cerebrospinal fluid and urine. Applications to pharmacokinetics and toxicology are illustrated. Interestingly, a number of biochemical components of fluids which are not usually assayed by conventional biochemical methods are readily detected by NMR spectroscopy which is clearly a new competitive entrant among the techniques used in clinical biology. Its ease-of-use, cost effectiveness and high informational content might turn it into a major diagnostic tool in the years to come [fr

  13. 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

  14. 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

  15. Structure, aromaticity and reactivity of corannulene and its analogues: a conceptual density functional theory and density functional reactivity theory study

    Science.gov (United States)

    Deng, Youer; Yu, Donghai; Cao, Xiaofang; Liu, Lianghong; Rong, Chunying; Lu, Tian; Liu, Shubin

    2018-04-01

    Corannulene is an interesting yet special molecule, which has witnessed widespread applications. It is aromatic, but not planar and the total number of 20 π electrons is in conflict with Hückel's 4n + 2 rule. In this work, we design a series of analogous model systems based on this molecule with the central ring size extended from five members to three to eight members. A number of theoretical and analytical tools available in the literature are employed to systematically examine their structure, aromaticity and reactivity properties. We found that structurally speaking, they change from bowl-like to planar and then to saddle shapes as the central ring size increases from three to eight. From the reactivity perspective, species with five and six-membered-rings in the centre are chemically more stable and less reactive, which are confirmed by the numerical results from aromaticity indexes and quantities from the information-theoretic approach. Overall, our results show that only corannulene and its six-membered-ring, coronene, analogue are aromatic. Even though these two systems are aromatic in nature, they are markedly different in a number of ways in structure, reactivity and other properties. These results should provide with us insights and understanding about the phenomenon of three-dimensional and non-planarity aromaticity.

  16. Discovery, synthesis and in combo studies of a tetrazole analogue of clofibric acid as a potent hypoglycemic agent.

    Science.gov (United States)

    Navarrete-Vázquez, Gabriel; Alaniz-Palacios, Alfredo; Hidalgo-Figueroa, Sergio; González-Acevedo, Cristina; Ávila-Villarreal, Gabriela; Estrada-Soto, Samuel; Webster, Scott P; Medina-Franco, José L; López-Vallejo, Fabian; Guerrero-Álvarez, Jorge; Tlahuext, Hugo

    2013-06-01

    A tetrazole isosteric analogue of clofibric acid (1) was prepared using a short synthetic route and was characterized by elemental analysis, NMR ((1)H, (13)C) spectroscopy, and single-crystal X-ray diffraction. The in vitro inhibitory activity of 1 against 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) was evaluated, showing a moderate inhibitory enzyme activity (51.17% of inhibition at 10 μM), being more active than clofibrate and clofibric acid. The antidiabetic activity of compound 1 was determined at 50 mg/Kg single dose using a non insulin dependent diabetes mellitus rat model. The results indicated a significant decrease of plasma glucose levels, during the 7h post-administration. Additionally, we performed a molecular docking of 1 into the ligand binding pocket of one subunit of human 11β-HSD1. In this model, compound 1 binds into the catalytic site of 11β-HSD1 in two different orientations. Both of them, show important short contacts with the catalytic residues Ser 170, Tyr 183, Asp 259 and also with the nicotinamide ring of NADP(+). Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Studies of Se-75 labelled bile acid analogue absorption in different forms of gastrointestinal diseases using a whole body counter

    International Nuclear Information System (INIS)

    Grebe, S.F.; Sattler, E.L.; Rinkenberger, C.; Bodenmueller, D.; Grebe, S.K.G.; Mueller, K.D.; Mueller, H.; Faengewisch, G.L.; Heckers, H.; Steckenmesser, R.

    1996-01-01

    It is possible to detect disturbances of bile acid absorption using a whole body counter after administration of Se-75 labelled bile acid analogues. We scrutinized the benefit of a modification of the test method. We investigated 77 patients with different forms of a gastrointestinal disease. After application of Se 75 homotaurocholic acid we measured patient-activity up to 7 days later including whole-body profile scans in the first 6 h. The fractional retention after 7 days was between 20 and 67%. In cases of impaired absorption it was below 12%. Patients with liver diseases and afer cholecystectomy (without bile acid resorption disturbance) showed normal values. Patients with Crohn's disease of the ileum or with intestinal ileas by-pass or with colestyramine treatment or with disturbance of vitamin B12-absorption or with cystic fibrosis showed a disturbance of bile acid absorption. The normal whole-body half-life was more than 2.8 days. The 24 and 72 h values were 62 and 31% in cases with normal absorption. Smaller values are signs of bile acid malabsorption. Impulse rates measured with the whole body counter are of an order of magnitude that allows to reduce the usually administered dose of 37 kBq to 9.25 kBq. This is an efficient method to detect disturbances of bile acid absorption. The usually adminstered activity of 37 kBq can be reduced to 9.25 kBq. (orig./MG) [de

  19. 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.

  20. 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.

  1. Ultraviolet resonance Raman studies of N-methylacetamide

    International Nuclear Information System (INIS)

    Mayne, L.C.; Ziegler, L.D.; Hudson, B.

    1985-01-01

    Resonance Raman spectra of the simple peptide model compound N-methylacetamide have been obtained with 218- and 200-nm laser radiation. A large enhancement of the amide II vibration is observed relative to that of Raman spectra obtained with visible radiation. Replacement of the amide hydrogen by deuterium results in a spectrum with most of its intensity in the amide II' mode. Excitation of this deuterated species with 200-nm radiation results in intensity in the overtones of this modes, a feature characteristic of resonance enhanced spectra. Isotopic substitution of the amide carbon and nitrogen by 13 C and 15 N results in a spectral shift to lower frequency by nearly the amount expected for a normal mode consisting primarily of the motion of the amide C and N atoms. These results, taken together, demonstrate that the geometry change of N-methylacetamide upon electronic excitation to the π-π/sup */ state is dominated by a change in the C-N bond length. Studies of mixtures of the deuterio and protio forms show that a significant normal mode rotation occurs on isotopic substitution such that the amide II' of the deuterio form becomes approximately equally distributed between the amide II and III vibrations of the protio form. The amide I and I' vibrations are very diffuse in aqueous solutions at the dilutions used. These bands become sharp in acetonitrile. This behavior is interpreted in terms of a range of frequencies for this vibration due to a distribution of hydrogen-bonded species. 23 references, 5 figures

  2. 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

  3. Photoemission study of Kr 3d→np autoionization resonances

    International Nuclear Information System (INIS)

    Lindle, D.W.; Heimann, P.A.; Ferrett, T.A.; Piancastelli, M.N.; Shirley, D.A.

    1987-01-01

    Resonant photoelectron spectra of Kr have been taken in the photon-energy ranges of the 3d/sub 5/2/→5p,6p and 3d/sub 3/2/→5p excitations. The spectra, which closely resemble normal Kr + 3d/sup -1/ Auger spectra, illustrate the importance of ''spectator'' Auger-like decay for inner-shell resonances, in which the initially excited electron does not participate in the core-hole deexcitation process, except to respond to the change in the atomic potential. Possible assignments for some of the spectator decay channels are discussed based on photoemission intensity measurements at the different 3d resonances. These assignments suggest that shake-up (e.g., 5p→6p) of the ''spectator'' electron during the decay process is not quite as important as previously suspected. The resonance profiles of some of the more intense satellites have been determined over the 3d→np resonances. Very small resonance effects also were observed in the partial cross section for 4p subshell ionization, which produced asymmetric Fano-type profiles. The 4p angular distribution, in contrast, exhibits a pronounced effect in the resonance energy range. The 4p results demonstrate that nonspectator autoionization also is present

  4. 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

  5. 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)

  6. Cation Binding to Xanthorhodopsin: Electron Paramagnetic Resonance and Magnetic Studies.

    Science.gov (United States)

    Smolensky Koganov, Elena; Leitus, Gregory; Rozin, Rinat; Weiner, Lev; Friedman, Noga; Sheves, Mordechai

    2017-05-04

    Xanthorhodopsin (xR) is a member of the retinal protein family and acts as a proton pump in the cell membranes of the extremely halophilic eubacterium Salinibacter ruber. In addition to the retinal chromophore, xR contains a carotenoid, which acts as a light-harvesting antenna as it transfers 40% of the quanta it absorbs to the retinal. Our previous studies have shown that the CD and absorption spectra of xR are dramatically affected due to the protonation of two different residues. It is still unclear whether xR can bind cations. Electron paramagnetic resonance (EPR) spectroscopy used in the present study revealed that xR can bind divalent cations, such as Mn 2+ and Ca 2+ , to deionized xR (DI-xR). We also demonstrate that xR can bind 1 equiv of Mn 2+ to a high-affinity binding site followed by binding of ∼40 equiv in cooperative manner and ∼100 equiv of Mn 2+ that are weakly bound. SQUID magnetic studies suggest that the high cooperative binding of Mn 2+ cations to xR is due to the formation of Mn 2+ clusters. Our data demonstrate that Ca 2+ cations bind to DI-xR with a lower affinity than Mn 2+ , supporting the assumption that binding of Mn 2+ occurs through cluster formation, because Ca 2+ cations cannot form clusters in contrast to Mn 2+ .

  7. 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

  8. 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.

  9. Nuclear Magnetic Resonance Study of Nanoscale Ionic Materials

    KAUST Repository

    Oommen, Joanna Mary; Hussain, Muhammad Mustafa; Emwas, Abdul-Hamid M.; Agarwal, Praveen; Archer, Lynden A.

    2010-01-01

    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

  10. Study on 2D arbitrary geometry coupling resonance method

    International Nuclear Information System (INIS)

    He Lei; Wu Hongchun; Cao Liangzhi

    2014-01-01

    The paper firstly proposes a coupling resonance method in which subgroup method is employed in the serried peak energy region, and wavelet expansion method is employed in single peak energy region. The original subgroup model and wavelet expansion model are improved and coupled through the calculation of scattering source from subgroup to wavelet expansion, so that the self-shielding cross section in the whole energy region can be calculated accurately. To verify these theories and to prove the improvements, a PWR cell benchmark problem is calculated. It is demonstrated that, compared with other traditional multi-group resonance methods and continuous energy resonance method, this coupling resonance method has the ability to accurately calculate the whole energy region's self-shielding cross section while Keeping enough efficiency and finally has an ability to offer the accurate self-shielding parameters for latter transport, calculation. (authors)

  11. 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).

  12. Fourier Transform Infrared and Resonance Raman Spectroscopic Studies of Bacteriorhodopsin.

    Science.gov (United States)

    Earnest, Thomas Nixon

    Fourier transform infrared and resonance Raman spectroscopy were used to investigate the structure and function of the light-activated, transmembrane proton pump, bacteriorhodopsin, from the purple membrane of Halobacterium halobium. Bacteriorhodopsin (bR) is a 27,000 dalton integral membrane protein consisting of 248 amino acids with a retinylidene chromophore. Absorption of a photon leads to the translocation of one or two protons from the inside of the cell to the outside. Resonance Raman spectroscopy allows for the study of the configuration of retinal in bR and its photointermediates by the selective enhancement of vibrational modes of the chromophore. This technique was used to determine that the chromophore is attached to lysine-216 in both the bR _{570} and the M _{412} intermediates. In bR with tyrosine-64 selectively nitrated or aminated, the chromophore appears to have the same configuration in that bR _{570} (all- trans) and M _{412} (13- cis) states as it does in unmodified bR. Polarized Fourier transform infrared spectroscopy (FTIR) permits the study of the direction of transition dipole moments arising from molecular vibrations of the protein and the retinal chromophore. The orientation of alpha helical and beta sheet components was determined for bR with the average helical tilt found to lie mostly parallel to the membrane normal. The beta sheet structures also exhibit an IR linear dichroism for the amide I and amide II bands which suggest that the peptide backbone is mostly perpendicular to the membrane plane although it is difficult to determine whether the bands originate from sheet or turn components. The orientation of secondary structure components of the C-1 (residues 72-248) and C-2 (residues 1-71) fragments were also investigated to determine the structure of these putative membrane protein folding intermediates. Polarized, low temperature FTIR -difference spectroscopy was then used to investigate the structure of bR as it undergoes

  13. Regional South Australia Health (RESONATE) survey: study protocol

    Science.gov (United States)

    Jones, Martin; Gillam, Marianne; May, Esther

    2018-01-01

    Introduction Access to quality healthcare services is considered a moral right. However, for people living in regional locations, timely access to the services that they need may not always be possible because of structural and attitudinal barriers. This suggests that people living in regional areas may have unmet healthcare needs. The aim of this research will be to examine the healthcare needs, expectations and experiences of regional South Australians. Methods and analysis The Regional South Australia Health (RESONATE) survey is a cross-sectional study of adult health consumers living in any private or non-private dwelling, in any regional, rural, remote or very remote area of South Australia and with an understanding of written English. Data will be collected using a 45-item, multidimensional, self-administered instrument, designed to measure healthcare need, barriers to healthcare access and health service utilisation, attitudes, experiences and satisfaction. The instrument has demonstrated acceptable psychometric properties, including good content validity and internal reliability, good test–retest reliability and a high level of acceptability. The survey will be administered online and in hard-copy, with at least 1832 survey participants to be recruited over a 12-month period, using a comprehensive, multimodal recruitment campaign. Ethics and dissemination The study has been reviewed and approved by the Human Research Ethics Committee of the University of South Australia. The results will be actively disseminated through peer-reviewed journals, conference presentations, social media, broadcast media, print media, the internet and various community/stakeholder engagement activities. PMID:29654014

  14. Magnetic Resonance Imaging Study Using True versus Sham Acupuncture

    Directory of Open Access Journals (Sweden)

    Chunxiao Wu

    2014-01-01

    Full Text Available Functional magnetic resonance imaging (fMRI has been shown to detect the specificity of acupuncture points, as proved by numerous studies. In this study, resting-state fMRI was used to observe brain areas activated by acupuncture at the Taichong (LR3 acupoint. A total of 15 healthy subjects received brain resting-state fMRI before acupuncture and after sham and true acupuncture, respectively, at LR3. Image data processing was performed using Data Processing Assistant for Resting-State fMRI and REST software. The combination of amplitude of low-frequency fluctuation (ALFF and regional homogeneity (ReHo was used to analyze the changes in brain function during sham and true acupuncture. Acupuncture at LR3 can specifically activate or deactivate brain areas related to vision, movement, sensation, emotion, and analgesia. The specific alterations in the anterior cingulate gyrus, thalamus, and cerebellar posterior lobe have a crucial effect and provide a valuable reference. Sham acupuncture has a certain effect on psychological processes and does not affect brain areas related to function.

