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Sample records for alpha reactions

  1. Probing surface distributions of $\\alpha$ clusters in $^{20}$Ne via $\\alpha$-transfer reaction

    OpenAIRE

    Fukui, Tokuro; Taniguchi, Yasutaka; Suhara, Tadahiro; Kanada-En'yo, Yoshiko; Ogata, Kazuyuki

    2015-01-01

    Direct evidence of the $\\alpha$-cluster manifestation in bound states has not been obtained yet, although a number of experimental studies were carried out to extract the information of the clustering. In particular in conventional analyses of $\\alpha$-transfer reactions, there exist a few significant problems on reaction models, which are insufficient to qualitatively discuss the cluster structure. We aim to verify the development of the $\\alpha$-cluster structure from observables. As the fi...

  2. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  3. alpha-Methoxymethyl ketones via aldol reaction

    Czech Academy of Sciences Publication Activity Database

    Kasal, Alexander; Buděšínský, Miloš

    2013-01-01

    Roč. 69, č. 46 (2013), s. 9663-9674. ISSN 0040-4020 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:61388963 Keywords : NMR * steroids * synthesis * aldol reaction Subject RIV: CC - Organic Chemistry Impact factor: 2.817, year: 2013

  4. Nuclear reaction diagnostics of fast confined and escaping alpha particles

    International Nuclear Information System (INIS)

    The resonant radiative capture nuclear reactions D(α,γ)6Li, 6Li(α,γ) 19B and 7Li(α,γ)11B are examined as diagnostics of the energy distribution of confined fast alpha particles in tokamak plasmas. Count rates for realistic Q=1 DT plasma conditions are presented and compared to expected backgrounds. The design of and preliminary results from the prototype fusion gamma ray detector on TFTR are presented. The activation reactions are similarly examined as diagnostics of escaping fast alpha particles. Where possible, count rate estimates for Q=1 DT plasmas and proposed ignition devices are presented

  5. Alcoholysis reactions from starch with alpha-amylases.

    Science.gov (United States)

    Santamaría, R I; Del Río, G; Saab, G; Rodríguez, M E; Soberón, X; López-Manguía, A

    1999-06-11

    The ability of alpha-amylases from different sources to carry out reactions of alcoholysis was studied using methanol as substrate. It was found that while the enzymes from Aspergillus niger and Aspergillus oryzae, two well-studied saccharifying amylases, are capable of alcoholysis reactions, the classical bacterial liquefying alpha-amylases from Bacillus licheniformis and Bacillus stearothermophilus are not. The effect of starch and methanol concentration, temperature and pH on the synthesis of glucosides with alpha-amylase from A. niger was studied. Although methanol may inactivate alpha-amylase, a 90% substrate relative conversion can be obtained in 20% methanol at a high starch concentration (15% w/v) due to a stabilizing effect of starch on the enzyme. As the products of alcoholysis are a series of methyl-oligosaccharides, from methyl-glucoside to methyl-hexomaltoside, alcoholysis was indirectly quantified by high performance liquid chromatography analysis of the total methyl-glucoside produced after the addition of glucoamylase to the alpha-amylase reaction products. More alcoholysis was obtained from intact soluble starch than with maltodextrins or pre-hydrolyzed starch. The biotechnological implications of using starch as substrate for the production of alkyl-glucosides is analyzed in the context of these results. PMID:10386619

  6. Probing surface distribution of $\\alpha$-cluster in $^{20}$Ne via $\\alpha$-transfer reaction

    CERN Document Server

    Fukui, Tokuro; Suhara, Tadahiro; Kanada-En'yo, Yoshiko; Ogata, Kazuyuki

    2015-01-01

    Direct evidence of the $\\alpha$-cluster development in bound states has not been obtained yet although a number of experimental studies were carried out to extract the information of the clustering. In particular in conventional analyses of $\\alpha$-transfer reactions, there exist a few significant problems on reaction models, which are insufficient to qualitatively discuss the cluster structure. We aim to verify the development of the $\\alpha$-cluster structure from observables. As the first application, it is argued to extract the spatial information of the cluster structure of the $^{20}$Ne nucleus in its ground state through the cross section of the $\\alpha$-transfer reaction $^{16}$O($^6$Li,~$d$)$^{20}$Ne. For the analysis of the transfer reaction, we work with the coupled-channels Born approximation (CCBA) approach, in which the breakup effect of $^6$Li is explicitly taken into account by means of the continuum-discretized coupled-channels method (CDCC) based on the three-body $\\alpha + d + {}^{16}$O mo...

  7. Nuclear Reactions Important in Alpha-Rich Freezeouts

    CERN Document Server

    Jordan, G C; Meyer, B S; The, L S

    2003-01-01

    The alpha-rich freezeout from equilibrium occurs during the core-collapse explosion of a massive star when the supernova shock wave passes through the Si-rich shell of the star. The nuclei are heated to high temperature and broken down into nucleons and alpha particles. These subsequently reassemble as the material expands and cools, thereby producing new heavy nuclei, including a number of important supernova observables. In this paper we introduce two web-based applications. The first displays the results of a reaction-rate sensitivity study of alpha-rich freezeout yields. The second allows the interested reader to run paramaterized explosive silicon burning calculations in which the user inputs his own parameters. These tools are intended to aid in the identification of nuclear reaction rates important for experimental study. We then analyze several iron-group isotopes (59Ni, 57Co, 56Co, and 55Fe) in terms of their roles as observables and examine the reaction rates that are important in their production.

  8. Study of $\\boldsymbol{(\\alpha,p)}$ and $\\boldsymbol{(\\alpha,n)}$ reactions with a Multi-Sampling Ionization Chamber

    CERN Document Server

    Avila, M L; Almaraz-Calderon, S; Ayangeakaa, A D; Dickerson, C; Hoffman, C R; Jiang, C L; Kay, B P; Lai, J; Nusair, O; Pardo, R C; Santiago-Gonzalez, D; Talwar, R; Ugalde, C

    2016-01-01

    A large number of $(\\alpha,p)$ and $(\\alpha,n)$ reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed a direct measurements of the previously measured reactions $^{17}$O$(\\alpha,n)^{20}$Ne, $^{23}$Na$(\\alpha,p)^{26}$Mg, and $^{23}$Na$(\\alpha,n)^{26}$Al. These reactions were investigated in inverse kinematics using $^{4}$He gas in the detector to study the excitation function in the range of about 2 to 6 MeV in the center of mass. We found good agreement between the cross sections of the $^{17}$O$(\\alpha,n)^{20}$Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the $^{23}$Na$(\\alpha,p)^{26}$Mg and $^{23}$Na$(\\alpha,n)^{26}$Al reactions.

  9. Olefination of alpha-hydroxy or alpha-aminoaldehyde derivatives via reaction of their arylsulfonylhydrazones with sulfonyl anions.

    Science.gov (United States)

    Wicha, Jerzy; Zarecki, Andrzej

    2004-08-20

    Reaction of tosylhydrazones of O-substituted alpha-hydroxy or N-substituted alpha-amino aldehydes (2, 7, 11, 15, 17, and 20) with selected alpha-magnesio alkyl phenyl sulfones afforded the respective derivatives of allylic alcohols or allylic amines. 2,3-O-Isopropylidene-D-glyceraldehyde (1) was transformed into its tosylhydrazone (2) and then olefins 4a with retention of optical purity. PMID:15307767

  10. Low-background spectrometer for the study of fast neutron-induced (n,alpha) reactions

    CERN Document Server

    Khriachkov, V A; Mitrofanov, V P; Semenova, N N

    2000-01-01

    An alpha-particle spectrometer based on an ionization chamber with Frisch grid and a waveform digitizer has been developed for studies of fast neutron-induced (n,alpha) reactions. The information on the energy of the alpha-particle and its emission angle can be obtained from the amplitude and rise time of the digitized anode signal. For a situation where both the solid target on the cathode of the ionization chamber and the working gas are the alpha-particle sources, a new method for the suppression of the neutron-induced background is proposed. The background due to gaseous alpha-particles was reduced by a factor of 30.

  11. Alpha scattering and capture reactions in the A = 7 system at low energies

    OpenAIRE

    Mohr, P; Abele, H.; ZWIEBEL, R.; Staudt, G.; Krauss, H; Oberhummer, H.; Denker, A; Hammer, J. W.; Wolf, G.

    1993-01-01

    Differential cross sections for $^3$He-$\\alpha$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ \\alpha$ and $^3$H $+ \\alpha$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(\\alpha,\\gamma)^7$Be and $^3$H$(\\alpha,\\gamma)^7$Li, and the branching ratio...

  12. About the reactions 3H(alpha,gamma)7Li and 3He(alpha,gamma)7Be

    International Nuclear Information System (INIS)

    In this article the current experimental and theoretical status of the radiative alpha capture reactions 3H(α,γ)7Li and 3He(α,γ)7Be and their relations to primordial nucleosynthesis and the solar neutrino problem are reviewed. (author)

  13. Cross sections of nuclear reactions induced by protons, deuterons, and alpha particles. Pt.6. Phosphorus

    International Nuclear Information System (INIS)

    Cross sections are reviewed for nuclear reactions induced by protons, deuterons, and alpha particles on phosphorus targets. When necessary, published experimental data are corrected, and, when possible, excitation functions are proposed

  14. Alpha cluster states in light nuclei populated through the (6Li,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Borello-Lewin, Thereza; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy). Istituto Nazionale di Fisica Nucleare. Lab. Nazionali del Sud; Ukita, Gilberto Mitsuo [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Fac. de Psicologia

    2011-07-01

    Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (x{alpha}) and(x{alpha}+{nu}) nuclei through the ({sup 6}Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (x{alpha}) and (x{alpha}+{nu}) thresholds. Measurements of the {sup 12},{sup 13}C({sup 6}Li,d) {sup 16},{sup 17}O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4{alpha}) breakup threshold in {sup 16}O, three narrow alpha resonances, not previously measured, were detected, revealing important {alpha} + {sup 12}C(G.S.) components. One of these resonances corresponds to the known 0{sup +} state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4{alpha} condensate state, with a very dilute density and a large component of {alpha} + {sup 12}C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the {alpha} + {sup 12}C(G.S.) component in the wave function. (author)

  15. Determination by transfer reaction of alpha widths in fluorine for astrophysical interest

    International Nuclear Information System (INIS)

    The nucleosynthesis of fluorine is not known. Several astrophysical models predict the alpha radiative capture onto N15 as the main fluorine production reaction. In the expression of the reaction rate, one parameter is missing: the alpha width of the resonance on the E = 4.377 MeV level in fluorine. A direct measurement is excluded due to the very low cross-section expected. We have determined this alpha width using a transfer reaction followed by analyses with FR-DWBA (Finite Range Distorted Wave Born Approximation) in a simple cluster alpha model. This experiment was carried out with a Li7 beam with E = 28 MeV onto a N15 gas target. The 16 first levels were studied. Spectroscopic factors were extracted for most of them. Alpha widths for unbound levels were determined. Many alpha width were compared with known values from direct reaction and the differences lie within the uncertainty range (factor 2). The alpha width for the E = 4.377 MeV level was determined (Γα = 1.5*10-15 MeV), its value is about 60 times weaker than the used value. The influence of our new rate was studied in AGB (Asymptotic Giant Branch) stars during thermal pulses. In this model the alteration is sensitive. (author)

  16. Reaction rates for the s-process neutron source 22Ne+{\\alpha}

    CERN Document Server

    Longland, Richard; Karakas, Amanda I

    2012-01-01

    The 22Ne({\\alpha},n)25Mg reaction is an important source of neutrons for the s-process. In massive stars responsible for the weak component of the s-process, 22Ne({\\alpha},n)25Mg is the dominant source of neutrons, both during core helium burning and in shell carbon burning. For the main s-process component produced in Asymptotic Giant Branch (AGB) stars, the 13C({\\alpha},n)16O reaction is the dominant source of neutrons operating during the interpulse period, with the 22Ne+{\\alpha} source affecting mainly the s-process branchings during a thermal pulse. Rate uncertainties in the competing 22Ne({\\alpha},n)25Mg and 22Ne({\\alpha},{\\gamma})26Mg reactions result in large variations of s-process nucleosynthesis. Here, we present up-to-date and statistically rigorous 22Ne+{\\alpha} reaction rates using recent experimental results and Monte Carlo sampling. Our new rates are used in post-processing nucleosynthesis calculations both for massive stars and AGB stars. We demonstrate that the nucleosynthesis uncertainties ...

  17. Neutron Production Using Alpha-Be Reaction on the Neutron Generator Accelerator

    International Nuclear Information System (INIS)

    In order to obtain data for development of small scale Accelerator Driven System (ADS), calculations of neutron production that use alpha-Be reaction on the acceleration energy range of 100 to 500 keV have been carried out. The result of neutron yield calculation was compared with calculation result of D-T reaction and both calculations were treated for thick target. At the energy of 100 keV; alpha-Be reaction produces neutron yield about 1/10 compared to that of D-T reaction and increases to 1/5 at energy of 500 keV. At the same acceleration voltage of 250 kV, where the alpha energy is 500 keV and deuteron energy is 250 keV; the neutron yield of alpha-Be reaction is 1/3 of that in D-T reaction. On the last mentioned condition and considering that target cost of Be is cheaper than the cost of T, neutron production on a neutron generator accelerator that uses alpha-Be reaction is a competitive method as neutron source, especially for ADS. (author)

  18. Angular correlations and decay branching ratio for excited state of 7Li*(7,45 MeV) in reactions 7Li(alpha, alpha)7Li*

    International Nuclear Information System (INIS)

    Measurements of differential cross-sections of alpha-particle inelastic scattering by 7Li nuclei and 7Li(alpha, alpha 6Li)n, 7Li(alpha, alpha alpha)t reactions have been performed at the energy Ea = 27,2 MeV. Probability of 7Li*(7,45 MeV) decay into 6Li + n channel has been determined from the ratio of cross-sections measured in kinematically complete and incomplete experiments. The large discrepancy of this value (P 0,49 ± 0,06) and of those obtained at the study of 7Li*(7,45 MeV) decay in binary reactions can be explained by the influence of Coulomb field of accompanied alpha-particle on the decay of near-threshold resonances in three-particle reactions

  19. Estimation of the {alpha} particles and neutron distribution generated during a fusion reaction; Evaluation de la distribution des particules {alpha} et des neutrons issus de la reaction de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Dellacherie, S.

    1997-12-01

    The respective distributions (or density probabilities) of {alpha} particles and neutrons have been modeled using a Monte-Carlo method for the thermonuclear fusion reaction D + T {yields} {alpha} + n + 17.6 MeV. (N.T.).

  20. Breakout from the hot CNO cycle: the {sup 15}O({alpha},{gamma}) and {sup 18}Ne({alpha},p) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bradfield-Smith, W.; Laird, A.M.; Davinson, T.; Pietro, A. di; Ostrowski, A.N.; Shotter, A.C.; Woods, P.J. [Dept. of Physics and Astronomy, Univ. of Edinburgh (United Kingdom); Cherubini, S.; Galster, W.; Graulich, J.S.; Leleux, P.; Michel, L.; Ninane, A.; Vervier, J. [Inst. de Physique Nucleaire, UCL, Louvain-la-Neuve (Belgium); Aliotta, M.; Cali, D.; Cappussello, F.; Cunsolo, A.; Spitaleri, C. [INFN, Catania (Italy); Gorres, J.; Wiescher, M. [Notre Dame Univ. (United States); Rahighi, J. [Van de Graaf Lab., Tehran (Iran, Islamic Republic of); Hinnefeld, J. [Indiana Univ., South Bend (United States)

    1998-06-01

    One of the most important reactions which determines the rate of breakout from the hot CNO cycle is the {sup 15}O({alpha},{gamma}){sup 19}Ne. The reaction {sup 18}Ne({alpha},p){sup 21}Na may also provide an alternative breakout route. Experiments are being undertaken at Louvain-La-Neuve using the radioactive {sup 18}Ne beam to study these reactions by measurement of {alpha}({sup 18}Ne,p){sup 21}Na and d({sup 18}Ne,p){sup 19}Ne{sup *} {yields} {sup 15}O + {alpha} (orig.)

  1. Study of the ABC Enhancement in the $\\overline{d}d\\to \\alpha X^{0}$ reaction

    CERN Document Server

    Wurzinger, R; Boivin, M; Courtat, P; Fäldt, Göran; Gacougnolle, R; Gardestig, A; Hibou, F; Le Bornec, Y; Martin, J M; Plouin, F; Tatischeff, B; Wilkin, C; Willis, N; Yonnet, J; Zghiche, A

    1999-01-01

    The polarized d d -> alpha X reaction at beam energies close to the eta threshold shows very strong structure in the missing mass corresponding to the ABC enhancement. The deuteron tensor analysing power A_yy, and the slope of the vector analysing power A_y with respect to angle, have been measured for this reaction around the forward direction. Both signals are small, and their variations with the alpha-particle momentum are in broad agreement with a theoretical model in which each pair of nucleons in the projectile and target deuterons undergoes pion production through the NN -> d pi reaction.

  2. Nuclear structure and reaction mechanisms studied on alpha-particle transitions

    International Nuclear Information System (INIS)

    Since the observation of the natural alpha decay of atomic nuclei the alpha particle was and is considered as an important component of the nuclear matter. The modern studies of alpha-particle transfer reactions are devoted to the question on four-particle correlations (alpha-particle clusters) generally in nuclear matter or also on nuclear surfaces. Thereby one is today yet absolutely far away from a unified picture of the mechanism of the alpha transfer: It is shown that different reaction and nuclear models must be used with different success for the interpretation of the data. Theoretical and experimental determination of spectroscopic strength distribution were thereby developed mutually supportingly each other. On the experimental side the question of the reaction mechanism and the determination of its details is to be clarified. Here approaches were developed which lead to a unified description in the sd shell. Calculations in the formalism of the coupled channels with spectroscopic factors calculated in the framework of the shell model lead to convincing agreements between theoretical and experimental angular distributions regarding both their shape and their amplitude. Hereby it was shown that beside the determination of the potential parameters a two-stage reaction mechanism as in an alpha-particle transition after or before an inelastic excitation of the target or residual nucleus is of decicive importance. (HSI)

  3. Nuclear reactions induced by high-energy alpha particles

    Science.gov (United States)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  4. Reaction of arylsulfonylhydrazones of aldehydes with alpha-magnesio sulfones. A novel olefin synthesis.

    Science.gov (United States)

    Kurek-Tyrlik, A; Marczak, S; Michalak, K; Wicha, J; Zarecki, A

    2001-10-19

    Reactions of representative tosylhydrazones of aldehydes and ketones with alpha-metalated sulfones were examined in order to develop a practical olefination method. Treatment of aldehyde tosylhydrazone 2 with an excess of alpha-lithiated methyl phenyl or dimethyl sulfones yielded 3a. The reaction of 2 with sterically unhindered lithiated alkyl sulfones gave mixtures of the respective olefination products 3b-d along with the Shapiro fragmentation product 4. Sterically hindered lithiated sulfones afforded Shapiro products exclusively. In contrast, aldehyde tosylhydrazones 2 or 6 in reactions with a variety of alpha-magnesio primary or secondary alkyl sulfones gave olefination products 3a-j and 7a-c in high yields (Tables 1 and 2). beta-Branched alkyl sulfones afforded predominantly (E)-alkenes, whereas unhindered primary sulfones gave mixtures of (E)- and (Z)-alkenes with low selectivity. Reaction of the 2,4,6-triisopropylbenzenesulfonylhydrazone (trisylhydrazone) of cyclodecanone 11c with alpha-magnesio methyl phenyl sulfone afforded the methylidene derivative 12a contaminated with the Shapiro product 13. Tosylhydrazone 2 resisted reaction with i-PrMgCl and gave only a small amount of the addition product in reaction with Bu(2)Mg. Some mechanistic aspects of the reaction of tosylhydrazones with organomagnesium compounds are discussed. PMID:11597219

  5. Pre-equilibrium alpha and nucleon emission in 59Co(α,zαypxn) reactions

    International Nuclear Information System (INIS)

    Pre-equilibrium alpha and nucleon emission were studied for the excitation functions on target element cobalt up to 120 MeV employing the stacked-foil activation technique. Alpha induced reactions for the production of a few radionuclides 60,58-56Co, 54-52Mn, 51Cr, 59Fe, 57,56Ni were measured. Most of these radionuclides are produced by one or two alpha emissions and a few by nucleon emission. The excitation functions were compared with semi classical models, like the INDEX and the recently developed COMPLET which takes into account the pre-equilibrium alpha particle and multinucleon emission. In general, the shapes of the excitation functions were rather fairly reproduced with the COMPLET model and it gives a better agreement than the INDEX model for all the reactions studied in the present work. (orig.)

  6. Alpha scattering and capture reactions in the A = 7 system at low energies

    CERN Document Server

    Mohr, P J; Zwiebel, R; Staudt, G; Krauss, H; Oberhummer, Heinz; Denker, A; Hammer, J W; Wolf, G

    1993-01-01

    Differential cross sections for $^3$He-$\\alpha$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ \\alpha$ and $^3$H $+ \\alpha$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(\\alpha,\\gamma)^7$Be and $^3$H$(\\alpha,\\gamma)^7$Li, and the branching ratios for the transitions into the two final $^7$Be and $^7$Li bound states, respectively. For $^3$He$(\\alpha,\\gamma)^7$Be excellent agreement between calculated and experimental data is obtained. For $^3$H$(\\alpha,\\gamma)^7$Li a $S(0)$ value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of $R = \\sigma(\\gamma_1)/\\sigma(\\gamma_0) \\approx 0.43$ has been obtained.

  7. $^{24}$Mg($p$, $\\alpha$)$^{21}$Na reaction study for spectroscopy of $^{21}$Na

    CERN Document Server

    Cha, S M; Kim, A; Lee, E J; Ahn, S; Bardayan, D W; Chipps, K A; Cizewski, J A; Howard, M E; Manning, B; O'Malley, P D; Ratkiewicz, A; Strauss, S; Kozub, R L; Matos, M; Pain, S D; Pittman, S T; Smith, M S; Peters, W A

    2015-01-01

    The $^{24}$Mg($p$, $\\alpha$)$^{21}$Na reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain spins and parities of energy levels in $^{21}$Na for the astrophysically important $^{17}$F($\\alpha, p$)$^{20}$Ne reaction rate calculation. 31 MeV proton beams from the 25-MV tandem accelerator and enriched $^{24}$Mg solid targets were used. Recoiling $^{4}$He particles from the $^{24}$Mg($p$, $\\alpha$)$^{21}$Na reaction were detected by a highly segmented silicon detector array which measured the yields of $^{4}$He particles over a range of angles simultaneously. A new level at 6661 $\\pm$ 5 keV was observed in the present work. The extracted angular distributions for the first four levels of $^{21}$Na and Distorted Wave Born Approximation (DWBA) calculations were compared to verify and extract angular momentum transfer.

  8. Primordial ${\\alpha} + d \\to {}^{6}{\\rm Li} + \\gamma$ reaction and second Lithium puzzle

    CERN Document Server

    Mukhamedzhanov, A M; Bertulani, C A

    2016-01-01

    During the Big Bang, ${}^{6}{\\rm Li}$ was synthesized via the ${}^{2}{\\rm H}(\\alpha,\\gamma){}^{6}{\\rm Li}$ reaction. After almost 25 years of the failed attempts to measure the ${}^{2}{\\rm H}(\\alpha,\\gamma){}^{6}{\\rm Li}$ reaction in the lab at the Big Bang energies, just recently the LUNA collaboration presented the first successful measurements at two different Big Bang energies [M. Anders {\\it et al.}, Phys. Rev. Lett. {\\bf 113}, 042501 (2014)]. In this paper we will discuss how to improve the accuracy of the direct experiment. To this end the photon's angular distribution is calculated in the potential model. It contains contributions from electric dipole and quadrupole transitions and their interference, which dramatically changes the photon's angular distribution. The calculated distributions at different Big Bang energies have a single peak at $\\sim 50^{\\circ}$. These calculations provide the best kinematic conditions to measure the ${}^{2}{\\rm H}(\\alpha,\\gamma){}^{6}{\\rm Li}$ reaction. The expressions...

  9. Proton and alpha evaporation spectra in low energy 12C and 16O induced reactions

    Indian Academy of Sciences (India)

    E T Mirgle; D R Chakrabarty; V M Datar; Suresh Kumar; A Mitra; H H Oza

    2006-08-01

    Proton and alpha particle spectra have been measured in the 12C+93Nb and 12C+58Ni reactions at E(12C) = 40 and 50 MeV and in the 16O+93Nb reaction at E(16O) = 75 MeV. The spectra are compared with the statistical model calculations. The shapes of the calculated spectra are in agreement with experimental data except for the alpha spectrum in the 12C+93Nb reaction at 40 MeV. The observed evaporation bump is at ∼ 2 MeV lower energy compared to the calculated one. This discrepancy could imply alpha particle emission from a deformed configuration before compound nucleus formation at this near Coulomb barrier beam energy.

  10. Experimental setup and procedure for the measurement of the $^{7}Be(n,{\\alpha}){\\alpha}$ reaction at n_TOF

    CERN Document Server

    Cosentino, L; Barbagallo, M; Pappalardo, A; Colonna, N; Damone, L; Piscopo, M; Finocchiaro, P; Maugeri, E; Heinitz, S; Schumann, D; Dressler, R; Kivel, N; Aberle, O; Andrzejewski, J; Audouin, L; Ayranov, M; Bacak, M; Barros, S; Balibrea-Correa, J; Beecares, V; Becvar, F; Beinrucker, C; Berthoumieux, E; Billowes, J; Bosnar, D; Brugger, M; Caamano, M; Calviani, M; Calvino, F; Cano-Ott, D; Cardella, R; Casanovas, A; Castelluccio, D M; Cerutti, F; Chen, Y H; Chiaveri, E; Cortes, G; Cortes-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Dupont, E; Duran, I; Fernandez-Dominguez, B; Ferrari, A; Ferreira, P; Furman, W; Ganesan, S; Garcia-Rios, A; Gawlik, A; Gheorghe, I; Glodariu, T; Goebel, K; Goncalves, I F; Gonzalez-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Harada, H; Heftrich, T; Heyse, J; Jenkins, D G; Jericha, E; Kaeppeler, F; Katabuchi, T; Kavrigin, P; Kimura, A; Kokkoris, M; Krticka, M; Leal-Chidonca, E; Lerendegui, J; Lederer, C; Leeb, H; Meo, S Lo; Lonsdale, S; Losito, R; Macina, D; Marganiec, J; Martinez, T; Massimi, C; Mastinu, P; Mastromarco, M; Matteucci, F; Mazzone, A; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Montesano, S; Nolte, R; Oprea, A; Patronis, N; Pavlik, A; Perkowski, J; Praena, J; Quesada, J; Rajeev, K; Rauscher, T; Reifarth, R; Riego-Perez, A; Rout, P; Rubbia, C; Ryan, J; Sabate-Gilarte, M; Saxena, A; Schillebeeckx, P; Schmidt, S; Sedyshev, P; Stamatopoulos, A; Tagliente, G; Tain, J L; Tarifeno-Saldivia, A; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Vlachoudis, V; Vlastou, R; Vollaire, J; Wallner, A; Warren, S; Weigand, M; Weiß, C; Wolf, C; Woods, P J; Wright, T; Zugec, P

    2016-01-01

    The newly built second experimental area EAR2 of the n_TOF spallation neutron source at CERN allows to perform (n, charged particles) experiments on short-lived highly radioactive targets. This paper describes a detection apparatus and the experimental procedure for the determination of the cross-section of the 7Be(n,{\\alpha}) reaction, which represents one of the focal points toward the solution of the cosmological Lithium abundance problem, and whose only measurement, at thermal energy, dates back to 1963. The apparently unsurmountable experimental difficulties stemming from the huge 7Be {\\gamma}-activity, along with the lack of a suitable neutron beam facility, had so far prevented further measurements. The detection system is subject to considerable radiation damage, but is capable of disentangling the rare reaction signals from the very high background. This newly developed setup could likely be useful also to study other challenging reactions requiring the detectors to be installed directly in the neutr...

  11. The C-14(alpha, gamma)O-18 reaction at astrophysical energies

    International Nuclear Information System (INIS)

    The C-14(alpha, gamma)O-18 reaction rate is estimated for temperatures important for He flashes in white dwarfs and for nonhomogeneous big-bang nucleosynthesis. If available, the resonant contributions to the rate are derived using recent experimental data. The direct capture rate is evaluated on the basis of a microscopic multichannel calculation of the C-14(alpha, gamma)O-18 reaction. Possible interference contributions are discussed. The present rate is compared to previous estimates of Hashimoto et al. (1986) and of Buchmann et al. (1988). 23 refs

  12. The C-14(alpha, gamma)O-18 reaction at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Funck, C.; Langanke, K. (Muenster Universitaet (Germany, F.R.))

    1989-09-01

    The C-14(alpha, gamma)O-18 reaction rate is estimated for temperatures important for He flashes in white dwarfs and for nonhomogeneous big-bang nucleosynthesis. If available, the resonant contributions to the rate are derived using recent experimental data. The direct capture rate is evaluated on the basis of a microscopic multichannel calculation of the C-14(alpha, gamma)O-18 reaction. Possible interference contributions are discussed. The present rate is compared to previous estimates of Hashimoto et al. (1986) and of Buchmann et al. (1988). 23 refs.

  13. Cross section measurement for (n,n{alpha}) reactions by 14 MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kasugai, Y.; Ikeda, Y.; Uno, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Yamamoto, H.; Kawade, K.

    1997-03-01

    Nine (n,n{alpha}) cross sections for (n,n{alpha}) reactions induced by 13.5-14.9 MeV neutrons were measured for {sup 51}V, {sup 65}Cu, {sup 71}Ga, {sup 76}Ge, {sup 87}Rb, {sup 91}Zr, {sup 93}Nb, {sup 96}Zr and {sup 109}Ag isotopes by using Fusion Neutronics Source (FNS) at JAERI. The reactions for 91Zr and 96Zr were measured for the first time. The evaluated data of JENDL-3 and ENDF/B-VI were compared with the present data. Some of the evaluated values are much different from our data by a factor more than ten. (author)

  14. Preequilibrium decay in alpha particle induced reactions in terbium

    International Nuclear Information System (INIS)

    The excitation functions of 159 Tb(α,n), (α,3 n), (α,4 n), (α,α3 n) reactions were measured using stacked foil activation technique and HPGe gamma ray spectroscopy method up to 50 MeV. The experimental results were compared with the theoretical predictions considering equilibrium as well as preequilibrium contributions using code ALICE/90. It was found that the initial exciton configuration n0 = 4(4p0h) that is pure particle state, appears to give good fit to the experimental data. (Authors)

  15. Inelastic Branch of the Stellar Reaction $^{14}$O$(\\alpha,p)^{17}$F

    CERN Multimedia

    Hass, M; Van duppen, P L E

    2002-01-01

    We propose to use the upgraded REX-ISOLDE beam energy to study the astrophysically important $^{14}$O($\\alpha$, p)$^{17}$F reaction in time reverse kinematics. In particular, we will use the highly efficient miniball + CD detection system to measure the previously undetermined inelastic proton branch of the 1$^-$ state at 6.15 MeV in $^{18}$Ne. This state dominates the reaction rate under X-ray burster conditions.