  15. 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)

  16. 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

  17. 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.

  18. Multinuclear nuclear magnetic resonance spectroscopic study of cartilage proteoglycans

    Energy Technology Data Exchange (ETDEWEB)

    Lerner, L.

    1985-01-01

    Hyaline cartilage is a composite material whose major function is to withstand compression while retaining flexibility. Its mechanical properties are affected by tissue hydration and ionic composition. Models of the mechanical behavior of cartilage have incorporated certain assumptions about the interactions of the major components of cartilage: collagen, proteoglycans, water, and cations. To determine the validity of these assumption, the authors have used nuclear magnetic resonance spectroscopy (NMR). Two approaches have been used: (a) natural abundance carbon-13 NMR; and (b) NMR of sodium-23, potassium-39, magnesium-25, and calcium-43. Evidence from studies in intact tissues are reinforced by extensive measurements on solutions of proteoglycans and other relevant macromolecules. Based on the measurements of NMR relaxation rates and lineshapes reported here, it is concluded that neither sodium nor potassium interact strongly with bovine nasal proteoglycan aggregates or their substituent glycosaminoglycan chains in solution. Proteoglycans do bind magnesium and calcium. Therefore there is a qualitative difference between monovalent and divalent cations, which is not taken into account by polyelectrolyte models or models for the ionic dependence of mechanical properties. Cation binding to heparin, which has a higher charge density than cartilage proteoglycans, was also studied. The results presented here establish that heparin binds sodium, magnesium, and calcium.

  19. 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.

  20. 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)

  1. Revealing Television's Analogue Heroes

    Directory of Open Access Journals (Sweden)

    Vanessa Jackson

    2013-12-01

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

  2. Natural analogue studies of bentonite reaction under hyperalkaline conditions. Overview of ongoing work at the Zambales ophiolite, Philippines

    International Nuclear Information System (INIS)

    Fujii, N.; Yanakawa, M.; Arcilla, C.A.; Pascua, C.; Namiki, K.; Sato, T.; Shikazono, N.; Alexander, W.R.

    2011-01-01

    Bentonite is one of the safety-critical components of the engineered barrier system for the disposal concepts developed for many types of radioactive waste. However, bentonite - especially the swelling clay component that contributes to its essential barrier functions - is unstable at high pH. To date, results from laboratory tests on bentonite degradation have been ambiguous as the reaction rates are so slow as to be difficult to observe. As such, a key goal in this project is to examine the reaction of natural bentonites in contact with natural hyperalkaline groundwaters to determine if any long-term alteration of the bentonite occurs. Ophiolites have been identified as sources of hyperalkaline groundwaters that can be considered natural analogues of the leachates produced by some cementitious materials in repositories for radioactive waste. At the Zambales ophiolite in the Philippines, widespread active serpentinisation results in hyperalkaline groundwaters with measured pH values of up to 11.7, falling into the range typical of low-alkali cement porewaters. These cements are presently being developed worldwide to minimise the geochemical perturbations which are expected to result from the use of OPC-based concretes (see Kamei et al., this conference, for details). In particular, it is hoped that the lower pH of the low-alkali cement leachates will reduce, or even avoid entirely, the potential degradation of the bentonite buffer which is expected at the higher pH levels (12.5 and above) common to OPC-based concretes. During recent field campaigns at two sites in the Zambales ophiolite (Mangatarem and Bigbiga), samples of bentonite and the associated hyperalkaline groundwaters have been collected by drilling and trenching. At Mangatarem, qualitative data from a 'fossil' (i.e. no groundwater is currently present) reaction zone indicates some alteration of the bentonite to zeolite, serpentine and CSH phases. Preliminary reaction path modelling suggests that the

  3. 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.

  4. Therapeutically interchangeable? A study of real-world outcomes associated with switching basal insulin analogues among US patients with type 2 diabetes mellitus using electronic medical records data.

    Science.gov (United States)

    Levin, P; Wei, W; Miao, R; Ye, F; Xie, L; Baser, O; Gill, J

    2015-03-01

    To evaluate real-world clinical outcomes for switching basal insulin analogues [insulin glargine (GLA) and insulin detemir (DET)] among US patients with type 2 diabetes mellitus (T2DM). Using the GE Centricity Electronic Medical Records database, this retrospective study examined two cohorts: cohort 1, comprising patients previously on GLA and then either switching to DET (DET-S) or continuing with GLA (GLA-C); and cohort 2, comprising patients previously on DET and then either switching to GLA (GLA-S) or continuing with DET (DET-C). Within each cohort, treatment groups were propensity-score-matched on baseline characteristics. At 1-year follow-up, insulin treatment patterns, glycated haemoglobin (HbA1c) levels, hypoglycaemic events, weight and body mass index (BMI) were evaluated. The analysis included 13 942 patients: cohort 1: n = 10 657 (DET-S, n = 1797 matched to GLA-C, n = 8860) and cohort 2: n = 3285 (GLA-S, n = 858 matched to DET-C, n = 2427). Baseline characteristics were similar between the treatment groups in each cohort. At 1-year follow-up, in cohort 1, patients in the DET-S subgroup were significantly less persistent with treatment, more likely to use a rapid-acting insulin analogue, had higher HbA1c values, lower HbA1c reductions and lower proportions of patients achieving HbA1c Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  5. Electron Spin Resonance (ESR) studies of returned comet nucleus samples

    International Nuclear Information System (INIS)

    Tsay, Fundow; Kim, S.S.; Liang, R.H.

    1989-01-01

    The most important objective of the Comet Nucleus Sample Returm Mission is to return samples which could reflect formation conditions and evolutionary processes in the early solar nebula. It is expected that the returned samples will consist of fine-grained silicate materials mixed with ices composed of simple molecules such as H 2 O, NH 3 , CH 4 as well as organics and/or more complex compounds. Because of the exposure to ionizing radiation from cosmic-ray, gamma-ray, and solar wind protons at low temperature, free radicals are expected to be formed and trapped in the solid ice matrices. The kind of trapped radical species together with their concentration and thermal stability can be used as a dosimeter as well as a geothermometer to determine thermal and radiation histories as well as outgassing and other possible alternation effects since the nucleus material was formed. Since free radicals that are known to contain unpaired electrons are all paramagnetic in nature, they can be readily detected and characterized in their native form by the Electron Spin Resonance (ESR) method. In fact, ESR has been shown to be a non-destructive, highly sensitive tool for the detection and characterization of paramagnetic, ferromagnetic, and radiation damage centers in terrestrial and extraterrestrial geological samples. The potential use of ESR as an effective method in the study of returned comet nucleus samples, in particular, in the analysis of fine-grained solid state icy samples is discussed

  6. 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

  7. Proton nuclear magnetic resonance studies on brain edema

    International Nuclear Information System (INIS)

    Naruse, S.; Horikawa, Y.; Tanaka, C.; Hirakawa, K.; Nishikawa, H.; Yoshizaki, K.

    1982-01-01

    The water in normal and edematous brain tissues of rats was studied by the pulse nuclear magnetic resonance (NMR) technique, measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). In the normal brain, T1 and T2 were single components, both shorter than in pure water. Prolongation and separation of T2 into two components, one fast and one slow, were the characteristic findings in brain edema induced by both cold injury and triethyl tin (TET), although some differences between the two types of edema existed in the content of the lesion and in the degree of changes in T1 and T2 values. Quantitative analysis of T1 and T2 values in their time course relating to water content demonstrated that prolongation of T1 referred to the volume of increased water in tissues examined, and that two phases of T2 reflected the distribution and the content of the edema fluid. From the analysis of the slow component of T2 versus water content during edema formation, it was demonstrated that the increase in edema fluid was steady, and its content was constant during formation of TET-induced edema. On the contrary, during the formation of cold-injury edema, water-rich edema fluid increased during the initial few hours, and protein-rich edema fluid increased thereafter. It was concluded that proton NMR relaxation time measurements may provide new understanding in the field of brain edema research

  8. [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.

  9. Ferromagnetic resonance study of Fe{sub 50}Ag{sub 50} granular film

    Energy Technology Data Exchange (ETDEWEB)

    Sarmiento, G. [Dpto. Electricicidad y Electronica, Universidad del Pais Vasco (UPV/EHU), Apdo. 644, 48080 Bilbao (Spain)]. E-mail: websamug@lg.ehu.es; Fdez-Gubieda, M.L. [Dpto. Electricicidad y Electronica, Universidad del Pais Vasco (UPV/EHU), Apdo. 644, 48080 Bilbao (Spain); Siruguri, V. [Dpto. Electricicidad y Electronica, Universidad del Pais Vasco (UPV/EHU), Apdo. 644, 48080 Bilbao (Spain); UGC-DAE Consortium for Scientific Research, R-5 Shed, BARC Campus, Mumbai 400085 (India); Lezama, L. [Dpto. Quimica Inorganica (UPV/EHU), Apdo. 644, 48080, Bilbao (Spain); Orue, I. [Servicios Generales de Investigacion (SGIKER), Vicerrectorado de Investigacion (UPV/EHU) (Spain)

    2007-09-15

    Fe{sub 50}Ag{sub 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.

  10. 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.

  11. A study of artificial satellite resonance orbits due to lunisolar perturbations

    International Nuclear Information System (INIS)

    Hughes, S.

    1978-01-01

    A study of artificial satellite resonance orbits due to lunisolar perturbations is given. Particular emphasis is placed on the following aspects: the classification of resonance orbits according to their commensurability condition; the form of the commensurability condition when expressed in terms of the orbital elements of a satellite; the predominant resonant terms for each commensurability condition; and criteria which determine the existence or non-existence of a particular commensurability condition. (author)

  12. 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.

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

    International Nuclear Information System (INIS)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A.; Djavidani, B.; Poschenrieder, F.; Feuerbach, S.; Schmid, C.; Kobuch, R.

    2008-01-01

    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 2 vs. 8.7 ± 2.3 cm 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.)

  14. 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.)

  15. Studies on motor neuron disease with cranial magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mitsui, Yoshiyuki; Takahashi, Mitsuo; Nakamura, Yusaku; Kitaguchi, Masataka; Yagi, Yuji (Kinki Univ., Osaka (Japan). School of Medicine)

    1992-05-01

    The present study was performed to examine the pyramidal tracts of the brain in both 51 normal subjects (21 male and 30 female subjects; mean age of 43.5[+-]16.1 years) and 12 patients with motor neuron disease (6 male and 6 female patients; mean age of 57.4[+-]7.9 years), using the magnetic resonance imaging (MRI). The 12 patients with motor neuron disease (MND) comprised 7 suffering from spinal progressive muscular atrophy (SPMA) and 5 from amyotrophic lateral sclerosis (ALS). The MRI used in this study was of both short spin echo and long spin echo sequence. Of the 52 normal subjects, 24 of them (47%) had the T2 prolonged small areas (high signal intensity areas) at the posterior limb of internal capsule. These findings were not found in the normal subjects over fifty years old. No similar finding was detected in the pyramidal tracts except the posterior limb of internal capsule. On the other hand, 8 patients with MND (67%) proved to have the high signal intensity areas in the pyramidal tracts. Moreover, these high intensity areas were extended from the crus cerebri to corona radiata in 7 patients (58%). In all patients with ALS, these areas were extended in whole areas of the pyramidal tracts, and the similar findings were also found in two patients with SPMA. These findings were demonstrated to be more extensive than those in the normal subjects. The results thus obtained warrant us to conclude that cranial MRI is useful to detect the degeneration of the pyramidal tracts of MND patients. (author).

  16. Studies on motor neuron disease with cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Mitsui, Yoshiyuki; Takahashi, Mitsuo; Nakamura, Yusaku; Kitaguchi, Masataka; Yagi, Yuji

    1992-01-01

    The present study was performed to examine the pyramidal tracts of the brain in both 51 normal subjects (21 male and 30 female subjects; mean age of 43.5±16.1 years) and 12 patients with motor neuron disease (6 male and 6 female patients; mean age of 57.4±7.9 years), using the magnetic resonance imaging (MRI). The 12 patients with motor neuron disease (MND) comprised 7 suffering from spinal progressive muscular atrophy (SPMA) and 5 from amyotrophic lateral sclerosis (ALS). The MRI used in this study was of both short spin echo and long spin echo sequence. Of the 52 normal subjects, 24 of them (47%) had the T2 prolonged small areas (high signal intensity areas) at the posterior limb of internal capsule. These findings were not found in the normal subjects over fifty years old. No similar finding was detected in the pyramidal tracts except the posterior limb of internal capsule. On the other hand, 8 patients with MND (67%) proved to have the high signal intensity areas in the pyramidal tracts. Moreover, these high intensity areas were extended from the crus cerebri to corona radiata in 7 patients (58%). In all patients with ALS, these areas were extended in whole areas of the pyramidal tracts, and the similar findings were also found in two patients with SPMA. These findings were demonstrated to be more extensive than those in the normal subjects. The results thus obtained warrant us to conclude that cranial MRI is useful to detect the degeneration of the pyramidal tracts of MND patients. (author)

  17. 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

  18. Magnetic resonance of seminal vesicles: a noninvasive study of seminal way

    International Nuclear Information System (INIS)

    Ocantos, J.A.; Rey Valzacchi, G.; Sinclair, M.E.; Loor Guadamud, G.