  16. Investigating the alpha-clustering on the surface of $^{120}$Sn via ($p$,$p\\alpha$) reaction and the validity of the factorization approximation

    CERN Document Server

    Yoshida, Kazuki; Ogata, Kazuyuki

    2016-01-01

    The $^{120}$Sn($p$,$p\\alpha$)$^{116}$Cd reaction at 392 MeV is investigated with the distorted wave impulse approximation (DWIA) framework. We show that this reaction is very peripheral mainly because of the strong absorption of $\\alpha$ by the reaction residue $^{116}$Cd, and the $\\alpha$-clustering on the nuclear surface can be probed clearly. We investigate also the validity of the so-called factorization approximation that has frequently been used so far. It is shown that the kinematics of $\\alpha$ in the nuclear interior region is significantly affected by the distortion of $^{116}$Cd, but it has no effect on the reaction observables because of the strong absorption in that region.

  17. Variation of fundamental constants and the triple-alpha reaction in Population III stars and BBN

    International Nuclear Information System (INIS)

    The effect of variations of the fundamental constants on the thermonuclear rate of the triple alpha reaction, 4He(αα, γ)12C, that bridges the gap between 4He and 12C is investigated. We have followed the evolution of 15 and 60 Msun zero metallicity stellar models, up to the end of core helium burning. The calculated oxygen and carbon abundances resulting from helium burning can then be used to constrain the variation of the fundamental constants. To investigate the effect of an enhanced triple alpha reaction rate in Big-Bang Nucleosynthesis, we first evaluated Standard Big-Bang Nucleosynthesis CNO production with a network of more than 400 reactions using the TALYS code to calculate missing rates.

  18. Fission time for the {sup 235}U + {alpha} reaction measured by the crystal blocking technique

    Energy Technology Data Exchange (ETDEWEB)

    Yuminov, O.A. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Vorobyevy Gory, Moscow 119991 (Russian Federation)], E-mail: yuminov@p5-lnr.sinp.msu.ru; Borisov, A.M.; Drozdov, V.A.; Eremenko, D.O.; Fotina, O.V. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Vorobyevy Gory, Moscow 119991 (Russian Federation); Malaguti, F. [Istituto Nazionale di Fisica Nucleare - Sezione di Bologna, Dipartimento di Fisica dell' Universita, Via Irnerio 46, Bologna (Italy); Olivo, P. [Dipartimento Matemates, Universita' di Bologna, Via Irnerio 46, Bologna (Italy); Platonov, S.Yu. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Vorobyevy Gory, Moscow 119991 (Russian Federation); Togo, V. [Istituto Nazionale di Fisica Nucleare - Sezione di Bologna, Dipartimento di Fisica dell' Universita, Via Irnerio 46, Bologna (Italy); Tulinov, A.F. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Vorobyevy Gory, Moscow 119991 (Russian Federation)

    2009-08-15

    The crystal blocking technique has been used to measure the total time of the induced fission process for the {sup 235}U + {alpha} reaction in the energy range of bombarding {alpha}-particles from 25.9 to 31.2 MeV. Experimental fission times observed in this reaction vary from 10{sup -17} to 10{sup -16} s, depending on the projectile energy. Together with the corresponding experimental data on angular anisotropy in the same reaction they were analyzed within the dynamic-statistical approach with allowance for the nuclear dissipation phenomenon and the double-humped fission barrier model. It was demonstrated that the time of induced fission at low excitation energies is sensitive to the nuclear dissipation magnitude.

  19. Measurement of (alpha,n) reaction cross sections of erbium isotopes for testing astrophysical rate predictions

    CERN Document Server

    Kiss, G G; Rauscher, T; Török, Zs; Csedreki, L; Fülöp, Zs; Gyürky, Gy; Halász, Z

    2015-01-01

    The $\\gamma$-process in core-collapse and/or type Ia supernova explosions is thought to explain the origin of the majority of the so-called $p$ nuclei (the 35 proton-rich isotopes between Se and Hg). Reaction rates for $\\gamma$-process reaction network studies have to be predicted using Hauser-Feshbach statistical model calculations. Recent investigations have shown problems in the prediction of $\\alpha$-widths at astrophysical energies which are an essential input for the statistical model. It has an impact on the reliability of abundance predictions in the upper mass range of the $p$ nuclei. With the measurement of the $^{164,166}$Er($\\alpha$,n)$^{167,169}$Yb reaction cross sections at energies close to the astrophysically relevant energy range we tested the recently suggested low energy modification of the $\\alpha$+nucleus optical potential in a mass region where $\\gamma$-process calculations exhibit an underproduction of the $p$ nuclei. Using the same optical potential for the $\\alpha$-width which was der...

  20. The $^{15}$N($\\bm\\alpha$,$\\bm\\gamma$)$^{19}$F reaction and nucleosynthesis of $^{19}$F

    OpenAIRE

    Wilmes, S.; Wilmes, V.; Staudt, G.; Mohr, P; Hammer, J. W.

    2002-01-01

    Several resonances in the $^{15}$N($\\alpha$,$\\gamma$)$^{19}$F reaction have been investigated in the energy range between 0.6 MeV and 2.7 MeV. Resonance strengths and branching ratios have been determined. High sensitivity could be obtained by the combination of the {\\sc{dynamitron}} high current accelerator, the windowless gas target system {\\sc{rhinoceros}}, and actively shielded germanium detectors. Two levels of $^{19}$F could be observed for the first time in the ($\\alpha$,$\\gamma$) chan...

  1. Trojan Horse method and radioactive ion beams: study of $^{18}$F(p,$\\alpha$)$^{15}$O reaction at astrophysical energies

    CERN Document Server

    Gulino, M; Rapisarda, G G; Kubono, S; Lamia, L; La Cognata, M; Yamaguchi, H; Hayakawa, S; Wakabayashi, Y; Iwasa, N; Kato, S; Komatsubara, H; Teranishi, T; Coc, A; De Séréville, N; Hammache, F; Spitaleri, C

    2012-01-01

    The Trojan Horse Method was applied for the first time to a Radioactive Ion Beam induced reaction to study the reaction $^{18}$F(p,$\\alpha$)$^{15}$O via the three body reaction $^{18}$F(d,$\\alpha$ $^{15}$O)n at the low energies relevant for astrophysics. The abundance of $^{18}$F in Nova explosions is an important issue for the understanding of this astrophysical phenomenon. For this reason it is necessary to study the nuclear reactions that produce or destroy $^{18}$F in Novae. $^{18}$F(p,$\\alpha$)$^{15}$O is one of the main $^{18}$F destruction channels. Preliminary results are presented in this paper.

  2. Stellar reaction rates of alpha capture on light (N not equal to Z) nuclei and their astrophysical implications

    International Nuclear Information System (INIS)

    A theoretical analysis of direct and resonant capture of alpha-particles in specific states for Be-7(alpha, gamma)C-11, Li-7(alpha, gamma)B-11, C-14(alpha, gamma)O-18, O-15(alpha, gamma)Ne-19, and O-18(alpha, gamma)Ne-22 is presented, with application to the study of nucleosynthesis in the early universe and light element production in supermassive objects. It is demonstrated that the rates of some of these reactions could increase significantly depending upon certain spectroscopic factors. The direct capture process is shown to be of importance for alpha-fusion processes in steller environments when reactions involving compound nuclei with low-level densities occur at relatively low stellar temperatures. 31 references

  3. Role of ($\\alpha$,n) reactions under $r$-process conditions in neutrino-driven winds revisited

    CERN Document Server

    Mohr, Peter

    2016-01-01

    Background: The astrophysical $r$-process occurs in an explosive astrophysical event under extremely neutron-rich conditions, leading to (n,$\\gamma$)-($\\gamma$,n) equilibrium along isotopic chains which peaks around neutron separation energies of a few MeV. Nuclei with larger $Z$ are usually produced by $\\beta^-$-decay, but under certain conditions also $\\alpha$-induced reactions may become relevant for the production of nuclei with $Z+2$. Purpose: The uncertainties of the reaction rates of these $\\alpha$-induced reactions are discussed within the statistical model. As an example, $\\alpha$-induced ($\\alpha$,n) and $(\\alpha$,$x$n) reaction cross sections for the neutron-rich $^{86}$Se nucleus are studied in detail. Method: In a first step, the relevance of ($\\alpha$,n) and $(\\alpha$,$x$n) reactions is analyzed. Next the uncertainties are determined from a variation of the $\\alpha$-nucleus potential which is the all-dominant parameter for the astrophysical $Z \\rightarrow Z+2$ reaction rate. Results: It is found...

  4. Alpha cluster states in light nuclei populated through the (6Li,d) reaction

    International Nuclear Information System (INIS)

    Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (xα) and(xα+ν) nuclei through the (6Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (xα) and (xα+ν) thresholds. Measurements of the 12,13C(6Li,d) 16,17O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4α) breakup threshold in 16O, three narrow alpha resonances, not previously measured, were detected, revealing important α + 12C(G.S.) components. One of these resonances corresponds to the known 0+ state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4α condensate state, with a very dilute density and a large component of α + 12C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the α + 12C(G.S.) component in the wave function. (author)

  5. Alpha Resonances in 13C Excited by the 9Be (6Li,d) Reaction

    International Nuclear Information System (INIS)

    The 9Be(6Li,d)13C reaction was used to investigate alpha resonant states in 13C up to 13 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. The resolution of 50 keV allowed for the separation of the resonant contributions to the known 7/2- at 10.753 MeV and (5/2-) at 10.818 MeV 13C states. The alpha resonance seen at the (3α+n) threshold was not previously reported. The experimental angular distributions are presented in comparison with DWBA predictions.

  6. Determination by transfer reaction of alpha widths in fluorine for astrophysical interest; Determination par reaction de transfert de largeurs alpha dans le fluor 19. Applications a l'astrophysique

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Santos, F. de

    1995-04-15

    The nucleosynthesis of fluorine is not known. Several astrophysical models predict the alpha radiative capture onto N{sup 15} as the main fluorine production reaction. In the expression of the reaction rate, one parameter is missing: the alpha width of the resonance on the E = 4.377 MeV level in fluorine. A direct measurement is excluded due to the very low cross-section expected. We have determined this alpha width using a transfer reaction followed by analyses with FR-DWBA (Finite Range Distorted Wave Born Approximation) in a simple cluster alpha model. This experiment was carried out with a Li{sup 7} beam with E = 28 MeV onto a N{sup 15} gas target. The 16 first levels were studied. Spectroscopic factors were extracted for most of them. Alpha widths for unbound levels were determined. Many alpha width were compared with known values from direct reaction and the differences lie within the uncertainty range (factor 2). The alpha width for the E = 4.377 MeV level was determined ({gamma}{sub {alpha}} = 1.5*10{sup -15} MeV), its value is about 60 times weaker than the used value. The influence of our new rate was studied in AGB (Asymptotic Giant Branch) stars during thermal pulses. In this model the alteration is sensitive. (author)

  7. Experimental investigation of the reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne and their impact on stellar nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Falahat, Sascha

    2010-06-10

    In the present dissertation, the nuclear reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne are investigated in the astrophysically interesting energy region from E{sub {alpha}}=1000 keV to E{sub {alpha}}=2450 keV. The experiments were performed at the Nuclear Structure Laboratory of the University of Notre Dame (USA) with the Van-de-Graaff accelerator KN. Solid state targets with evaporated magnesium or anodized oxygen were bombarded with {alpha}-particles and the released neutrons detected. For the detection of the released neutrons, computational simulations were used to construct a neutron detector based on {sup 3}He counters. Because of the strong occurrence of background reactions, different methods of data analysis were employed. Finally, the impact of the reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne on stellar nucleosynthesis is investigated by means of network calculations. (orig.)

  8. Space distributions and decay probability for excited state of 7Li*(7,45 MeV) in reaction 7Li(alpha, alpha6Li)n

    International Nuclear Information System (INIS)

    Differential cross-sections of excitation and decay of 7Li*(7,45 MeV) resonance into 6Li + n channel in three particle reaction 7Li(alpha, alpha6Li)n at alpha-particle energy of 27,2 MeV have been determined in kinematically complete and incomplete experiments. Usage of position sensitive detector made it possible to obtain the data on space distributions of decay events for full range of possible angles and to determine the total probability of this process, which value essentially differs from the data for binary reactions. This result is agreed with previously obtained [1] and confirms the theoretical calculations [2] of decay branching ratio for short lived near-threshold resonances in three particle reactions

  9. The reaction 13C(alpha,n)16O: a background for the observation of geo-neutrinos

    OpenAIRE

    Harissopulos, S.; Becker, H. W.; Hammer, J. W.; Lagoyannis, A.; Rolfs, C.; Strieder, F

    2005-01-01

    The absolute cross section of the $^{13}$C($\\alpha$,n)$^{16}$O reaction has been measured at E$_{\\alpha}$ = 0.8 to 8.0 MeV with an overall accuracy of 4%. The precision is needed to subtract reliably a background in the observation of geo-neutrinos, e.g. in the KamLAND detector.

  10. Resonance analysis of the {sup 12}C,{sup 13}C({alpha},n) reactions and evaluation of neutron yield data of the reaction

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Toru [AITEL Corp., Tokyo (Japan)

    1998-03-01

    The {sup 12}C({alpha},n){sup 15}O reaction and the {sup 13}C({alpha},n){sup 16}O reaction were analyzed with a resonance formula in the incident {alpha}-particle energy range of 1.0 to 16.0 MeV. With the obtained resonance parameters, branching ratios of the emitted neutrons to the several levels of the residual nucleus and their angular distributions were calculated to obtain the energy spectrum of emitted neutrons. Thick target neutron yield of carbon were also calculated and compared with the experimental data. (author)

  11. Near threshold eta meson production in the d+d->alpha+eta reaction

    CERN Document Server

    Wronska, A; Hanhart, C; Hejny, V; Koch, H R; Komarov, V; Kulikov, A; Magiera, A; Mersmann, T; Mikirtytchiants, S; Ohm, H; Prasuhn, D; Schleichert, R; Stein, H J; Ströher, H; Wilkin, C

    2005-01-01

    The d+d->alpha+eta reaction has been investigated near threshold using the ANKE facility at COSY-Juelich. Both total and differential cross sections have been measured at two excess energies, Q=2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q=-2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for determination of the s-wave eta-alpha scattering length are discussed.

  12. Alpha induced reaction cross section measurements on 162Er for the astrophysical gamma process

    CERN Document Server

    Kiss, G G; Rauscher, T; Török, Zs; Fülöp, Zs; Gyürky, Gy; Halász, Z; Somorjai, E

    2014-01-01

    The cross sections of the 162Er(a,g,)166Yb and 162Er(a,n)165Yb reactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from Ec.m. = 16.09 down to Ec.m. = 11.21 MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48 MeV at 3 GK stellar temperature). The 162Er(a,n)165Yb reaction was studied above the reaction threshold between Ec.m. = 12.19 and 16.09 MeV. The fact that the 162Er(a,g)166Yb cross sections were measured below the (a,n) threshold at first time in this mass region opens the opportunity to study directly the a-widths required for the determination of astrophysical reaction rates. The data clearly show that compound nucleus formation in this reaction proceeds differently than previously predicted.

  13. Alpha induced reaction cross section measurements on 162Er for the astrophysical γ process

    International Nuclear Information System (INIS)

    The cross sections of the 162Er(α,γ)166Yb and 162Er(α,n)165Yb reactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from Ec.m.=16.09 MeV down to Ec.m.=11.21 MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48 MeV at 3 GK stellar temperature). The 162Er(α,n)165Yb reaction was studied above the reaction threshold between Ec.m.=12.19 and 16.09 MeV. The fact that the 162Er(α,γ)166Yb cross sections were measured below the (α,n) threshold at first time in this mass region opens the opportunity to study directly the α-widths required for the determination of astrophysical reaction rates. The data clearly show that compound nucleus formation in this reaction proceeds differently than previously predicted

  14. Microscopic study of the /sup 14/O(. cap alpha. ,p)/sup 17/F reactions at stellar energies

    Energy Technology Data Exchange (ETDEWEB)

    Funck, C.; Langanke, K.

    1988-03-28

    We have studied the /sup 14/O(..cap alpha..,p)/sup 17/F reaction at astrophysically important energies within a microscopic multichannel calculation based on the framework of the generator coordinate method. Our study gives a consistent description of the /sup 18/Ne states close to the ..cap alpha..-threshold as well as of the direct (..cap alpha..,p) reaction process which has not been considered in previous calculations. We find that the /sup 14/O(..cap alpha..,p)/sup 17/F rate at temperatures T less than or equal to 5x10/sup 8/ K is strongly influenced by the 2/sup +/ resonance at E = 30 keV above the ..cap alpha..-threshold and by the direct reaction cross section. At higher temperatures /sup 18/Ne states not present in our model space become important. We have estimated the influence of these resonances on the /sup 14/O(..cap alpha..,p)/sup 17/F rate within the standard formalism developed by Fowler assigning experimentally unknown spins to the states on the basis of a Thomas-Ehrman shift analysis using theoretical and experimental informations on the respective analogue states in /sup 18/O. We find an /sup 14/O(..cap alpha..,p)/sup 17/F rate which is noticeably higher than the rate estimated by Wiescher et al. for T less than or equal to 5x10/sup 8/ K. Both rates are of the same magnitude for T greater than or equal to 10/sup 9/ K. Our estimate predicts that the /sup 14/O(..cap alpha..,p)/sup 17/F rate is compatible to the /sup 15/O(..cap alpha..,..gamma..)/sup 19/Ne rate under nova conditions. For explosive burning on accreting neutron stars our rate allows for a break-out from the CNO cycle via the /sup 14/O(..cap alpha..,p)/sup 17/F reaction.

  15. Validity test of the Trojan Horse Method applied to the {sup 7}Li+p{yields} {alpha}+{alpha} reaction via the {sup 3}He break-up

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Sergi, M.L.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Tudisco, S. [Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Kroha, V.; Burjan, V.; Novac, J.; Vincour, J. [Nuclear Physics Institute of ASCR, Rez, Prague (Czech Republic); Fueloep, Z.; Somorjai, E. [Institute of Nuclear Research of Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Pizzone, R.G. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method (THM) was applied to the {sup 3}He+{sup 7}Li interaction in order to investigate the quasi-free {sup 7}Li(p,{alpha}){sup 4}He reaction. The three-body experiment was performed at 33 MeV corresponding to a {sup 7}Li-p relative energy ranging from 50 keV to 7 MeV. The extracted {sup 7}Li(p,{alpha}){sup 4}He quasi-free cross-section was compared with the behavior of direct data, as well as with the result of a previous THM investigation on the {sup 7}Li(p,{alpha}){sup 4}He reaction off the neutron in {sup 2}H. A good agreement between data sets shows up throughout the energy range investigated, providing a very important validity test of the pole approximation for the THM. (orig.)

  16. Testing an ionization chamber with gaseous samples and measurements of the (n, alpha) reaction cross sections

    CERN Document Server

    Gledenov, Yu M; Salatskii, V I; Sedyshev, P V; Andrzejewski, J; Szalanski, P

    1999-01-01

    A new ionization chamber with gaseous samples (GIC) has been designed and tested on the thermal and resonance neutron beams of FLNP's neutron sources. The exposed gas volume serves as a target for neutrons. The obtained thermal cross sections for the sup 1 sup 7 O(n, alpha) sup 1 sup 4 C, sup 2 sup 1 Ne(n, alpha) sup 1 sup 8 O and sup 3 sup 6 Ar(n, alpha) sup 3 sup 3 S reactions are (233+-12) mb, (0.18+-0.09) mb and (5.43+-0.27) mb, respectively. These measurements have been performed on a pure beam of thermal neutrons from the high flux reactor IBR-2; and they demonstrated high efficiency and reliability of the method. Compared to samples on substrates, the application of gaseous samples makes the beam background essentially lower, and what is more important, the background component is totally absent due to the absence of Li and B microimpurities in gaseous samples while they do present in the samples on substrates. The method is also applicable to measurements with resonance neutrons. The recovery capabili...

  17. Alpha capture reaction cross section measurements on Sb isotopes by activation method

    Science.gov (United States)

    Korkulu, Z.; Özkan, N.; Kiss, G. G.; Szücs, T.; Fülöp, Zs; Güray, R. T.; Gyürky, Gy; Halász, Z.; Somorjai, E.; Török, Zs; Yalçin, C.

    2016-01-01

    Alpha induced reactions on natural and enriched antimony targets were investigated via the activation technique in the energy range from 9.74 MeV to 15.48 MeV, close to the upper end of the Gamow window at a temperature of 3 GK relevant to the γ-process. The experiments were carried out at the Institute for Nuclear Research, the Hungarian Academy of Sciences (MTA Atomki). 121Sb(α,γ)125I, 121Sb(α,n)124I and 123Sb(α,n)126I reactions were measured using a HPGe detector. In this work, the 121Sb(α,n)124 cross section results and the comparison with the theoretical predictions (obtained with standard settings of the statistical model codes NON-SMOKER and TALYS) were presented.

  18. First observation of a superdeformed nucleus produced in an [alpha] x n reaction channel

    Energy Technology Data Exchange (ETDEWEB)

    Duprat, J.; Gall, B.J.P.; Porquet, M.G.; Hannachi, F.; Azaiez, F.; Aiche, M.; Bastin, G.; Beausang, C.W.; Beraud, R.; Bourgeois, C.; Clark, R.M.; Deloncle, I.; Duffait, R.; Hauschild, K.; Huebel, H.; Joyce, M.J.; Kaci, M.; Korichi, A.; Coz, Y. le; Meyer, M.; Paul, E.S.; Perrin, N.; Poffe, N.; Redon, N.; Schueck, C.; Sergolle, H.; Sharpey-Schafer, J.F.; Simpson, J.; Smith, A.G.; Wadsworth, R. (Inst. de Physique Nucleaire, 91 Orsay (France) C.S.N.S.M., IN2P3-CNRS, 91 Orsay (France) Oliver Lodge Lab., Univ. of Liverpool (United Kingdom) Inst. de Physique Nucleaire, CNRS-IN2P3, 69 Villeurbanne (France) Univ. of York, Dept. of Physics, Helsington (United Kingdom) Inst. fuer Kernphysik der Univ., Bonn (Germany) Univ. of Oxford, Dept. of Physics (United Kingdom) SERC, Daresbury Lab., Warrington (United Kingdom) Schuster Lab., Univ. of Manchester (United Kingdom))

    1994-07-01

    Recent data from the EUROGAM array have revealed the population of the yrast superdeformed (SD) band of [sup 192]Hg in the [alpha]4n exit channel of the [sup 16]O+[sup 184]W reaction at 113 MeV beam energy. The nucleus assignment was made on the basis of the SD band transition energies, and the observation of characteristic X-rays and low-lying yrast [gamma]-transition of [sup 192]Hg in coincidence with the SD band [gamma]-rays. Both the feeding and decay-out patterns of the observed SD band have been found similar to the ones previously measured in the ([sup 36]S, 4n) reaction. (orig.)

  19. Study of excitation function for alpha induced reactions in natural iridium

    International Nuclear Information System (INIS)

    Excitation function of (α, χn) reactions on 191Ir (37.3%) and on 191Ir (62.7%) have been measured for 17-55 MeV alpha particle bombarding energy range. Stacked foil activation technique and gamma spectroscopy were used to determine the cross-sections. The experimental data were compared with calculated values obtained by means of geometry dependent hybrid model. The initial exciton number no = 4 with n = 2, p = 2 and h = 0 gives the best agreements with the presently measured values. To calculate the excitation function theoretically the ALICE/LIVERMORE-82 computer code was used. This set of excitation functions provides a data basis for probing the validity of combined equilibrium and pre-equilibrium reaction models in a considerable energy range. (author). 34 refs, 9 figs

  20. The key reactions in Stellar helium burning: {sup 12}C({alpha},{gamma}){sup 16}O and {sup 22}Ne({alpha},n){sup 25}Mg

    Energy Technology Data Exchange (ETDEWEB)

    Fey, M. E-mail: fey@ifs.physik.uni-stuttgart.de; Kunz, R.; Hammer, J.W.; Jaeger, M.; Mayer, A.; Krmpotic, E.; Bauer, C.; Meyer, C.; Harissopulos, S.; Paradellis, T.; Staudt, G.; Haas, F.; Papka, P.; Kratz, K.-L.; Pfeiffer, B

    2003-05-05

    The excitation functions of {sup 12}C({alpha},{gamma}){sup 16}O and {sup 22}Ne({alpha},n){sup 25}Mg have been determined with a yet unequaled experimental sensitivity of 10{sup -11} b. From {gamma}-angular distributions the S{sub E1}-and S{sub E2}-factors for {sup 12}C({alpha},{gamma}){sup 16}O have been deduced and extrapolated into the range of helium burning temperatures using the R-matrix method. An improved reaction rate has been calculated: N{sub A}<{sigma}{nu}>=(7.9{+-}2.5)x10{sup -15}cm{sup 3}(mols){sup -1} at T{sub 9} = 0.2. For a more precise extrapolation the excitation function has to be measured with better statistics. Therefore a new experiment on {sup 12}C({alpha},{gamma}){sup 16}O with a better suited setup has been started recently. The accuracy of the {sup 22}Ne({alpha},n){sup 25}Mg reaction rate could be improved considerably compared to previous compilations: N{sub A}<{sigma}{nu}> = (0.88{sub -0.3}{sup +2.6}) x 10{sup -16}cm{sup 3}(mols){sup -1} at T{sub 9} = 0.2.

  1. Quasi-bound alpha resonant states populated by the 12C(6Li, d) reaction

    International Nuclear Information System (INIS)

    Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (xα) and (xα+n) nuclei through the (6Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4α) threshold in the nucleus 16O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in 12C [6]. The existence of a rotational band with the α +12 C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the 12C(6Li, d)16O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 μm thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J. Mod. Mod. Phys E 20, 1018-1021 (2011). [4] T. Borello-Lewin et

  2. Measurement of alpha-induced reaction cross sections on erbium isotopes for γ process studies

    Science.gov (United States)

    Kiss, G. G.; Szücs, T.; Török, Zs.; Fülöp, Zs.; Gyürky, Gy.; Halász, Z.; Somorjai, E.; Rauscher, T.

    2014-05-01

    The cross sections of the 162Er(α,γ)166Yb and 162,164,166Er(α,n)165,167,169Yb reactions have been measured at MTA Atomki. The radiative alpha capture reaction cross section was measured between Ec.m. = 11.21 MeV and Ec.m. = 16.09 MeV just above the astrophysically relevant energy region (which lies between 7.8 and 11.48 MeV at T9 = 3 GK). The 162Er(α,n)165Yb, 164Er(α,n)167Yb and 166Er(α,n)169Yb reactions were studied between Ec.m. = 12.19 and 16.09 MeV, Ec.m. = 13.17 and 16.59 MeV and Ec.m. = 12.68 and 17.08 MeV, respectively. The aim of this work is to provide experimental data for modeling the γ process which is thought to be responsible for the production of the proton-rich isotopes heavier than iron.

  3. A new study of $^{10}$B(p,$\\alpha$)$^{7}$Be reaction at low energies

    CERN Document Server

    Caciolli, A; Broggini, C; La Cognata, M; Lamia, L; Menegazzo, R; Mou, L; Puglia, S M R; Rigato, V; Romano, S; Alvarez, C Rossi; Sergi, M L; Spitaleri, C; Tumino, A

    2016-01-01

    The $^{10}$B(p,$\\alpha$)$^{7}$Be reaction is of great interest since it has many applications in different fields of research such as nuclear astrophysics, nuclear physics, and models of new reactors for clean energy generation. This reaction has been studied at the AN2000 accelerator of the INFN National Laboratories of Legnaro (LNL). The total cross section has been measured in a wide energy range (250 $-$ 1182 keV) by using the activation method. The decays of the $^7$Be nuclei produced by the reaction were measured at the low counting facility of LNL by using two fully shielded high-purity germanium detectors. The present dataset shows a large discrepancy with respect to one of the previous data at the same energies and reduces the total uncertainty to the level of 6\\%. An R-matrix calculation has been performed on the present data using the parameters from previous Trojan Horse measurements for the 10 and 500 keV resonances. The present data do not lay on the R-matrix fit in one point suggesting the exis...

  4. Cross sections of $\\alpha$-induced reactions for targets with masses $A \\approx 20-50$ at low energies

    CERN Document Server

    Mohr, Peter

    2015-01-01

    A simple reduction scheme using so-called reduced energies $E_{\\rm{red}}$ and reduced cross sections $\\sigma_{\\rm{red}}$ allows the comparison of heavy-ion induced reaction cross sections for a broad range of masses of projectile and target and over a wide energy range. A global behavior has been found for strongly bound projectiles whereas much larger reduced cross sections have been observed for weakly bound and halo projectiles. It has been shown that this simple reduction scheme works also well for $\\alpha$-particle induced reactions on heavy target nuclei, but very recently significant deviations have been seen for $\\alpha$+$^{33}$S and $\\alpha$+$^{23}$Na. Motivated by these unexpected discrepancies, the present study analyses $\\alpha$-induced reaction cross sections for targets with masses $A \\approx 20-50$. The study shows that the experimental data for $\\alpha$-induced reactions on nuclei with $A \\approx 20-50$ deviate slightly from the global behavior of reduced cross sections. However, in general th...

  5. EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study.

    Science.gov (United States)

    Sonnleitner, Andreas; Treder, Matthias Sebastian; Simon, Michael; Willmann, Sven; Ewald, Arne; Buchner, Axel; Schrauf, Michael

    2014-01-01

    Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers' mental states during a primary driving task. N=20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers' mental states. Results show that reaction times and alpha spindle rate increased with time-on-task. Moreover, brake reaction times and alpha spindle rate were significantly higher while driving with auditory secondary task opposed to driving only. In single-trial classification, a combination of spindle parameters yielded a median classification error of about 8% in discriminating the distracted from the alert driving. Reduced driving performance (i.e., prolonged brake reaction times) during increased cognitive load is assumed to be indicated by EEG alpha spindles, enabling the quantification of driver distraction in experiments on public roads without verbally assessing the drivers' mental states. PMID:24144496

  6. Study of the {sup 7}Li (p,{alpha}){sup 4}He Reaction at Astrophysical Energies Through the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Pellegriti, M.G.; Aliotta, M.; Cherubini, S.; Lattuada, M.; Miljanic, D.; Pizzone, R.G.; Romano, S.; Soic, N.; Spitaleri, C.; Zadro, M.; Zappala, R.A.

    2000-12-31

    The Trojan Horse Method has been applied to obtain information about {sup 7}Li(p,{alpha}),{sup 4}He reaction at astrophysical energies. The {sup 7}Li(d,{alpha} n){sup 4}He reaction has been used and the two body reaction cross section for the {sup 7}Li(p,{alpha}){sup 4}He has been extracted together with its astrophysical factor S(E).

  7. The resonance triplet at E_alpha = 4.5 MeV in the 40Ca(alpha,gamma)44Ti reaction

    CERN Document Server

    Schmidt, Konrad; Anders, Michael; Bemmerer, Daniel; Boretzky, Konstanze; Caciolli, Antonio; Degering, Detlev; Dietz, Mirco; Dressler, Rugard; Elekes, Zoltán; Fülöp, Zsolt; Gyürky, György; Hannaske, Roland; Junghans, Arnd R; Marta, Michele; Menzel, Marie-Luise; Munnik, Frans; Schumann, Dorothea; Schwengner, Ronald; Szücs, Tamás; Wagner, Andreas; Yakorev, Dmitry; Zuber, Kai

    2013-01-01

    The 40Ca(alpha,gamma)44Ti reaction is believed to be the main production channel for the radioactive nuclide 44Ti in core-collapse supernovae. Radiation from decaying 44Ti has been observed so far for two supernova remnants, and a precise knowledge of the 44Ti production rate may help improve supernova models. The 40Ca(alpha,gamma)44Ti astrophysical reaction rate is determined by a number of narrow resonances. Here, the resonance triplet at E_alpha = 4497, 4510, and 4523 keV is studied both by activation, using an underground laboratory for the gamma counting, and by in-beam gamma spectrometry. The target properties are determined by elastic recoil detection analysis and by nuclear reactions. The strengths of the three resonances are determined to omega gamma = (0.92+-0.20), (6.2+-0.5), and (1.32+-0.24) eV, respectively, a factor of two more precise than before. The strengths of this resonance triplet may be used in future works as a point of reference. In addition, the present new data directly affect the as...

  8. Study of transfer reactions ({alpha},t), ({alpha},{sup 3}He) in the f-p shell: mechanism and spectroscopic use; Etude des reactions de transfert ({alpha},t), ({alpha},{sup 3}He) dans la couche f-p mecanisme et utilisation spectroscopique

    Energy Technology Data Exchange (ETDEWEB)

    Roussel, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-05-01

    We describe an experimental study of ({alpha},t), ({alpha},{sup 3}He) reactions at 44 MeV using a solid-state identifier, on the target-nuclei {sup 54}Fe and {sup 58,60,62,64}Ni. A critical study of optical model and of disturbed wave analysis has been performed. We show the complementarity of different transfer-reactions, the ambiguity of spectroscopic factors, the importance of the problem of the reaction mechanism. (author) [French] On decrit une etude experimentale des reactions ({alpha},t), ({alpha},{sup 3}He) a 44 MeV utilisant un systeme identificateur de particules sur les noyaux-cibles {sup 54}Fe et {sup 58,60,62,64}Ni. Une etude critique de modele optique et d'analyse en ondes deformees (D.W.B.A.) a ete entreprise. On montre la complementarite des differentes reactions de transfert, l'ambiguite des facteurs spectroscopiques, l'importance du probleme du mecanisme. (auteur)

  9. Reaction of HO/sub 2//O/sub 2//sup -/ with. cap alpha. -tocopherol in ethanolic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Arudi, R.L.; Sutherland, M.W.; Bielski, B.H.J.

    1982-01-01

    The HO/sub 2/ perhydroxyl radical reacts with ..cap alpha..-tocopherol in 85% ethanol containing some H/sub 2/SO/sub 4/, EDTA, and O/sub 2/. The resulting transient has a spectral maximum near 390 ..mu... The final product is mostly ..cap alpha..-tocopherylquinone. Best reproducibility for reaction of O/sub 2//sup -/ with ..cap alpha..-tocopherol was obtained in a deoxygenated reaction mixture of 26 +- 3 ..mu..M O/sub 2//sup -/, 0.0565M ..cap alpha..-tocopherol, 5..mu..M EDTA, and 0.005 M KOH in 85% EtOH; the upper limit for the reaction was 6.0 +- 3.0 M/sup -1/ s/sup -1/, indicating that for all practical purposes O/sub 2//sup -/ does not react at all with ..cap alpha..-tocopherol. Preliminary experiments with Trolox, a vitamin E model compound, indicates that it too reacts with HO/sub 2/ but not with O/sub 2//sup -/. Membrane-bound tocopherols in vivo may fulfil a dual antioxidant role. (DLC)

  10. Proton and alpha-particle capture reactions at sub-Coulomb energies relevant to the p process

    Energy Technology Data Exchange (ETDEWEB)

    Harissopulos, S [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Lagoyannis, A [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Spyrou, A [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Zarkadas, Ch [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Galanopoulos, S [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Perdikakis, G [Tandem Accelerator Facility, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Becker, H-W [Dynamitron-Tandem-Laboratorium, Ruhr Universitaet Bochum, 44801 Bochum (Germany); Rolfs, C [Institut fuer Physik mit Ionenstrahlen, EP-II, Ruhr-Universitaet BochumI, 44801 Bochum (Germany); Strieder, F [Institut fuer Physik mit Ionenstrahlen, EP-II, Ruhr-Universitaet BochumI, 44801 Bochum (Germany); Kunz, R [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Fey, M [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Hammer, J W [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Dewald, A [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Zell, K-O [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Brentano, P von [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Julin, R [Department of Physics, University of Jyvaeskylae, 40014 Jyvaeskylae (Finland); Demetriou, P [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, CP226, 1050 Brussels (Belgium)

    2005-10-01

    Several cross-section measurements of proton as well as {alpha}-particle capture reactions in the Se-Sb region have been carried out at sub-Coulomb energies with the aim to obtain global input parameters for Hauser-Feshbach (HF) calculations. Some of the results are compared with HF calculations using various optical model potentials and nuclear level densities.

  11. AVERAGE REACTION CROSS-SECTIONS FOR 74-MEV TO 112-MEV ALPHA-PARTICLES ON I-127 AND CS-133

    NARCIS (Netherlands)

    WARNER, RE; WILSCHUT, HW; RULLA, WF; FELDER, GN

    1991-01-01

    The average reaction cross section for 74- to 112-MeV alpha particles on I-127 and Cs-133 was measured by a new method using a magnetic spectrograph and a CsI scintillation detector. The result, sigma-R = 2220+/-50 mb, is in good agreement with optical model calculations and finite-range microscopic

  12. Study of the {sup 9}Be(p,{alpha}){sup 6}Li reaction via the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Romano, S.; Lamia, L.; Spitaleri, C.; Cherubini, S.; Gulino, M.; La Cognata, M.; Tumino, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); Li, C.; Pizzone, R.G. [INFN, Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method has been applied to the {sup 2}H({sup 9}Be,{sup 6}Li{alpha})n three-body reaction in order to investigate the {sup 9}Be(p,{alpha}){sup 6}Li two-body reaction, which is involved in the study of light element abundances (lithium, beryllium and boron). A coincidence measurement was performed in order to identify the presence of the quasi-free mechanism in the three-body reaction, needed for the application of the method. The astrophysical S(E)-factor was extracted and compared to direct data. No information about electron screening effects can be extracted due to the poor resolution of the indirect data. (orig.)

  13. Alpha adrenergic modulation on effects of norepinephrine transporter inhibitor reboxetine in five-choice serial reaction time task

    Directory of Open Access Journals (Sweden)

    Liu Yia-Ping

    2009-08-01

    Full Text Available Abstract The study examined the effects of a norepinephrine transporter (NET inhibitor reboxetine (RBX on an attentional performance test. Adult SD rats trained with five-choice serial reaction time task (5-CSRTT were administered with RBX (0, 3.0 and 10 mg/kg in the testing day. Alpha-1 adrenergic receptor antagonist PRA and alpha-2 adrenergic receptor antagonist RX821002 were used to clarify the RBX effect. Results revealed that rat received RBX at 10 mg/kg had an increase in the percentage of the correct response and decreases in the numbers of premature response. Alpha-1 adrenergic receptor antagonist Prazosin (PRA at 0.1 mg/kg reversed the RBX augmented correct responding rate. However, alpha-2 adrenergic receptor antagonist RX821002 at 0.05 and 0.1 mg/kg dose dependently reversed the RBX reduced impulsive responding. Our results suggested that RBX as a norepinephrine transporter inhibitor can be beneficial in both attentional accuracy and response control and alpha-1 and alpha-2 adrenergic receptors might be involved differently.

  14. Deformation behaviour of {gamma}+{alpha}{sub 2} Ti aluminide processed through reaction synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.K., E-mail: rohitkumar_gupta@vssc.gov.in [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India); Pant, Bhanu [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India); Kumar, Vinod [SAIL-RDCIS, Ranchi (India); Agarwala, Vijaya [Indian Institute of Technology, Roorkee 247 667 (India); Sinha, P.P. [Vikram Sarabhai Space Centre, ISRO, Trivandrum, Kerala 695 022 (India)

    2013-01-01

    {gamma}+{alpha}{sub 2} titanium aluminide alloys made through reaction synthesis have been used for deformation study. Hot isothermal compression test is carried out to study the deformation characteristics of the alloys using Gleeble thermomechanical simulator. Three alloys based on Ti48Al2Cr2Nb0.1B (at%) are tested at different temperatures and at different strain rates. True stress-true strain plots are analyzed along with analysis of tested specimens. Tested specimens are observed under optical and electron microscopes. Presence of various deformation morphologies and phases were confirmed. Microhardness evaluation and transmission electron microscopic examination are used to confirm the presence of different phases. It is found that dynamic recrystallization is mainly playing role in deformation of these alloys. Presence of dynamically recrystallized (DRX) grains and lamellar microstructures is confirmed at the intergranular area and inside the grains, respectively. A nucleation model is suggested for DRX and lamellar grain nucleation during deformation. Attempt has been made to quantify the presence of various phases through optical microscopy. Hot workability map is also suggested on the basis of microstructural and visual observation of compression tested specimens.

  15. Cross Section and Tensor Analysing Power of the $\\vec{d}d\\to \\eta\\alpha$ Reaction Near Threshold

    CERN Document Server

    Budzanowski, A; Gebel, R; Hawranek, P; Jahn, R; Jha, V; Kilian, K; Kliczewski, S; Kirillov, Da; Kirillov, Di; Kolev, D; Kravcikova, M; Lesiak, M; Lieb, J; Machner, H; Magiera, A; Maier, R; Martinská, G; Nedev, S; Piskunov, N; Prasuhn, D; Protić, D; Ritman, J; Von Rossen, P; Roy, B J; Sitnik, U; Siudak, R; Tsenov, R; Urbán, J; Vankova, G; Wilkin, C

    2008-01-01

    The angular distributions of the unpolarised differential cross section and tensor analysing power $A_{xx}$ of the $\\vec{d}d\\to\\alpha \\eta$ reaction have been measured at an excess energy of 16.6 MeV. The ambiguities in the partial-wave description of these data are made explicit by using the invariant amplitude decomposition. This allows the magnitude of the s-wave amplitude to be extracted and compared with results published at lower energies. In this way, firmer bounds could be obtained on the scattering length of the $\\eta \\alpha$ system. The results do not, however, unambiguously prove the existence of a quasi-bound $\\eta \\alpha$ state.

  16. Spectroscopy of $^{19}$Ne for the thermonuclear $^{15}$O($\\alpha,\\gamma$)$^{19}$Ne and $^{18}$F($p,\\alpha$)$^{15}$O reaction rates

    CERN Document Server

    Parikh, A; de Séréville, N; Wimmer, K; Faestermann, T; Hertenberger, R; Seiler, D; Wirth, H -F; Adsley, P; Fulton, B R; Hammache, F; Kiener, J; Stefan, I

    2015-01-01

    Uncertainties in the thermonuclear rates of the $^{15}$O($\\alpha,\\gamma$)$^{19}$Ne and $^{18}$F($p,\\alpha$)$^{15}$O reactions affect model predictions of light curves from type I X-ray bursts and the amount of the observable radioisotope $^{18}$F produced in classical novae, respectively. To address these uncertainties, we have studied the nuclear structure of $^{19}$Ne over $E_{x} = 4.0 - 5.1$ MeV and $6.1 - 7.3$ MeV using the $^{19}$F($^{3}$He,t)$^{19}$Ne reaction. We find the $J^{\\pi}$ values of the 4.14 and 4.20 MeV levels to be consistent with $9/2^{-}$ and $7/2^{-}$ respectively, in contrast to previous assumptions. We confirm the recently observed triplet of states around 6.4 MeV, and find evidence that the state at 6.29 MeV, just below the proton threshold, is either broad or a doublet. Our data also suggest that predicted but yet unobserved levels may exist near the 6.86 MeV state. Higher resolution experiments are urgently needed to further clarify the structure of $^{19}$Ne around the proton thresh...

  17. Differential cross section measurements for the 6Li(n,t)alpha reaction in the few MeV region

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, Matthew J [Los Alamos National Laboratory; Taddeucci, Terence N [Los Alamos National Laboratory; Hale, Gerald M [Los Alamos National Laboratory; Haight, Robert C [Los Alamos National Laboratory; O' Donnell, Johhn M [Los Alamos National Laboratory

    2008-01-01

    New measured differential cross sections of tritons and alpha particles following the {sup 6}Li(n,t){alpha} reaction are reported for incident neutron energies between 0.2 and approximately 20 MeV. The neutrons were produced by spallation at the WNR facility at the Los Alamos Neutron Science CEnter (LANSCE), with the incident neutron energy determined by the time-of-flight method. Four E-{Delta}E telescopes were used at eight laboratory angles. These data have been incorporated into a prior R-matrix fit for the compound {sup 7}Li system, and result in an (n,t) reaction cross section that is 4% to 10% higher than previous evaluations in the 1-3 MeV incident neutron energy region.

  18. Mechanisms of the p(He 6,He 5)d, p(He 6,{alpha})t and p(He 6,t){alpha} reactions

    Energy Technology Data Exchange (ETDEWEB)

    Heiberg-Andersen, Henning

    2002-07-01

    This work was devoted to nucleon induced transfer reactions having the potential to probe the sub-cluster structures of the benchmark halo nucleus He 6, without the question marks the necessarily omitted exchange effects tend to put behind the CRC results when both collision partners are composite systems. Still, the exchange complications entered the analysis in an ironic way: The high Q-value of the p(He 6,{alpha})t and p(He 6, t){alpha} reactions caused sensitivity to the t - {alpha} optical potential at small radii, where the one-nucleon exchange effects are strongest. Since the attempt to throw them out of the extracted tau - {alpha} potential failed, it was necessary to extend the model space to avoid a too difficult modelling of the local equivalent t - {alpha} potential. By this step, all the complications originating from antisymmetrization within a larger model space entered the analysis. However, the persistent failures of the two-channel calculations of this and previous works can hardly be due to incorrect treatment of exchange effects only, so the loss of simplicity is probably illusory. Even at small angles, where the surface processes dominate, none of the two-channel calculations with various choices of t - {alpha} optical potentials managed to reproduce the p(He 6, {alpha})t (p(He 6,t){alpha}) data. This motivated inclusion of sequential transfers through the d + He 5 channel, where the sequential triton transfer process, included just for consistency in the coupling scheme of the four-channel calculation, turned out to be more influent than expected. The satisfactory reproduction of both the p(He 6, He 5)d and the p(He 6,{alpha})t (p(He 6,t){alpha}) data by the four-channel approach and the required re-normalization the real part of the p - He 6 optical potential are strong indications of substantial contributions from sequential transfer of the halo neutrons at this energy. The conclusions that can be drawn from this work are limited by the

  19. Alpha resonances excited in13C and 16O by the (6Li,d) reaction

    International Nuclear Information System (INIS)

    The investigation of a cluster correlations is the main purpose of the research program in progress, focusing on xα and xα + ν nuclei. The reactions 9Be(6Li,d)13C and 12C(6Li,d)16O measured at the bombarding energy of 25.5 MeV, employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique, were used to enhance a resonant states in 13C and 16O. An energy resolution of 20-40 keV was obtained and up to 15.5 MeV of excitation, in both nuclei, several resonances not previously measured, revealing a quasi-bound behavior, were detected. Focusing on 13C, the experimental angular distributions associated with the resonances just above the 9Be + α and 3α + ν thresholds[2] were compared with DWBA predictions. Seen at the 9Be + α threshold, a pure L = 4 transfer is indicated for each transition to the known 7/2- and (5/2-) states instead of L = 2 obtained in the former fit[3] to the integrated contribution. The narrow resonance detected at 12.3 MeV of excitation, close to the 3α + ν threshold and populated by an L = 2 transfer, reveals a 9Be(G.S.) + α component for the 1/2- cluster state candidate, 12C(Hoyle) + ν, at this threshold. Considering the 16O, states were revealed around the 4α threshold (14.44 MeV) and the upper limit resonant widths were obtained. The resonance at 14.670 MeV was reached by an L = 5 direct transfer in agreement with the 5- attribution. The upper limit width obtained, near the experimental resolution, is inconsistent with the usual experimental[4,5] and theoretical[6-7] interpretations of the 5- state revealed as a broad resonance in the same excitation energy region and considered to be a member of the Kπ = 0- band with the 12C(G.S.) + α structure. In the same excitation energy range, a narrow 5- resonance decaying to 12C(2+ 1), was predicted by Suzuki using a comprehensive semi-microscopic alpha cluster calculation, in agreement with the present findings. Haigh et al., in the investigation of the 12C

  20. Study of the astrophysically important $\\boldsymbol{^{23}\\mathrm{Na}(\\alpha,p)^{26}\\mathrm{Mg}}$ and $\\boldsymbol{^{23}\\mathrm{Na}(\\alpha,n)^{26}\\mathrm{Al}}$ reactions

    CERN Document Server

    Avila, M L; Almaraz-Calderon, S; Ayangeakaa, A D; Dickerson, C; Hoffman, C R; Jiang, C L; Kay, B P; Lai, J; Nusair, O; Pardo, R C; Santiago-Gonzalez, D; Talwar, R; Ugalde, C

    2016-01-01

    The $^{23}$Na$(\\alpha,p)^{26}$Mg and $^{23}$Na$(\\alpha,n)^{26}$Al reactions are important for our understanding of the $^{26}$Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using $^{4}$He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the $^{23}$Na$(\\alpha,p)^{26}$Mg and the $^{23}$Na$(\\alpha,n)^{26}$Al reactions are in good agreement with previous experiments, and with statistical model calculations.

  1. Partition of cross sections in asymmetric nucleus-nucleus reactions and the origin of fast alpha particles

    International Nuclear Information System (INIS)

    To investigate the mechanism of asymmetric nucleus-nucleus reactions from the Coulomb barrier to intermediate energies the 14N + 159Tb reaction was studied at five bombarding energies between 8 and 23 MeV/u via particle-particle correlations (at selected energies) and particle KX-ray coincidences to identify the specific reaction channels. With the KX-ray method partial cross sections for projectile-like fragments (PLF) as a function of the atomic number (Z/sub res/) of the residual nucleus can be determined. The charge balance yields the ''missing charge'' dZ = Z/sub proj/ + Z/sub targ/ - Z/sub PLF/ - Z/sub TLF/ that indicates whether, in addition to the PLF, other charged particles are emitted. A large fraction of the inclusive cross sections is found to originate from such channels with two or more fragments in the exit channel, and this fraction increases as the PLF is further removed in mass from the incident projectile, and with increasing bombarding energy. From the particle-particle correlation studies it is found that sequential decays of PLF's are dominant. ''Non-sequential'' processes, if present, are associated with inelastic reactions involving excitations of both projectile and target. The bulk of the large alpha-particle cross section at small angles is found to be associated with channels in which, in addition to the alpha particle, only nucleons and other alpha particles are emitted. From γ-ray multiplicity measurements and from the broad distribution of the strength with Z/sub res/ it is concluded that these alpha particles originate from inelastic (damped) processes. 27 refs., 10 figs

  2. Trojan Horse Method and RIBs: The {sup 18}F(p,{alpha}){sup 15}O reaction at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Cherubini, S.; Gulino, M.; Rapisarda, G. G.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Kubono, S.; Yamaguchi, H.; Hayakawa, S.; Wakabayashi, Y.; Iwasa, N.; Kato, S.; Komatsubara, H.; Teranishi, T.; Coc, A.; De Sereville, N.; Hammache, F. [Dipartimento di Fisica ed Astronomia, Universita di Catania and INFN-LNS, Catania (Italy); INFN-LNS, Catania (Italy) and UniKORE, Enna (Italy)

    2012-11-12

    The abundance of {sup 18}F in Nova explosions is an important issue for the understanding of this astrophysical phenomenon. For this reason it is necessary to study the nuclear reactions that produce or destroy this isotope in novae. Among these latter processes, the {sup 18}F(p,{alpha}){sup 15}O is one of the main {sup 18}F destruction channels. We report here on the preliminary results of the first experiment that applies the Trojan Horse Method to a Radioactive Ion Beam induced reaction. The experiment was performed using the CRIB apparatus of the Center for Nuclear Study of The Tokyo University.

  3. Quasi-bound alpha resonant states populated by the {sup 12}C({sup 6}Li, d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M.R.D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [Istituto Nazionale di Fisica Nucleare (LNS/INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculdade de Psicologia

    2012-07-01

    Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (x{alpha}) and (x{alpha}+n) nuclei through the ({sup 6}Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4{alpha}) threshold in the nucleus {sup 16}O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in {sup 12}C [6]. The existence of a rotational band with the {alpha} +{sup 12} C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the {sup 12}C({sup 6}Li, d){sup 16}O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 {mu}m thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J

  4. Triethylaluminum- or triethylborane-induced free radical reaction of alkyl iodides and alpha,beta-unsaturated compounds.

    Science.gov (United States)

    Liu, Jing-Yuan; Jang, Yoeng-Jiunn; Lin, Wen-Wei; Liu, Ju-Tsung; Yao, Ching-Fa

    2003-05-16

    A series of alpha,beta-unsaturated compounds, 1a-c, 9, 13, and 17, were used as reactants in free radical conjugate addition reactions with different radicals generated from alkyl iodides such as 3, 4, or 5 in the presence of triethylborane-oxygen in air or via the use of triethylaluminum-benzoyl peroxide as a free radical initiator. When the reactions were carried out using triethylborane-air, the products, in most cases, were clean and were easily purified. However, higher yields of the 1,4-adducts and less side reactions occurred when less reactive substrates were used as Michael acceptors in reactions with triethylaluminum-benzoyl peroxide and alkyl iodide under similar conditions. A mechanism for this is proposed in Scheme 1. PMID:12737587

  5. Activation cross sections of $\\alpha$-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of $^{178}$W/$^{178m}$Ta generator

    CERN Document Server

    Tárk'anyi, F; Ditrói, F; Hermanne, A; Ignatyuk, A V; Uddin, M S

    2014-01-01

    In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of $^{178m}$Ta through $^{nat}$Hf($\\alpha$,xn)$^{178}$W-$^{178m}$Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions $^{nat}$Hf($\\alpha$,x)$^{179,177,176,175}$W, $^{183,182,178g,177,176,175}$Ta, $^{179m,177m,175}$Hf were also assessed. Stacked foil irradiation technique and $\\gamma$-ray spectrometry were used. New experimental cross section data for the $^{nat}$Ta(d,xn)$^{178}$W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and ($^3$He,x)) production routes for $^{178}$W.

  6. Near Fermi Energy reaction dynamics and clustering in alpha-conjugate systems

    Science.gov (United States)

    Cao, Xiguang; Schmidt, Katarzyna; Kim, E.-J.; Hagel, K.; Barbui, M.; Wuenschel, S.; Natowitz, J. B.; Zheng, H.; Blando, N.; Bonasera, A.; Giuliani, G.

    2015-10-01

    Theoretical study predicted that the self-organizing of alpha cluster is favored over deuteron below a critical density with moderate temperature, where the possible Bose-Einstein condensation (BEC) is expected to occur. However the experimental information about the alpha states at low density is scarce. It is natural to pursue experiments with α conjugate beams and advanced detection apparatus to explore the collective dynamics of alpha clustered systems at low density. Systematical experiments were carried out with 40Ca and 28Si beams at 10, 25, 35 MeV/u incident on 28Si, 12C, 40Ca and 180Ta targets, detected with the NIMROD-ISiS 4 Pi detector array. It is found that there is a strong neck-like emission, which consists mainly of alpha-like fragments. The characteristic of the α emission source is explored by shape analysis, multi-particle correlation and quantum fluctuation approaches. How these observables reveal the possible alpha BEC in low density and possible exotic toroidal and linear chain configurations made out of alpha clusters is discussed.

  7. Measurement of the reaction O-17(\\alpha,n)Ne-20 and its impact on the s process in massive stars

    CERN Document Server

    Best, A; Görres, J; Couder, M; deBoer, R; Falahat, S; Güray, R T; Kontos, A; Kratz, K -L; LeBlanc, P J; Li, Q; O'Brien, S; Özkan, N; Pignatari, M; Sonnabend, K; Talwar, R; Tan, W; Uberseder, E; Wiescher, M; 10.1103/PhysRevC.87.045805

    2013-01-01

    The ratio between the rates of the reactions O-17(\\alpha,n)Ne-20 and O-17(\\alpha,\\gamma)Ne-21 determines whether O-16 is an efficient neutron poison for the s process in massive stars, or if most of the neutrons captured by O-16(n,\\gamma) are recycled into the stellar environment. This ratio is of particular relevance to constrain the s process yields of fast rotating massive stars at low metallicity. Recent results on the (\\alpha,\\gamma) channel have made it necessary to measure the (\\alpha,n) reaction more precisely and investigate the effect of the new data on s process nucleosynthesis in massive stars. We present a new measurement of the O-17(\\alpha, n) reaction using a moderating neutron detector. In addition, the (\\alpha, n_1) channel has been measured independently by observation of the characteristic 1633 keV \\gamma-transition in Ne-20. The reaction cross section was determined with a simultaneous R-matrix fit to both channels. (\\alpha,n) and (\\alpha, \\gamma) resonance strengths of states lying below ...

  8. The Trojan-Horse Method applied to the {sup 6}Li(p,{alpha}){sup 3}He reaction down to astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Pappalardo, L.; Cherubini, S.; Del Zoppo, A.; La Cognata, M.; Musumarra, A.; Pellegriti, M.G.; Pizzone, R.G.; Rinollo, A.; Romano, S.; Typel, S

    2004-04-05

    The Trojan-Horse Method has been applied to the three-body d({sup 6}Li,{alpha}{sup 3}He)n break-up reaction in order to extract the bare nucleus S(E) factor for the {sup 6}Li(p,{alpha}){sup 3}He down to astrophysical energies.

  9. Effects of spins and resonance parities of 12C on the mechanism of emission of three alpha particles in the 11B (p, 3 α) reaction

    International Nuclear Information System (INIS)

    This research thesis reports the study of the mechanism of emission of alpha particles in the 11B (p, 3 α) reaction with respect to the effects of spins and parities of the various resonances met between 150 keV and 4 MeV. From an experimental point of view, the reaction has been studied by two methods: the detection of alpha particles by a semiconductor-based counter located at a given angle with respect to the beam direction and study of continuous spectra of alpha particles with respect to projectile energies, and recording, for a given resonance, of alpha-alpha coincidences by using the multi-parametric technique with two semiconductor-based sensors with a varying relative angular position. After a discussion of the main characteristics of resonance and of the mechanism of emission of alpha particles, the author first reports the theoretical study of a reaction producing three particles in the final state, and then reports the theoretical calculation of direct alpha spectrum shapes in the case of the 11B (p, 3 α) reaction (statistic hypothesis, hypothesis of interaction with two particles in the final state). The next part reports the experimental study of the 11B (p, 3 α) reaction

  10. New High-Precision Measurement of the Reaction Rate of the 18O(p,alpha)15N Reaction via THM

    CERN Document Server

    La Cognata, M; Mukhamedzhanov, A M; Irgaziev, B; Tribble, R E; Banu, A; Cherubini, S; Coc, A; Crucilla, V; Goldberg, V Z; Gulino, M; Kiss, G G; Lamia, L; Chengbo, L; Mrazek, J; Pizzone, R G; Puglia, S M R; Rapisarda, G G; Romano, S; Sergi, M L; Tabacaru, G; Trache, L; Trzaska, W; Tumino, A

    2009-01-01

    The 18O(p,alpha)15N reaction rate has been extracted by means of the Trojan-Horse method. For the first time the contribution of the 20-keV peak has been directly evaluated, giving a value about 35% larger than previously estimated. The present approach has allowed to improve the accuracy of a factor 8.5, as it is based on the measured strength instead of educated guesses or spectroscopic measurements. The contribution of the 90-keV resonance has been determined as well, which turned out to be of negligible importance to astrophysics.

  11. Reaction of blood pressure and mesenteric blood flow to an infusion of biogenic amines in rats: Influence of irradiation and alpha blockers

    International Nuclear Information System (INIS)

    The reaction of systemic blood pressure and mesenteric blood flow to an infusion of different biogenic amines was determined in controls and in lethally (8 Gy) X-irradiated rats. The influence of the alpha blocker phenoxybenzamine on these reactions was also investigated. Changes in blood pressure and flow response similar to, but less marked than, those seen earlier after a supralethal (20 Gy) exposure were detected 3 and 8 days after irradiation. These observations as well as the consequences of alpha blockade suggest that the reactivity of alpha receptors in blood vessels is reduced after irradiation, and that the function of the heart is impaired. (orig.)