    2010-01-01

    The magnetic resonance without endorectal coil is an excellent diagnostic tool for studying the entire route of seminal non-invasive way in a single step diagnosis. We call magnetic resonance of seminal vesicles, but includes both the study of the seminal vesicles as the channels of the seminal way. [es

  19. Magnetic resonance appearance of monoclonal gammopathies of unknown significance and multiple myeloma. The GRI Study Group.

    Science.gov (United States)

    Bellaïche, L; Laredo, J D; Lioté, F; Koeger, A C; Hamze, B; Ziza, J M; Pertuiset, E; Bardin, T; Tubiana, J M

    1997-11-01

    A prospective multicenter study. To evaluate the use of magnetic resonance imaging, in the differentiation between monoclonal gammopathies of unknown significance and multiple myeloma. Although multiple myeloma has been studied extensively with magnetic resonance imaging, to the authors' knowledge, no study has evaluated the clinical interest of magnetic resonance imaging in the differentiation between monoclonal gammopathies of unknown significance and multiple myeloma. The magnetic resonance examinations of the thoracolumbar spine in 24 patients with newly diagnosed monoclonal gammopathies of unknown significance were compared with those performed in 44 patients with newly diagnosed nontreated multiple myeloma. All findings on magnetic resonance examination performed in patients with monoclonal gammopathies of unknown significance were normal, whereas findings on 38 (86%) of the 44 magnetic resonance examinations performed in patients with multiple myeloma were abnormal. Magnetic resonance imaging can be considered as an additional diagnostic tool in differentiating between monoclonal gammopathies of unknown significance and multiple myeloma, which may be helpful when routine criteria are not sufficient. An abnormal finding on magnetic resonance examination in a patient with monoclonal gammopathies of unknown significance should suggest the diagnosis of multiple myeloma after other causes of marrow signal abnormalities are excluded. Magnetic resonance imaging also may be proposed in the long-term follow-up of monoclonal gammopathies of unknown significance when a new biologic or clinical event suggests the diagnosis of malignant monoclonal gammopathy.

  20. 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.

  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. 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.

  3. 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.)

  4. Photochemical cycle of bacteriorhodopsin studied by resonance Raman spectroscopy.

    Science.gov (United States)

    Stockburger, M; Klusmann, W; Gattermann, H; Massig, G; Peters, R

    1979-10-30

    Individual species of the photochemical cycle of bacteriorhodopsin, a retinal-protein complex of Halobacteria, were studied in aqueous suspensions of the "purple membrane" at room temperature by resonance Raman (RR) spectroscopy with flow systems. Two pronounced deuterium shifts were found in the RR spectra of the all-trans complex BR-570 in H2O-D2O suspensions. The first is ascribed to C=NH+ (C=ND+) stretching vibrations of the protonated Schiff base which links retinal to opsin. The second is assigned tentatively to an "X-H" ("X-D") bending mode, where "X" is an atom which carries an exchangeable proton. A RR spectrum of the 13-cis-retinal complex "BR-548" could be deduced from spectra of the dark-adapted purple membrane. The RR spectrum of the M-412 intermediate was monitored in a double-beam pump-probe experiment. The main vibrational features of the intermediate M' in the reaction M-412 in equilibrium hv M' leads to delta BR-570 could be deduced from a photostationary mixture of M-412 and M'. Difference procedures were applied to obtain RR spectra of the L-550 intermediate and of two new long-lived species, R1'-590 and R2-550. From kinetic data it is suggested that T1'-590 links the proton-translocating cycle to the "13-cis" cycle of BR-548. The protonation and isomeric states of the different species are discussed in light of the new spectroscopic and kinetic data. It is found that conformational changes during the photochemical cycle play an important role.

  5. 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).

  6. 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)

  7. 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...

  8. Resonant photoemission study of CeRu4Sb12

    International Nuclear Information System (INIS)

    Ishii, Hiroyoshi; Miyahara, Tsuneaki; Takayama, Yasuhiro; Shiozawa, Hidetsugu; Obu, Kenji; Matsuda, Tatsuma D.; Aoki, Yuji; Sugawara, Hitoshi; Sato, Hideyuki

    2005-01-01

    We have measured the Ce 4d-4f and Ce 3d-4f resonant photoemission spectra of CeRu 4 Sb 12 . The Ce 4f spectra show the spectral features corresponding to a weakly hybridized system. The number of 4f electrons is estimated to be ∼1.0

  9. 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

  10. 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...

  11. 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

  12. 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...

  13. 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.)

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices

    OpenAIRE

    Hai Jiang; Jianfang Liu; Qingqing Lv; Shoudong Gu; Xiaoyang Jiao; Minjiao Li; Shasha Zhang

    2016-01-01

    The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter) is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radi...

  19. Nuclear Magnetic Resonance spectroscopy studies of proteins-glycoconjugates interactions

    OpenAIRE

    Marchetti, Roberta

    2013-01-01

    This PhD thesis work has been focused on the analysis of the structural requisites for recognition and binding between proteins and glycoconjugates, essential for the comprehension of mechanisms of paramount importance in chemistry, biology and biomedicine. A large variety of techniques, such as crystallographic analysis, titration microcalorimetry (ITC), surface plasmon resonance (SPR) and fluorescence spectroscopy, allows the elucidation of molecular recognition events. In the last years...

  20. A case study on lightning protection, building resonances considered

    OpenAIRE

    Deursen, van, A.P.J.; Geers - Bargboer, G.

    2011-01-01

    In a recent paper (G. Bargboer and A. P. J. van Deursen, IEEE Trans. Electromagn. Compat., vol. 52, no. 3, pp. 684-90, Aug. 2010) we dealt with current injection measurements to test the lightning protection system of a newly built pharmaceutical plant. In a tentative extrapolation, the measurements were extrapolated to actual lightning. Here, we extend the model and calculate the response of the installation on lightning currents and include resonances in the cable trays and test cables cont...

  1. Magnetic resonance spectroscopic study of parkinsonism related to boxing.

    OpenAIRE

    Davie, C A; Pirtosek, Z; Barker, G J; Kingsley, D P; Miller, P H; Lees, A J

    1995-01-01

    Proton magnetic resonance spectroscopy, localised to the lentiform nucleus, was carried out in three ex-professional boxers who developed a parkinsonian syndrome, six patients with idiopathic Parkinson's disease, and six age matched controls. The three ex-boxers all showed a pronounced reduction in the absolute concentration of N-acetylaspartate compared with the patients with idiopathic Parkinson's disease and the control group. This reduction is likely to reflect neuronal loss occurring in ...

  2. A novel lunar bed rest analogue.

    Science.gov (United States)

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

    2013-11-01

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

  3. 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.

  4. Progresses in the Studies of Adiabatic Splitting of Charged Particles Beams by Crossing Nonlinear Resonances

    CERN Document Server

    Franchi, A; Giovannozzi, M; CERN. Geneva. BE Department

    2009-01-01

    The multi-turn 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 non-linear 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.

  5. 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)

  6. 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.)

  7. 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.)

  8. Analogue computer display of accelerator beam optics

    International Nuclear Information System (INIS)

    Brand, K.

    1984-01-01

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

  9. Synthesis, radiosynthesis and biological evaluation of quinoline carboxamide analogues of Talnetant (SB 223412) to study by PET or SPECT imaging the NK-3 receptor

    International Nuclear Information System (INIS)

    Bennacef, Idriss

    2003-01-01

    With the aim of visualizing NK-3 receptors in vivo by medical imaging techniques (positron emission tomography and single photon emission computed tomography), the synthesis of novel 2-phenylquinoline-4-carboxamides, derived from SB 223412 or SB 222 200, two non peptide potent (hNK-3-CHO: K i = 1.0 nM; K i = 4.4 nM respectively) and selective (NK-3/NK-1 ≥10 5 ) human NK-3 receptor antagonists, has been studied. The compounds obtained are characterized by the presence, on the quinoline moiety, of an atom of carbon, fluorine or iodine that can be substituted by their β + emitter (carbon-11, t(1/2) = 20 min; fluorine-18, t(1/2) = 110 min) or γ emitter (iodine-123, t(1/2) = 13 h) radio-isotopes. Monohalogenated (fluorinated or iodinated) quinolines were prepared using an efficient synthesis based on the Pfitzinger reaction. Di-halogenated analogues, bearing both an iodine and a fluorine atom, were obtained via a regioselective ortho-metalation reaction. Biological evaluation of these compounds led to the determination of potent and selective structures towards the NK-3 receptor, for which labeling will be envisaged. Functionalization in position 3 of quinoline-4-carboxamides, using a directed metalation reaction, allowed the introduction of various (hetero)elements (chlorine, bromine, iodine, trialkystannyle or silyle moiety). This research allowed to perform the radiosynthesis of [ 11 C]SB 222200 using a Stille coupling with [ 11 C]iodomethane. (author) [fr

  10. Study of the sorption of actinide analogues on calcite and smectite as a model to predict the evolution of radioactive waste disposal in geological sites

    International Nuclear Information System (INIS)

    Budiman Sastrowardoyo, Pratomo

    1991-01-01

    In the framework of the problem of the radioactive waste disposal in deep geological sites, the purpose of this study is to predict the sorption of radionuclides on minerals within the geological barrier, after the rupture of the containers and the release of the radionuclides into underground water. Neodymium labelled by 147 Nd was used as an analogue of trivalent actinides. Calcite and smectite were used as examples of altered minerals of granitic sites. In simple media, neodymium is retained with a high affinity on both minerals. Fast kinetics of fixation, high distribution coefficients and sorption capacities are favorable factors for the slowing down of radionuclide migration in underground water. Fixation on calcite is quasi irreversible. A second kinetic step was observed, leading to an increase of the retention capacity. In the first step, this is probably a superficial sorption, but with a non-homogeneous affinity for sorption sites. An exchange mechanism of Nd 3+ with Na + et Ca 2+ ions of smectite occurs. The Freundlich isotherm observed for both minerals can be used for predicting the retention of radioelements as a function of their concentration and introducing these data in a migration model after comparison with the results of dynamic and field experiments. (author) [fr

  11. Spin labelled nitrosoureas and triazenes and their non-labelled clinically used analogues--a comparative study on their physicochemical properties and antimelanomic effects.

    Science.gov (United States)

    Zheleva, A M; Gadjeva, V G

    2001-01-16

    Physicochemical properties, such as half life time (tau0.5), alkylating and carbamoylating activity and in vivo antimelanomic effects against B16 melanoma of spin labeled (containing nitroxyl free radical moiety) amino acid nitrosoureas, synthesized in our laboratory, have been studied and compared to those of the antitumor drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU). We have shown that the introduction of amino acid moieties and the replacement of cyclohexylamine with nitroxyl moiety leads to a faster decomposition, higher alkylating, lower carbamoylating activity, better antimelanomic activity and lower general toxicity, when compared to those of CCNU. It was also established that spin labeled triazenes, previously synthesized by us, were more stable in phosphate saline than their nonlabeled analogue, 5-(3,3-dimethyltriazene-1-yl)-imidazole-4-carboxamide (dacarbazine, DTIC). A higher cytotoxicity to B16 melanoma cells than to YAC-1 and lymphocytes was demonstrated for all spin labeled triazenes, in comparison with DTIC. An assumption has been made to explain the lower general toxicity of the spin labeled nitrosoureas compared to that of CCNU. Based on the results presented, we accept that a new trend for synthesis of more selective and less toxic nitrosourea and triazene derivatives as potential antimelanomic drugs might be developed.

  12. Moessbauer effect and electron paramagnetic resonance studies on yeast aconitase

    International Nuclear Information System (INIS)

    Suzuki, Takashi; Maeda, Yutaka; Sakai, Hiroshi; Fujimoto, Shigeru; Morita, Yuhei.

    1975-01-01

    The Moessbauer effect and electron paramagnetic resonance (EPR) of yeast aconitase [EC 4.2.1.3] purified from the cells of Candida lipolytica (ATCC 20114) were measured. Moessbauer spectra suggested that yeast acontitase mostly contained two high-spin Fe(III) ions in an antiferromagnetically coupled binuclear complex that resembled oxidized 2 Fe ferredoxins, together with a small amount of high-spin Fe(II). EPR spectra recorded no signal at 77 0 K, but showed a slightly asymmetric signal centered at g=2.0 at 4.2 0 K, presumably due to the small amount of Fe(II) Fe(III) pairs. (auth.)

  13. Transistor regenerative spectrometer for 14N nuclear quadrupole resonance study

    International Nuclear Information System (INIS)

    Anferov, V.P.; Mikhal'kov, V.M.

    1981-01-01

    Improvement of the Robinson transducer for investigations of nuclear quadrupole resonance (NQR) in 14 N is described. Amplifier of the suggested transducer is made using p-n field effect transistor and small-noise SHF bipolar transistor. Such a circuit permits to obtain optimal relation between input resistance, low-frequency noises and transconductance which provides uniform gain of the transducer in the frequency range of 0.6-12 MHz and permits to construct a transistor spectrometer of NQR not yielding to a lamp spectrometer in sensitivity [ru

  14. 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.

  15. 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)

  16. 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

  17. 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.

  18. Chemopreventive properties of curcumin analogues ...

    African Journals Online (AJOL)

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

  19. Binding of Bisphenol-F, a bisphenol analogue, to calf thymus DNA by multi-spectroscopic and molecular docking studies.