  12. Nucleophilic Substitution and Redox Reactions with alpha-Chloro beta-Oxo Sulfenyl Chlorides

    DEFF Research Database (Denmark)

    El-Essawy, Farag A.G.; Yassin, Salah M.; El-Sakka, Ibrahim A.; Khattab, Ahmed F.; Søtofte, Inger; Madsen, Jørgen Øgaard; Senning, Alexander Erich Eugen

    Alpha-Chloro sulfenyl chlorides such as 1 and 4 could not be reduced to the corresponding disulfides. Under reducing conditions they are instead dechlorinated to the corresponding thiocarbonyl compounds. Starting from the chroman-4-one derivatives 1 a number of 1,3,4-oxadithiins 3 have been...

  13. Cross section measurements of $\\alpha$-induced reactions on $^{92,94}$Mo and $^{112}$Sn for $p$-process studies

    CERN Document Server

    Rapp, W; Käppeler, F; Giesen, U; Klein, H; Rauscher, T; Hentschel, D; Hilpp, S

    2008-01-01

    The $^{92}$Mo($\\alpha,n$)$^{95}$Ru, $^{94}$Mo($\\alpha,n$)$^{97}$Ru, and $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te cross sections were measured at the upper end of the $p$-process Gamow window between 8.2 MeV and 11.1 MeV. Our results are slightly lower than global Hauser-Feshbach calculations from the code NON-SMOKER, but still within the uncertainty of the prediction. The $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te cross section agrees well with a recently measured thick-target cross section in the same energy range. For the $^{92,94}$Mo($\\alpha,n$) reactions the present data close to the reaction thresholds could eliminate previous uncertainties within a factor of 20, and we can present now useful comparisons to statistical model calculations with different optical potentials.

  14. Effects of a new triple-$\\alpha$ reaction rate on the helium ignition of accreting white dwarfs

    OpenAIRE

    Saruwatari, Motoaki; Hashimoto, Masa-aki

    2010-01-01

    Effects of a new triple-alpha reaction rate on the ignition of carbon-oxygen white dwarfs accreting helium in a binary systems have been investigated. The ignition points determine the properties of a thermonuclear explosion of a Type Ia supernova. We examine the cases of different accretion rates of helium and different initial masses of the white dwarf, which was studied in detail by Nomoto. We find that for all cases from slow to intermediate accretion rates, nuclear burnings are ignited a...

  15. The 65 keV resonance in the {sup 17}O(p,alpha){sup 14}N thermonuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sergi, M.L. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Spitaleri, C. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Coc, A. [CSNSM, UMR 8609, CNRS/IN2P3and Universite Paris Sud 11, Batiment 104, 91405 Orsay Campus (France); Mukhamedzhanov, A. [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States); Burjan, S.V. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); Gulino, M. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Hammache, F. [IPN, IN2P3-CNRS et Universite de Paris-Sud 11, 91406 Orsay Cedex (France); Hons, Z. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology Topi District Swabi NWFP (Pakistan); Kiss, G.G. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Kroha, V. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); La Cognata, M. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lamia, L.; Pizzone, R.G. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Sereville, N. de [IPN, IN2P3-CNRS et Universite de Paris-Sud 11, 91406 Orsay Cedex (France); Somorjai, E. [ATOMKI, Debrecen (Hungary)

    2010-03-01

    The indirect measurement of {sup 17}O(p,alpha){sup 14}N cross section was performed by means of the Trojan Horse Method. This approach allowed to investigate the ultra-low energy range (E{sub c.m.}=0-300 keV) relevant for several astrophysics environments, where two resonant levels of {sup 18}F at E{sub c.m.}{sup R}=65 keV and E{sub c.m.}{sup R}=183 keV play a significant role in the reaction rate determination.

  16. Investigation of (n,alpha) Reaction for Rare-earth Elements in the MeV Neutron Energy Region

    Energy Technology Data Exchange (ETDEWEB)

    Gledenov, R. Y. [Joint Institute for Nuclear Research, Dubna, Russia; Koehler, Paul Edward [ORNL; N_TOF collaboration, [CNR-INFM, Trieste, Italy

    2011-01-01

    Cross sections and forward/backward ratios in the laboratory reference system were measured for {sup 143}Nd(n, {alpha}){sup 140}Ce at 4.0, 5.0, and 6.0 MeV, {sup 147}Sm(n, {alpha}){sup 144}Nd at 5.0 and 6.0 MeV, and {sup 149}Sm(n, {alpha}){sup 146}Nd at 6.0 MeV. A twin gridded ionization chamber and large-area back-to-back {sup 143}Nd{sub 2}O{sub 3} and {sup 147,149}Sm{sub 2}O{sub 3} samples were employed. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was employed for absolute neutron flux determination and a BF{sub 3} long counter was used as neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.

  17. $\\mathbf{\\alpha}$-induced reaction cross sections in the mass range $\\mathbf{A \\approx 20 - 50}$: a critical review

    CERN Document Server

    Mohr, Peter

    2016-01-01

    In a recent review it was shown that the cross sections of $\\alpha$-induced reactions in the $A \\approx 20 - 50$ mass range follow a general and smooth trend in most cases. For comparison of cross sections of different targets at various energies the method of reduced cross sections $\\sigma_{\\rm{red}}$ and reduced energies $E_{\\rm{red}}$ was used. Four outliers were identified: $^{36}$Ar and $^{40}$Ar with unusally small cross sections and $^{23}$Na and $^{33}$S with unusually large cross sections. New data for $^{23}$Na were presented at this NPA-7 conference; contrary to the previous data, these new data fit into the general systematics. In addition, a relation between the most effective energy $E_0$ for astrophysical reaction rates (the so-called Gamow window) and the reduced energy $E_{\\rm{red}}$ is presented.

  18. Neutron, Proton and Alpha Emission Spectra of Nickel Isotopes for Proton Induced Reactions

    Science.gov (United States)

    Tel, E.; Kara, A.

    2012-06-01

    The fusion energy is attractive as an energy source because the fusion will not produce CO2 or SO2 and so fusion will not contribute to environmental problems, such as particulate pollution and excessive CO2 in the atmosphere. The fusion reaction does not produce radioactive nuclides and it is not self-sustaining, as is a fission reaction when a critical mass of fissionable material is assembled. Since the fusion reaction is easily and quickly quenched the primary sources of heat to drive such an accident are heat from radioactive decay and heat from chemical reactions. Both the magnitude and time dependence of the generation of heat from radioactive decay can be controlled by proper selection and design of materials. Nickel (Ni) is an important structural material in fusion (and also fission) reactor technologies and many other fields. So, the working out the reaction cross sections of the Ni isotopes is very important for selection of the fusion materials. In this study, 58Ni(p,xn), 58Ni(p,xp), 60Ni(p,xp), 60Ni(p,xα) and 62Ni(p,xp) reactions have been investigated using nuclear reaction models. And also the 58Ni(p,xn) reaction has been calculated through a method of offered by Tel et al. The calculated results are discussed and compared with the experimental data taken from EXFOR database.

  19. On the reaction pathways and determination of transition-state structures for retaining alpha-galactosyltransferases.

    Science.gov (United States)

    André, Isabelle; Tvaroska, Igor; Carver, Jeremy P

    2003-04-22

    The catalytic mechanism of retaining glycosyltransferases is not yet completely understood, but one possible mechanism, by analogy with retaining glycosidases, is a double-displacement mechanism via a covalent glycosyl-enzyme intermediate (CGE). We have investigated various reaction pathways for this mechanism using non-empirical quantum mechanical methods. Because a double-displacement mechanism presumes a reaction happening in two steps, we have used predefined reaction coordinates to calculate the potential energy surface describing each step of the mechanism. By investigating several potential candidates to act as a catalytic base, this study attempts to shed some light on the unclear mechanism of the second step of the reaction. All intermediates and transition states on the reaction pathways were characterized using basis sets up to the DFT/B3LYP/6-311++G**//DFT/B3LYP/6-31G* level. Reaction pathways and structural changes were compared with the results previously obtained for inverting glycosyltransferases. The outcome of this study indicates, that among the reaction models investigated, the energetically favorable one is also the most plausible given the existing experimental data. This model requires the presence of only one catalytic acid in the active site with the UDP functioning as a general base in the second step of the reaction. This mechanism is in agreement with both kinetic data in the literature and the description of X-ray structures of retaining glycosyltransferases solved up to today. PMID:12681911

  20. Cross-section measurement of the 18F(alpha,p)21Ne reaction and possible implication for neutron production in explosive helium burning

    Energy Technology Data Exchange (ETDEWEB)

    Couture, Aaron Joseph [Los Alamos National Laboratory; Lee, Hye Young [Los Alamos National Laboratory; Couder, Manoel [UNIV OF NOTRE DAME; Falahat, Sascha [UNIV OF NOTRE DAME; Gorres, Joachim [UNIV OF NOTRE DAME; Lamm, Larry O [UNIV OF NOTRE DAME; Le Blanc, P J [UNIV OF NOTRE DAME; O' Brien, Shawn P [UNIV OF NOTRE DAME; Palumbo, Annalia [UNIV OF NOTRE DAME; Stech, Edward J [UNIV OF NOTRE DAME; Strandberg, Elizabeth [UNIV OF NOTRE DAME; Tan, Wanpeng [UNIV OF NOTRE DAME; Ugalde, Claudio [ANL; Wiescher, Michael C. F. [UNIV OF NOTRE DAME

    2009-01-01

    At the high temperature and density conditions of hot or explosive helium burning, the {sup 18}F({alpha},p){sup 21}Ne reaction may compete successfully wilh the {sup 18}F({beta}{sup +}{nu}) decay. This suggesls {sup 21}Ne({alpha},n) as an alternative neutron source in Ihe r-process. We have determined the total cross section of the {sup 18}F({alpha},p){sup 21}Ne reaction by studying the time-reverse reaction {sup 21}Ne(p,{alpha}){sup 18}F. Using the activation technique, the total reaction yield was measured in the proton beam energy range of 2.3-4.0 MeV, which corresponds to energies of 0.5-2.1 MeV in the {sup 18}F + {alpha} system. The resulting yield curve was analyzed in terms of the thick target formalism and the R-matrix theory. The reaction rate was deduced experimentally for the first time for the temperature of 0.1 < T{sub 9} < I. The experimemal reaction rate was compared with Hauser-Feshbach predictions. The astrophysical implications of the new rate are discussed.

  1. Kinetics of ozonation. 4. Reactions of ozone with. cap alpha. -tocopherol and oleate and linoleate esters in carbon tetrachloride and in aqueous micellar solvents

    Energy Technology Data Exchange (ETDEWEB)

    Giamalva, D.H.; Church, D.F.; Pryor, W.A.

    1986-10-15

    Vitamin E (..cap alpha..-tocopherol; ..cap alpha..-T) is known to protect animals against the deleterious effects of ozone in polluted air; one such effect is the ozone-initiated autooxidation of polyunsaturated fatty acids (PUFA) that occur in membranes. In order to assess the possibility of a direct reaction of ozone with ..cap alpha..-T competing with the very fast ozone-PUFA reaction, we have measured the rates of reaction of ozone with ..cap alpha..-T, oleic acid, and linoleic acid. I CCl/sub 4/ as solvent, ..cap alpha..-T reacts with ozone with a rate constant of about 5500 M/sup -1/ s/sup -1/; methyl oleate and methyl linoleate react 2 orders of magnitude faster. In aqueous micellar solutions the rate constants for ..cap alpha..-T and the fatty acids are more similar. The k for the ozone/..cap alpha..-T reaction is about 1 x 10/sup 6/ M/sup -1/ s/sup -1/ at pH 7, but decreases as the solution becomes more acidic; the k's for oleic acid and linoleic acid are ca. 1 x 10/sup 6/ M/sup -1/ s/sup -1/ and exhibit no significant pH dependence. Since the ratio of fatty acids to ..cap alpha..-T in membranes is typically at least 100-1000 to 1, we conclude that the direct reaction of ozone with ..cap alpha..-T is unlikely. Thus, the protection that vitamin E provides to animals breathing ozone-containing air must result from vitamin E acting as a free radical scavenger. We have also detected the ..cap alpha..-tocopheroxyl radical as an intermediate from the reaction of ozone with ..cap alpha..-T both in CCl/sub 4/ and aqueous micelles using electron spin resonance spectroscopy. The authors suggest that the observation of this intermediate is consistent with an initial electron transfer from ..cap alpha..-T to ozone.

  2. Reaction of /alpha/,/beta/-unsaturated acyl isothiocyanates with salts of dithiocarbamic acids

    Energy Technology Data Exchange (ETDEWEB)

    Krus, K.; Masias, A.; Beletskaya, I.P.

    1989-01-10

    The reaction of unsaturated isothiocyanates with the sodium and calcium salts of N-alkyl- and N,N-dialkyldithiocarbamic acids was studied. Depending on the structure of the dithiocarbamate, the reaction products are thiazines or acyl dithiocarbamates. For the salts of methyldithiocarbamic acid the effect of the concentration and the nature of the metal on the relative yields of 6-phenyl-3-methylpropiorhodanine and 6-phenylpropiorhodanine was studied. A method is proposed for the synthesis of 3-substituted propiorhodanines.

  3. The triple alpha reaction rate and the 2$^+$ resonances in $^{12}$C

    CERN Document Server

    de Diego, R; Fedorov, D V; ~Jensen, A S

    2010-01-01

    The triple alpha rate is obtained from the three-body bound and continuum states computed in a large box. The results from this genuine full three-body calculation are compared with standard reference rates obtained by two sequential two-body processes. The fairly good agreement relies on two different assumptions about the lowest $2^+$ resonance energy. With the same $2^+$ energy the rates from the full three-body calculation are smaller than those of the standard reference. We discuss the rate dependence on the experimentally unknown $2^+$ energy. Substantial deviations from previous results appear for temperatures above $3$~GK.

  4. Measurement and analysis of the excitation function for alpha induced reaction on Ga and Sb isotopes

    International Nuclear Information System (INIS)

    Excitation functions for the reactions 69Ga(αxn)sup(73-x)As, 69Ga(α,p3n)69Ge, 69Ga(α,2p4n)67Ga, 71Ga(α,xn)sup(75-x)As, 121Sb(α,xn)sup(125-x)I, 121Sb(α,p3n)121Te and 123Sb(α,xn)sup(127-x)I were obtained from the measurements of the residual activity of stacked foils of gallium nitrate evaporated on aluminium backings from threshold to 65 MeV. The excitation functions for the production of 74As, 72As, 71As, 69Ge and 67Ga from α - induced reactions on Ga and 126I, 124I, 123I, 121I and 121Te from α - induced reactions on Sb are presented. The experimental data are compared with calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the hybrid model of Blann (1971). The high energy part of the excitation functions are dominated by the pre-equilibrium reaction mechanism. Calculations were done using the a priori calculational method of Overlaid Alice Code of Blann. From the reactions 71Ga(α,3n)72As and 123Sb(α,3n)124I an initial exciton number nsub(o)=4(nsub(n)=2, nsub(p)=2, nsub(h)=0) with the mean free path multiplier parameter k set to 2 has been deduced for both the targets. However, there are a few exceptions (i) the theory overestimates the cross-section for the 69Ga(α,2p4n)67Ga reaction whereas it underestimate the cross-section for the 121Sb(α,p3n)121Te reaction and the high energy tail of 121Sb(α,2n)123I excitation function. Factors to which these discrepancies between theory and experiment in case of these reactions may be attributed are indicated. Barring these reactions the overall agreement between theory and experiment is good taking into account the limitations of the theory. (author). 43 refs., 7 tabs., 19 figs

  5. Multiple-scattering effects in proton- and alpha-nucleus reactions with Glauber theory

    International Nuclear Information System (INIS)

    We study the total reaction and elastic differential cross sections for proton-nucleus and 4He-nucleus reactions in the framework of the Glauber theory which describes multiplescattering processes. The input wave functions are obtained using the Skyrme-Hartree-Fock method and prepared for a wide range of mass numbers, O, Ca, Ni, Sn, and Pb isotopes. The theory reproduces experimental data very well. An effect of the multiple scattering is discussed by comparing with a standard optical-limit approximation. We see that the multiple-scattering effects play a crucial role, especially in enhancing the elastic differential cross sections at large scattering angles

  6. Reactions between a <111> screw dislocation and <100> interstitial dislocation loops in alpha-iron modelled at atomic-scale

    Energy Technology Data Exchange (ETDEWEB)

    Terentyev, Dmitry [Belgian Nuclear Research Centre, SCK-CEN; Bacon, David J [University of Liverpool; Osetskiy, Yury N [ORNL

    2010-03-01

    Interstitial dislocation loops with Burgers vector of <100> type are observed in {alpha}-iron irradiated by neutrons or heavy ions, and their population increases with increasing temperature. Their effect on motion of a 1/2<111> edge dislocation was reported earlier 1. Results are presented of a molecular dynamics study of interactions between a 1/2<111> screw dislocation and <100> loops in iron at temperature in the range 100 to 600 K. A variety of reaction mechanisms and outcomes are observed and classified in terms of the resulting dislocation configuration and the maximum stress required for the dislocation to break away. The highest obstacle resistance arises when the loop is absorbed to form a helical turn on the screw dislocation line, for the dislocation cannot glide away until the turn closes and a loop is released with the same Burgers vector as the line. Other than one situation found, in which no dislocation-loop reaction occurs, the weakest obstacle strength is found when the original <100> loop is restored at the end of the reaction. The important role of the cross-slip and the influence of model boundary conditions are emphasised and demonstrated by examples.

  7. Structural Basis on the Catalytic Reaction Mechanism of Novel 1,2-Alpha L-Fucosidase (AFCA) From Bifidobacterium Bifidum

    Energy Technology Data Exchange (ETDEWEB)

    Nagae, M.; Tsuchiya, A.; Katayama, T.; Yamamoto, K.; Wakatsuki, S.; Kato, R.

    2009-06-03

    1,2-alpha-L-fucosidase (AfcA), which hydrolyzes the glycosidic linkage of Fucalpha1-2Gal via an inverting mechanism, was recently isolated from Bifidobacterium bifidum and classified as the first member of the novel glycoside hydrolase family 95. To better understand the molecular mechanism of this enzyme, we determined the x-ray crystal structures of the AfcA catalytic (Fuc) domain in unliganded and complexed forms with deoxyfuconojirimycin (inhibitor), 2'-fucosyllactose (substrate), and L-fucose and lactose (products) at 1.12-2.10 A resolution. The AfcA Fuc domain is composed of four regions, an N-terminal beta region, a helical linker, an (alpha/alpha)6 helical barrel domain, and a C-terminal beta region, and this arrangement is similar to bacterial phosphorylases. In the complex structures, the ligands were buried in the central cavity of the helical barrel domain. Structural analyses in combination with mutational experiments revealed that the highly conserved Glu566 probably acts as a general acid catalyst. However, no carboxylic acid residue is found at the appropriate position for a general base catalyst. Instead, a water molecule stabilized by Asn423 in the substrate-bound complex is suitably located to perform a nucleophilic attack on the C1 atom of L-fucose moiety in 2'-fucosyllactose, and its location is nearly identical near the O1 atom of beta-L-fucose in the products-bound complex. Based on these data, we propose and discuss a novel catalytic reaction mechanism of AfcA.

  8. Finite-range DWBA analysis of anomalous analyzing powers in (p, alpha) reactions

    International Nuclear Information System (INIS)

    Anomalous analyzing powers in reactions Ni(p vector, α)Co(3/2+) are studied in the framework of distorted-waves Born approximation. The anomaly is well reproduced by calculations based on the form factors and spectroscopic amplitudes which are derived from microscopic model wave functions. (author)

  9. Discussion on importance of e+e- pair emission in the 12C(alpha, gamma)16O capture reaction below 1.9 MeV energy

    International Nuclear Information System (INIS)

    The cross section of the direct E0 pair emission has meaningful contribution to the total cross section of the 12C(alpha, gamma)16O reaction at low energy <= 1.9 MeV . E0 resonance emission and internal pair conversion have significant effect to the total cross section of the 12C(alpha, gamma)16O reaction. In this paper e+e- paired emission has been focused on taking into account the angular correlation. E0 contribution is also significant in a presence of E1 and E2 transition, therefore e+e- pair emission may not be neglected and has a significant effect on the total cross section in the case of the 12C(alpha, gamma)16O reaction.

  10. Research on the reactions {sup 9}Be ({sup 3}He, 3 {alpha}) and {sup 10}B (d, 3 {alpha}); Contribution a l'etude experimentale des reactions {sup 9}Be ({sup 3}He, 3 {alpha}) et {sup 10}B (d, 3 {alpha})

    Energy Technology Data Exchange (ETDEWEB)

    Thouvenin, P. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1967-06-15

    For studying these reactions, the detection of the final particles emitted in coincidence in the directions {theta}{sub 1} and {theta}{sub 2}, together with the bi-parametric analysis of the corresponding pulses are used. This method enables us to obtain the orthogonal Dalitz diagrams (E{sub 1}, E{sub 2}). An examination of the spectra obtained shows that the sequential mechanism appears to predominate. The contribution of the purely statistical process is less than 15 per cent of the total spectrum. In the case of {sup 10}B (d, 3 {alpha}), for E{sub d} = 1.5 MeV, 2,66 MeV and 3 MeV, the width of the peak of the first particles emitted, with respect to {sup 8}Be excitations close to 11 MeV, is found to be equal to 2.6 {+-} 0.6 MeV, much less than the width of the 2. excited state observed by {alpha} - {alpha} scattering. The coincidence spectra and the free spectra give an excitation energy of E{sub x} = 2.68 {+-} 0.07 MeV for the first excited state of {sup 8}Be. Some remarks are made concerning the anomalies observed for E{sub d} = 5 MeV and 9 MeV. The excited levels of {sup 8}Be at 13.91 MeV and 7.56 MeV which have been described in the past are not observed. (author) [French] La detection de deux des particules finales emises en cofncidence dans les directions {theta}{sub 1} et {theta}{sub 2}, et l'analyse biparametrique des impulsions correspondantes sont utilisees pour etudier ces reactions. Cette methode nous permet d'obtenir des diagrammes de Dalitz orthogonaux (E{sub 1}, E{sub 2}). L'examen des spectres obtenus montre que le mecanisme sequentiel semble predominant. La contribution du processus purement statistique est inferieure a 15 pour cent du spectre total. Dans le cas de {sup 10}B (d, 3 {alpha}), pour E{sub d} = 1,5 MeV, 2,66 MeV et 3 MeV, la largeur du pic des premieres particules emises relatives a des excitations de {sup 8}Be voisines de 11 MeV, est trouvee egale a 2,6 {+-} 0,6 MeV, tres inferieure a la largeur du 2. etat excite

  11. On the decay of compound nuclei following alpha-particle and 12C induced reactions

    International Nuclear Information System (INIS)

    Multiple coincidence rates have been measured using a detector system consisting of a Ge(Li) spectrometer and eight NaI(Tl) or eight liquid scintillators. Reactions induced by α-particles with energies of 51-55 MeV and 118 MeV 12C ions are studied. The data are analysed to give the first and second central moments of the distribution of the number of γ-rays feeding individual levels in the final nuclei. When these numbers are compared to spin distributions calculated with the statistical model code GROGI the relative importance of dipole and quadrupole deexcitation modes can be ascertained. In particular, in the 122Te(α,4n)122Xe reaction the γ-decay prior to the entry into the ground band is well described as a statistical process proceeding to 50% by dipole and 50% by quadrupole radiation. In the 166Er(α,4n)166Yb and 192Os(α,4n)192Pt reactions the relative amount of quadrupole radiation is larger and it seems that the dipole and quadrupole decay takes place via separate cascades. In the 164Dy(12C,7-8n) reactions the average multiplicity is independent of spin, suggesting that the nucleus forgets the spin of the entry state before the process enters into the ground band. In the 176Yb(12C,8n)180Os reaction, finally, the nucleus difinitely retains memory of the entry state during the decay. In this last case the multiplicity measurement is combined with a γ-ray singles measurement to give an average excitation energy prior to the α-decay and the average moment of inertia characterising the decay of the high-spin states. (orig.)

  12. New $\\alpha$ ANC measurement of the 1/2$^+$ state in $^{17}$O at 6.356 MeV, that dominates the $^{13}$C($\\alpha$,n)$^{16}$O reaction rate at temperatures relevant for the s-process

    CERN Document Server

    Avila, M L; Koshchiy, E; Baby, L T; Belarge, J; Kemper, K W; Kuchera, A N; Santiago-Gonzalez, D

    2015-01-01

    Background: Accurate knowledge of the $^{13}$C($\\alpha$,$n$)$^{16}$O reaction cross section is important for the understanding of the s-process in AGB stars, since it is considered to be the main source of neutrons. The sub-threshold 1/2$^+$ state at excitation energy of 6.356 MeV in $^{17}$O has a strong influence on the reaction cross section at energies relevant for astrophysics. Several experiments have been performed to determine the contribution of this state to the $^{13}$C($\\alpha,n)^{16}$O reaction rate. Nevertheless, significant discrepancies between different measurements remain. Purpose: The aim of this work is to investigate these discrepancies. Method: An 8 MeV $^{13}$C beam (below the Coulomb barrier) was used to study the $\\alpha$-transfer reaction $^6$Li($^{13}$C,$d$)$^{17}$O. Results: The squared Coulomb modified ANC of the 1/2$^+$ state in $^{17}$O measured in this work is $(\\tilde C^{^{17}\\text{O}(1/2+)}_{\\alpha-^{13}\\text{C}})^2=3.6\\pm0.7\\hspace{0.2cm}\\text{fm}^{-1}$. Conclusions: Discrep...

  13. Hydrothermal synthesis of cubic {alpha}-Fe{sub 2}O{sub 3} microparticles using glycine: Surface characterization, reaction mechanism and electrochemical activity

    Energy Technology Data Exchange (ETDEWEB)

    Yin Chunyang, E-mail: c.yin@murdoch.edu.au [School of Chemical and Mathematical Sciences, Murdoch University, Murdoch, 6150 WA (Australia); Minakshi, Manickam; Ralph, David E. [School of Chemical and Mathematical Sciences, Murdoch University, Murdoch, 6150 WA (Australia); Jiang Zhongtao [School of Engineering and Energy, Murdoch University, Murdoch, 6150 WA (Australia); Xie Zonghan; Guo Hua [School of Engineering, Edith Cowan University, Joondalup, WA, 6027 (Australia)

    2011-10-13

    Graphical abstract: Highlights: > We synthesize cubic {alpha}-Fe{sub 2}O{sub 3} (hematite) microparticles. > Their morphological, mineralogical and surface properties are determined. > Reaction mechanism based on thermodynamics and ionic equilibrium concepts are described. > Microparticles have charge capacity of 160 mAh/g and good columbic efficiency of 94%. - Abstract: Cubic {alpha}-Fe{sub 2}O{sub 3} (hematite) microparticles (side lengths = 0.3-1.3 {mu}m) have been synthesized using glycine and ferric chloride via a simple one-step hydrothermal reaction. Their morphological, mineralogical and surface properties have been determined using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). XRD analysis indicated that the synthesized {alpha}-Fe{sub 2}O{sub 3} microparticles were minerallogically pure. An increase in hydrothermal reaction duration from 10 to 24 h increased the atomic percentages of {alpha}-Fe{sub 2}O{sub 3} on the surface of the microparticles by almost 8%. The mechanism concerning reactions of species to produce this microparticles precipitate was elucidated based on thermodynamics and ionic equilibrium aspects. In the electrochemical analysis, the synthesized {alpha}-Fe{sub 2}O{sub 3} microparticles (as cathode material) exhibit an approximate charge capacity of 160 mAh/g and excellent coulombic efficiency of 94%.

  14. Cross-section measurement for the {sup 67}Zn(n, {alpha}){sup 64}Ni reaction at 6.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guohui; Wu, Hao; Zhang, Jiaguo; Liu, Jiaming; Chen, Jinxiang [Institute of Heavy Ion Physics, Peking University, State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Gledenov, Yu.M.; Sedysheva, M.V. [Frank Laboratory of Neutron Physics, JINR, Dubna (Russian Federation); Khuukhenkhuu, G. [National University of Mongolia, Nuclear Research Centre, Ulaanbaatar (Mongolia); Szalanski, P.J. [Institute of Physics, University of Lodz, Lodz (Poland)

    2010-01-15

    Up to now, no experimental cross-section data exist for the {sup 67}Zn(n,{alpha}){sup 64}Ni reaction in the MeV neutron energy region. In the present work, the cross-section of the {sup 67}Zn(n,{alpha}) {sup 64}Ni reaction was measured at E{sub n}=6.0 MeV. Experiments were performed at the Van de Graaff accelerator of Peking University, China. Fast neutrons were produced through the D(d,n){sup 3}He reaction using a deuterium gas target. Absolute neutron flux was determined by a small {sup 238}U fission chamber and a BF{sub 3} long counter was used as a neutron flux monitor. A twin gridded ionization chamber was employed as the {alpha} -particle detector and two back-to-back {sup 67}Zn samples were used for {alpha} events measurement. Background was measured and subtracted from foreground. The measured cross-section of the {sup 67}Zn(n,{alpha}){sup 64}Ni reaction was 7.3(1{+-}15%) mb at 6.0 MeV. The present result was compared with existing evaluations and TALYS code calculations. (orig.)

  15. Dipole strength in 144Sm studied via (gamma,n), (gamma,p) and (gamma,alpha) reactions

    CERN Document Server

    Nair, Chithra; Erhard, Martin; Bemmerer, Daniel; Beyer, Roland; Grosse, Eckart; Kosev, Krasimir; Marta, Michele; Rusev, Gencho; Schilling, Klaus-Dieter; Schwengner, Ronald; Wagner, Andreas

    2010-01-01

    Photoactivation measurements on 144Sm have been performed with bremsstrahlung endpoint energies from 10.0 to 15.5 MeV at the bremsstrahlung facility of the superconducting electron accelerator ELBE of Forschungszentrum Dresden-Rossendorf. The measured activation yield for the 144Sm(gamma,n) reaction is compared with the calculated yield using cross sections from previous photoneutron experiments. The activation yields measured for all disintegration channels 144Sm(gamma,n), (gamma,p) and (gamma,alpha) are compared to the yield calculated by using Hauser-Feshbach statistical models. A new parametrization of the photon strength function is presented and the yield simulated by using the modified photon strength parameters are compared to the experimental data.