    Science.gov (United States)

    Usman, Afia; Ahmad, Masood

    2017-08-01

    BPF (Bisphenol-F), a member of the bisphenol family, having a wide range of industrial applications is gradually replacing Bisphenol-A. It is a recognized endocrine disrupting chemical (EDC). EDCs have been implicated in increased incidences of breast, prostate and testis cancers besides diabetes, obesity and decreased fertility. Due to the adverse effects of EDCs on human health, attempts have been directed towards their mechanism of toxicity especially at the molecular level. Hence, to understand the mechanism at the DNA level, interaction of BPF with calf thymus DNA was studied employing multi-spectroscopic, voltammetric and molecular docking techniques. Fluorescence spectra, cyclic voltammetry (CV), circular dichroism (CD) and molecular docking studies of BPF with DNA were suggestive of minor groove binding of BPF. UV-visible absorption and fluorescence spectra suggested static quenching due to complex formation between BPF and ctDNA. Hoechst 33258 (HO) and ethidium bromide (EB) displacement studies further confirmed such mode of BPF interaction. Thermodynamic and molecular docking parameters revealed the mechanism of binding of BPF with ctDNA to be favorable and spontaneous due to negative ΔG and occurring through hydrogen bonds and van der waals interactions. BPF induced DNA cleavage under in vitro conditions by plasmid nicking assay suggested it to be genotoxic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. 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

  1. 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

  2. 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.

  3. 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...

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

    International Nuclear Information System (INIS)

    Noseck, Ulrich

    2008-01-01

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

  5. Cephalostatin analogues--synthesis and biological activity.

    Science.gov (United States)

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

    2004-01-01

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

  6. Discovery and structure-activity relationships study of thieno[2,3-b]pyridine analogues as hepatic gluconeogenesis inhibitors.

    Science.gov (United States)

    Ma, Fei; Liu, Jian; Zhou, Tingting; Lei, Min; Chen, Jing; Wang, Xiachang; Zhang, Yinan; Shen, Xu; Hu, Lihong

    2018-05-25

    Type 2 diabetes mellitus (T2DM) is a chronic, complex and multifactorial metabolic disorder, and targeting gluconeogenesis inhibition is a promising strategy for anti-diabetic drug discovery. This study discovered a new class of thieno[2,3-b]pyridine derivatives as hepatic gluconeogenesis inhibitors. First, a hit compound (DMT: IC 50  = 33.8 μM) characterized by a thienopyridine core was identified in a cell-based screening of our privileged small molecule library. Structure activity relationships (SARs) study showed that replaced the CF 3 in the thienopyridine core could improve the potency and led to the discovery of 8e (IC 50  = 16.8 μM) and 9d (IC 50  = 12.3 μM) with potent inhibition of hepatic glucose production and good drug-like properties. Furthermore, the mechanism of 8e for the inhibition of hepatic glucose production was also identified, which could be effective through the reductive expression of the mRNA transcription level of gluconeogenic genes, including glucose-6-phosphatase (G6Pase) and hepatic phosphoenolpyruvate carboxykinase (PEPCK). Additionally, 8e could also reduce the fasting blood glucose and improve the oral glucose tolerance and pyruvate tolerance in db/db mice. The optimization of this class of derivatives had provided us a start point to develop new anti-hepatic gluconeogenesis agents. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  7. DFT/TDDFT study on the electronic structure and spectral properties in annulated analogue of phenyl heteroazulene derivative

    International Nuclear Information System (INIS)

    Gasiorski, P.; Danel, K.S.; Matusiewicz, M.; Uchacz, T.; Kuźnik, W.; Piatek, Ł.; Kityk, A.V.

    2012-01-01

    Highlights: ► Cyclic voltammetry study of heteroazulene derivative PTNA. ► DFT/TDDFT/PCM calculations of molecular geometry and electronic states in PTNA. ► TDDFT/PCM calculations of the absorption and fluorescence spectra in PTNA. ► Comparison between TDDFT/PCM calculated and measured optical spectra. - Abstract: Paper reports the DFT/TDDFT study on the electronic structure and spectral properties of the seven-membered annulated heteroazulene derivative 6-phenyl-6H-5,6,7-triazadibenzo[f,h]naphtho[3,2,1-cd]azulene (PTNA) by means of polarizable continuum model (PCM) and Lippert–Mataga–Onsager reaction field (LM-ORF) model at the B3LYP/6-31+G(d,p) level of theory. The results of calculations are compared with the measured optical absorption and fluorescence spectra as well as with the cyclic voltammetry data. The DFT/TDDFT methods exhibit rather good quantitative agreement regarding the spectral position of the first absorption band; the discrepancy between the experiment and theory is less than 0.1 eV. As for the fluorescence emission the TDDFT calculations underestimate the transition energy of about 0.45 eV. The discrepancy should be attributed to insufficient accuracy of the TDDFT optimization in the excited state. In the polar solvent environment, all the TDDFT/PCM approaches give the bathochromic (red) shift for the fluorescence emission and the hypsochromic (blue) shift for the optical absorption in accordance with the experimental observation. As for the fluorescence emission fairly good agreement with the experiment provides the hybrid approach being the combination of the TDDFT/PCM optimization with the semiempirical electronic structure calculations by PM3 method and solvation LM-ORF model predicting the emission energy in different solvents with the accuracy better than 0.06 eV.

  8. 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.)

  9. 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.

  10. 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.

  11. 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.

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

    International Nuclear Information System (INIS)

    Torres-Vega, Gabino

    2012-01-01

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

  13. A nuclear magnetic resonance study of (TMTSF) 2PF 6

    Science.gov (United States)

    McBrierty, V. J.; Douglass, D. C.; Wudl, F.

    1982-09-01

    Inverse linewidths and spin-lattice relaxation times of fluorine and proton magnetic resonance spectra are used to examine molecular motion in the organic superconductor (TMTSF) 2PF 6. The results clearly show that rotation of the PF 6- anion is the principal agent for the observed relaxation of fluorine contrary to some suggestions in the current literature. This interpretation is based upon qualitative comparison with relaxation in plastic crystals, where molecular rotation is well characterized, and upon the quantitative agreement between the calculated and observed linewidth change near 90K and the maximum spin-lattice relaxation rate at 140K. There is also motional evidence, supported by X-ray structure measurements, that a phase transition occurs in the vicinity of 160K.

  14. 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

  15. Metal dioxides as analogue of SiO2 under strong compression studied by synchrotron XRD and simulations

    Science.gov (United States)

    Liu, H.; Liu, L. L.

    2017-12-01

    The phase transition sequence of SiO2 inducing by high pressure was theoretically predicted as coordination number (CN=6) structures (rutile, pyrite), CN=8 (Pnma) and CN=9 (P-62m) structures, but only the phases up to pyrite structure in SiO2 were observed experimentally up to now. The CN8 phase and CN9 phases of SiO2 were predicted to be stable at least 650 GPa, which is challenging to achieve in the static DAC experiment at present. In other metal dioxide systems, such as TiO2, the ambient rutile and anatase phases first transform to pyrite (CN6), then to the baddeleyite (CN7) phase, to a Pnma (CN8) phase and P-62m(CN9) phase. In this report, under strong compression at room temperature, several metal dioxides were studied experimentally and theoretically, to verify whether this theoretical predicted trend is common transition path under strong compression. This work was supported by Natural Science Foundation of China (11374075), Heilongjiang Province Science Fund for Distinguished Young Scholars (JC201005), Longjiang Scholar, the Fundamental Research Funds for the Central Universities (HIT. BRET1.2010002, HIT. IBRSEM.A.201403).

  16. 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.

  17. 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

  18. Utility of the Mild Brain Injury Atypical Symptoms Scale to detect symptom exaggeration: an analogue simulation study.

    Science.gov (United States)

    Lange, Rael T; Edmed, Shannon L; Sullivan, Karen A; French, Louis M; Cooper, Douglas B

    2013-01-01

    Brief self-report symptom checklists are often used to screen for postconcussional disorder (PCD) and posttraumatic stress disorder (PTSD) and are highly susceptible to symptom exaggeration. This study examined the utility of the five-item Mild Brain Injury Atypical Symptoms Scale (mBIAS) designed for use with the Neurobehavioral Symptom Inventory (NSI) and the PTSD Checklist-Civilian (PCL-C). Participants were 85 Australian undergraduate students who completed a battery of self-report measures under one of three experimental conditions: control (i.e., honest responding, n = 24), feign PCD (n = 29), and feign PTSD (n = 32). Measures were the mBIAS, NSI, PCL-C, Minnesota Multiphasic Personality Inventory-2, Restructured Form (MMPI-2-RF), and the Structured Inventory of Malingered Symptomatology (SIMS). Participants instructed to feign PTSD and PCD had significantly higher scores on the mBIAS, NSI, PCL-C, and MMPI-2-RF than did controls. Few differences were found between the feign PCD and feign PTSD groups, with the exception of scores on the NSI (feign PCD > feign PTSD) and PCL-C (feign PTSD > feign PCD). Optimal cutoff scores on the mBIAS of ≥8 and ≥6 were found to reflect "probable exaggeration" (sensitivity = .34; specificity = 1.0; positive predictive power, PPP = 1.0; negative predictive power, NPP = .74) and "possible exaggeration" (sensitivity = .72; specificity = .88; PPP = .76; NPP = .85), respectively. Findings provide preliminary support for the use of the mBIAS as a tool to detect symptom exaggeration when administering the NSI and PCL-C.

  19. 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.

  20. Studies on polyaspartamide gadolinium complexes as potential magnetic resonance imaging contrast agents

    International Nuclear Information System (INIS)

    Yan Guoping; Liu Maili; Li Liyun

    2005-01-01

    Purpose: A series of polyaspartamide gadolinium complexes containing pyridoxamine groups were studied as the potential magnetic resonance imaging (MRI) contrast agents for liver enhancement. Methods: These polyaspartamide gadolinium complexes were prepared and evaluated by relaxivity, acute toxicity studies and magnetic resonance imaging of the liver in rats. Results: These polyaspartamide gadolinium complexes have higher relaxation effectiveness than that of the clinically used gadolinium diethylenetriaminepentaacetic acid and possess the low intravenous acute toxicities to Institute for Cancer Research (ICR) mice. Magnetic resonance imaging of the liver in rats indicated that they greatly enhance the contrast of magnetic resonance images and provide prolonged intravascular duration in the liver. Conclusion: These results indicated that the polyaspartamide gadolinium complexes containing pyridoxamine groups could be considered as the appropriate MRI contrast agents for liver enhancement

  1. 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

  2. A study on CYP1A inhibitory action of E-2-(4'-methoxybenzylidene)-1-benzosuberone and some related chalcones and cyclic chalcone analogues

    International Nuclear Information System (INIS)

    Monostory, Katalin; Tamasi, Viola; Vereczkey, Laszlo; Perjesi, Pal

    2003-01-01

    In vivo investigation of E-2-(4'-methoxybenzylidene)-1-benzosuberone (4a) on the 7,12-dimethylbenz[a]anthracene (DMBA)-induced onco/tumor suppressor gene expressions suggested that inhibition of metabolic activation of DMBA might play a role in the observed activity of the compound. In order to explore this possible biological action we have investigated whether 4a and some of its structurally related analogues had inhibitory effects on the CYP1A enzymes. During our study 7-ethoxyresorufin O-dealkylation activity of CYP1A isoenzymes was measured in liver microsomes prepared from 3-methylcholanthrene treated male rats. Inhibition constants (K i values) were determined by using different concentrations of 7-ethoxyresorufin and the investigated chalcones (1), E-2-benzylidene-1-indanones (2), -tetralones (3) and -benzosuberones (4). Each compound was found to be a strong competitive inhibitor of the CYP1A enzymes. Their inhibitory activity was comparable with or even higher than that of 7,8-benzoflavone, the known strong CYP1A inhibitor used as reference substance. By proper selection of the substituents on the benzylidene moiety we investigated how the inhibitory activity (K i value) of 1-4 varied as a function of the ring size (n=0, 5, 6, 7) carbon atoms, and the nature as well as the position of the substituents. To test applicability of the previously set structural requirements for binding of xenobiotics to the CYP1A enzymes we compared some topological, physico-chemical and quantum mechanical parameters of 1-4 with 7-ethoxyresorufin and 7,8-benzoflavone, the investigated CYP1A substrate and inhibitor, respectively

  3. 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.

  4. 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)

  5. Insulin analogues in pregnancy and specific congenital anomalies

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  6. 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

  7. Simulation study of two-ion hybrid resonance heating

    International Nuclear Information System (INIS)

    Riyopoulos, S.; Tajima, T.

    1986-02-01

    A one-dimensional low-noise, low-frequency electromagnetic particle simulation code that is appropriate for investigation of ion cyclotron resonance heating (ICRH) is developed. Retaining the hyperbolicity of the electromagnetic waves and exploiting nearly one-dimensional characteristics (perpendicular to the external magnetic field) of the ICRH, we use the guiding center electron approximation for the transverse electronic current calculation. We observe mode conversion of the incoming magnetosonic wave into the electrostatic ion-ion hybrid mode accompanied by strong ion-heating. The dependence of this heating on the different plasma parameters is examined through a series of simulations, focusing mainly on wave incidence from the high field side. Because K/sub parallel/ = 0 in our runs, the conventional Landau damping cannot explain the ion heating. Non-linear mechanisms for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy absorption during radio frequency heating in the ion cyclotron regime. 32 refs., 17 figs

  8. Late whiplash syndrome: a clinical and magnetic resonance imaging study.

    Science.gov (United States)

    Bonuccelli, U; Pavese, N; Lucetti, C; Renna, M R; Gambaccini, G; Bernardini, S; Canapicchi, R; Carrozzi, L; Murri, L

    1999-01-01

    Cervical hyperextension injuries are common and are associated with significant morbidity. Clinically two syndromes are described: "acute" whiplash syndrome and "late" whiplash syndrome (in which the patients are still symptomatic after six months despite normal physical and radiological examination). In order to clarify the pathology of the persistent pain in late whiplash syndrome we performed a cervical spine magnetic resonance imaging (MRI) in 33 consecutive patients suffering from this condition. Twenty-six patients (78.8%) showed MRI abnormalities, the most common MRI finding (57.6%) was pre-existent spondylosis. Indeed, the group of patients with spondylosis and other MRI changes had higher clinical scores than those without MRI abnormalities as measured by a three-point grading system based upon the symptoms and signs shown. Several MRI changes, most of them already demonstrable by standard X-ray were seen among 33 patients suffering from late whiplash syndrome. Although no one of these findings appears to be specific and certainly related to the previous neck injury, they could represent a risk factor for a longer pain duration.