  16. THE 2H(alpha, gamma6LI REACTION AT LUNA AND BIG BANG NUCLEOSYNTHETIS

    Directory of Open Access Journals (Sweden)

    Carlo Gustavino

    2013-12-01

    Full Text Available The 2H(α, γ6Li reaction is the leading process for the production of 6Li in standard Big Bang Nucleosynthesis. Recent observations of lithium abundance in metal-poor halo stars suggest that there might be a 6Li plateau, similar to the well-known Spite plateau of 7Li. This calls for a re-investigation of the standard production channel for 6Li. As the 2H(α, γ6Li cross section drops steeply at low energy, it has never before been studied directly at Big Bang energies. For the first time the reaction has been studied directly at Big Bang energies at the LUNA accelerator. The preliminary data and their implications for Big Bang nucleosynthesis and the purported 6Li problem will be shown.

  17. Study of the {sup 18}F(p,{alpha}){sup 15}O reaction by transfer reaction for application to {gamma}-ray emission from Novae; Etude de la reaction {sup 18}F(p,{alpha}){sup 15}O par reaction de transfert pour application a l'emission {gamma} des Novae

    Energy Technology Data Exchange (ETDEWEB)

    Sereville, N. de

    2003-12-15

    The gamma emission from novae at/or below 511 keV is due to the annihilation of the positrons produced in the beta + decay of F{sup 18}. The interpretation of this emission through observations made by the Integral satellite for instance, requires a good knowledge of F{sup 18} nucleosynthesis. The reaction rate of the F{sup 18}(p,{alpha})O{sup 15} is the least known because of 2 resonances corresponding to the levels 6.419 and 6.449 MeV of Ne{sup 19} whose proton widths are completely unknown. We have determined these proton widths via the study of one-nucleon transfer reaction D(F{sup 18},p{alpha})N{sup 15} populating equivalent levels in F{sup 19}. We have used a 14 MeV F{sup 18} radioactive beam on a CD{sub 2} target for inverse kinematics studies and the multi-track silicon detector LEDA. A DWBA (Distorted Wave Bound Approximation) has enabled us to determine the proton width of both resonances and has showed that they have an impact in the calculation of the reaction rate. A thorough study of the remaining uncertainties of the reaction rate has been undertaken, particularly for those concerning interferences between these resonances and a higher resonance of Ne{sup 19}. The reaction rate that we have obtained is very similar to the previous rate used but now it rests on a more solid basis.

  18. First application of the Trojan Horse Method with a Radioactive Ion Beam: study of the $^{18}$F($p,{\\alpha}$)$^{15}$O}} reaction at astrophysical energies

    CERN Document Server

    Cherubini, S; Spitaleri, C; Rapisarda, G G; La Cognata, M; Lamia, L; Pizzone, R G; Romano, S; Kubono, S; Yamaguchi, H; Hayakawa, S; Wakabayashi, Y; Iwasa, N; Kato, S; Komatsubara, T; Teranishi, T; Coc, A; de Séréville, N; Hammache, F; Kiss, G; Bishop, S; Binh, D N

    2015-01-01

    Measurement of nuclear cross sections at astrophysical energies involving unstable species is one of the most challenging tasks in experimental nuclear physics. The use of indirect methods is often unavoidable in this scenario. In this paper the Trojan Horse Method is applied for the first time to a radioactive ion beam induced reaction studying the $^{18}$F($p,{\\alpha}$)$^{15}$O process at low energies relevant to astrophysics via the three body reaction $^{2}$H($^{18}$F,${\\alpha}^{15}$O)n. The knowledge of the $^{18}$F($p, {\\alpha}$)$^{15}$O reaction rate is crucial to understand the nova explosion phenomena. The cross section of this reaction is characterized by the presence of several resonances in $^{19}$Ne and possibly interference effects among them. The results reported in Literature are not satisfactory and new investigations of the $^{18}$F($p,{\\alpha}$)$^{15}$O reaction cross section will be useful. In the present work the spin-parity assignments of relevant levels have been discussed and the astro...

  19. Efficient one-pot enzymatic synthesis of alpha-(1-->4)-glucosidic disaccharides through a coupled reaction catalysed by Lactobacillus acidophilus NCFM maltose phosphorylase.

    Science.gov (United States)

    Nakai, Hiroyuki; Dilokpimol, Adiphol; Abou Hachem, Maher; Svensson, Birte

    2010-05-27

    Lactobacillus acidophilus NCFM maltose phosphorylase (LaMalP) of glycoside hydrolase family 65 catalysed enzymatic synthesis of alpha-(1-->4)-glucosidic disaccharides from maltose and five monosaccharides in a coupled phosphorolysis/reverse phosphorolysis one-pot reaction. Thus phosphorolysis of maltose to beta-glucose 1-phosphate circumvented addition of costly beta-glucose 1-phosphate for reverse phosphorolysis with different monosaccharide acceptors, resulting in 91%, 89%, 88%, 86% and 84% yield of alpha-d-glucopyranosyl-(1-->4)-N-acetyl-D-glucosaminopyranose [N-acetyl-maltosamine], alpha-D-glucopyranosyl-(1-->4)-D-glucosaminopyranose [maltosamine], alpha-D-glucopyranosyl-(1-->4)-D-mannopyranose, alpha-D-glucopyranosyl-(1-->4)-L-fucopyranose and alpha-D-glucopyranosyl-(1-->4)-D-xylopyranose, respectively, from 0.1M maltose, 0.5M N-acetyl glucosamine, 0.1M glucosamine, 0.1M mannose, 1M L-fucose and 0.5M xylose in 0.2M phosphate-citrate pH 6.2. These current yields of 0.27-0.34 g of disaccharide products from 10 mL reaction mixtures are easy to scale up and moreover the strategy can be applied to large-scale production of other oligosaccharides from low-cost disaccharides as catalysed by phosphorylases with different substrate specificities. PMID:20392438

  20. Absolute hydrogen depth profiling using the resonant $^{1}$H($^{15}$N,$\\alpha\\gamma$)$^{12}$C nuclear reaction

    CERN Document Server

    Reinhardt, Tobias P; Bemmerer, Daniel; Stöckel, Klaus; Wagner, Louis

    2016-01-01

    Resonant nuclear reactions are a powerful tool for the determination of the amount and profile of hydrogen in thin layers of material. Usually, this tool requires the use of a standard of well-known composition. The present work, by contrast, deals with standard-less hydrogen depth profiling. This approach requires precise nuclear data, e.g. on the widely used $^{1}$H($^{15}$N,$\\alpha\\gamma$)$^{12}$C reaction, resonant at 6.4\\,MeV $^{15}$N beam energy. Here, the strongly anisotropic angular distribution of the emitted $\\gamma$-rays from this resonance has been re-measured, resolving a previous discrepancy. Coefficients of (0.38$\\pm$0.04) and (0.80$\\pm$0.04) have been deduced for the second and fourth order Legendre polynomials, respectively. In addition, the resonance strength has been re-evaluated to (25.0$\\pm$1.5)\\,eV, 10\\% higher than previously reported. A simple working formula for the hydrogen concentration is given for cases with known $\\gamma$-ray detection efficiency. Finally, the absolute approach i...

  1. Cross-section measurement for the 10B(n, alpha)7Li reaction at 4.0 and 5.0 MeV.

    Science.gov (United States)

    Zhang, Guohui; Guo, Li'an; Cao, Rongtai; Zhang, Jiaguo; Chen, Jinxiang

    2008-10-01

    Cross-sections of the (10)B(n, alpha)(7)Li reaction were measured at En=4.0 and 5.0 MeV. A gridded ionization chamber (GIC) was used as charged particle detector. Neutrons were produced through the D(d, n)(3)He reaction with a deuterium gas target. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University. Cross-section data of the (238)U(n, f) reaction were employed as standard. The measured cross-sections of the (10)B(n, alpha)(7)Li reaction at 4.0 and 5.0 MeV are 211+/-17 and 169+/-14 mb, respectively, and they are compared with existing results of measurements and evaluations. PMID:18387305

  2. Cross sections of the reaction Pa-231(d,3n)U-230 for the production of U-230/Th-226 for targeted alpha therapy

    Czech Academy of Sciences Publication Activity Database

    Morgenstern, A.; Lebeda, Ondřej; Štursa, Jan; Capote, R.; Sin, M.; Bruchertseifer, F.; Zielinska, B.; Apostolidis, C.

    2009-01-01

    Roč. 80, č. 5 (2009), 054612/1-054612/6. ISSN 0556-2813 Institutional research plan: CEZ:AV0Z10480505 Keywords : Pa-231 * U-230 * Th-226 * reaction cross section * targeted alpha therapy Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.477, year: 2009

  3. THE RGB AND AGB STAR NUCLEOSYNTHESIS IN LIGHT OF THE RECENT {sup 17}O(p, {alpha}){sup 14}N AND {sup 18}O(p, {alpha}){sup 15}N REACTION-RATE DETERMINATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Palmerini, S.; Sergi, M. L.; La Cognata, M.; Pizzone, R. G.; Spitaleri, C. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Lamia, L. [Dipartimento di Fisica e Astronomia, Universita di Catania, Catania (Italy)

    2013-02-20

    In recent years, the Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of proton-induced reactions on A = 17 and A = 18 oxygen isotopes, overcoming extrapolation procedures and enhancement effects due to electron screening. In particular, the strengths of the 20 keV and 65 keV resonances in the {sup 18}O(p, {alpha}){sup 15}N and {sup 17}O(p, {alpha}){sup 14}N reactions, respectively, have been extracted, as well as the contribution of the tail of the broad 656 keV resonance in the {sup 18}O(p, {alpha}){sup 15}N reaction inside the Gamow window. The strength of the 65 keV resonance in the {sup 17}O(p, {alpha}){sup 14}N reaction, measured by means of the THM, has been used to renormalize the corresponding resonance strength in the {sup 17}O + p radiative capture channel. As a result, more accurate reaction rates for the {sup 18}O(p, {alpha}){sup 15}N, {sup 17}O(p, {alpha}){sup 14}N, and {sup 17}O(p, {gamma}){sup 18}F processes have been deduced, devoid of systematic errors due to extrapolation or the electron screening effect. Such rates have been introduced into state-of-the-art red giant branch and asymptotic giant branch (AGB) models for proton-capture nucleosynthesis coupled with extra-mixing episodes. The predicted abundances have been compared with isotopic compositions provided by geochemical analysis of presolar grains. As a result, an improved agreement is found between the models and the isotopic mix of oxide grains of AGB origins, whose composition is the signature of low-temperature proton-capture nucleosynthesis. The low {sup 14}N/{sup 15}N found in SiC grains cannot be explained by the revised nuclear reaction rates and remains a serious problem that has not been satisfactorily addressed.

  4. Asymmetric Strecker-Type Reaction of alpha-Aryl Ketones. Synthesis of (S)-alphaM4CPG, (S)-MPPG, (S)-AIDA, and (S)-APICA, the Antagonists of Metabotropic Glutamate Receptors.

    Science.gov (United States)

    Ma, Dawei; Tian, Hongqi; Zou, Guixiang

    1999-01-01

    Heating a mixture of alpha-aryl ketone with (R)-phenylglycinol produces a mixture of imine and 1,3-dioxazolidine. Treatment of this mixture with trimethylsilyl cyanide followed by transformation of nitrile to ester gives Strecker-type reaction products. The diastereoselectivity of the generated alpha-amino esters is from 2/1 to 7/1, and the (R,S)isomer is found as the major product. The (R,S) and (R,R)isomers can be separated by conversion to their N-Cbz or cyclization derivatives. Using this methodology, four antagonists of metabotropic glutamate receptors, (S)-alphaM4CPG, (S)-MPPG, (S)-AIDA, and (S)-APICA, are synthesized. PMID:11674092

  5. Stromal fibrosis reaction in rat prostates induced by alpha 1 adrenergic stimulation.

    Science.gov (United States)

    Rosenzweig-Bublil, Nurit; Abramovici, Armand

    2006-01-01

    Most of the publications dealing with the experimental induction of prostatic neoplasia have focused on the description of epithelial lesions, but little attention has been paid to the involvement of their stromal alterations. The present study is a first attempt to assess the stromal changes in both collagen and elastic fibrils as well as in its cellular constituents, which accompany prostatic intraepithelial neoplastic (PIN)-like lesions induced by phenylephrine (PE) in rats. Adolescent rats received subcutaneous injections of PE daily (10 mg/kg/d) for 1 month. At the end of the experimental period the rats were sacrificed; the dissected ventral prostates were fixed in Stieve solution and paraffin-embedded; and sections were cut and stained accordingly. Most of the stromal cells were identified by immunohistochemistry techniques using primary antibodies to ED2 (resident macrophages), actin (fibrocytes and vascular smooth muscle cells), vimentin (mesenchymal cells), and 5'-bromo-2'-deoxyuridine (S-phase proliferating cells). Collagen stromal mass was visualized by Gomori trichrome and individual collagen fibers by picrosirius red staining under polarized light, whereas the fine fibrils were stained according to the Pinkus method. The untreated rat prostates are characterized by a delicate interacinar stroma with scanty cells and fibrils. The PE-treated prostates showed a significant increase in both cellular and fibrillar elements as well as an increase in arteriolar density, in addition to the typical PIN lesions. The presence of such an interstitial fibrosis, which also includes inflammatory cells, neoangiogenesis, and synthesis de novo of collagen and fibers, might be regarded as a desmoplastic reaction. It is suggested that these changes could be related to a tissue repair process occurring subsequent to the inflammatory exudate that takes place during the incipient phases of the PE treatment. PMID:16304211

  6. Total and partial cross sections of the $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te reaction measured via in-beam $\\gamma$-ray spectroscopy

    CERN Document Server

    Netterdon, L; Scholz, P; Zilges, A

    2015-01-01

    An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\\alpha$,$\\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\\alpha$-particle energies from $E_\\alpha = 10.5$ MeV to $E_\\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the...

  7. Exploring the N{alpha}+3n light nuclei via the ({sup 7}Li,{sup 7}Be) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nociforo, C.; Cappuzzello, F.; Orrigo, S.E.A.; Winfield, J.S. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Cunsolo, A.; Cavallaro, M. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN-Sezione di Catania, Catania (Italy); Fortier, S.; Beaumel, D. [Institut de Physique Nucleaire, Orsay Cedex (France); Lenske, H. [Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)

    2006-03-15

    Experimental signatures of the dynamical correlations of a core with a single-particle neutron have been found in light neutron-rich nuclei investigated via the ({sup 7}Li,{sup 7}Be) charge-exchange reactions at around 8 MeV/u. Of particular astrophysical relevance are low-lying narrow resonances ({gamma}{proportional_to}200 keV FWHM) BSEC (Bound States Embedded in the Continuum). Because of their long lifetime BSEC states are likely to effect the capture rates in any scenario for nucleosynthesis in neutron-rich environment. They have been observed in the continuum of {sup 11}Be and {sup 15}C nuclei. A microscopic nuclear structure model based on QRPA theory, which takes into account Dynamical Core Polarisation (DCP) correlations, gives a suitable description of these resonances as well as single-particle states of the studied systems. In this context, high-energy narrow structures populated in nuclei having an integer number of {alpha}-particles plus three neutrons are good BSEC candidates and can be systematically investigated. (orig.)

  8. A kinetics study for reaction process of Rn daughter and atmospheric trace gas using alpha track detection

    International Nuclear Information System (INIS)

    A number of investigators have reported formation of radiolytic ultrafine particles produced by the interaction of ionizing radiation with atmospheric trace gases. Previous studies have suggested that a very high localized concentration of the hydroxyl radical produced by the radiolysis of water can react with atmospheric trace gases such as SO2 and produce lower vapor pressure compounds that can subsequently nucleate. To determine the trace gas and water vapor concentration dependence of the active, positively charged, first decay product of radon (Po-218), a well-controlled radon chamber was used in this research. The mobility spectrum of the decay products in the range of 0.07-5.0 cm2/V.sec from the radon chamber was measured using alpha track detector installed inside a specially-designed electrostatic spectrometer. Measurements were taken for different concentrations (0.5 ppm to 5 ppm) of SO2 in purified, compressed air. A kinetics study following the clustering of SO2 around the PoOx + ion in an excess of SO2 for interpretation of the reaction processes was performed

  9. Indirect measurement of the {sup 15}N(p,{alpha}){sup 12}C reaction cross section through the Trojan-Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    La Cognata, M.; Romano, S.; Spitaleri, C.; Cherubini, S.; Lamia, L.; Pizzone, R.G.; Tumino, A. [Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); INFN, Laboratori Nazionali del Sud, Catania (Italy); Tribble, R.; Trache, L.; Fu, Changbo; Mukhamedzhanov, A.; Tabacaru, G. [Texas A and M University, Cyclotron Institute, College Station, TX (United States); Rolfs, C. [Ruhr-Universitaet, Bochum (Germany)

    2006-03-15

    The low-energy, bare-nucleus cross section for {sup 15}N(p,{alpha}){sup 12}C is extracted by means of the Trojan-Horse Method applied to the {sup 2}H({sup 15}N,{alpha}{sup 12}C)n reaction at E{sub beam}=60 MeV. The astrophysical S-factor is compared to the direct data in the same energy region. A nice agreement shows up down to 100 keV, while the low-energy behaviour of the S-factor suggests a smaller rate than is reported in the literature. (orig.)

  10. Dose-response effects of estrogenic mycotoxins (zearalenone, alpha- and beta-zearalenol on motility, hyperactivation and the acrosome reaction of stallion sperm

    Directory of Open Access Journals (Sweden)

    Colenbrander Ben

    2011-10-01

    Full Text Available Abstract Background The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-estradiol was used as a positive control for 'estrogen-like' effects. Methods Stallion spermatozoa were exposed in vitro to zearalenone, alpha-zearalenol, beta-zearalenol or 17beta-estradiol at concentrations ranging from 1 pM - 0.1 mM. After 2 hours exposure, motility parameters were evaluated by computer-assisted analysis, and acrosome integrity was examined by flow cytometry after staining with fluoroscein-conjugated peanut agglutinin. Results Mycotoxins affected sperm parameters only at the highest concentration tested (0.1 mM after 2 hours exposure. In this respect, all of the compounds reduced the average path velocity, but only alpha-zearalenol reduced percentages of motile and progressively motile sperm. Induction of motility patterns consistent with hyperactivation was stimulated according to the following rank of potency: alpha-zearalenol >17beta-estradiol > zearalenone = beta-zearalenol. The hyperactivity-associated changes observed included reductions in straight-line velocity and linearity of movement, and an increase in the amplitude of lateral head displacement, while curvilinear velocity was unchanged. In addition, whereas alpha- and beta- zearalenol increased the percentages of live acrosome-reacted sperm, zearalenone and 17beta-estradiol had no apparent effect on acrosome status. In short, alpha-zearalenol inhibited normal sperm motility, but stimulated hyperactive motility in the remaining motile cells and simultaneously induced the acrosome reaction. Beta-zearalenol induced the acrosome reaction without altering motility

  11. Resonance strengths in the 14N(p,gamma)15O and 15N(p,alpha gamma)12C reactions

    CERN Document Server

    Marta, Michele; Bemmerer, Daniel; Beyer, Roland; Broggini, Carlo; Caciolli, Antonio; Erhard, Martin; Fülöp, Zsolt; Grosse, Eckart; Gyürky, György; Hannaske, Roland; Junghans, Arnd R; Menegazzo, Roberto; Nair, Chithra; Schwengner, Ronald; Szücs, Tamás; Vezzú, Simone; Wagner, Andreas; Yakorev, Dmitry

    2010-01-01

    The 14N(p,gamma)15O reaction is the slowest reaction of the carbon-nitrogen-oxygen cycle of hydrogen burning in stars. As a consequence, it determines the rate of the cycle. The 15N(p,alpha gamma)12C reaction is frequently used in inverse kinematics for hydrogen depth profiling in materials. The 14N(p,gamma)15O and 15N(p,alpha gamma)12C reactions have been studied simultaneously, using titanium nitride targets of natural isotopic composition and a proton beam. The strengths of the resonances at Ep = 1058 keV in 14N(p,gamma)15O and at Ep = 897 and 430 keV in 15N(p,alpha gamma)12C have been determined with improved precision, relative to the well-known resonance at Ep = 278 keV in 14N(p,gamma)15O. The new recommended values are \\omega\\gamma = 0.352$\\pm$0.018, 362$\\pm$20, and 22.0$\\pm$0.9\\,eV for their respective strengths. In addition, the branching ratios for the decay of the Ep = 1058 keV resonance in 14N(p,gamma)15O have been redetermined. The data reported here should facilitate future studies of off-resona...

  12. Free-polymer controlling morphology of {alpha}-MoO{sub 3} nanobelts by a facile hydrothermal synthesis, their electrochemistry for hydrogen evolution reactions and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Sinaim, Hathai [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Ham, Dong Jin; Lee, Jae Sung [Eco-friendly Catalysis and Energy Laboratory (NRL), Department of Chemical Engineering, School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Phuruangrat, Anukorn, E-mail: phuruangrat@hotmail.com [Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: ttpthongtem@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2012-03-05

    Highlights: Black-Right-Pointing-Pointer MoO{sub 3} nanobelts as an n-type semiconducting material. Black-Right-Pointing-Pointer It was successfully synthesized by a facile hydrothermal reaction. Black-Right-Pointing-Pointer A promising material with 3.75 eV band gap for hydrogen evolution reaction (HER). - Abstract: Orthorhombic molybdenum oxide ({alpha}-MoO{sub 3}) nanobelts were successfully synthesized by the 100-180 Degree-Sign C and 2-20 h hydrothermal reactions of (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24}{center_dot}4H{sub 2}O solutions containing 15 ml 2 M acid (HNO{sub 3}, H{sub 2}SO{sub 4} or HCl) with no surfactant and template adding. These products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, and electron microscopy (EM). In the present research, the product synthesized by the 180 Degree-Sign C and 20 h hydrothermal reaction of the solution containing HNO{sub 3} was {alpha}-MoO{sub 3} nanobelts with >10 {mu}m long and <200 nm wide. Electrochemistry for hydrogen evolution reactions (HER) and optical properties of the as-synthesized {alpha}-MoO{sub 3} nanobelts were characterized by linear sweep voltammetry (LSV) and Tafel plot, including UV-vis and photoluminescence (PL) spectroscopy. These imply that {alpha}-MoO{sub 3} nanobelts show satisfied performance for HER, with the 3.75 eV direct allowed band gap (E{sub g}) due to the charged transition of O{sub 2p} {yields} Mo{sub 4d}, including the emission of 437 nm wavelength at room temperature.

  13. A compilation of information on the {sup 31}P(p,{alpha}){sup 28}Si reaction and properties of excited levels in the compound nucleus {sup 32}S

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.E.; Smith, D.L. [Argonne National Lab., IL (United States). Technology Development Div.

    1997-11-01

    This report documents a survey of the literature, and provides a compilation of data contained therein, for the {sup 31}P(p,{alpha}){sup 28}Si reaction. Attention is paid here to resonance states in the compound-nuclear system {sup 32}S formed by {sup 31}P + p, with emphasis on the alpha-particle decay channels, {sup 28}Si + {alpha} which populate specific levels in {sup 28}Si. The energy region near the proton separation energy for {sup 32}S is especially important in this context for applications in nuclear astrophysics. Properties of the excited states in {sup 28}Si are also considered. Summaries of all the located references are provided and numerical data contained in them are compiled in EXFOR format where applicable.

  14. Separation of reaction mechanisms at low energy. Study of the reactions: {sup 27}Al(d,p) {sup 28}Al, {sup 24}Mg(d,p) {sup 25}Mg, and {sup 24}Mg(d, {alpha}) {sup 22}Na; Sur la separation des mecanismes de reaction a basse energie. Etude des reactions: {sup 27}Al(d,p) {sup 28}Al, {sup 24}Mg(d,p) {sup 25}Mg, et {sup 24}Mg(d, {alpha}) {sup 22}Na

    Energy Technology Data Exchange (ETDEWEB)

    Mermaz, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-06-01

    The two sets of angular distributions of (d,p) reactions on Al and Mg, measured between 2 and 6 MeV, have given the possibility to test, in analysing the statistical fluctuations of cross-section, the validity of the separation of their mean values in two parts, one 'direct', another given by the statistical mechanism. With the same method of analysis we have studied excitation functions for several alpha groups of the reaction {sup 24}Mg(d, {alpha}) {sup 22}Na and given an evidence for an intermediate structure for the alpha channel leading to the 3. excited state of {sup 22}Na. The angular distribution of the wide resonance at 15.9 MeV in {sup 26}Al has been obtained. (author) [French] Les deux ensembles de distributions angulaires des reactions (d,p) sur Al et Mg, mesures entre 2 et 6 MeV, nous ont permis, en analysant les fluctuations statistiques de sections efficaces, de verifier la possibilite de la separation de leurs valeurs moyennes en deux composantes: l'une 'directe', l'autre due au mecanisme statistique. Avec la meme methode d'analyse nous avons etudie les fonctions d'excitation des premiers groupes alpha de la reaction {sup 24}Mg(d,{alpha}) {sup 22}Na et mis en evidence une structure intermediaire pour la voie de reaction aboutissant au 3eme niveau de {sup 22}Na. Nous avons obtenu la distribution angulaire de la resonance large situee a une energie d'excitation de 15,9 MeV dans {sup 26}Al. (auteur)

  15. Experimental Study of the {sup 6}Li(d,{alpha}){sup 4}He Reaction and its Astrophysical Implications via the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Pizzone, R.G.; Aliotta, M.; Blagus, S.; Cherubini, S.; Figuera, P.; Lattuada, M; Milin, M.; Miljanic, D.; Pellegriti, M.G.; Rendic, D.; Romano, S.; Soic, N.; Spitaleri, C.; Zadro, M.; Zappala, R.A.

    2000-12-31

    The {sup 6}Li(d, {alpha}){sup 4}He reaction, whose astrophysical importance is connected to the primordial nucleosynthesis in the framework of the Inhomogeneous Big Bang, has been studied by using the Trojan Horse Method (THM). We derive and discuss the cross section and the astrophysical S(E)-factor for E{sub cm}=0.025-0.7 MeV. Results are compared with data from a direct measurement.

  16. Cross Section Measurement for the 95Mo(n,alpha)92Zr Reaction at 4.0, 5.0 and 6.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guohui [Peking University; Wu, Hao [Peking University; Zhang, Jiaguo [Peking University; Liu, Jiaming [Peking University; Yin, Yuxiang [Peking University; Chen, Jinxiang [Peking University; Gledenov, Youri Mikhailovich [ORNL; Sedysheva, M. V. [Joint Institute for Nuclear Research, Dubna, Russia; Khuukhenkhuu, G [National University of Mongolia; Koehler, Paul Edward [ORNL; Szalanski, P. [University of Lodz

    2010-01-01

    Measurements of cross sections of the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction at E{sub n} = 4.0, 5.0 and 6.0 MeV were carried out at the 4.5 MV Van de Graaff of Peking University, China. A twin gridded ionization chamber and two large-area {sup 95}Mo samples were adopted. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was employed for absolute neutron flux determination. Present data are compared with existing evaluations and measurement.

  17. Cross section measurement for the (95)Mo(n, alpha)(92)Zr reaction at 4.0, 5.0 and 6.0MeV.

    Science.gov (United States)

    Zhang, Guohui; Wu, Hao; Zhang, Jiaguo; Liu, Jiaming; Yin, Yuxiang; Chen, Jinxiang; Gledenov, Yu M; Sedysheva, M V; Khuukhenkhuu, G; Koehler, P E; Szalanski, P J

    2010-01-01

    Measurements of cross sections of the (95)Mo(n, alpha)(92)Zr reaction at E(n)=4.0, 5.0 and 6.0MeV were carried out at the 4.5MV Van de Graaff of Peking University, China. A twin gridded ionization chamber and two large-area (95)Mo samples were adopted. Fast neutrons were produced through the D(d, n)(3)He reaction by using a deuterium gas target. A small (238)U fission chamber was employed for absolute neutron flux determination. Present data are compared with existing evaluations and measurement. PMID:19811925

  18. Cross Section Measurement for the 95Mo(n, {alpha})92Zr Reaction at 4.0, 5.0 and 6.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guohui [Peking University; Wu, Hao [Peking University; Zhang, Jiaguo [Peking University; Liu, Jiaming [Peking University; Yin, Yuxiang [Peking University; Chen, Jinxiang [Peking University; Gledenov, Youri Mikhailovich [ORNL; Sedysheva, M. V. [Joint Institute for Nuclear Research, Dubna, Russia; Khuukhenkhuu, G [National University of Mongolia; Koehler, Paul Edward [ORNL; Szalanski, P. [University of Lodz

    2011-01-01

    For the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction cross section, there is only one experimental datum in the MeV neutron energy region with large uncertainty. As a result, very large deviations exist in different evaluated nuclear data libraries. This paper report the measurement of cross sections of the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction at En = 4.0, 5.0 and 6.0 MeV. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. A twin gridded ionization chamber was used as alpha particle detector and two large area {sup 95}Mo samples placed back to back were adopted. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was adopted for absolute neutron flux determination and a BF{sub 3} long counter was used for neutron flux monitor. Present experimental data are compared with existing evaluations and measurement.

  19. The fluorine destruction in stars: First experimental study of the {sup 19}F(p,{alpha}){sup 16}O reaction at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S. [INFN-LNS, Catania (Italy); Cyclotron Institute, Texas A and M University, College Station, Texas (United States); University of Catania and INFN-LNS, Catania (Italy); and others

    2012-11-12

    The {sup 19}F(p,{alpha}){sup 16}O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E{sub cm}{approx} 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the {sup 2}H({sup 19}F,{alpha}{sup 16}O)n reaction. The TH measurement of the {alpha}{sub 0} channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

  20. Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

    CERN Document Server

    Anders, M; Bellini, A; Aliotta, M; Bemmerer, D; Broggini, C; Caciolli, A; Costantini, H; Corvisiero, P; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D; Somorjai, E; Straniero, O; Szücs, T

    2013-01-01

    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction....

  1. Neutron-induced background by an {alpha}-beam incident on a deuterium gas target and its implications for the study of the {sup 2}H({alpha},{gamma}){sup 6}Li reaction at LUNA

    Energy Technology Data Exchange (ETDEWEB)

    Anders, M.; Bemmerer, D.; Elekes, Z.; Marta, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Trezzi, D.; Mazzocchi, C. [INFN, Sezione di Milano, Milano (Italy); Bellini, A.; Costantini, H.; Corvisiero, P.; Lemut, A.; Prati, P. [Universita di Genova (Italy); INFN, Sezione di Genova, Dipartimento di Fisica, Genova (Italy); Aliotta, M.; Davinson, T.; Scott, D. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Broggini, C.; Caciolli, A.; Erhard, M.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Formicola, A.; Junker, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Fueloep, Zs.; Gyuerky, G.; Somorjai, E.; Szuecs, T. [Institute of Nuclear Research (ATOMKI), Debrecen (Hungary); Gervino, G. [Universita di Torino (Italy); INFN, Dipartimento di Fisica Sperimentale, Torino (Italy); Guglielmetti, A. [INFN, Sezione di Milano, Milano (Italy); Universita degli Studi di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [INFN, Sezione di Napoli, Napoli (Italy); Osservatorio Astronomico di Collurania, Teramo (Italy); Collaboration: LUNA Collaboration

    2013-02-15

    The production of the stable isotope {sup 6}Li in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological {sup 6}Li plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of {sup 7}Li abundances and would point to a predominantly primordial origin of {sup 6}Li, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang {sup 6}Li production must be revisited. The main production channel for {sup 6}Li in the Big Bang is the {sup 2}H({alpha},{gamma}){sup 6}Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the {sup 2}H(d,n){sup 3}He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400keV {alpha}-beam energy and for comparison also using an americium-beryllium neutron source. (orig.)

  2. Cross section balance in the 14N+159Tb reaction and the origin of fast alpha particles

    International Nuclear Information System (INIS)

    Exclusive cross sections have been obtained from particle-K X-ray coincidence data measured at 236 MeV for ejectiles ranging from 4He to 15N. Production cross sections for primary fragments and alpha particle multiplicities associated with different channels have been deduced. The major fraction of the alpha particles appears to originate from inelastic (damped) processes in which only light particles with Z<=2 are emitted. (orig.)

  3. New Constraints on the 18F(p,alpha) 15O Rate in Novae from (d,p) Reaction Sum Rules

    CERN Document Server

    Kozub, R L; Batchelder, J C; Blackmon, J C; Brune, C R; Champagne, A E; Cizewski, J A; Davinson, T; Greife, U; Gross, C J; Jewett, C C; Livesay, R J; Ma, Z; Moazen, B H; Nesaraja, C D; Sahin, L; Scott, J P; Shapira, D; Smith, M S; Thomas, J S; Woods, P J

    2004-01-01

    The degree to which the (p,gamma) and (p,alpha) reactions destroy 18F at temperatures 1-4x10^8 K is important for understanding the synthesis of nuclei in nova explosions and for using the long-lived radionuclide 18F, a target of gamma-ray astronomy, as a diagnostic of nova mechanisms. The reactions are dominated by low-lying proton resonances near the 18F+p threshold (E_x=6.411 MeV in 19Ne). To gain further information about these resonances, we have used a radioactive 18F beam from the Holifield Radioactive Ion Beam Facility to selectively populate corresponding mirror states in 19F via the inverse d(18F,p)19F neutron transfer reaction. Neutron spectroscopic factors were measured for states in 19F in the excitation energy range 0-9 MeV and appropriately scaled to conform to sum rule limits. The results would suggest significantly lower 18F(p,gamma)19Ne and 18F(p,alpha)15O reaction rates than reported previously, thereby increasing the prospect of observing the 511-keV annihilation radiation associated with ...

  4. Measurement of the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction cross section, of relevance to $\\gamma$-ray observation of core collapse supernovae, using reclaimed $^{44}$Ti

    CERN Multimedia

    Despite decades of research, fundamental uncertainties remain in the underlying explosion mechanism of core collapse supernovae. One of the most direct methods that might help resolve this problem is a comparison of the predicted to the observed flux of $\\gamma$-rays due to decay of $^{44}$Ti produced in the explosion, as it is believed this could reveal the location of the mass cut, a key hydrodynamical property of the explosion. Such a study is at present limited by the uncertainty in the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction rate. In this experiment we propose to measure the cross section for this reaction at astrophysically relevant energies. The single previous measurement of this reaction was limited to higher energies due to low beam intensities. Here, a more intense beam will be employed, generated from $^{44}$Ti reclaimed as part of the ERAWAST project at PSI.

  5. Cross-section measurement and analysis for the 149Sm(n,alpha)146Nd reaction at 6.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gledenov, Yu. M. [Joint Institute for Nuclear Research, Dubna, Russia; Zhang, Guohui [Peking University; Khuukhenkhuu, G [National University of Mongolia; Sedysheva, M. V. [Joint Institute for Nuclear Research, Dubna, Russia; Szalanski, P. [University of Lodz; Koehler, Paul Edward [ORNL; Liu, Jiaming [Peking University; Wu, Hao [Peking University; Liu, Xiang [Peking University; Chen, Jinxiang [Peking University

    2010-01-01

    We have measured the {sup 149}Sm(n,{alpha}){sup 146}Nd cross section at 6.0 MeV to be 0.12 {+-} 0.018 mb. This is the first reported result for this cross section in the MeV region and so should be helpful for constraining nuclear data evaluations (which differ by a factor of 40 for this reaction at this energy) and for testing and improving nuclear models. The experiment was performed at the at the 4.5-MV Van de Graaff accelerator of Peking University. Neutrons were produced via the {sup 2}H(d,n){sup 3}He reaction using a deuterium gas target, and absolute neutron flux was determined with a small {sup 238}U fission chamber. Alpha particles were detected using a two-section gridded ionization chamber in which two large-area {sup 149}Sm{sub 2}O{sub 3} samples were placed back-to-back so that the cross section and forward/backward ratio were measured for nearly the entire 4{pi} solid angle. The data were compared to statistical-model predictions using the code talys. Good agreement between the measured and theoretical cross sections could be obtained with a small modification of the {alpha}-optical potential parameters from their default values in talys. However, we were not able to reproduce the measured forward/backward ratio. In addition, using the previously reported {sup 147}Sm(n,{alpha}){sup 144}Nd cross section at 6.0 MeV together with our new result, good agreement was found between the measured and predicted cross-section ratio for these two isotopes. Finally, none of the existing evaluated data libraries are in agreement with our new data to within the experimental uncertainties.

  6. Nuclear gamma rays from 720-MeV alpha-induced reactions on Al-27 and Si-28

    Science.gov (United States)

    Lieb, B. J.; Plendl, H. S.; Funsten, H. O.; Stronach, C. E.; Lind, V. G.

    1980-01-01

    Prompt gamma rays from the interaction of 720-MeV alpha particles with Al-27 and Si-28 were detected and analyzed to identify residual nuclei and to determine cross sections for production of specific levels. No gamma-ray transitions were detected from nuclei heavier than the target. From Doppler broadening, the momentum of the residual nuclei was estimated. The results are compared with previous results for 140- and 1600-MeV alphas on Al-27 and approximately 200-MeV positive or negative pions on Al-27 and Si-28 and fitted to a spallation-yield formula.

  7. Manufacturing of thin films of boron for the measurement of the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Smilgys, Barbara; Oliveira, Sandro Guedes de; Hadler Neto, Julio Cesar; Vellame, Igor Alencar [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Soares, Cleber Jose; Salim, Leonardo Alfredo [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Coelho, Paulo Rogerio Pinto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2011-07-01

    Full text: The Boron Neutron Capture Therapy (BNCT) is considered to be a possible treatment for different types of aggressive cancers located in areas of difficult access or which already have metastasis. The working principle of this therapy is the selective delivery of a greater amount of boron to the tumor cells than to the healthy ones, followed by the neutron irradiation that will induce the emission of {alpha} particles through the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT reaction. The high energy deposition of the product particles causes the death of the cells and this therapy becomes much effective if the healthy tissue is less exposed to this radiation. The objective of this work is to develop a method for measuring the rate of this reaction by using thin films of boron. We have manufactured thin films with different concentrations of boron deposited on mica and the thin films were exposed to different irradiation time intervals at the reactor IEA-R1 located at IPEN, Sao Paulo. Here we show our first results on the density and uniformity of the thin films, where the detection of the particles is made using plastic track detectors (CR-39) which have their structures damaged by the passage of ions. (author)

  8. AN UPDATED {sup 6}Li(p, {alpha}){sup 3}He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

    Energy Technology Data Exchange (ETDEWEB)

    Lamia, L.; Spitaleri, C.; Sergi, M. L. [Dipartimento di Fisica e Astronomia, Universita di Catania, I-95123 Catania (Italy); Pizzone, R. G.; Tumino, A.; La Cognata, M. [INFN-Laboratori Nazionali del Sud, I-95125 Catania (Italy); Tognelli, E.; Degl' Innocenti, S.; Prada Moroni, P. G. [Dipartimento di Fisica, Universita di Pisa, I-56127 Pisa (Italy); Pappalardo, L. [Dipartimento di Fisica e Scienze della Terra, Universita di Ferrara, I-44100 Ferrara (Italy)

    2013-05-01

    The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. {sup 6}Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low {sup 6}Li ignition temperature. Thus, gaining an understanding of {sup 6}Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, U{sub e} . Thanks to recent direct measurements, new estimates of the {sup 6}Li(p, {alpha}){sup 3}He bare-nucleus S(E) factor and the corresponding U{sub e} value have been obtained by applying the Trojan Horse method to the {sup 2}H({sup 6}Li, {alpha} {sup 3}He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T{sub 9} and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

  9. High sensitivity boron quantification in bulk silicon using the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Marcos V.; Silva, Tiago F. da; Added, Nemitala; Rizutto, Marcia A.; Tabacniks, Manfredo H. [Instituto de Fisica da Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Neira, John B.; Neto, Joao B. F. [Institute of Research Tecnology, Cidade Universitaria, SP, 05508-091 (Brazil)

    2013-05-06

    There is a great need to quantify sub-ppm levels of boron in bulk silicon. There are several methods to analyze B in Si: Nuclear Reaction Analysis using the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be reaction exhibits a quantification limit of some hundreds ppm of B in Si. Heavy Ion Elastic Recoil Detection Analysis offers a detection limit of 5 to 10 at. ppm. Secondary Ion Mass Spectrometry is the method of choice of the semiconductor industry for the analysis of B in Si. This work verifies the use of NRA to quantify B in Si, and the corresponding detection limits. Proton beam with 1.6 up to 2.6 MeV was used to obtain the cross-section of the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be nuclear reaction at 170 Degree-Sign scattering angle. The results show good agreementwith literature indicating that the quantification of boron in silicon can be achieved at 100 ppm level (high sensitivity) at LAMFI-IFUSP with about 16% uncertainty. Increasing the detection solid angle and the collected beam charge, can reduce the detection limit to less than 100 ppm meeting present technological needs.

  10. Glucansucrases : Three-dimensional structures, reactions, mechanism, alpha-glucan analysis and their implications in biotechnology and food applications

    NARCIS (Netherlands)

    Leemhuis, Hans; Pijning, Tjaard; Dobruchowska, Justyna M.; van Leeuwen, Sander S.; Kralj, Slavko; Dijkstra, Bauke W.; Dijkhuizen, Lubbert

    2013-01-01

    Glucansucrases are extracellular enzymes that synthesize a wide variety of alpha-glucan polymers and oligosaccharides, such as dextran. These carbohydrates have found numerous applications in food and health industries, and can be used as pure compounds or even be produced in situ by generally regar

  11. Calculation of excitation functions of proton, alpha and deuteron induced reactions for production of medical radioisotopes {sup 122–125}I

    Energy Technology Data Exchange (ETDEWEB)

    Artun, Ozan, E-mail: ozanartun@yahoo.com; Aytekin, Hüseyin, E-mail: huseyinaytekin@gmail.com

    2015-02-15

    In this work, the excitation functions for production of medical radioisotopes {sup 122–125}I with proton, alpha, and deuteron induced reactions were calculated by two different level density models. For the nuclear model calculations, the Talys 1.6 code were used, which is the latest version of Talys code series. Calculations of excitation functions for production of the {sup 122–125}I isotopes were carried out by using the generalized superfluid model (GSM) and Fermi-gas model (FGM). The results have shown that generalized superfluid model is more successful than Fermi-gas model in explaining the experimental results.

  12. A microdosimetric study of {sup 10}B(n,{alpha}){sup 7}Li and {sup 157}Gd(n,{gamma}) reactions for neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.K.C.; Sutton, M.; Evans, T.M. [Georgia Inst. of Tech., Atlanta, GA (United States); Laster, B.H. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    1999-01-01

    This paper presents the microdosimetric analysis for the most interesting cell survival experiment recently performed at the Brookhaven National Laboratory (BNL). In this experiment, the cells were first treated with a gadolinium (Gd) labeled tumor-seeking boronated porphyrin (Gd-BOPP) or with BOPP alone, and then irradiated with thermal neutrons. The resulting cell-survival curves indicate that the {sup 157}Gd(n,{gamma}) reactions are very effective in cell killing. The death of a cell treated with Gd-BOPP was attributed to either the {sup 10}B(n,{alpha}){sup 7}Li reactions or the {sup 157}Gd(n,{gamma}) reactions (or both). However, the quantitative relationship between the two types of reaction and the cell-survival fraction was not clear. This paper presents the microdosimetric analysis for the BNL experiment based on the measured experimental parameters, and the results clearly suggest a quantitative relationship between the two types of reaction and the cell survival fraction. The results also suggest new research in gadolinium neutron capture therapy (GdNCT) which may lead to a more practical modality than the boron neutron capture therapy (BNCT) for treating cancers.

  13. Measurement of the 10 keV resonance in the $^{10}$B($p, \\alpha_0$)$^7$Be reaction via the Trojan Horse Method

    CERN Document Server

    Spitaleri, C; Puglia, S M R; Romano, S; La Cognata, M; Crucilla, V; Pizzone, R G; Rapisarda, G G; Sergi, M L; Del Santo, M Gimenez; Carlin, N; Munhoz, M G; Souza, F A; de Toledo, A Szanto; Tumino, A; Irgaziev, B; Mukhamedzhanov, A; Tabacaru, G; Burjan, V; Kroha, V; Hons, Z; Mrazek, J; Zhou, Shu-Hua; Li, Chengbo; Wen, Qungang; Wakabayashi, Y; Yamaguchi, H

    2014-01-01

    The $^{10}$B(p,$\\alpha_0$)$^7$Be bare nucleus astrophysical S(E)-factor has been measured for the first time at energies from about 100 keV down to about 5 keV by means of the Trojan Horse Method (THM). In this energy region, the S(E)-factor is strongly dominated by the 8.699 MeV $^{11}$C level (J$^{\\pi}$=$\\frac{5}{2}$$^+$), producing an s-wave resonance centered at about 10 keV in the entrance channel. Up to now, only the high energy tail of this resonant has been measured, while the low-energy trend is extrapolated from the available direct data. The THM has been applied to the quasi-free $^2$H($^{10}$B,$\\alpha_0$$^7$Be)n reaction induced at a boron-beam energy of 24.5 MeV. An accurate analysis brings to the determination of the $^{10}$B(p,$\\alpha_0$)$^7$Be S(E)-factor and of the corresponding electron screening potential $U_e$, thus giving for the first time an independent evaluation of it.

  14. Measurement of cross sections for the 147Sm(n, alpha)144Nd reaction at 5.0 and 6.0 MeV.

    Science.gov (United States)

    Zhang, Guohui; Zhang, Jiaguo; Guo, Li'an; Wu, Hao; Chen, Jinxiang; Tang, Guoyou; Gledenov, Yu M; Sedysheva, M V; Khuukhenkhuu, G; Szalanski, P J

    2009-01-01

    Cross sections of the (147)Sm(n, alpha)(144)Nd reaction were measured at En=5.0 and 6.0MeV. A twin gridded ionization chamber was used as a charged particle detector and two large area (147)Sm(2)O(3) samples placed back to back were employed. Experiments were performed at the 4.5MV Van de Graaff accelerator of Peking University. Neutrons were produced through the D(d, n)(3)He reaction with a deuterium gas target. Absolute neutron flux was determined by a small (238)U fission chamber. Present cross-section data are compared with existing results of evaluations and measurements. PMID:18707895

  15. Alpha-spectroscopic factors from (d,6Li) and (3He,7Be) reactions on 12C,24Mg,40Ca and 58Ni

    International Nuclear Information System (INIS)

    An attempt has been made to compare the alpha-spectroscopic factors (Ssub(α)) resulting from (d,6Li) and (3He,7Be) reactions on 12C,24Mg,40Ca and 58Ni employing potentials characterizing the same potential family for the deuteron and for the 3He-channels and another set of potentials characterizing a particular potential family for 6Li and 7Be-channels respectively. It is found that the extracted spectroscopic factors for 12C,24Mg and 40Ca agree well, while that for the target 58Ni differs by an order of magnitude from the other two reactions. A possible reason has been discussed. (author)

  16. Study of the O-17(n,alpha)C-14 reaction: extension of the Trojan Horse Method to neutron induced reactions

    Czech Academy of Sciences Publication Activity Database

    Guardo, G. L.; Lamia, L.; Spitaleri, C.; Gulino, M.; Burjan, Václav; Cherubini, S.; Goldberg, V. Z.; Hons, Zdeněk; Kroha, Václav; La Cognata, M.; Mrázek, Jaromír

    Vol. 1594. Melville: American Institute of Physics, 2014, s. 215-219. ISBN 978-0-7354-1228-6. ISSN 0094-243X. [12th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG). Tsukuba (JP), 18.11.2013-21.11.2013] Institutional support: RVO:61389005 Keywords : nuclear astrophysics * neutron induced reactions * deuteron induced reactions Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  17. Selective alpha particle decay of /sup 12/C + /sup 12/C resonances to excited /sup 20/Ne rotational bands observed in the /sup 12/C(/sup 12/C,. cap alpha. ) /sup 20/Ne reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, R.J.; Ordonez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.

    1984-09-01

    Excitation functions of the /sup 12/C(/sup 12/C, ..cap alpha..)/sup 20/Ne reaction were measured at Theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14-40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.

  18. Selective alpha particle decay of /sup 12/C+ /sup 12/C resonances to excited /sup 20/Ne rotational bands observed in the /sup 12/C(/sup 12/C,. cap alpha. ) /sup 20/Ne reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, R.J.; Ordoez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.

    1984-09-01

    Excitation functions of the /sup 12/C(/sup 12/C,..cap alpha..) /sup 20/Ne reaction were measured at theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14--40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.

  19. Evaluation of nuclear reaction cross section data for the production of (87)Y and (88)Y via proton, deuteron and alpha-particle induced transmutations.

    Science.gov (United States)

    Zaneb, H; Hussain, M; Amjad, N; Qaim, S M

    2016-06-01

    Proton, deuteron and alpha-particle induced reactions on (87,88)Sr, (nat)Zr and (85)Rb targets were evaluated for the production of (87,88)Y. The literature data were compared with nuclear model calculations using the codes ALICE-IPPE, TALYS 1.6 and EMPIRE 3.2. The evaluated cross sections were generated; therefrom thick target yields of (87,88)Y were calculated. Analysis of radio-yttrium impurities and yield showed that the (87)Sr(p, n)(87)Y and (88)Sr(p, n)(88)Y reactions are the best routes for the production of (87)Y and (88)Y respectively. The calculated yield for the (87)Sr(p, n)(87)Y reaction is 104 MBq/μAh in the energy range of 14→2.7MeV. Similarly, the calculated yield for the (88)Sr(p, n)(88)Y reaction is 3.2 MBq/μAh in the energy range of 15→7MeV. PMID:27016709

  20. New High-Precision Measurement of the Reaction Rate of the O-18(p, alpha)N-15 Reaction via THM

    Czech Academy of Sciences Publication Activity Database

    La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A. M.; Irgaziev, B.; Tribble, R. E.; Banu, A.; Cherubini, S.; Coc, A.; Crucilla, V.; Goldberg, V. Z.; Gulino, M.; Kiss, G. G.; Lamia, L.; Chengbo, L.; Mrázek, Jaromír; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Trzaska, W.; Tumino, A.

    2009-01-01

    Roč. 26, č. 3 (2009), s. 237-242. ISSN 1323-3580 Institutional research plan: CEZ:AV0Z10480505 Keywords : nuclear reactions * nucleosynthesis * abundances Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.786, year: 2009

  1. The FLUORINE-17(PROTON, PHOTON)NEON-18 and Oxygen -14(ALPHA Particle, PROTON)FLUORINE-17 Reaction Rates and the Structure of NEON-18 (NEON-18, FLUORINE-17, Oxygen -14, Astrophysical Hydrogen Burning)

    Science.gov (United States)

    Hahn, Kevin Insik

    1993-01-01

    The 14O(alpha,p) 17F and ^ {17}F(p,gamma)18Ne reactions play crucial roles in the advanced stages of astrophysical hydrogen burning. The ^{14 }O(alpha,p)^ {17}F(p,gamma) ^ {18}Ne(beta^+nu) 18F(p,alpha)^ {15}O reaction sequence can provide a path around the relatively slow positron decay of 14O in the HCNO cycle, while the similar reaction sequence, ^{14 }O(alpha ,p) 17F(p,gamma)^ {18}Ne(beta ^+nu) 18F(p,gamma)^ {19}Ne, can provide an alternate path from the HCNO cycle to the rp-process. The 17F(p,gamma)18Ne reaction rate could provide the principal source of 18O. Under some astrophysical conditions, the ^{14 }O(alpha,p)^ {17}F reaction is expected to compete with the 15O(alpha, gamma)19Ne reaction in providing a path through which nuclei involved in the HCNO cycle can be transformed into heavier nuclei with Z >= 10.. In order to better determine the rates of these two reactions, we measured the properties of the resonances in 18Ne; the excitation energies, the spins, and the partial and total widths of the relevant resonances. By comparing the previously observed states in 18Ne to the well-studied isospin mirror nucleus, ^{18 }O, it is clear that there are a number of missing levels in 18Ne in the region rm Ex > 4 MeV. These missing states in ^ {18}Ne could be important in determining the 17F(p, gamma)18rm Ne and 14O(alpha ,p)17F reaction rates. We have studied the ^{12 }C(12C,^6He)^{18 }Ne, 20rm Ne(p{,}t)18Ne, and 16O(^3He{, }n)18Ne reactions to measure new nuclear structure information of ^{18 }Ne. From our experiments, we have the following major results: (a) an evidence of the 3^+ Funck et al. and Wiescher et al. have based on theoretical predictions and incomplete experimental information about the level structure of 18 Ne in the energy region of rm E_ {x} > 5.0 MeV. On the basis of the nuclear structure information for 18 Ne measured in our experiments, we have improved the calculation of the ^{14 }O(alpha,p)17F reaction rate.

  2. Investigation of the Triton Emission Asymmetry in the $^{6}$Li(n, alpha)$^{3}$H Reaction with Polarized Thermal Neutrons

    CERN Document Server

    Gledenov, Yu M; Nesvizhevsky, V V; Petukhov, A K; Sedyshev, P V; Soldner, T; Shulgina, E V; Zimmer, O

    2002-01-01

    An experiment was carried out at the high-intensity polarized cold neutron beam of the PF1B instrument of the ILL reactor, Grenoble, France. As a detector, the 48-section ionization chamber with the ^{6}LiF targets was used. An integral (current) method of the event detection with compensation of the reactor power fluctuation was applied. Special measurement technique was used for minimization and estimation of the possible false effect contribution. A value of the P-odd (sigma_{\\bf n}, {\\bf P}_{\\bf n}) correlation has been obtained: alpha_{PN}=-(7.1\\pn 3.9)\\cdot 10^{-8}. At the base of the cluster model, the most accurate at present day estimation of the weak neutral current constant has been given: f_n \\leq 1.2\\cdot 10^{-7}.

  3. Study of the B-10(p,alpha)Be-7 Reaction through the Indirect Trojan Horse Method

    Czech Academy of Sciences Publication Activity Database

    Puglia, S. M. R.; Spitaleri, C.; Lamia, L.; Romano, S.; Burjan, Václav; Carlin, N.; Chengbo, L.; Kroha, Václav; Hons, Zdeněk; Mrázek, Jaromír

    Vol. 1645. Melville: American Institute of Physics, 2015, s. 382-386. ISBN 978-0-7354-1284-2. ISSN 0094-243X. [Carpathian Summer School of Physics. Sinaia (RO), 13.07.2014-26.07.2014] Institutional support: RVO:61389005 Keywords : Trojan Horse Method * B-10 * reactions Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  4. Resonance strength measurement at astrophysical energies: the O-17(p, alpha)N-14 reaction studied via Trojan Horse Method

    Czech Academy of Sciences Publication Activity Database

    Sergi, M. L.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Rapisarda, G. G.; Mukhamedzhanov, A. M.; Irgaziev, B.; Tang, X. D.; Wiescher, M.; Mrázek, Jaromír; Kroha, Václav

    Vol. 1681. Melville: American Institute of Physics, 2015, s. 050005. (AIP Conference Proceedings). ISBN 978-0-7354-1328-3. ISSN 0094-243X. [3rd International Conference on Nuclear Structure and Dynamics. Portoroz (SI), 14.06.2015-19.06.2015] Institutional support: RVO:61389005 Keywords : thermonuclear reaction rates * cross-section * nucleosynthesis Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  5. Backangle anomaly in scattering of {alpha} -particles from {sup 28} Si at low energies[25.55.Ci; 25.70.Ef; Nuclear reactions 28 Si( {alpha},{alpha})28 Si; E{alpha}=3.0 -7.8 MeV; Measured {sigma}(E{alpha},{theta}); {theta}lab=30 deg. -175 deg.; Deduced Regge-pole parameters; Natural target

    Energy Technology Data Exchange (ETDEWEB)

    Coban, A.; Khiari, F.Z.; Abdelmonem, M.S.; Aksoy, A.; Naqvi, A.A

    2000-09-25

    In order to resolve the differences in the literature on the existence of quasi-molecular states in the {alpha} -{sup 28} Si system, excitation functions were measured for the scattering of {alpha} -particles from {sup 28} Si in the incident energy range E{sub lab}=3 -7.8 MeV. An angular distribution measurement was carried out in the angular range {theta}{sub lab}=30 deg. -174.5 deg. for every potential resonance observed in the excitation functions. Data was analysed using a Regge-pole formalism by coherently adding specific resonances to an underlying diffraction term calculated by a strong absorption model. Furthermore, the usual compound elastic contribution was incoherently added to the direct interaction part of the cross section. The 6.8 MeV resonance was confirmed with J=3 and some evidence was observed for a J=1 resonance around 6.0 MeV.

  6. {sup 10}Boron distribution measurement in laser ablated B{sub 4}C thin films using (n,alpha) reaction and LR-115 passive detector

    Energy Technology Data Exchange (ETDEWEB)

    Sajo-Bohus, L., E-mail: sajobohus@gmail.co [Universidad Simon Bolivar, Nuclear Physics Section, Valle de Sartenejas, Caracas 89000A (Venezuela, Bolivarian Republic of); Simon, A. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen 4026 (Hungary); Csako, T. [Dep. of Optics and Quantum Electronics, University of Szeged, P.O. Box 406, H-6701 Szeged (Hungary); Nemeth, P.; Palacios, D. [Universidad Simon Bolivar, Nuclear Physics Section, Valle de Sartenejas, Caracas 89000A (Venezuela, Bolivarian Republic of); Espinosa, G. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Greaves, E.D. [Universidad Simon Bolivar, Nuclear Physics Section, Valle de Sartenejas, Caracas 89000A (Venezuela, Bolivarian Republic of); Szoerenyi, T. [Dep. of Nat. Sci. and Environ. Prot., College of Dunaujvaros, P.O. Box 152, H-2401 Dunaujvaros (Hungary); Barros, H. [Universidad Simon Bolivar, Nuclear Physics Section, Valle de Sartenejas, Caracas 89000A (Venezuela, Bolivarian Republic of)

    2009-10-15

    Lateral distribution of the {sup 10}B isotope within a boron carbide film of 550 nm maximum thickness deposited on silicon wafer using pulsed laser deposition technique has been determined taking advantage of the high cross section for (n,alpha) reaction and nuclear tracks detectors (NTD - LR-115 Kodak Pathe). A radioisotope neutron source ({sup 252}Cf, 20 mug) and a 60 x 60 x 80 cm{sup 3} graphite cube as moderator produce a relatively uniform thermal neutron field. Details of the passive detector etching process and data processing are included. The track density reveals the boron density spatial distribution. A 3D picture is produced to visualize the boron-10 spatial distribution. The result suggests that a gradient in the boron distribution exists to almost a factor of three. The advantages of the technique are discussed.

  7. Diagnosis of. alpha. sub 1 -antitrypsin deficiency by enzymatic amplification of human genomic DNA and direct sequencing of polymerase chain reaction products

    Energy Technology Data Exchange (ETDEWEB)

    Newton, C.R.; Graham, A.; Powell, S.; Gammack, A.; Riley, J.; Markham, A.F. (ICI Diagnostics, Cheshire (England)); Kalsheker, N. (Univ. of Wales, Cardiff (Wales))

    1988-09-12

    The authors have compared sequencing of cloned polymerase chain reaction (PCR) products and the direct sequencing of PCR products in the examination of individuals from six families affected with {alpha}{sub 1}-antitrypsin (AAT) deficiency. In families where paternity was in question they confirmed consanguinity by DNA fingerprinting using a panel of locus-specific minisatellite probes. They demonstrate that direct sequencing of PCR amplification products is the method of choice for the absolutely specific diagnosis of AAT deficiency and can distinguish normals, heterozygotes and homozygotes in a single, rapid and facile assay. Furthermore, they demonstrate the reproducibility of the PCR and a rapid DNA isolation procedure. They have also shown that two loci can be simultaneously amplified and that the PCR product from each locus can be independently examined by direct DNA sequencing.