  9. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J.

    1991-01-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain

  10. 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)

  11. 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

  12. Lead optimization of antimalarial propafenone analogues.

    Science.gov (United States)

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

    2012-07-12

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

  13. Experimental study on flow-induced acoustic resonance in square closed side branch

    International Nuclear Information System (INIS)

    Zhang Hui; Gu Hanyang; Liu Xiaojing; Zhang Kai; Xie Yongcheng; Zu Hongbiao

    2014-01-01

    Flow-induced acoustic resonance is a phenomenon caused by the interaction of flow and acoustic fields in special structure. Acoustic resonance characteristic experiments were carried out on square closed side branch. The influences of the velocity in main pipe and the length of the side branch on acoustic resonance were studied. The range of occurrence and characteristics of pressure pulsation were analyzed. Three lengths of side branches (L/d=5.6 and 7) were experimentally studied and the Reynolds number in the experiment was 2.74 X 10 4 -2.429 X 10 5 while the Mach number was 0.025-0.218. The results show that the resonance frequency shows a lock-in phenomenon with the increase of velocity. As the length of the side branch increasing, the amplitude of the acoustic pressure and the resonance frequency decrease. In the considered structure, the acoustic resonance occurs when Strouhal number is 0.3-0.6 and 0.7-1.0. (authors)

  14. 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

  15. 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

  16. Experimental study of the influence of different resonators on thermoacoustic conversion performance of a thermoacoustic-Stirling heat engine.

    Science.gov (United States)

    Luo, E C; Ling, H; Dai, W; Yu, G Y

    2006-12-22

    In this paper, an experimental study of the effect of the resonator shape on the performance of a traveling-wave thermoacoustic engine is presented. Two different resonators were tested in the thermoacoustic-Stirling heat. One resonator is an iso-diameter one, and the other is a tapered one. To have a reasonable comparison reference, we keep the same traveling-wave loop, the same resonant frequency and the same operating pressure. The experiment showed that the resonator shape has significant influence on the global performance of the thermoacoustic-Stirling heat engine. The tapered resonator gives much better performance than the iso-diameter resonator. The tapered resonator system achieved a maximum pressure ratio of about 1.3, a maximum net acoustical power output of about 450 W and a highest thermoacoustic efficiency of about 25%.

  17. 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.

  18. Study on electromagnetic characteristics of the magnetic coupling resonant coil for the wireless power transmission system.

    Science.gov (United States)

    Wang, Zhongxian; Liu, Yiping; Wei, Yonggeng; Song, Yilin

    2018-01-01

    The resonant coil design is taken as the core technology in the magnetic coupling resonant wireless power transmission system, which achieves energy transmission by the coupling of the resonant coil. This paper studies the effect of the resonant coil on energy transmission and the efficiency of the system. Combining a two-coil with a three-coil system, the optimum design method for the resonant coil is given to propose a novel coil structure. First, the co-simulation methods of Pspice and Maxwell are used. When the coupling coefficient of the resonant coil is different, the relationship between system transmission efficiency, output power, and frequency is analyzed. When the self-inductance of the resonant coil is different, the relationship between the performance and frequency of the system transmission is analyzed. Then, two-coil and three-coil structure models are built, and the parameters of the magnetic field of the coils are calculated and analyzed using the finite element method. In the end, a dual E-type simulation circuit model is used to optimize the design of the novel resonance coil. The co-simulation results show that the coupling coefficients of the two-coil, three-coil, and novel coil systems are 0.017, 0.17 and 0.0126, respectively. The power loss of the novel coil is 16.4 mW. There is an obvious improvement in the three-coil system, which shows that the magnetic leakage of the field and the energy coupling are relatively small. The new structure coil has better performance, and the load loss is lower; it can improve the system output power and transmission efficiency.

  19. 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

  20. 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)

  1. Laboratory studies of the dynamic of resonance cones formation in magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Nazarov, V. V.; Starodubtsev, M. V.; Kostrov, A. V. [Russian Academy of Sciences, Institute of Applied Physics, Nizhny Novgorod (Russian Federation)

    2013-03-15

    The paper is devoted to experimental studies of formation of resonance cones in magnetized plasmas by pulsed RF source in the lower-hybrid (whistler) and the upper-hybrid frequency ranges. It is shown that in both frequency ranges, resonance cones exhibit similar dynamics after switching-on the RF source: at first, wide maxima of radiation are formed in non-resonance directions, which then become narrower, with their direction approaching the resonance one. While the resonance cones are being formed, one observes a fine structure in the form of secondary radiation maxima. It is shown that the characteristic formation time of stationary resonance cones is determined by the minimal value of the group velocity of the quasi-electrostatic waves excited by the antenna. In the low-temperature plasma, this value is limited in the lower-hybrid frequency range by the spatial spectrum of the emitting antenna and in the upper-hybrid range, by the effects of spatial plasma dispersion.

  2. Assessment of CO2 discharge in a spring using time-variant stable carbon isotope data as a natural analogue study of CO2 leakage

    Science.gov (United States)

    Yu, Soonyoung; Chae, Gitak; Jo, Minki; Kim, Jeong-Chan; Yun, Seong-Taek

    2015-04-01

    CO2-rich springs have been studied as a natural analogue of CO2 leakage through shallow subsurface environment, as they provide information on the behaviors of CO2 during the leakage from geologic CO2 storage sites. For this study, we monitored the δ13C values as well as temperature, pH, EC, DO, and alkalinity for a CO2-rich spring for 48 hours. The water samples (N=47) were collected every hour in stopper bottles without headspace to avoid the interaction with air and the CO2 degassing. The δ13C values of total dissolved inorganic carbon (TDIC) in the water samples were analyzed using a cavity ring-down spectroscopy (CRDS) system (Picarro). The values of δ13CTDIC, temperature, pH, EC, DO, and alkalinity were in the range of -9.43 ~ -8.91 o 12.3 ~ 13.2oC, 4.86 ~ 5.02, 186 ~ 189 μS/cm, 1.8 ~ 3.4 mg/L, and 0.74 ~ 0.95 meq/L, respectively. The concentrations of TDIC calculated using pH and alkalinity values were between 22.5 and 34.8 mmol/L. The δ13CTDIC data imply that dissolved carbon in the spring was derived from a deep-seated source (i.e., magmatic) that was slightly intermixed with soil CO2. Careful examination of the time-series variation of measured parameters shows the following characteristics: 1) the δ13CTDIC values are negatively correlated with pH (r = -0.59) and positively correlated with TDIC (r = 0.58), and 2) delay times of the change of pH and alkalinity following the change of δ13CTDIC values are 0 and -3 hours, respectively; the pH change occurs simultaneously with the change of δ13CTDIC, while the alkalinity change happens before 3 hours. Our results indicate that the studied CO2-rich spring is influenced by the intermittent supply of deep-seated CO2. [Acknowledgment] This work was financially supported by the fundamental research project of KIGAM and partially by the "Geo-Advanced Innovative Action (GAIA) Project (2014000530003)" from Korea Ministry of Environment (MOE).

  3. Identification of methionine aminopeptidase 2 as a molecular target of the organoselenium drug ebselen and its derivatives/analogues: Synthesis, inhibitory activity and molecular modeling study.

    Science.gov (United States)

    Węglarz-Tomczak, Ewelina; Burda-Grabowska, Małgorzata; Giurg, Mirosław; Mucha, Artur

    2016-11-01

    A collection of twenty-six organoselenium compounds, ebselen and its structural analogues, provided a novel approach for inhibiting the activity of human methionine aminopeptidase 2 (MetAP2). This metalloprotease, being responsible for the removal of the amino-terminal methionine from newly synthesized proteins, plays a key role in angiogenesis, which is essential for the progression of diseases, including solid tumor cancers. In this work, we discovered that ebselen, a synthetic organoselenium drug molecule with anti-inflammatory, anti-oxidant and cytoprotective activity, inhibits one of the main enzymes in the tumor progression pathway. Using three-step synthesis, we obtained twenty-five ebselen derivatives/analogues, ten of which are new, and tested their inhibitory activity toward three neutral aminopeptidases (MetAP2, alanine and leucine aminopeptidases). All of the tested compounds proved to be selective, slow-binding inhibitors of MetAP2. Similarly to ebselen, most of its analogues exhibited a moderate potency (IC 50 =1-12μM). Moreover, we identified three strong inhibitors that bind favorably to the enzyme with the half maximal inhibitory concentration in the submicromolar range. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 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

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

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  7. Possibilities and limitations of analogue methods for studying the dynamics of nuclear power stations; Possibilites et limitations du calcul analogique pour les etudes dynamiques de centrales nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Caillet, C; Deat, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    1. Introduction: the present paper is devoted to analog simulation of problems related to nuclear reactors other than the simulation of the kinetic equations which is well known. 2. Thermodynamic problems: various problems relative to temperature evolution in a reactor, in a pipe, in an exchanger, in a turbine, are studied, and simulation techniques used by earlier authors are critically reviewed. 3. Pipe simulators: it is shown that this problem can be solved by the use of specialized simulators which will be described and analysed. 4. Rotating machine simulators: the particular aspect of rotating machine calculations introducing frequent use of diagrams is emphasized. A simulator requiring both digital and analogue methods is described. 5. The study of a nuclear power station: as an example it is proposed to discuss problems a rising in connection with the preceding elements (a, b, c, d) when simulating the behaviour of large nuclear plants. The part played by ordinary computing elements for the simulation of the different servomechanism transfer functions is considered and process of regulation is outlined. 6. Conclusion: the necessity of the use of high quality simulators and computers is underlined and the accuracy of the solutions is discussed. (author)Fren. [French] 1. Cinetique des reacteurs: la simulation des equations cinetiques d'un reacteur nucleaire ne pose desormais plus de probleme. II est donc possible de faire le point des differentes applications de la technique analogique dans ce domaine. 2. Les problemes thermodynamiques: on discute les differents problemes poses par l'evolution des temperatures dans un reacteur, dans une tuyauterie, dans un echangeur, dans une turbine, et on passe en revue les techniques de simulation proposees jusqu'a ce jour. 3s simulateurs de tuyauteries: on montre comment les differents problemes poses ci-dessus peuvent etre resolus, pour une classe tres vaste de reacteurs par l'emploi de simulateurs speciaux que l

  8. 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.)

  9. 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

  10. Blowing loop in the EL-4 reactor: CO{sub 2} flow control analogue study; Boucle de soufflage de la centrale EL-4 - regulation du debit CO{sub 2} - etude analogique

    Energy Technology Data Exchange (ETDEWEB)

    Chazal, G; Merle, J P; Guillemard, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Leroy, C; Robin, L; Jacquin, J C; Cornudet, A [Societe INDATOM, France (France)

    1966-07-01

    This report describes one study which contributed to the construction of the Monts d'Arree nuclear power station: EL-4. The reactor is cooled by a CO{sub 2} current provided by 3 turbo-blower groups. The priming vapour for the turbines is taken at the exit of the main CO{sub 2} - H{sub 2}O exchangers. The operation of EL 4 is based on a high degree of centralization of the controls which attributes an important role to the general regulation circuits. This general regulation includes in particular an internal blowing loop which controls the CO{sub 2} flow. The study of the control of this CO{sub 2} flow is made up of 3 parts: - analogue representation of the reactors cooling circuit and of the turbo blower unit. - first test campaign using the analogue computer describing the natural behaviour of the system in the absence of control. theoretical determination of the regulation factors; definition of the regulation using an analogue computer and second test campaign for recording the performances of the blowing loop. The 4. part of the report deals with the analogue study: analogue equations - development. (authors) [French] Ce rapport prend place parmi les etudes de realisation de la Centrale des Monts d'Arree EL-4. Le reacteur est refroidi par une circulation de CO{sub 2} assuree par 3 groupes turbosoufflantes. La vapeur d'entrainement des turbines est prelevee a la sortie des echangeurs principaux CO{sub 2} - H{sub 2}O. L'exploitation de EL-4 repose sur une centralisation poussee des moyens de controle-commande qui attribue un role essentiel aux circuits de regulation generale. Cette regulation generale comporte en particulier une boucle interne de soufflage qui realise un asservissement du debit de CO{sub 2}. L'etude de cette regulation du debit CO{sub 2} comprend 3 parties: - representation analogique du circuit de refroidissement du reacteur et de l'ensemble turbine-soufflante. - premiere campagne d'essais sur calculateur analogique decrivant le comportement

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

    Science.gov (United States)

    Usman, Afia; Ahmad, Masood

    2016-09-01

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

  12. 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.

  13. 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

  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. 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

  16. 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

  17. Causal structure of analogue spacetimes

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Visual activation in infants and young children studied by functional magnetic resonance imaging

    DEFF Research Database (Denmark)

    Born, Alfred Peter; Leth, H; Miranda Gimenez-Ricco, Maria Jo

    1998-01-01

    The purpose of this study was to determine whether visual stimulation in sleeping infants and young children can be examined by functional magnetic resonance imaging. We studied 17 children, aged 3 d to 48 mo, and three healthy adults. Visual stimulation was performed with 8-Hz flickering light...... through the sleeping childs' closed eyelids. Functional magnetic resonance imaging was performed with a gradient echoplanar sequence in a l.5-T magnetic resonance scanner. Six subjects were excluded because of movement artifacts; the youngest infant showed no response. In 10 children, we could demonstrate...... flow during activation. The different response patterns in young children and adults can reflect developmental or behavioral differences. Localization of the activation seemed to be age-dependent. In the older children and the adults, it encompassed the whole length of the calcarine sulcus, whereas...