  8. Thermodynamics of the hydrolysis reactions of {alpha}-D-galactose 1-phosphate, sn-glycerol 3-phosphate, 4-nitrophenyl phosphate, phosphocreatine, and 3-phospho-D-glycerate

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Robert N. [Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20876 (United States); Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States)], E-mail: robert.goldberg@nist.gov; Lang, Brian E. [Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20876 (United States)], E-mail: brian.lang@nist.gov; Lo, Catherine [Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20876 (United States)], E-mail: catherine.lo@nist.gov; Ross, David J. [Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20876 (United States)], E-mail: david.ross@nist.gov; Tewari, Yadu B. [Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20876 (United States)], E-mail: yadu.tewari@nist.gov

    2009-05-15

    Microcalorimetry, high-performance liquid chromatography (h.p.l.c.), and an enzymatic assay have been used to conduct a thermodynamic investigation of five phosphate hydrolysis reactions: {l_brace}{alpha}-D-galactose 1-phosphate(aq) + H{sub 2}O(l) = D-galactose(aq) + orthophosphate(aq){r_brace} (1), {l_brace}sn-glycerol 3-phosphate(aq) + H{sub 2}O(l) = glycerol(aq) + orthophosphate(aq){r_brace} (2), {l_brace}4-nitrophenyl phosphate(aq) + H{sub 2}O(l) = 4-nitrophenol(aq) + orthophosphate(aq){r_brace} (3), {l_brace}phosphocreatine(aq) + H{sub 2}O(l) = creatine(aq) + orthophosphate(aq){r_brace} (4), and {l_brace}3-phospho-D-glycerate(aq) + H{sub 2}O(l) = D-glycerate(aq) + orthophosphate(aq){r_brace} (5). Calorimetrically determined enthalpies of reaction {delta}{sub r}H(cal) were measured for reactions (1)-(5) and the apparent equilibrium constant K' was measured for reaction (2). The pKs and standard enthalpies of reaction {delta}{sub r}H{sup 0} for the H{sup +} and Mg{sup 2+} binding reactions of the reactants and products in the aforementioned reactions were obtained either from the literature or by estimation. A chemical equilibrium model was then used to calculate standard equilibrium constants K and standard enthalpies of reaction {delta}{sub r}H{sup 0} for chemical reference reactions that correspond to the overall biochemical reactions that were studied experimentally. Property values from the literature and thermodynamic network calculations were used to obtain values of the equilibrium constants for the chemical reference reactions that correspond to the overall biochemical reactions (1). These values were compared with other results from the literature and also correlated with structural features. The results obtained in this study can be used in the chemical equilibrium model to calculate values of K', the standard apparent Gibbs free energy changes {delta}{sub r}G{sup '0}, the standard apparent enthalpy changes {delta}{sub r}H{sup '0

  9. Novel 4{pi} Detection System for the Measurement of the {sup 6}Li(n,{alpha}){sup 3}H Reaction Cross Section

    Energy Technology Data Exchange (ETDEWEB)

    Giorginis, Georgios; Bencardino, Raffaele [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel (Belgium)

    2011-12-13

    A dedicated one-dimensional Time Projection Chamber (1D-TPC) was designed and produced at IRMM to determine the {sup 6}Li(n,{alpha}){sup 3}H cross section in the 0.4-2.8 MeV energy range, aiming at 5% accuracy. The basic TPC components were a twin gridded ionisation chamber (GIC) with interwired electrodes and fast digitisation of the anode and cathode signals. The energy of both reaction products emitted from a thin {sup 6}LiF sample at the common TPC cathode was measured. A Kr(97%)CO{sub 2}(3%) mixture was used as the detector gas at a pressure up to 3.5 bar. A {sup 238}U sample mounted on the cathode of an ionisation chamber without grid was used as the neutron flux monitor. Special care was taken to reduce the experimental sources of uncertainty. The beam-monitor {sup 238}U sample was characterised at IRMM by low-geometry {alpha}-counting with an accuracy of 0.1%. A {sup 6}Li sample was produced at IRMM by vacuum evaporation of {sup 6}LiF onto transparent aluminium backing. The number of {sup 6}Li atoms will be measured via Thermal Neutron Depth Profiling with an expected accuracy of 2% with respect to an IRMM Standard Reference Material. First test measurements were performed using a monoenergetic neutron beam produced by the T(p,n){sup 3}He reaction at the IRMM 7 MV Van de Graaff accelerator. The experimental method and preliminary results are presented.

  10. Indirect study of {sup 11}B(p,alpha{sub 0}){sup 8}Be and {sup 10}B(p,alpha){sup 7}Be reactions at astrophysical energies by means of the Trojan Horse Method: recent results

    Energy Technology Data Exchange (ETDEWEB)

    Lamia, L.; Puglia, S.M.R.; Spitaleri, C.; Romano, S. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Del Santo, M. Gimenez; Carlin, N.; Munhoz, M. Gameiro [Departamento de Fisica Nuclear, Universitade de Sao Paulo, Sao Paulo (Brazil); Cherubini, S. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Kiss, G.G. [Laboratori Nazionali del Sud, Catania (Italy); Atomki, Debrecen (Hungary); Kroha, V. [Institute for Nuclear Physics, Prague (Czech Republic); Kubono, S. [CNS, University of Tokyo, Tokyo (Japan); La Cognata, M. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Li Chengbo [China Institute of Atomic Energy, Department of Physics, Beijing (China); Pizzone, R.G. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Wen Qungang [China Institute of Atomic Energy, Department of Physics, Beijing (China); Sergi, M.L. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Szanto de Toledo, A. [Departamento de Fisica Nuclear, Universitade de Sao Paulo, Sao Paulo (Brazil); Wakabayashi, Y. [CNS, University of Tokyo, Tokyo (Japan); Advanced Science Research Center - JAEA - Ibaraki (Japan); Yamaguchi, H. [CNS, University of Tokyo, Tokyo (Japan); Zhou Shuhua [China Institute of Atomic Energy, Department of Physics, Beijing (China)

    2010-03-01

    Nuclear (p,alpha) reactions destroying the so-called 'light-elements' lithium, beryllium and boron have been largely studied in the past mainly because their role in understanding some astrophysical phenomena, i.e. mixing-phenomena occurring in young F-G stars [A.M. Boesgaard et al., Astr. Phys. J, 991, 2005, 621]. Such mechanisms transport the surface material down to the region close to the nuclear destruction zone, where typical temperatures of the order of approx10{sup 6} K are reached. The corresponding Gamow energy E{sub 0}=1.22(Z{sub x}{sup 2}Z{sub X}{sup 2}T{sub 6}{sup 2}){sup 1/3} keV [C. Rolfs and W. Rodney, 'Cauldrons in the Cosmos', The Univ. of Chicago press, 1988] is about approx10 keV if one considers the 'boron-case' and replaces in the previous formula Z{sub x}=1, Z{sub X}=5 and T{sub 6}=5. Direct measurements of the two {sup 11}B(p,alpha{sub 0}){sup 8}Be and {sup 10}B(p,alpha){sup 7}Be reactions in correspondence of this energy region are difficult to perform mainly because the combined effects of Coulomb barrier penetrability and electron screening [H.J. Assenbaum, K. Langanke and C. Rolfs, Z. Phys., 327, 1987, 461]. The indirect method of the Trojan Horse (THM) [G. Baur et al., Phys. Lett. B, 178, 1986, 135; G. Calvi et al., Nucl. Phys. A, 621, 1997, 139; C. Spitaleri et al., Phys. Rev. C, 493, 1999, 206] allows one to extract the two-body reaction cross section of interest for astrophysics without the extrapolation-procedures. Due to the THM formalism, the extracted indirect data have to be normalized to the available direct ones at higher energies thus implying that the method is a complementary tool in solving some still open questions for both nuclear and astrophysical issues [S. Cherubini et al., Astr. Phys. J, 457, 1996, 855; C. Spitaleri et al., Phys. Rev. C, 63, 2001, 005801; C. Spitaleri et al., Phys. Rev. C, 63, 2004, 055806; A. Tumino et al., Phys. Rev. Lett., 98, 2007, 252502; M. La Cognata et al., Phys

  11. Study of the Nuclear Transparency in $\\alpha$ + A Reactions at Energies $\\geq$ 12 GeV/nucleon

    CERN Multimedia

    2002-01-01

    The question about transparency is crucial for heavy ion reaction studies. If the transparency is low at 10-15 GeV per nucleon then very large baryon densities can be achieved in this energy range, maybe enough to produce quark-gluon plasma in U+U collisions. We propose to measure, event by event, pseudo-rapidity and multiplicity distributions of singly charged relativistic particles (@b~$>$~0.7) globally and in selected regions of rapidity as well as multiplicities of recoiling protons (30-400~Me charged nuclear fragments. These studies will explore general features of @a+A reactions at energies @$>$~12~GeV/nucleon. The main goal of the experiment is to measure the transparency of nuclear matter in this energy range. The detector will be nuclear emulsion.

  12. Paradoxical reactions induced by tumor necrosis factor-alpha antagonists: A literature review based on 46 cases.

    Science.gov (United States)

    Olteanu, Rodica; Zota, Alexandra

    2016-01-01

    Anti-tumor necrosis factor (TNFα) agents have acquired a prominent place in the treatment options for inflammatory disorders. Among the side effects of these agents are the so-called paradoxical reactions which have increasingly been reported in recent years. A review of literature was carried out using Medline (PubMed) database from January 2010 to December 2014 to collect all published articles on cases of anti-TNFα-induced psoriasis and psoriatic arthritis. Published articles were identified, reviewed and the relevant data extracted. A total of 22 studies (46 patients) fulfilled the inclusion criteria and were selected for analysis. Of the 46 patients, 45 (97.8%) developed psoriasis and 1 (2.1%) psoriatic arthritis. The mean age of patients was 47 years; three (6.5%) patients had a past history of psoriasis. Infliximab caused cutaneous reactions in the most number, 26 (56.5%) cases. Thirty seven (80.4%). patients developed primary plaque-type psoriasis. Women accounted for 86.9% of patients. There was complete resolution of psoriasis in 12 (26%) patients despite differences in the therapeutic approach. Cessation of the incriminated drug led to resolution of cutaneous lesions in 5 (10.8%), switching to another TNFα antagonist led to resolution in 6 (13%) and one (2.1%) patient improved despite continuation of the drug. As for the lone case of psoriatic arthritis, drug withdrawal did not result in improvement; only switching to another anti-TNFα agent helped. Since our sample was small, it was not adequately powered to draw any firm conclusions. However, in this analysis, we found that paradoxical reactions occurred predominantly in adult women, there were only isolated cases with a personal history of psoriasis, infliximab was responsible for most cases of these reactions and the most prevalent form was plaque-type psoriasis. The decision whether to continue or discontinue the triggering anti-TNFα agent should be individualized as results are highly variable

  13. The 65 keV resonance in the O-17(p,alpha)N-14 thermonuclear reaction

    Czech Academy of Sciences Publication Activity Database

    Sergi, M. L.; Spitaleri, C.; Coc, A.; Mukhamedzhanov, A. M.; Burjan, Václav; Gulino, M.; Hammache, F.; Hons, Zdeněk; Irgaziev, B.; Kiss, G.G.; Kroha, Václav; La Cognata, M.; Lamia, L.; Pizzone, R. G.; de Sereville, N.; Somorjai, E.

    2010-01-01

    Roč. 834, 1-4 (2010), 676C-678C. ISSN 0375-9474. [10th International Conference on Nucleus-Nucleus Collisions (NN2009). Beijing, 16.08.2009-21.08.2009] Institutional research plan: CEZ:AV0Z10480505 Keywords : REACTION-RATES * ENERGIES Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.986, year: 2010

  14. Ab initio alpha-alpha scattering.

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  15. Ab initio alpha-alpha scattering

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.

    2015-12-01

    Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  16. Study of the $^{44}$Ti$(\\alpha,p)^{47}$V47 reaction and implications for core collapse supernovae

    CERN Document Server

    Margerin, V; Davinson, T; Dressler, R; Fallis, J; Kankainen, A; Laird, A M; Lotay, G; Mountford, D J; Murphy, C D; Seiffert, C; Schumann, D; Stowasser, T; Stora, T; Wang, C H -T; Woods, P J

    2014-01-01

    The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ -ray observations of the isotope 44 Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of 44 Ti in supernovae is 44 Ti ( α , p ) 47 V. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a 44 Ti beam at E lab = 2 . 16 MeV / u, corresponding to an energy distribution, for reacting α -particles, centred on E cm = 4 . 15 with a 1 σ width of 0.23 MeV. This is, for the first time, well within the Gamow window for core collapse supernovae. The material from which the 44 Ti beam was extracted originates from highly irradiated components of the SINQ spallation neutron source of the Paul Scherr...

  17. Measurements of neutron-induced capture and fission reactions on $^{235}$ U: cross sections and ${\\alpha}$ ratios, photon strength functions and prompt ${\\gamma}$-ray from fission

    CERN Multimedia

    We propose to measure the neutron-induced capture cross section of the fissile isotope $^{235}$U using a fission tagging set-up. This new set-up has been tested successfully in 2010 and combines the n_TOF 4${\\pi}$ Total Absorption Calorimeter (TAC) with MicroMegas (MGAS) fission detectors. It has been proven that such a combination of detectors allows distinguishing with very good reliability the electromagnetic cascades from the capture reactions from dominant ${\\gamma}$-ray background coming from the fission reactions. The accurate discrimination of the fission background is the main challenge in the neutron capture cross section measurements of fissile isotopes. The main results from the measurement will be the associated capture cross section and ${\\alpha}$ ratio in the resolved (0.3-2250 eV) and unresolved (2.25-30 keV) resonance regions. According to the international benchmarks and as it is mentioned in the NEA High Priority Request List (HPRL), the 235U(n,${\\gamma}$) cross section is of utmost impo...

  18. Investigation of the impact of the $^{39}$Ar(n , $\\alpha)^{36}$S reaction on the nucleosynthesis of the rare isotope $^{36}$S

    CERN Multimedia

    Geltenbort, P

    2002-01-01

    The origin of the rare, neutron rich isotope $^{36}$S remains a debated question. One of the key reactions in the s-process nucleosynthesis network leading to $^{36}$S is $^{39}$Ar(n , $\\alpha) ^{36}\\!$S. This reaction has never been studied so far, which is due to the fact that $^{39}$Ar is a radioactive (T$_{1/2}$ = 269 y) gas, which is not commercially available. During a three days experimental campaign, an optimized $^{39}$Ar sample was prepared at ISOLDE. A dedicated titaniumoxide target (8 g/cm$^{2}$) was bombarded with 1 GeV protons from the PS Booster. In order to obtain a pure argon beam, a water-cooled transfer line was used to freeze-out less volatile isobars before they can reach the ion source. Adding stable argon with a calibrated leak to the ion source enabled to determine the ionization efficiency (3.5%). For the isotope separation, the low-mass side (GLM) of the General Purpose Separator was used. After magnetic separation, $^{39}$Ar ions (1+) were implanted at 60 keV in a 12 mm thick alumin...

  19. Does Dietary Deoxynivalenol Modulate the Acute Phase Reaction in Endotoxaemic Pigs?—Lessons from Clinical Signs, White Blood Cell Counts, and TNF-Alpha

    Directory of Open Access Journals (Sweden)

    Tanja Tesch

    2015-12-01

    Full Text Available We studied the interaction between deoxynivalenol (DON-feeding and a subsequent pre- and post-hepatic immune stimulus with the hypothesis that the liver differently mediates the acute phase reaction (APR in pigs. Barrows (n = 44 were divided into a DON-(4.59 mg DON/kg feed and a control-diet group, surgically equipped with permanent catheters pre- (V. portae hepatis and post-hepatic (V. jugularis interna and infused either with 0.9% NaCl or LPS (7.5 µg/kg BW. Thus, combination of diet (CON vs. DON and infusion (CON vs. LPS, jugular vs. portal created six groups: CON_CONjug.-CONpor., CON_CONjug.-LPSpor., CON_LPSjug.-CONpor., DON_CONjug.-CONpor., DON_CONjug.-LPSpor., DON_LPSjug.-CONpor.. Blood samples were taken at −30, 15, 30, 45, 60, 75, 90, 120, 150, 180 min relative to infusion and analyzed for leukocytes and TNF-alpha. Concurrently, clinical signs were scored and body temperature measured during the same period. LPS as such induced a dramatic rise in TNF-alpha (p < 0.001, hyperthermia (p < 0.01, and severe leukopenia (p < 0.001. In CON-fed pigs, an earlier return to physiological base levels was observed for the clinical complex, starting at 120 min post infusionem (p < 0.05 and persisting until 180 min. DON_LPSjug.-CONpor. resulted in a lower temperature rise (p = 0.08 compared to CON_LPSjug.-CONpor.. In conclusion, APR resulting from a post-hepatic immune stimulus was altered by chronic DON-feeding.

  20. A proposed direct measurement of cross section at Gamow window for key reaction $^{19}$F($p$,$\\alpha$)$^{16}$O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

    CERN Document Server

    He, J J; Ma, S B; Hu, J; Zhang, L Y; Fu, C B; Zhang, N T; Lian, G; Su, J; Li, Y J; Yan, S Q; Shen, Y P; Hou, S Q; Jia, B L; Zhang, T; Zhang, X P; Guo, B; Kubono, S; Liu, W P

    2016-01-01

    In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key $^{19}$F($p$,$\\alpha$)$^{16}$O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.

  1. Coefficient Alpha

    OpenAIRE

    Panayiotis Panayides

    2013-01-01

    Heavy reliance on Cronbach’s alpha has been standard practice in many validation studies. However, there seem to be two misconceptions about the interpretation of alpha. First, alpha is mistakenly considered as an indication of unidimensionality and second, that the higher the value of alpha the better. The aim of this study is to clarify these misconceptions with the use of real data from the educational setting. Results showed that high alpha values can be obtained in multidimensional scale...

  2. Synthesis of a precursor for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha,17 beta-diol 17-glucuronide

    International Nuclear Information System (INIS)

    Starting from 11 beta-hydroxytestosterone, the synthesis of a strategic precursor, C-9 (11) unsaturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (9a), for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide has been achieved. The authors optimized the reaction conditions for catalytic reduction employing hydrogen and subsequent base hydrolysis followed by purification on Amberlite XAD-2 resin to obtain the saturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide

  3. Cross section measurement for the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction at 4.0, 5.0 and 6.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guohui [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China)], E-mail: guohuizhang@pku.edu.cn; Wu Hao; Zhang Jiaguo; Liu Jiaming; Yin Yuxiang; Chen Jinxiang [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China); Gledenov, Yu.M.; Sedysheva, M.V. [Frank Laboratory of Neutron Physics, JINR, Dubna 141980 (Russian Federation); Khuukhenkhuu, G. [Nuclear Research Centre, National University of Mongolia, Ulaanbaatar (Mongolia); Koehler, P.E. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Szalanski, P.J. [University of Lodz, Institute of Physics, Lodz (Poland)

    2010-01-15

    Measurements of cross sections of the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction at E{sub n}=4.0, 5.0 and 6.0 MeV were carried out at the 4.5 MV Van de Graaff of Peking University, China. A twin gridded ionization chamber and two large-area {sup 95}Mo samples were adopted. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was employed for absolute neutron flux determination. Present data are compared with existing evaluations and measurement.

  4. The Branchings of the Main s-process: Their Sensitivity to alpha-induced Reactions on 13C and 22Ne and to the Uncertainties of the Nuclear Network

    CERN Document Server

    Bisterzo, Sara; Kaeppeler, Franz; Wiescher, Michael; Imbriani, Gianluca; Straniero, Oscar; Cristallo, Sergio; Goerres, Joachim; deBoer, Richard

    2015-01-01

    This paper provides a detailed analysis of the main component of the slow neutron capture process (the s-process), which accounts for the solar abundances of half of the nuclei with 90 <~ A <~ 208. We examine the impact of the uncertainties of the two neutron sources operating in low-mass asymptotic giant branch (AGB) stars: the 13C(alpha, n)16O reaction, which releases neutrons radiatively during interpulse periods (kT ~ 8 keV), and the 22Ne(alpha, n)25Mg reaction, partially activated during the convective thermal pulses (TPs). We focus our attention on the branching points that mainly influence the abundance of s-only isotopes. In our AGB models, the 13C is fully consumed radiatively during interpulse. In this case, we find that the present uncertainty associated to the 13C(alpha, n)16O reaction has marginal effects on s-only nuclei. On the other hand, a reduction of this rate may increase the amount of residual (or unburned) 13C at the end of the interpulse: in this condition, the residual 13C is bur...

  5. Efficient one-pot enzymatic synthesis of alpha-(1 -> 4)-glucosidic disaccharides through a coupled reaction catalysed by Lactobacillus acidophilus NCFM maltose phosphorylase

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Dilokpimol, Adiphol; Abou Hachem, Maher;

    2010-01-01

    -b-glucopyranosyl( 1 -> 4)-o-glucosaminopyranose I maltosaminej, a-a-glucopyranosyl-(1 -> 4)-b-mannopyranose, alpha-n-glucopyranosyl-(1 -> 4)-t-fucopyranose and alpha-b-glucopyranosyl-(1 -> 4)-D-xylopyranose, respectively, from 0 1 M maltose, 0.5 M N-acetyl glucosamine, 0.1 M glucosamine. 0.1 M mannose, 1 M t-fucose...

  6. Measurement of the astrophysical S-factor for the {sup 18}F(p,{alpha}) reaction at E = 662 keV/u with a {sup 18}F radioactive beam

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.E.; Blumenthal, D.J.; Gehring, J. [and others

    1995-08-01

    {sup 18}F is produced in stars during the so-called breakout from the hot CNO cycle and is important as one of the links connecting the HCNO cycle with the rp-process by producing {sup 19}Ne via the {sup 18}F(p,{gamma}) reaction. There is, however, a competing reaction {sup 18}F(p,{alpha}){sup 15}O which leads back into the CNO cycle. The importance of {sup 18}F for producing {sup 19}Ne therefore depends strongly on the (p,{gamma}) to (p,{alpha}) cross sections ratio. We have begun to study the {sup 18}F(p,{alpha}){sup 15}O reaction using a {sup 18}F beam. {sup 18}F, which is a well-studied PET isotope, is generated at the medical cyclotron of the University of Wisconsin. Aqueous [{sup 18}F] fluoride ions are produced via the {sup 18}O(p,n){sup 18}F reaction using a 30-{mu}A, 11.4-MeV proton beam bombarding a 95% enriched [{sup 18}O] water target and electroplated onto the end of a 3-mm diameter Al anode. After electroplating, the anodized Al is pressed into a copper cathode insert for the National Electrostatics Corporation SNICS ion source, transported to Argonne National Laboratory and installed in the ion source of the Tandem accelerator at ATLAS. With an activity at the end of the electroplating process of 530 mCi, the starting activity after 2 h, which is the time needed to transport and install the material in the SNICS source, was 250 mCi, corresponding to a total number of {sup 18}F atoms of 8.8 x 10{sup 13}.

  7. The alpha channeling effect

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N. J.

    2015-12-10

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  8. From the drawbacks of the Arrhenius-f({alpha}) rate equation towards a more general formalism and new models for the kinetic analysis of solid-gas reactions

    Energy Technology Data Exchange (ETDEWEB)

    Michele, Pijolat, E-mail: mpijolat@emse.fr [LPMG-CNRS SISFRE 3312, Centre SPIN, Ecole Nationale Superieure des Mines, 158 Cours Fauriel, 42023 Saint-Etienne Cedex 2 (France); Loic, Favergeon; Michel, Soustelle [LPMG-CNRS SISFRE 3312, Centre SPIN, Ecole Nationale Superieure des Mines, 158 Cours Fauriel, 42023 Saint-Etienne Cedex 2 (France)

    2011-10-20

    Highlights: {yields} Discussion of the most relevant drawbacks linked to the rate equation d{alpha}/dt = A exp (- (E/RT))f({alpha}). {yields} Proposal of a more general equation d{alpha}/dt = {phi}(T, P{sub i})S{sub m}(t, ...), with {phi} in mol m{sup -2} s{sup -1} and S{sub m} in m{sup 2} mol{sup -1}. {yields} New growth models and surface nucleation-anisotropic or isotropic growth models. {yields} Description of CIN3 software for simulation and fitting of isothermal kinetic data. - Abstract: Since many years the kinetic models used for interpreting the kinetic curves {alpha}(t) relative to the chemical transformations of solids such as thermal decomposition, reduction, oxidation, etc., rely on very restrictive assumptions to which corresponds the following equation: (a)(d{alpha})/(dt) =Aexp(-E/(RT) )f({alpha}) where A is called the 'pre-exponential term', E is the 'apparent activation energy', and f({alpha}) is a mathematical function which depends of the kinetic model. This article first presents a critical analysis of Eq. by detailing the conditions in which it is rigorously correct. A more general equation is then proposed on the basis of assumptions related to the nucleation and growth processes of the new phase: (b)(d{alpha})/(dt) ={phi}(T,P{sub i})S{sub m}(t,...) S{sub m}(t,...) being a function of {alpha} only in very particular cases of instantaneous nucleation or growth, and {phi} being related to the rate-determining step and varying only with thermodynamic variables (temperature, partial pressures P{sub i},...).The advantages of Eq. are of two types: firstly, the variables temperature and partial pressure of gases may not be separated in the expression of {phi} (no Arrhenius dependence with temperature); secondly, in gas-solid systems, when the nucleation process takes place at the surface of the solid and along the course of the transformation (nucleation and growth processes are simultaneous), the rate cannot be expressed by means

  9. Alpha Particle Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  10. Study of the vibrational nucleus sup 1 sup 0 sup 0 Ru by the sup 9 sup 8 Mo(alpha,2n gamma) and sup 9 sup 9 Ru(n,gamma) reactions

    CERN Document Server

    Genilloud, L; Corminboeuf, F; Doll, C; Drissi, S; Jentschel, M; Jolie, J; Kern, J; Lehmann, H; Warr, N

    2000-01-01

    The nuclear structure of sup 1 sup 0 sup 0 Ru was investigated using the sup 9 sup 9 Ru(n,gamma) and sup 9 sup 8 Mo(alpha,2n gamma) reactions. In the in-beam spectroscopy study, the use of a coincidence system equipped with five Compton-suppression spectrometers allowed to place 207 transitions in the decay scheme. Spin and parity assignments of the states were determined using angular distribution analysis together with the excitation function slopes and side-feeding intensities. The photons following the neutron capture were observed using curved crystal and pair spectrometers. Using the results of both reactions, the level scheme was extended by 36 new levels. The interpretation of the resulting level scheme was performed in the framework of the spdf interacting boson model.

  11. Table of cross section (n,p), (n,{alpha}) and (n, 2n) reactions in steel components and other nuclear materials; Secciones eficaces (n, p), (n,{alpha}) y (n, 2n) de los componentes de los aceros y otros materiales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Jimenez, J.

    1972-07-01

    Reactions (n,p) and (n, {alpha} ) produce in the materials large amount of hydrogen and helium atoms. The presence, specially of helium, changes the physical properties of materials and particularly reduce the ductility of irradiated stainless steel cladding above 500 degree centigree. Cross sections of all isotopes which constitute the S.S. and other clad materials, have been completed. Experimental available data were obtained from BNL (1956, 64 and 68), and the rest, from J.C, ROY and J . J . HAWTON calculations in a fission neutron spectrum (1960). (Author)

  12. E2 contribution to the /sup 12/C(. cap alpha. ,. gamma. )/sup 16/O reaction at stellar energies in a coupled channel approach

    Energy Technology Data Exchange (ETDEWEB)

    Funck, C.; Langanke, K.; Weiguny, A.

    1985-02-28

    The E2 part of the /sup 12/C(..cap alpha..,..gamma..)/sup 16/O capture process at stellar energies is calculated in a microscopically founded coupled channel approach based on the rotational model of Tamura. At the astrophysically most effective energy we obtain an S-factor for E2 capture of Ssub(E2)(300 keV)=0.10 MeV b.

  13. E2 contribution to the /sup 12/C(. alpha. ,. gamma. )/sup 16/O reaction at stellar energies in a coupled channel approach

    Energy Technology Data Exchange (ETDEWEB)

    Funck, C.; Langanke, K.; Weiguny, A.

    1985-02-28

    The E2 part of the /sup 12/C(..alpha..,..gamma..)/sup 16/O capture process at stellar energies is calculated in a microscopically founded coupled channel approach based on the rotational model of Tamura. At the astrophysically most effective energy we obtain an S-factor for E2 capture of Ssub(E2)(300 keV) = 0.10 MeV b. (orig.).

  14. Acute-phase reaction induces a specific complex between hepatic nuclear proteins and the interleukin 6 response element of the rat alpha 2-macroglobulin gene.

    OpenAIRE

    Hattori, M; Abraham, L J; Northemann, W; Fey, G H

    1990-01-01

    Interleukin 6 (IL-6) was established as a transcriptional inducer of the rat alpha 2-macroglobulin gene, a prototype liver acute-phase gene. Maximum induction occurred when the 5' flanking sequences of this gene (position -209 to -43) directed expression from the gene's own TATA box and transcription start site. Removal of the hexanucleotide CTGGGA (position -164 to -159) abolished 60-70% of the hormonal induction in FAO1 rat hepatoma cells. This hexanucleotide was defined as the IL-6 respons...

  15. The 7Be(n,alpha)4He reaction and the Cosmological Lithium Problem: measurement of the cross section in a wide energy range at n_TOF (CERN)

    CERN Document Server

    Barbagallo, M; Cosentino, L; Maugeri, E; Heinitz, S; Mengoni, A; Dressler, R; Schumann, D; Kaeppeler, F; Colonna, N; Finocchiaro, P; Ayranov, M; Damone, L; Kivel, N

    2016-01-01

    The energy-dependent cross section of the 7Be(n,alpha)4He reaction, of interest for the so-called Cosmological Lithium Problem in Big Bang Nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of 7Be and by the low reaction cross section have been overcome at n_TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n_TOF facility at CERN, the availability of a sufficient amount of chemically pure 7Be, and a specifically designed experimental setup. Coincidences between the two alpha-particles have been recorded in two Si-7Be-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 60's at a nuclear reactor. The energy dependence here reported clearly indicates the inadequacy of the cross section estimates currently used in ...

  16. Constraining the 6.05 MeV 0$^+$ and 6.13 MeV 3$^-$ cascade transitions in the $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O reaction using the Asymptotic Normalization Coefficients

    CERN Document Server

    Avila, M L; Koshchiy, E; Baby, L T; Belarge, J; Kemper, K W; Kuchera, A N; Mukhamedzhanov, A M; Santiago-Gonzalez, D; Uberseder, E

    2014-01-01

    Background. The $^{12}$C($\\alpha,\\gamma$)$^{16}$O reaction plays a fundamental role in astrophysics because its cross section near 300 keV in c.m. determines the $^{12}$C/$^{16}$O ratio at the end of the helium burning stage of stellar evolution. The astrophysically desired accuracy of better than 10\\% has not been achieved. Cascade $\\gamma$ transitions through the excited states of $^{16}$O are contributing to the uncertainty. Purpose. To measure the Asymptotic Normalization Coefficients (ANCs) for the 0$^+$ (6.05 MeV) and 3$^-$ (6.13 MeV) excited states in $^{16}$O and provide constraints on the cross section for the corresponding cascade transitions. Method. The ANCs were measured using the $\\alpha$-transfer reaction $^{12}$C($^6$Li,$d$)$^{16}$O performed at sub-Coulomb energies for both the entrance and exit channels. Results. The ANCs for the 0$^+$(6.05 MeV), 3$^-$(6.13 MeV), 2$^+$(6.92 MeV) and 1$^-$(7.12 MeV) states in $^{16}$O have been measured. The contribution of the 0$^+$ and 3$^-$ cascade transit...