  3. A study of the high frequency limitations of series resonant converters

    Science.gov (United States)

    Stuart, T. A.; King, R. J.

    1982-01-01

    A transformer induced oscillation in series resonant (SR) converters is studied. It may occur in the discontinuous current mode. The source of the oscillation is an unexpected resonant circuit formed by normal resonance components in series with the magnetizing inductance of the output transformers. The methods for achieving cyclic stability are: to use a half bridge SR converter where q0.5. Q should be as close to 1.0 as possible. If 0.5q1.0, the instability will be avoided if psi2/3q-1/3. The second objective was to investigate a power field effect transistor (FET) version of the SR converter capable of operating at frequencies above 100 KHz, to study component stress and losses at various frequencies.

  4. Interactions of cisplatin analogues with lysozyme: a comparative analysis.

    Science.gov (United States)

    Ferraro, Giarita; De Benedictis, Ilaria; Malfitano, Annamaria; Morelli, Giancarlo; Novellino, Ettore; Marasco, Daniela

    2017-10-01

    The biophysical characterization of drug binding to proteins plays a key role in structural biology and in the discovery and optimization of drug discovery processes. The search for optimal combinations of biophysical techniques that can correctly and efficiently identify and quantify binding of metal-based drugs to their final target is challenging, due to the physicochemical properties of these agents. Different cisplatin derivatives have shown different citotoxicities in most common cancer lines, suggesting that they exert their biological activity via different mechanisms of action. Here we carried out a comparative analysis, by studying the behaviours of three Pt-compounds under the same experimental conditions and binding assays to properly deepen the determinants of the different MAOs. Indeed we compared the results obtained using surface plasmon resonance, isothermal titration calorimetry, fluorescence spectroscopy and thermal shift assays based on circular dichroism experiments in the characterization of the formation of adducts obtained upon reaction of cisplatin, carboplatin and iodinated analogue of cisplatin, cis-Pt (NH 3 ) 2 I 2 , with the model protein hen egg white lysozyme, both at neutral and acid pHs. Further we reasoned on the applicability of employed techniques for the study the thermodynamics and kinetics of the reaction of a metallodrug with a protein and to reveal which information can be obtained using a combination of these analyses. Data were discussed on the light of the existing structural data collected on the platinated protein.

  5. Total and fission cross-sections of 239Pu - statistical study of resonance parameters

    International Nuclear Information System (INIS)

    Derrien, H.; Blons, J.; Eggermann, C.; Michaudon, A.; Paya, D.; Ribon, P.

    1967-01-01

    The authors measured the total and fission cross-sections of 239 Pu with the linear accelerator at Saclay as a pulsed source of neutrons. The total cross-section was measured in the range from 4 to 700 eV and the best resolution used was 1.5 ns/m; the fission cross-section was measured between 4 eV and 6 keV, the best resolution having been 6 ns/m. The transmission measurements on five samples were made at the temperature of liquid nitrogen, and comparisons made with supplementary experiments at ambient temperature made it possible to determine the Doppler broadening factor (Δ = η√E). The resonances were identified from 4 to 500 eV in the total cross-section; the average level spacing was of the order of 2.4 eV. It would appear that, in this energy range, nearly all the levels were identified. The resonance parameters were determined by analysis of shape in conjunction with a least-squares programme on an IBM-7094 computer. The existence of a large number of broad resonances corresponding to very large fission widths has been shown to exist. Statistical study of the fission widths actually shows the existence of two families of resonances, one corresponding to a mean Γ f of the order of 45 meV and the other to a mean Γ/f of about 750 meV. The authors were therefore able to postulate a classification of resonances in terms of two spin states, the level population ratio in each family being: (2J 1 +1)/(2J 2 +1) = 1/3; J 1 = 0 corresponds to the broad resonances and J 2 = 1 to the narrow ones. The partial widths for radiative capture fluctuate slightly around a mean value of 40 meV. By using a multilevel programme, the authors were able to investigate the extent to which the existence of large fission widths might give rise to fictitious resonances (quasi-resonances) and perturbations and also to make a statistical study of the resonance parameters. (author) [fr

  6. 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.

  7. 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.

  8. Resonant x-ray scattering study of the antiferroelectric and ferrielectric phases in liquid crystal devices

    International Nuclear Information System (INIS)

    Matkin, L. S.; Watson, S. J.; Gleeson, H. F.; Pindak, R.; Pitney, J.; Johnson, P. M.; Huang, C. C.; Barois, P.; Levelut, A.-M.; Srajer, G.

    2001-01-01

    Resonant x-ray scattering has been used to investigate the interlayer ordering of the antiferroelectric and ferrielectric smectic C * subphases in a device geometry. The liquid crystalline materials studied contain a selenium atom and the experiments were carried out at the selenium K edge allowing x-ray transmission through glass. The resonant scattering peaks associated with the antiferroelectric phase were observed in two devices containing different materials. It was observed that the electric-field-induced antiferroelectric to ferroelectric transition coincides with the chevron to bookshelf transition in one of the devices. Observation of the splitting of the antiferroelectric resonant peaks as a function of applied field also confirmed that no helical unwinding occurs at fields lower than the chevron to bookshelf threshold. Resonant features associated with the four-layer ferrielectric liquid crystal phase were observed in a device geometry. Monitoring the electric field dependence of these ferrielectric resonant peaks showed that the chevron to bookshelf transition occurs at a lower applied field than the ferrielectric to ferroelectric switching transition

  9. Electron spin resonance studies of iron-group impurities in beryllium fluoride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Griscom, D L; Stapelbroek, M [Naval Research Lab., Washington, DC (USA); Weber, M J [California Univ., Livermore (USA). Lawrence Livermore National Lab.

    1980-11-01

    Electron spin resonance investigations have been carried out on unirradiated BeF/sub 2/ glasses. Two relatively intense resonances were observed in a water-free distilled glass known to contain 49 ppM Ni, 13 ppM Mn, and < 20 ppM Fe. One of these was the paramagnetic resonance spectrum of Mn/sup 2 +/. Analysis of the observed /sup 19/F superhyperfine structure demonstrated this manganese to occupy distorted octahedral sites in the glass network. The second resonance was shown by temperature and frequency dependence studies, coupled with computer line shape analysis, to be a ferromagnetic resonance signal due to precipitated ferrite phases. The data suggest that these ferrites are somewhat heterogeneous and most likely comprize magnetite-like phases similar to NiFe/sub 2/O/sub 4/. An optical extinction curve rising into the ultraviolet with an approximate lambda/sup -4/ dependence is tentatively ascribed to light scattering by ferrite particles approximately 1000 Angstroems in diameter.

  10. Evolving a polymerase for hydrophobic base analogues.

    Science.gov (United States)

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

    2009-10-21

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

  11. 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

  12. Placental Growth during Normal Pregnancy - A Magnetic Resonance Imaging Study

    DEFF Research Database (Denmark)

    Langhoff, Lasse; Grønbeck, Lene; von Huth, Sebastian

    2017-01-01

    were measured in both sagittal and transversal slices. All placentas were weighed after delivery to make a comparative study. RESULTS: Sixteen of the 20 women had increasing placental volumes from the 14th to 38th week of gestation. The 6th and 7th scan showed that 4 women had placentas of the same...... was 640 g (range 500-787 g). All pregnancies were carried to term, resulting in the delivery of healthy infants with good correlation between placental size and birth weight (R = 0.56, p = 0.009). CONCLUSION: Placental growth was measured systematically in a longitudinal study through the second and third...

  13. 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

  14. 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.

  15. 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 ...

  16. 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.

  17. 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.

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

    African Journals Online (AJOL)

    Sally Mahmood Mohamed Hussin Omar

    2015-07-10

    Jul 10, 2015 ... The tendon sheath of the posterior tibial muscle covers the posterior and ..... may be associated with avulsion fractures at either the origin or the insertion .... 14. Shibata Y, Nishi G, Masegi A. Stress test and anatomical study of.

  19. Bud abortion in tulip bulbs studied by magnetic resonance imaging

    NARCIS (Netherlands)

    Kilsdonk, van M.G.; Nicolaij, K.; Franssen, J.M.; Kollöffel, C.

    2002-01-01

    After storage and subsequent planting of flower bulbs, the flower bud frequently appears to be aborted. This physiological aberration is probably caused by a change in the water status of the bulb and may be initiated during storage. The development of bud abortion in tulip bulbs was studied during

  20. 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...... and to assist assignment of the resonance Raman spectra. A new and improved scaled quantum mechanical force field for the butadiene radical cation was also determined. The presence of more than one rotamer was observed in all the polyene radical cations we investigated. (C) 1997 Elsevier Science B.V....

  1. 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.

  2. Outcrop analogue study of Permocarboniferous geothermal sandstone reservoir formations (northern Upper Rhine Graben, Germany): impact of mineral content, depositional environment and diagenesis on petrophysical properties

    Science.gov (United States)

    Aretz, Achim; Bär, Kristian; Götz, Annette E.; Sass, Ingo

    2016-07-01

    The Permocarboniferous siliciclastic formations represent the largest hydrothermal reservoir in the northern Upper Rhine Graben in SW Germany and have so far been investigated in large-scale studies only. The Cenozoic Upper Rhine Graben crosses the Permocarboniferous Saar-Nahe Basin, a Variscan intramontane molasse basin. Due to the subsidence in this graben structure, the top of the up to 2-km-thick Permocarboniferous is located at a depth of 600-2900 m and is overlain by Tertiary and Quaternary sediments. At this depth, the reservoir temperatures exceed 150 °C, which are sufficient for geothermal electricity generation with binary power plants. To further assess the potential of this geothermal reservoir, detailed information on thermophysical and hydraulic properties of the different lithostratigraphical units and their depositional environment is essential. Here, we present an integrated study of outcrop analogues and drill core material. In total, 850 outcrop samples were analyzed, measuring porosity, permeability, thermal conductivity and thermal diffusivity. Furthermore, 62 plugs were taken from drillings that encountered or intersected the Permocarboniferous at depths between 1800 and 2900 m. Petrographic analysis of 155 thin sections of outcrop samples and samples taken from reservoir depth was conducted to quantify the mineral composition, sorting and rounding of grains and the kind of cementation. Its influence on porosity, permeability, the degree of compaction and illitization was quantified. Three parameters influencing the reservoir properties of the Permocarboniferous were detected. The strongest and most destructive influence on reservoir quality is related to late diagenetic processes. An illitic and kaolinitic cementation and impregnation of bitumina document CO2- and CH4-rich acidic pore water conditions, which are interpreted as fluids that migrated along a hydraulic contact from an underlying Carboniferous hydrocarbon source rock. Migrating

  3. Resonant particle production during inflation: a full analytical study

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Lauren; Peloso, Marco [School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States); Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu [Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, 1126 Lederle Graduate Research Tower (LGRT), Amherst, MA 01003 (United States)

    2017-05-01

    We revisit the study of the phenomenology associated to a burst of particle production of a field whose mass is controlled by the inflaton field and vanishes at one given instance during inflation. This generates a bump in the correlators of the primordial scalar curvature. We provide a unified formalism to compute various effects that have been obtained in the literature and confirm that the dominant effects are due to the rescattering of the produced particles on the inflaton condensate. We improve over existing results (based on numerical fits) by providing exact analytic expressions for the shape and height of the bump, both in the power spectrum and the equilateral bispectrum. We then study the regime of validity of the perturbative computations of this signature. Finally, we extend these computations to the case of a burst of particle production in a sector coupled only gravitationally to the inflaton.

  4. Primary CNS lymphoma in nonimmunocompromised patients magnetic resonance study

    International Nuclear Information System (INIS)

    Pena, J.; Fernandez, J.M.; Galarraga, M.I.; Pozo, A.; Montes, A.; Ablanedo, P.

    1995-01-01

    Prymary lymphoma of the CNS (PLCNS) is a relatively infrequent malignant tumor that has become increasingly common over the past decade. The radiological signs, although not pathognomonic, are quite specific and suggestive of the correct diagnosis, thus facilitating therapeutic management. We present six cases of PLCNS in nonimmunocopromised patients studied by MR in our hospital over the past two and a half years. We describe theradiological findings, correlating them with those mentioned in the literature. 14 refs

  5. Electron paramagnetic resonance studies of defects in dilute magnetic alloys

    International Nuclear Information System (INIS)

    Suss, J.T.; Raizman, A.

    1980-01-01

    The EPR spectrum of erbium was used to study the effects of cold-working (rolling and mechanical polishing) in dilute gold-erbium alloys. Variation in the EPR linewidth, intensity and asymmetry parameter (A/B ratio) were investigated. Most of the results could be interpreted in terms of segregation of erbium ions to subgrain boundaries (dislocations) in a surface layer of a few thousand Angstroms. (author)

  6. 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)

  7. Childhood temporal lobe epilepsy: correlation between electroencephalography and magnetic resonance spectroscopy: a case-control study.

    Science.gov (United States)

    Azab, Seham Fa; Sherief, Laila M; Saleh, Safaa H; Elshafeiy, Mona M; Siam, Ahmed G; Elsaeed, Wafaa F; Arafa, Mohamed A; Bendary, Eman A; Sherbiny, Hanan S; Elbehedy, Rabab M; Aziz, Khalid A

    2015-04-18

    The diagnosis of epilepsy should be made as early as possible to give a child the best chance for treatment success and also to decrease complications such as learning difficulties and social and behavioral problems. In this study, we aimed to assess the ability of magnetic resonance spectroscopy (MRS) in detecting the lateralization side in patients with Temporal lobe epilepsy (TLE) in correlation with EEG and MRI findings. This was a case-control study including 40 patients diagnosed (clinically and by EEG) as having temporal lobe epilepsy aged 8 to 14 years (mean, 10.4 years) and 20 healthy children with comparable age and gender as the control group. All patients were subjected to clinical examination, interictal electroencephalography and magnetic resonance imaging (MRI). Proton magnetic resonance spectroscopic examination (MRS) was performed to the patients and the controls. According to the findings of electroencephalography, our patients were classified to three groups: Group 1 included 20 patients with unitemporal (lateralized) epileptic focus, group 2 included 12 patients with bitemporal (non-lateralized) epileptic focus and group 3 included 8 patients with normal electroencephalography. Magnetic resonance spectroscopy could lateralize the epileptic focus in 19 patients in group 1, nine patients in group2 and five patients in group 3 with overall lateralization of (82.5%), while electroencephalography was able to lateralize the focus in (50%) of patients and magnetic resonance imaging detected lateralization of mesial temporal sclerosis in (57.5%) of patients. Magnetic resonance spectroscopy is a promising tool in evaluating patients with epilepsy and offers increased sensitivity to detect temporal pathology that is not obvious on structural MRI imaging.

  8. Non-contrast enhanced magnetic resonance angiography techniques in candidates for kidney transplantation: A comparative study

    International Nuclear Information System (INIS)

    Blankholm, Anne Dorte; Ginnerup-Pedersen, Bodil; Stausbøl-Grøn, Brian; Haislund, Margit; Laustsen, Sussie; Ringgaard, Steffen

    2013-01-01

    Aim: Detailed knowledge of vessel status in potential candidates for kidney transplantation is essential for the surgeon. Contrast enhanced magnetic resonance angiography has previously been used intensively for assessing this, but the discovery that use of gadolinium based contrast agents in magnetic resonance imaging can cause Nephrogenic Systemic Fibrosis in patients suffering from severe kidney disease has lead to renewed interest in non-contrast enhanced magnetic resonance angiography. The aim of this study was to find a non-contrast enhanced magnetic resonance angiography method for preoperative evaluation of the pelvic vessels prior to kidney transplantation, providing a sufficient image quality. Method: In a prospective study we consecutively included 54 patients undergoing examinations prior to kidney transplantation. The patients were examined with the following magnetic resonance angiography sequences: A 2D Time of flight (n = 54), 3D Time of flight (n = 52) patients, 3D Phase Contrast (n = 54), 3D Balanced Steady State Free Precession (n = 52) and a 2D TRiggered Angiography Non-Contrast Enhanced (TRANCE) (a Spin Echo sequence with subtraction) (n = 48). The sequences were evaluated with respect to contrast, diagnostic performance and artefact burden. Results: Evaluating contrast, 3D Phase Contrast was significantly better than 2D Time of flight (p 0.2). The 2D Time of flight was significantly better than the other sequences (p < 0.001) in all cases. The artefact score was lowest for the Phase Contrast images and significantly superior to the 2D Time of flight (p < 0.005). The 2D Time of flight was significantly better than the three other sequences (p < 0.001) in all cases. Conclusion: Non-contrast enhanced magnetic resonance angiography offers a safe preoperative examination for assessment of vessel status before kidney transplantation. A combination of 2D Time of flight and 3D Phase Contrast acquisitions is recommended and can be performed within a

  9. The long-term effect of hydrogen on the UO2 spent fuel stability under anoxic conditions: Findings from the Cigar Lake Natural Analogue study

    International Nuclear Information System (INIS)

    Bruno, Jordi; Spahiu, Kastriot

    2014-01-01

    Highlights: • We have reviewed current information on the effect of hydrogen in UO 2 spent fuel. • We explored the radiolytic models generated in the Cigar Lake project. • The Cigar Lake data supports that H 2 reduces alpha radiolysis oxidants. • The results indicate the hydrogen effect is present after 100.000 years deposition. - Abstract: The present paradigm on UO 2 spent fuel stability under anoxic conditions assumes that the potential oxidative alteration of the matrix is suppressed in the presence of the hydrogen generated by the anoxic corrosion of iron by water. The observations from the Cigar Lake Natural Analogue project indicated the long-term stability of the uraninite ore under anoxic conditions and with substantial hydrogen generation. The radiolytic models developed in the analogue project have been used to test some of the hypothesis concerning the activation of hydrogen on the uranium(IV) oxide surface. Suggestions to pathways of radiolytic oxidant consumption by other processes than uranium dioxide or sulphide oxidation are presented. The stability of the ore body for billions of year indicates the presence of processes which neutralise radiolytic oxidants and one major factor may be the presence of dissolved hydrogen in the groundwaters contacting the ore body. The results from this test would indicate that hydrogen is activated on the surface of the Cigar Lake uraninites by alpha radiation consuming the generated radiolytic oxidants

  10. Application of a fluorescent cobalamin analogue for analysis of the binding kinetics. A study employing recombinant human transcobalamin and intrinsic factor

    DEFF Research Database (Denmark)

    Fedosov, Sergey N; Grissom, Charles B; Fedosova, Natalya U

    2006-01-01

    facilitated detailed kinetic analysis of Cbl binding. We found that TC had the same affinity for CBC and Cbl (K(d) = 5 x 10(-15) m), whereas interaction of CBC with the highly specific protein IF was more complex. For instance, CBC behaved normally in the partial reactions CBC + IF(30) and CBC + IF(20) when...... complexes. We suggest that the correct domain-domain interactions are the most important factor during recognition and fixation of the ligands by IF. Dissociation of IF-CBC was biphasic, and existence of multiple protein-analogue complexes with normal and partially corrupted structure may explain...... this behaviour. The most stable component had K(d) = 1.5 x 10(-13) m, which guarantees the binding of CBC to IF under physiological conditions. The specific intestinal receptor cubilin bound both IF-CBC and IF-Cbl with equal affinity. In conclusion, the fluorescent analogue CBC can be used as a reporting agent...

  11. 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.

  12. 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.

  13. 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.

  14. Ultraviolet-resonance femtosecond stimulated Raman study of the initial events in photoreceptor chromophore

    Directory of Open Access Journals (Sweden)

    Tahara T.

    2013-03-01

    Full Text Available Newly-developed ultraviolet-resonance femtosecond stimulated-Raman spectroscopy was utilized to study the initial structural evolution of photoactive yellow protein chromophore in solution. The obtained spectra changed drastically within 1 ps, demonstrating rapid in-plane deformations of the chromophore.

  15. 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

  16. 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…

  17. 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.

  18. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices

    Science.gov (United States)

    Jiang, Hai; Liu, Jianfang; Lv, Qingqing; Gu, Shoudong; Jiao, Xiaoyang; Li, Minjiao; Zhang, Shasha

    2016-09-01

    The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter) is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radii. Specifically, the levitation force is improved to a maximum degree when the resonance tube radius is slightly larger than the size of the reflector end face. Furthermore, the stability of acoustic levitation device is improved to a maximum degree by introducing a resonance tube of R=1.023λ. The experimental platform and levitation force measurement system of the acoustic levitation device with concave-end-face-type emitter and reflector are developed, and the test of suspended matters and liquid drops is conducted. Results show that the Φ6.5-mm steel ball is suspended easily when the resonance tube radius is 1.023λ, and the Φ5.5-mm steel ball cannot be suspended when the resonance tube radius is 1.251λ. The levitation capability of the original acoustic levitation device without a resonance tube is weakened when a resonance tube of R=1.251λ is applied. These results are consistent with the ANSYS simulation results. The levitation time of the liquid droplet with a resonance tube of R=1.023λ is longer than without a resonance tube. This result is also supported by the MATLAB simulation results. Therefore, the performance of acoustic levitation device can be improved by introducing a resonant tube with an appropriate radius.

  19. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices

    Directory of Open Access Journals (Sweden)

    Hai Jiang

    2016-09-01

    Full Text Available The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radii. Specifically, the levitation force is improved to a maximum degree when the resonance tube radius is slightly larger than the size of the reflector end face. Furthermore, the stability of acoustic levitation device is improved to a maximum degree by introducing a resonance tube of R=1.023λ. The experimental platform and levitation force measurement system of the acoustic levitation device with concave-end-face-type emitter and reflector are developed, and the test of suspended matters and liquid drops is conducted. Results show that the Φ6.5-mm steel ball is suspended easily when the resonance tube radius is 1.023λ, and the Φ5.5-mm steel ball cannot be suspended when the resonance tube radius is 1.251λ. The levitation capability of the original acoustic levitation device without a resonance tube is weakened when a resonance tube of R=1.251λ is applied. These results are consistent with the ANSYS simulation results. The levitation time of the liquid droplet with a resonance tube of R=1.023λ is longer than without a resonance tube. This result is also supported by the MATLAB simulation results. Therefore, the performance of acoustic levitation device can be improved by introducing a resonant tube with an appropriate radius.

  20. Nuclear Magnetic Resonance Study of Fluorine-Graphite Intercalation Compounds

    International Nuclear Information System (INIS)

    Panich, A.M.; Goren, S.D.; Nakajima, T.; Vieth, H.-M.; Privalov, A.

    1998-01-01

    To study the origin of semimetal-metal and metal-insulator transformations, localization effects and C-E bonding in fluorine-intercalated graphite C x F, 13 C and 19 F NMR investigations have been carried out for a wide range of fluorine content, 3.8 8, are attributed to mobile fluorine acceptor species which are responsible for the increase of electric conductivity in the dilute compound. When increasing the fluorine content to x ∼ 8 corresponding to the maximum electric conductivity, covalent C-P bonds start to oc- cur. The number of these bonds grows with fluorine content resulting in the decrease in conductivity which is caused by a percolation mechanism rather than by a change in bond length. A difference in 19 F chemical shift for fluorine-intercalated graphite C x F and covalent graphite fluoride (CF) n has been observed and is attributed to different C-P bonding in these compounds

  1. 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)

  2. 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

  3. Ferromagnetic resonance study of sputtered NiFe/V/NiFe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Alayo, W., E-mail: willian.rodriguez@ufpel.edu.br [Departamento de Física – IFM, Universidade Federal de Pelotas, 96010-900 Rio Grande do Sul (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, RJ, 22290-180 (Brazil)

    2015-03-01

    The Ni{sub 81}Fe{sub 19}/V/Ni{sub 81}Fe{sub 19} heterostructures has been produced by magnetron sputtering and analyzed by ferromagnetic resonance. Two systems were investigated: the non symmetrical NiFe(50 Å)/V(t)/NiFe(30 Å) trilayers and the symmetrical NiFe(80 Å)/V(t)/NiFe(80 Å) trilayers, with variable ultrathin V thickness t. Ferromagnetic exchange coupling was evidenced for t below 10 Å by the excitation of the optic mode, in the case of the non symmetrical samples, and by the observation of a single resonance mode for the symmetrical trilayers. For larger V thickness, all samples exhibited two modes, which were attributed to the resonance of the individual NiFe layers with different effective magnetizations. The analysis with the equilibrium and resonance conditions provided the exchange coupling constants and effective magnetizations. - Highlights: • We present a study of symmetrical and non symmetrical NiFe/V/NiFe trilayers deposited on Si single crystals by ferromagnetic resonance (FMR) at room temperature. • For the non symmetrical trilayers, the FMR spectra show the optic and acoustic modes for samples with very thin V layer thicknesses, evidencing ferromagnetic exchange coupling, whereas, for larger V thickness, the spectra exhibited two well resolved modes associated to each independent NiFe layer. For the symmetrical trilayers, strong ferromagnetic exchange coupling is evidenced by the observation of a single resonance mode. • The analysis with the equilibrium condition and dispersion relation provides the exchange coupling constants and effective magnetizations.

  4. Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy

    International Nuclear Information System (INIS)

    Cova, M.; Frezza, F.; Pozzi-Mucelli, R.S.; Dalla-Palma, L.; Toffanin, R.; Pozzi-Mucelli, M.; Mlynarik, V.; Vittur, F.

    1998-01-01

    The aims of this study were (a) to compare the MR appearance of normal articular cartilage in ex vivo MR imaging (MRI) and MR microscopy (MRM) images of disarticulated human femoral heads, (b) to evaluate by MRM the topographic variations in articular cartilage of disarticulated human femoral heads, and subsequently, (c) to compare MRM images with histology. Ten disarticulated femoral heads were examined. Magnetic resonance images were obtained using spin-echo (SE) and gradient-echo (GE) sequences. Microimages were acquired on cartilage-bone cylindrical plugs excised from four regions (superior, inferior, anterior, posterior) of one femoral head, using a modified SE sequence. Both MRI and MRM images were obtained before and after a 90 rotation of the specimen, around the axis perpendicular to the examined cartilage surface. Finally, MRM images were correlated with histology. A trilaminar appearance of articular cartilage was observed with MRI and with a greater detail with MRM. A good correlation between MRI and MRM features was demonstrated. Both MRI and MRM showed a loss of the trilaminar cartilage appearance after specimen rotation, with greater evidence on MRM images. Cartilage excised from the four regions of the femoral head showed a different thickness, being thickest in the samples excised from the superior site. The MRM technique confirms the trilaminar MRI appearance of human articular cartilage, showing good correlation with histology. The loss of the trilaminar appearance of articular cartilage induced by specimen rotation suggests that this feature is partially related to the collagen-fiber orientation within the different layers. The MRM technique also shows topographic variations in thickness of human articular cartilage. (orig.)

  5. 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).

  6. 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

  7. 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

  8. Assessment of six dissimilarity metrics for climate analogues

    Science.gov (United States)

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

    2013-04-01

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

  9. High resolution study of proton resonances in 65Ga and 67Ga

    International Nuclear Information System (INIS)

    Sales, K.B.

    1980-01-01

    Differential cross sections were measured for 64 Zn(p,p) from 2.50 to 3.24 MeV and for 66 Zn(p,p) from 2.60 to 3.26 MeV at laboratory angles of 90 0 , 105 0 , 135 0 , and 160 0 . These experiments were performed with the Triangle Universities Nuclear Laboratory 3 MV Van de Graaff accelerator and associated electrostatic analyzer-homogenizer system. The total overall energy resolution was 420 to 525 eV for 64 Zn(p,p) and 360 to 405 eV for 66 Zn(p,p). Resonances observed in the excitation functions were analyzed with a multilevel R-Matrix formalism. Resonance energies, spins, parities, and elastic widths were extracted for 39 resonances in 65 Ga and 148 resonances in 67 Ga. The l = 0 proton strength functions were calculated for 64 Zn and 66 Zn. The s-wave strength function shows an increase for A=66, which is consistent with earlier results from (p,n) cross section studies. Statistical properties of the 1/2 + resonances in 65 Ga and 67 Ga were examined. The spacing and reduced width distributions were compared with the Wigner and Porter-Thomas distributions, respectively. This comparison indicates that 50% of the 1/2 + resonances were missed in 65 Ga and that 70% of the 1/2 + resonances were missed in 67 Ga. The observed s-wave level densities in 65 Ga and 67 Ga are compared with predictions from conventional level density models. The analogs of the 0.867 MeV, the 0.910 MeV, and the 1.370 MeV states of 65 Zn are observed in 65 Ga; the analogs of the 0.093 MeV and the 0.394 MeV states of 67 Zn are observed in 67 Ga. The analog states in 65 Ga were fragmented into only two or three resonances, while the two analog states in 67 Ga were highly fragmented. Fits to the fine structure distributions of these two analogs were obtained and the resulting parameters compared with the Robson model. Coulomb energies were extracted for these five analogs

  10. 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

  11. 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.)

  12. 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.)

  13. Design studies of heavy ion linear accelerators constructed of independently phased spiral resonators

    International Nuclear Information System (INIS)

    Stokes, R.H.; Armstrong, D.D.

    1975-01-01

    Preliminary design studies are reported for two linear accelerators for heavy ions. One accelerator is a high-intensity machine which would operate with 100 percent duty factor and would produce tin ions with 6.1 MeV/A. Alternatively, it could be operated under pulsed conditions with 25 percent duty factor and would then accelerate uranium ions to 8.1 MeV/A, tin ions to 10.5 MeV/A, and all lighter ions to higher velocities. It would be injected with a positive multicharge ion source and a 4-MV single-ended dc generator. Also, design studies are reported for small postaccelerator injected by a model FN tandem. Both accelerators use three-drift-tube spiral resonators operating at room temperature. Magnetic quadrupole singlets are placed between all resonators to provide radial focussing. Each resonator is independently phased according to the velocity of the ion to be accelerated. The ability to adjust the phase of each resonator permits variations in final energy and other beam properties with great flexibility. (U.S.)

  14. Two-dimensional NMR and photo-CIDNP studies of the insulin monomer: Assignment of aromatic resonances with application to protein folding, structure, and dynamics

    International Nuclear Information System (INIS)

    Weiss, M.A.; Shoelson, S.E.; Nguyen, D.T.; O'Shea, E.; Karplus, M.; Khait, I.; Neuringer, L.J.; Inouye, K.; Frank, B.H.; Beckage, M.

    1989-01-01

    The aromatic 1 H NMR resonances of the insulin monomer are assigned at 500 MHz by comparative studies of chemically modified and genetically altered variants, including a mutant insulin (PheB25 → Leu) associated with diabetes mellitus. The two histidines, three phenylalanines, and four tyrosines are observed to be in distinct local environments; their assignment provides sensitive markers for studies of tertiary structure, protein dynamics, and protein folding. The environments of the tyrosine residues have also been investigated by photochemically induced dynamic nuclear polarization (photo-CIDNP) and analyzed in relation to packing constrains in the crystal structures of insulin. Dimerization involving specific B-chain interactions is observed with increasing protein concentration and is shown to depend on temperature, pH, and solvent composition. The differences between proinsulin and mini-proinsulin suggest a structural mechanism for the observation that the fully reduced B29-A1 analogue folds more efficiently than proinsulin to form the correct pattern of disulfide bonds. These results are discussed in relation to molecular mechanics calculations of insulin based on the available crystal structures

  15. 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.

  16. Contribution to the Study of Nuclear Magnetic Resonance in Ferromagnets; Contribution a l'etude de la resonance nucleaire dans les corps ferromagnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Robert, C. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    Properties of nuclear magnetic resonance in the field acting on the nucleus in a ferromagnet were studied. Nuclei were {sup 57}Fe in iron and yttrium iron garnet. Static properties of resonance (frequency, line-width, dipolar structure) were investigated and compared with magnetic behavior and magnetic structure of the materials. Relaxation in garnet points out importance of long range fluctuations induced by impurities in a ferromagnetic lattice. (author) [French] Nous avons etudie les proprietes de la resonance nucleaire dans le champ existant a remplacement d'un noyau dans un corps ferromagnetique (champ local). Les noyaux etaient ceux de {sup 57}Fe dans le fer et dans le grenat d'yttrium et de fer. Les proprietes statiques de la resonance (frequence de resonance, largeur de la raie, structures dues a l'interaction dipolaire) ont ete etudiees et reliees aux caracteristiques magnetiques et a la structure de ces corps. La relaxation dans le grenat a mis en evidence les fluctuations a longue distance induites par des impuretes dans un reseau ferromagnetique. (auteur)

  17. Contribution to the Study of Nuclear Magnetic Resonance in Ferromagnets; Contribution a l'etude de la resonance nucleaire dans les corps ferromagnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Robert, C [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1962-07-01

    Properties of nuclear magnetic resonance in the field acting on the nucleus in a ferromagnet were studied. Nuclei were {sup 57}Fe in iron and yttrium iron garnet. Static properties of resonance (frequency, line-width, dipolar structure) were investigated and compared with magnetic behavior and magnetic structure of the materials. Relaxation in garnet points out importance of long range fluctuations induced by impurities in a ferromagnetic lattice. (author) [French] Nous avons etudie les proprietes de la resonance nucleaire dans le champ existant a remplacement d'un noyau dans un corps ferromagnetique (champ local). Les noyaux etaient ceux de {sup 57}Fe dans le fer et dans le grenat d'yttrium et de fer. Les proprietes statiques de la resonance (frequence de resonance, largeur de la raie, structures dues a l'interaction dipolaire) ont ete etudiees et reliees aux caracteristiques magnetiques et a la structure de ces corps. La relaxation dans le grenat a mis en evidence les fluctuations a longue distance induites par des impuretes dans un reseau ferromagnetique. (auteur)

  18. 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.

  19. 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

  20. 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.

  1. Binding-Induced Fluorescence of Serotonin Transporter Ligands: A Spectroscopic and Structural Study of 4-(4-(Dimethylamino)phenyl)-1-methylpyridinium (APP+) and APP+ Analogues

    Science.gov (United States)

    2014-01-01

    The binding-induced fluorescence of 4-(4-(dimethylamino)-phenyl)-1-methylpyridinium (APP+) and two new serotonin transporter (SERT)-binding fluorescent analogues, 1-butyl-4-[4-(1-dimethylamino)phenyl]-pyridinium bromide (BPP+) and 1-methyl-4-[4-(1-piperidinyl)phenyl]-pyridinium (PPP+), has been investigated. Optical spectroscopy reveals that these probes are highly sensitive to their chemical microenvironment, responding to variations in polarity with changes in transition energies and responding to changes in viscosity or rotational freedom with emission enhancements. Molecular docking calculations reveal that the probes are able to access the nonpolar and conformationally restrictive binding pocket of SERT. As a result, the probes exhibit previously not identified binding-induced turn-on emission that is spectroscopically distinct from dyes that have accumulated intracellularly. Thus, binding and transport dynamics of SERT ligands can be resolved both spatially and spectroscopically. PMID:24460204

  2. A comparison of a patient-rated visual analogue scale with the Liebowitz Social Anxiety Scale for social anxiety disorder: A cross-sectional study

    OpenAIRE

    興津, 裕美

    2014-01-01

    博士(医学) 乙第2814号, 著者名:Hiromi Okitsu・Jitsuki Sawamura・Katsuji Nishimura・Yasuto Sato・Jun Ishigooka,タイトル:A comparison of a patient-rated visual analogue scale with the Liebowitz Social Anxiety Scale for social anxiety disorder: A cross-sectional study,掲載誌:Open Journal of Psychiatry (2161-7325),巻・頁・年:4巻1号 p.68~74 (2014),著作権関連情報:Copyright © 2014 by authors and Scientific Research Publishing Inc.,DOI:10.4236/ojpsych.2014.41010...

  3. 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

  4. 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.

  5. Brain pathology after mild traumatic brain injury: an exploratory study by repeated magnetic resonance examination.

    Science.gov (United States)

    Lannsjö, Marianne; Raininko, Raili; Bustamante, Mariana; von Seth, Charlotta; Borg, Jörgen

    2013-09-01

    To explore brain pathology after mild traumatic brain injury by repeated magnetic resonance examination. A prospective follow-up study. Nineteen patients with mild traumatic brain injury presenting with Glasgow Coma Scale (GCS) 14-15. The patients were examined on day 2 or 3 and 3-7 months after the injury. The magnetic resonance protocol comprised conventional T1- and T2-weighted sequences including fluid attenuated inversion recovery (FLAIR), two susceptibility-weighted sequences to reveal haemorrhages, and diffusion-weighted sequences. Computer-aided volume comparison was performed. Clinical outcome was assessed by the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Hospital Anxiety and Depression Scale (HADS) and Glasgow Outcome Scale Extended (GOSE). At follow-up, 7 patients (37%) reported ≥  3 symptoms in RPQ, 5 reported some anxiety and 1 reported mild depression. Fifteen patients reported upper level of good recovery and 4 patients lower level of good recovery (GOSE 8 and 7, respectively). Magnetic resonance pathology was found in 1 patient at the first examination, but 4 patients (21%) showed volume loss at the second examination, at which 3 of them reported GOSE scores of 8. Loss of brain volume, demonstrated by computer-aided magnetic resonance imaging volumetry, may be a feasible marker of brain pathology after mild traumatic brain injury.

  6. Theoretical study of ferromagnetic resonance in exchange - coupled magnetic / nonmagnetic / magnetic multilayer structure

    International Nuclear Information System (INIS)

    Oezdogan, K.; Oezdemir, M.; Yalcin, O.; Aktas, B.

    2002-01-01

    The dispersion relation on ferromagnetic films was calculation by using torque equation of motion with a damping term. The total energy including zeeman, demagnetizing and anisotropy energy terms was used to get ferromagnetic resonance frequency for both uniform and higher order spin wave modes. In antiferromagnetic films, the torque equation of motion for each sub-lattice were written to derive an expression for the dispersion relation. The magnetic trilayer system under investigation consist of two ferromagnetic layers separated by a nonmagnetic layer. The dispersion relation of magnetic/nonmagnetic/magnetic three layers is calculated by using Landau-Lifshitz dynamic equation of motion for the magnetization with interlayer exchange energy. As for the exchange-coupled resonance of ferromagnetic resonance (FMR), the theoretical study has been calculated for both symmetrical and asymmetrical structures. In this systems, the exchange-coupling parameter A 12 between neighboring layers was used to get resonance fields as a function of the angle between the magnetization vectors of each magnetic layers

  7. 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.

  8. Study of hyperon-pion resonances from kaonic absorption with KLOE

    Directory of Open Access Journals (Sweden)

    Vázquez Doce Oton

    2015-01-01

    The study of the antiK-hadron interactions inside the drift chamber of KLOE was initiated in order to search for signals from the formation of deeply bound kaonic nuclear states and the study of resonances like the Λ(1405 and the Σ(1385, and constitute a first step towards the preparation of the AMADEUS experiment at DAFNE, the e+e− collider of the Frascati National Laboratories (Italy of INFN.

  9. Love-related changes in the brain: A resting-state functional magnetic resonance imaging study

    OpenAIRE

    Hongwen eSong; Zhiling eZou; Juan eKou; Yang eLiu; LiZhuang eYang; Anna ezilverstand; Federicod’Oleire eUquillas; Xiaochu eZhang; Xiaochu eZhang; Xiaochu eZhang

    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. Studies with functional magnetic resonance imaging (fMRI) have found activation increases in brain regions involved in processing of reward, emotion, motivation when romantic lovers view photographs of their partners. However, not much is known on whether romantic love affects the brain’s functional architecture during rest. In the present study, resting state...

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. Fungal growth inhibitory properties of new phytosphingolipid analogues.

    Science.gov (United States)

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

    2008-04-01

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

  15. 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.

  16. Study by magnetic resonance and relaxation of carbon 13 of some paramagnetic coordination complexes

    International Nuclear Information System (INIS)

    Ronfard-Haret, Jean-Claude

    1977-01-01

    This research thesis reports the study of coordination complexes by using NMR. After a brief recall of the theoretical background required for the processing of experimental data (hyper-fine coupling and magnetic resonance, spin density distribution, chemical displacement, dipolar, scalar and electronic relaxation), the author describes the conditions in which experiments have been performed and presents measurement methods (pulsed nuclear magnetic resonance, relaxation time measurement, determination of hyper-fine coupling constants, spectrometers and reactants). The next chapters address the study of different coordination complexes: [(pyridine-N-oxide) 2 Ni(acetylacetonate) 2 ], carbon 13 in alkyl-anilines-Ni II, complexation of 1- and 2-aminonaphthalene by transition ions, complexation of pyridine-N-oxide by the nickel Ni ++ ion in presence of water

  17. 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.

  18. Quantitative and qualitative assessment of structural magnetic resonance imaging data in a two-center study

    OpenAIRE

    Chalavi Sima; Simmons Andrew; Dijkstra Hildebrand; Barker Gareth J; Reinders AAT Simone

    2012-01-01

    Abstract 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 interaction between the sequence parameters and the effect of interest, and to minimise any such interaction by careful choice of acquisition parameters. As an exemplar of the issues involved in ...

  19. 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

  20. 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.)