  17. Investigation of the thermal sup 2 sup 6 Al(n,p sub i) sup 2 sup 6 Mg and sup 2 sup 6 Al(n,alpha sub i) sup 2 sup 3 Na reactions

    CERN Document Server

    Wagemans, J; Goeminne, G; Geltenbort, P; Moens, A

    2001-01-01

    A homogeneous deposit of (2.58+-0.12)x10 sup 1 sup 7 sup 2 sup 6 Al atoms was produced applying the method of electrodeposition. With this target, the sup 2 sup 6 Al(n sub t sub h ,p sub i) sup 2 sup 6 Mg and the sup 2 sup 6 Al(n sub t sub h ,alpha sub i) sup 2 sup 3 Na reactions were studied at the high flux reactor of the ILL in Grenoble. Thermal cross section values for five transitions were obtained. The value for the sup 2 sup 6 Al(n sub t sub h , p sub 0) sup 2 sup 6 Mg cross section, (8.1+-0.8) mb, is a factor 3 lower than reported in the literature. For the sup 2 sup 6 Al(n sub t sub h , p sub 1) sup 2 sup 6 Mg cross section, a value of (1942+-95) mb was found, which is in reasonable agreement with the literature values. The result obtained for the sup 2 sup 6 Al(n sub t sub h , p sub 2) sup 2 sup 6 Mg cross section, (17+-4) mb, lies more than a factor 10 below the upper limit reported. A cross section value for the sup 2 sup 6 Al(n sub t sub h ,alpha sub 0) sup 2 sup 3 Na reaction of (261+-13) mb was...

  18. Measurement of the -3 keV resonance in the {sup 13}C({alpha},n){sup 16}O reaction and its influence on the synthesis of s-process nuclei

    Energy Technology Data Exchange (ETDEWEB)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Sparta, R. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy) and Dipartimento di Fisica e Astronomia, Universita di Catania, Catania (Italy); and others

    2012-11-20

    The {sup 13}C({alpha},n){sup 16}O reaction is the neutron source for the main component of the s-process, responsible of the production of most nuclei in the mass range 90 < A < 204. It is active inside the helium-burning shell in asymptotic giant branch stars, at temperatures < 10{sup 8} K, corresponding to an energy interval where the {sup 13}C({alpha},n){sup 16}O is effective of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in {sup 17}O, giving rise to a steep increase of the S-factor. Notwithstanding that it plays a crucial role in astrophysics, no direct measurements exist. Therefore, we have applied the Trojan Horse Method (THM) to the {sup 13}C({sup 6}Li,n{sup 16}O)d quasi-free reaction to achieve an experimental estimate of such contribution. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM as well as the n-partial width, allowing to attain an unprecedented accuracy in the {sup 13}C({alpha},n){sup 16}O study. Though a larger ANC for the 6.356 MeV level is measured, our experimental S(E) factor agrees with the most recent extrapolation in the literature in the 140 - 230 keV energy interval, the accuracy being greatly enhanced thanks to this innovative approach.

  19. Folding model study of the elastic $\\alpha + \\alpha$ scattering at low energies

    CERN Document Server

    Tan, Ngo Hai; Khoa, Dao T

    2014-01-01

    The folding model analysis of the elastic $\\alpha + \\alpha$ scattering at the incident energies below the reaction threshold of 34.7 MeV (in the lab system) has been done using the well-tested density dependent versions of the M3Y interaction and realistic choices for the $^4$He density. Because the absorption is negligible at the energies below the reaction threshold, we were able to probe the $\\alpha + \\alpha$ optical potential at low energies quite unambiguously and found that the $\\alpha + \\alpha$ overlap density used to construct the density dependence of the M3Y interaction is strongly distorted by the Pauli blocking. This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic $\\alpha + \\alpha$ and $\\alpha$-nucleus scattering at low energies using the same realistic density dependent M3Y interaction.

  20. Luteal 3beta-hydroxysteroid dehydrogenase and 20alpha-hydroxysteroid dehydrogenase activities in the rat corpus luteum of pseudopregnancy: Effect of the deciduoma reaction

    Directory of Open Access Journals (Sweden)

    Telleria Carlos M

    2004-05-01

    Full Text Available Abstract Background In the rat, the maintenance of gestation is dependent on progesterone production from the corpora lutea (CL, which are under the control of pituitary, decidual and placental hormones. The luteal metabolism of progesterone during gestation has been amply studied. However, the regulation of progesterone synthesis and degradation during pseudopregnancy (PSP, in which the CL are mainly under the control of pituitary prolactin (PRL, is not well known. The objectives of this investigation were: i to study the luteal metabolism of progesterone during PSP by measuring the activities of the enzymes 3beta-hydroxysteroid dehydrogenase (3betaHSD, involved in progesterone biosynthesis, and that of 20alpha-hydroxysteroid dehydrogenase (20alphaHSD, involved in progesterone catabolism; and ii to determine the role of decidualization on progesterone metabolism in PSP. Methods PSP was induced mechanically at 10:00 h on the estrus of 4-day cycling Wistar rats, and the stimulus for decidualization was provided by scratching the uterus on day 4 of PSP. 3betaHSD and 20alphaHSD activities were measured in the CL isolated from ovaries of PSP rats using a spectrophotometric method. Serum concentrations of progesterone, PRL, androstenedione, and estradiol were measured by radioimmunoassay (RIA. Results The PSP stage induced mechanically in cycling rats lasted 11.3 ± 0.09 days (n = 14. Serum progesterone concentration was high until day 10 of PSP, and declined thereafter. Serum PRL concentration was high on the first days of PSP but decreased significantly from days 6 to 9, having minimal values on days 10 and 11. Luteal 3betaHSD activities were elevated until day 6 of PSP, after which they progressively declined, reaching minimal values at the end of PSP. Luteal 20alphaHSD activities were very low until day 9, but abruptly increased at the end of PSP. When the deciduoma was induced by scratching the uterus of pseudopregnant animals on day 4 (PSP

  1. Alpha fetoprotein

    Science.gov (United States)

    Fetal alpha globulin; AFP ... Greater than normal levels of AFP may be due to: Cancer in testes , ovaries, biliary (liver secretion) tract, stomach, or pancreas Cirrhosis of the liver Liver cancer ...

  2. Excited levels of 238Np from spectroscopic measurements of the 237Np(n,γ)238Np reaction and /sup 242m/Am alpha decay

    International Nuclear Information System (INIS)

    The gamma rays and conversion electrons emitted following neutron capture in a 237Np target have been measured by use of the GAMS and BILL spectrometers at Grenoble. Gamma ray and alpha particle measurements of /sup 242m/Am alpha decay (Ge(Li)γ singles, γ-γ coincidences, α singles) have been made at Livermore. The data from these measurements have been combined with earlier measurements (Ionescu 1979, Asaro 1964) to produce a more detailed level scheme for 238Np. Approximately 36 levels have been identified from all of the experimental evidence. The experimentally-observed bandhead energies can be compared with predicted values derived from a simple linear addition of excitation energies observed in neighboring odd-mass nuclei. Values for the Gallagher-Moszkowski splitting of each configurational pair were obtained from theoretical calculations (Piepenbring 1978). We have assigned configurations to ten rotational bands whose bandhead energies range from 0 to 342 keV and which represent all but one of the configurations predicted to occur below 385 keV

  3. Study of alpha-emitters produced in nuclear reactions induced by 12C a 86 MeV/n on medium and heavy targets

    International Nuclear Information System (INIS)

    The work reported in this research thesis is a result from the very first experiments performed on the new Carbon 12 beam proposed by the CERN synchrotron (20 MeV< E/A<100 MeV). By means of an electrostatic collecting system developed within the laboratory, associated with an α detection device, the author measured the productions, energies, recoil distributions and angular distributions of α emitters produced in nuclear reactions induced by Carbon 12 at 1032 MeV, i.e. 86 MeV/n, on heavy targets ranging from Gadolinium to Uranium. These data and the comparison with results obtained by means of an intra-nuclear cascade model allow the main characteristics of these reactions to be identified. These characteristics will be very interesting for the understanding of phenomena occurring at these energy levels, and for the elaboration of a theoretical model describing the evolution of nuclear reactions

  4. Investigation of the triton emission asymmetry in the sup 6 Li(n, alpha) sup 3 H reaction with polarized thermal neutrons

    CERN Document Server

    Gledenov, Yu M; Petukhov, A K; Sedyshev, P V; Shulgina, E V; Soldner, T; Vesna, V A; Zimmer, O

    2002-01-01

    An experiment was carried out at the high-intensity polarized cold neutron beam of the PF1B instrument of the ILL reactor, Grenoble, France. As a detector, the 48-section ionization chamber with the sup 6 LiF targets was used. An integral (current) method of the event detection with compensation of the reactor power fluctuation was applied. Special measurement technique was used for minimization and estimation of the possible false effect contribution. A value of the P-odd (sigma sub n , P sub t) correlation has been obtained: alpha sub P sub N = -(7.1 +- 3.9) centre dot 10 sup - sup 8. On the basis of the cluster model, the most accurate at present day estimation of the weak neutral current constant has been given: f subpi <= 1.2 centre dot 10 sup - sup 7.

  5. Improvement of the high-accuracy O-17(p, alpha)N-14 reaction-rate measurement via the Trojan Horse method for application to O-17 nucleosynthesis

    Czech Academy of Sciences Publication Activity Database

    Sergi, M. L.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Rapisarda, G. G.; Tang, X. D.; Bucher, B.; Couder, M.; Davies, P.; deBoer, R.; Fang, X.; Lamm, L.; Ma, C.; Notani, M.; O'Brien, S.; Roberson, D.; Tan, W.; Wiescher, M.; Irgaziev, B.; Mukhamedzhanov, A.; Mrázek, Jaromír; Kroha, Václav

    2015-01-01

    Roč. 91, č. 6 (2015), 065803. ISSN 0556-2813 R&D Projects: GA MŠk LC07050 Institutional support: RVO:61389005 Keywords : thermonuclear reaction rates * cross section * O-17 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.733, year: 2014

  6. New results for reaction cross sections of intermediate energy alpha-particles on targets from sup 9 Be to sup 2 sup 0 sup 8 Pb 25.55.Ci; 24.10.Ht

    CERN Document Server

    Ingemarsson, A; Renberg, P U; Sundberg, O; Carlson, R F; Cox, A J; Auce, A; Johansson, R; Tibell, G; Khoa, D T; Warner, R E

    2000-01-01

    Reaction cross sections for alpha-particles have been measured for sup 9 Be, sup 1 sup 2 C, sup 1 sup 6 O, sup 2 sup 8 Si, sup 4 sup 0 Ca, sup 5 sup 8 sup , sup 6 sup 0 Ni, sup 1 sup 1 sup 2 sup , sup 1 sup 1 sup 6 sup , sup 1 sup 2 sup 0 sup , sup 1 sup 2 sup 4 Sn, and sup 2 sup 0 sup 8 Pb at 117.2, 163.9 and 192.4 MeV and for the lighter nuclei also at 69.6 MeV. The results are compared with predictions from optical model calculations using phenomenological, global and double-folded optical potentials. Comparisons are also made with predictions using the Glauber model approach suggested by Bertsch, Brown and Sagawa.

  7. Cross Sections for proton induced high energy $\\gamma$-ray emission (PIGE) in reaction $^{19}$F(p,$\\alpha\\gamma$)$^{16}$O at incident proton energies between 1.5 and 4 MeV

    CERN Document Server

    Cabanelas, P; Fonseca, M; Galaviz, D; Henriques, A; Jesus, A P; Luís, H; Sánchez-Benítez, A; Santos, C; Silva, H; Teubig, P; Velho, P

    2016-01-01

    We have studied the high energy gamma-rays produced in the reaction $^{19}$F(p,$\\alpha\\gamma$)$^{16}$O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF$_2$/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130$^{o}$ with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base. Results are in agreement with previous measurements in similar conditions.

  8. Two novel nonradioactive polymerase chain reaction-based assays of dried blood spots, genomic DNA, or whole cells for fast, reliable detection of Z and S mutations in the alpha 1-antitrypsin gene

    DEFF Research Database (Denmark)

    Andresen, B S; Knudsen, I; Jensen, P K;

    1992-01-01

    Two new nonradioactive polymerase chain reaction (PCR)-based assays for the Z and S mutations in the alpha 1-antitrypsin gene are presented. The assays take advantage of PCR-mediated mutagenesis, creating new diagnostic restriction enzyme sites for unambiguous discrimination between test samples...... from individuals who are normal, heterozygous, or homozygous for the mutations. We show that the two assays can be performed with purified genomic DNA as well as with boiled blood spots. The new assays were validated by parallel testing with a technique in which PCR is combined with allele......-specific oligonucleotide (ASO) probes. In all cases tested the results obtained by the different techniques were in accordance. The new assays can be used for prenatal diagnostics and can be performed directly with boiled tissue samples. Because the new assays are easy to perform and reliable, we conclude that they are...

  9. THM determination of the 65 keV resonance strength intervening in the O-17(p,alpha)N-14 reaction rate

    Czech Academy of Sciences Publication Activity Database

    Sergi, M. L.; Spitaleri, C.; Burjan, Václav; Cherubini, S.; Coc, A.; Gulino, M.; Hammache, F.; Hons, Zdeněk; Izgaziev, B.; Kroha, Václav

    Vol. 1645. Melville: American Institute of Physics, 2015, s. 392-396. ISBN 978-0-7354-1284-2. ISSN 0094-243X. [Carpathian Summer School of Physics. Sinaia (RO), 13.07.2014-26.07.2014] R&D Projects: GA MŠk LC07050; GA MŠk(CZ) LH11001 Institutional support: RVO:61389005 Keywords : nuclear astrophysics * direct reactions * nucleosynthesis in novae * supernovae * other explosive environments Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  10. EPR spectroscopy of catalytic systems based on nickel complexes of 1,4-diaza-1,3-butadiene (alpha-diimine) ligands in hydrogenation and polymerization reactions

    International Nuclear Information System (INIS)

    The catalytic systems based on .-diimine complexes of Ni(0) and Ni(II) of the general formulas NiBr2(DAD-R) (R = -C3H7 or -CH3) and Ni(DAD-CH3)2 (DAD(-C3H7) = 1,4-bis(2,6-diiso-propylphenyl)-2,3-(dimethyl-1,4-diazabuta-1,3-diene, DAD(-CH3) = 1,4-bis 2,6-dimethylphenyl)-2,3-dimethyl-1,4-diazabuta-1,3-diene), with Lewis acids (AlEt3, AlEt2Cl, AlEtCl2, B(F5C6)3, BF3 centre dot OEt2) in hydrogenation and polymerization reactions were investigated by the EPR spectroscopy method. The Ni(I) complexes of a (DAD-R)NiX2AlXy(C2H5)3-y composition (instead of the aluminum atom may be a boron atom) were identified where R = -CH3 or -C3H7, X = Br, X = Cl or -C2H5. The .-diimines radical-anions are included in the derivatives of aluminum or boron. It is found that there occur oxidation reactions between Ni(DAD-CH3)2 and aluminum organic compounds or boron derivatives, resulting in the formation of paramagnetic complexes. It is shown that there is no direct relationship between activity in polymerization or hydrogenation reactions and concentration of paramagnetic particles.

  11. $\\alpha_s$ review (2016)

    CERN Document Server

    d'Enterria, David

    2016-01-01

    The current world-average of the strong coupling at the Z pole mass, $\\alpha_s(m^2_{Z}) = 0.1181 \\pm 0.0013$, is obtained from a comparison of perturbative QCD calculations computed, at least, at next-to-next-to-leading-order accuracy, to a set of 6 groups of experimental observables: (i) lattice QCD "data", (ii) $\\tau$ hadronic decays, (iii) proton structure functions, (iv) event shapes and jet rates in $e^+e^-$ collisions, (v) Z boson hadronic decays, and (vi) top-quark cross sections in p-p collisions. In addition, at least 8 other $\\alpha_s$ extractions, usually with a lower level of theoretical and/or experimental precision today, have been proposed: pion, $\\Upsilon$, W hadronic decays; soft and hard fragmentation functions; jets cross sections in pp, e-p and $\\gamma$-p collisions; and photon F$_2$ structure function in $\\gamma\\,\\gamma$ collisions. These 14 $\\alpha_s$ determinations are reviewed, and the perspectives of reduction of their present uncertainties are discussed.

  12. Clustering effect of {sup 12}C fragmentation in p+{sup 12}C, {alpha}+{sup 12}C and {sup 14}N+{sup 12}C reactions

    Energy Technology Data Exchange (ETDEWEB)

    Takemoto, Hiroki; Horiuchi, Hisashi [Kyoto Univ. (Japan). Dept. of Physics; Ono, Akira

    1997-05-01

    In general, self-conjugate 4n-nuclei have anomalous excited states with the excitation energy 10-15 MeV, which are recognized to be generated by the change of the structure from the shell-model-like one into the cluster one due to the activation of the clustering degrees of freedom. In AMD (Antisymmetrized Molecular Dynamics) fermic nature of nucleons is treated exactly, because the wave function of A-body system is antisymmetrized by a Slater determinant. Hence Pauli principle has been fully incorporated in AMD. As a result, it was concluded that the features of {sup 12}C fragmentation are originated from the activation of alpha-cluster degrees of freedom by indicating the excitation energy spectra of {sup 12}C before its breakup at the dynamical stage. Excitation energy spectrum before {sup 12}C breakup into any fragments consists of two components. One distributes in the range 7-15 MeV and the other in the range above 15 MeV. Accordingly, the features is related to those excited states excited states of {sup 12}C that is considered to have the cluster structure. (G.K.)

  13. The O-17(p,alpha)N-14 reaction measurement via the Trojan Horse Method and its application to O-17 nucleosynthesis

    Czech Academy of Sciences Publication Activity Database

    Sergi, M. L.; Spitaleri, C.; Pizzone, R. G.; Burjan, Václav; Cherubini, S.; Gulino, M.; Hons, Zdeněk; Kroha, Václav; La Cognata, M.; Lamia, L.

    Vol. 1594. Melville: American Institute of Physics, 2014, s. 201-205. ISBN 978-0-7354-1228-6. ISSN 0094-243X. [12th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG). Tsukuba (JP), 18.11.2013-21.11.2013] R&D Projects: GA MŠk(CZ) LH11001; GA MŠk LC07050 Institutional support: RVO:61389005 Keywords : nuclear astrophysics * direct reactions * nucleosynthesis in novae * supernovae * other explosive environments Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  14. A note on the use/determination of relative alpha scattering phases in the 12C(α,γ)16O reaction

    International Nuclear Information System (INIS)

    A new experiment to determine the thermonuclear cross section of the 12C(α,γ)16O reaction has been performed in regular kinematics using an intense α-particle beam. In this experiment a 4π-detector setup has been used for the first time to measure all angles of each γ-angular distribution simultaneously. The 12C targets were isotopically enriched by magnetic separation during implantation. The depth profiles of the implanted carbon in the 12C targets have been determined by Rutherford backscattering for purposes of cross section normalization and absolute determination of the E1- and E2-S-factors. Angular distributions have been measured. From these distributions, astrophysical E1- and E2-S-factor functions vs. energy have been calculated, both of which are indispensable for modelling of this reaction and the extrapolation towards lower energies. The separation of the E1- and E2-S-capture channels has been done both by taking the phase value φ12 as a free parameter and by fixing it using the results of elastic α-particle scattering on 12C in the same energy range. The precision and accuracy of these new measurements make it possible to distinguish between the two methods of analysis. Preliminary values of S-factors extrapolated to 300 keV will be presented. (author)

  15. The $\\alpha-\\alpha$ fishbone potential revisited

    CERN Document Server

    Day, J P; Elhanafy, M; Smith, E; Woodhouse, R; Papp, Z

    2011-01-01

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $\\alpha-\\alpha$ fishbone potential by simultaneously fitting to two-$\\alpha$ resonance energies, experimental phase shifts and three-$\\alpha$ binding energies. We found that essentially a simple gaussian can provide a good description of two-$\\alpha$ and three-$\\alpha$ experimental data without invoking three-body potentials.

  16. Alpha One Foundation

    Science.gov (United States)

    ... Tested Find Support Find Doctor What Is Alpha-1? Alpha-1 Antitrypsin Deficiency (Alpha-1) is a ... results for inhaled augmentation More News Our Number One Goal: Find a cure for Alpha-1. Website ...

  17. Alpha-1 Antitrypsin Test

    Science.gov (United States)

    ... helpful? Also known as: Alpha 1 -antitrypsin; A1AT; AAT Formal name: Alpha 1 Antitrypsin; α1-antitrypsin Related ... know? How is it used? Alpha-1 antitrypsin (AAT) testing is used to help diagnose alpha-1 ...

  18. Alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Felix; Wilsenach, Heinrich; Zuber, Kai [IKTP TU-Dresden, Dresden (Germany)

    2014-07-01

    Alpha decays from long living isotopes are one of the limiting backgrounds for experiments searching for rare decays with stringent background constrains, such as neutrinoless double beta decay experiments. It is thus very important to accurately measure the half-lives of these decays, in order to properly model their background contribution. Therefore, it is important to be able to measure half-lives from alpha decays of the order of 1 x 10{sup 15} yr. A measurement of such a long lived decay imposes, however, a series of challenges, where the correct discrimination between background and true signal is critical. There is also a more general interest in such long living half-life measurements, as their value depends crucially on the underlying nuclear model. This work proposes a setup to measure long lived alpha decays, based on the design of the Frisch-Grid ionisation chamber. It is shown that the proposed design provides a good separation of signal and background events. It is also demonstrated that, with pulse shape analysis, it is possible to constrain the source position of the decay, further improving the quality of the data. A discussion of the characterisation of the detector is also presented as well as some results obtained with calibration sources.

  19. Alpha spectroscopy

    International Nuclear Information System (INIS)

    Alpha decays from long living isotopes are one of the limiting backgrounds for experiments searching for rare decays with stringent background constrains, such as neutrinoless double beta decay experiments. It is thus very important to accurately measure the half-lives of these decays, in order to properly model their background contribution. Therefore, it is important to be able to measure half-lives from alpha decays of the order of 1 x 1015 yr. A measurement of such a long lived decay imposes, however, a series of challenges, where the correct discrimination between background and true signal is critical. There is also a more general interest in such long living half-life measurements, as their value depends crucially on the underlying nuclear model. This work proposes a setup to measure long lived alpha decays, based on the design of the Frisch-Grid ionisation chamber. It is shown that the proposed design provides a good separation of signal and background events. It is also demonstrated that, with pulse shape analysis, it is possible to constrain the source position of the decay, further improving the quality of the data. A discussion of the characterisation of the detector is also presented as well as some results obtained with calibration sources.

  20. Ion-exchange separation of radioiodine and its application to production of 124I by alpha particle induced reactions on antimony

    International Nuclear Information System (INIS)

    The basic parameters related to radiochemical separation of iodine from tellurium and antimony by anion-exchange chromatography using the resin Amberlyst A26 were studied. The separation yield of 124I amounted to 96% and the decontamination factor from 121Te and 122Sb was > 104. The method was applied to the production of 124I via the 123Sb(α, 3n) reaction. In an irradiation of 110 mg of natSb2O3 (thickness ∝0.08 g/cm2) with 38 MeV α-particles at 1.2 μA beam current for 4 h, corresponding to the beam energy range of Eα = 37 → 27 MeV, the batch yield of 124I obtained was 12.42 MBq and the 125I and 126I impurities amounted to 3.8% and 0.7%, respectively. The experimental batch yield of 124I amounted to 80% of the theoretically calculated value but the level of the radionuclidic impurities were in agreement with the theoretical values. About 96% of the radioiodine was in the form of iodide and the inactive impurities (Te, Sb, Sn) were below the permissible level. Due to the relatively high level of radionuclidic impurity the 124I produced would possibly be useful only for restricted local consumption or for animal experiments.

  1. Ion-exchange separation of radioiodine and its application to production of {sup 124}I by alpha particle induced reactions on antimony

    Energy Technology Data Exchange (ETDEWEB)

    Shuza Uddin, Md. [Forschungszentrum Juelich (Germany). Inst. fuer Neurowissenschaften und Medizin, INM-5: Nuklearchemie; Atomic Energy Research Establishment, Inst. of Nuclear Science and Technology, Dhaka (Bangladesh); Qaim, Seyed M.; Spahn, Ingo; Spellerberg, Stefan; Scholten, Bernhard; Coenen, Heinz H. [Forschungszentrum Juelich (Germany). Inst. fuer Neurowissenschaften und Medizin, INM-5: Nuklearchemie; Hermanne, Alex [Vrije Univ. Brussel (Belgium). Cyclotron Lab.; Hossain, Syed Mohammod [Atomic Energy Research Establishment, Inst. of Nuclear Science and Technology, Dhaka (Bangladesh)

    2015-07-01

    The basic parameters related to radiochemical separation of iodine from tellurium and antimony by anion-exchange chromatography using the resin Amberlyst A26 were studied. The separation yield of {sup 124}I amounted to 96% and the decontamination factor from {sup 121}Te and {sup 122}Sb was > 10{sup 4}. The method was applied to the production of {sup 124}I via the {sup 123}Sb(α, 3n) reaction. In an irradiation of 110 mg of {sup nat}Sb{sub 2}O{sub 3} (thickness ∝0.08 g/cm{sup 2}) with 38 MeV α-particles at 1.2 μA beam current for 4 h, corresponding to the beam energy range of E{sub α} = 37 → 27 MeV, the batch yield of {sup 124}I obtained was 12.42 MBq and the {sup 125}I and {sup 126}I impurities amounted to 3.8% and 0.7%, respectively. The experimental batch yield of {sup 124}I amounted to 80% of the theoretically calculated value but the level of the radionuclidic impurities were in agreement with the theoretical values. About 96% of the radioiodine was in the form of iodide and the inactive impurities (Te, Sb, Sn) were below the permissible level. Due to the relatively high level of radionuclidic impurity the {sup 124}I produced would possibly be useful only for restricted local consumption or for animal experiments.

  2. Observation of a dynamical deformation and informations about the density levels in the sequential reaction 12C(28Si, 2 alphas)32S

    International Nuclear Information System (INIS)

    We have measured the reaction 12C+28Si leading to the low lying states of 32S by emission of 8Be or of two sequential α particles using a 28Si beam with energies from 60 to 90 MeV and different detection techniques and geometries. The relative intensities of the different final states and the integrated excitation functions of sequential α particles are in good agreement with statistical model predictions. That means we are in presence of sequential α particle decay of the 40Ca compound nucleus. We extend the statistical model code CASCADE in order to calculate differential cross sections. The code CORANG was written for the calculation of the angular correlation of the two α particles taking in account all the angular momenta of the intermediate 36Ar. By comparing the measured angular correlations with the predictions of our calculation we found evidence for strong deformation effects in the first step of the sequential decay. We observed structures at high excitation energy in 36Ar spectra. The coherence width of 40Ca has been obtained through the analysis of cross-correlations of the 36Ar energy spectra at different incident energies. In addition to the expected width there is an indication for the presence of a second coherence width wich could correspond to anomalous long living compound nucleus states. The averaging over Ericson fluctuations permits to get the structures corresponding only to level density effects in 36Ar

  3. 24Mg(α,γ)28Si reaction at alpha-particle energies from 3.2 to 6.2 MeV

    International Nuclear Information System (INIS)

    The 24Mg(α,γ)28Si reaction has been used to study excited states in 28Si. Targets of enriched 24Mg on a tantalum backing were bombarded by an α-particle beam from the CN Van de Graaff accelerator of The Pennsylvania State University. A large NaI(Tl) detector was placed immediately adjacent to the target in order to increase the probability of summing of the signals from different members of a cascade; windows were set for transitions to the ground state and the first few excited states. The energy of the α-particles was increased in steps of 2 to 5 keV from 3.2 to 6.2 MeV. Thirty-two resonances were located by sharp increases in the number of events recorded. At each resonance a spectrum was taken using a 55 cm3 Ge(Li) detector placed 5 cm from the target at an angle of 550 to the beam axis, the data being recorded on a PDP-15 on-line computer. The spectra were analyzed off-line using the program SAMPO of the Lawrence Berkeley Laboratory. (Diss. Abstr. Int., B)

  4. The 3He(alpha, gamma)7Be reaction rate, solar 7Be and 8B neutrino fluxes, and the production of 7Li during the Big Bang

    International Nuclear Information System (INIS)

    The 3He(α,γ)7Be reaction plays an important role both in determining the predicted fluxes of 7Be and 8B neutrinos from our Sun, and in the calculation of primordial 7Li production. In light of the highly precise determination of the baryon-to-photon ratio from the cosmic microwave background data, it is necessary to re-determine primordial 7Li production. Recent experimental nuclear astrophysics work has led to an improved determination of the 3He(α,γ)7Be cross section, with several experiments clustered at E = 0.5 MeV center-of-mass energy and above [2, and references therein]. On the other hand, precisely calibrated 7Be and 8B neutrino fluxes from the Sun are now available. Assuming the accepted solar central temperature to be correct, the neutrino flux data can be used to determine the 3He(α,γ)7Be cross section at the solar Gamow peak, E = 0.03 MeV. The energy range relevant for Big Bang 7Li production lies just between 0.03 and 0.5 MeV. The poster aims to use the two above described levels in order to improve the precision of the predicted primordial abundance of 7Li. It updates a previous work that appeared before the new cross section, solar neutrino and microwave background data were available. (author)

  5. Sensitivity of alpha-decay to the real alpha-nucleus potential

    International Nuclear Information System (INIS)

    The information which can be obtained from studies of low energy alpha-particle scattering from heavy nuclei and from alpha-decay is discussed. The sensitivity of calculated widths and lifetimes for alpha-decay to the real nuclear potential is examined in detail using a formalism based on the unified theory of nuclear reactions. It is shown that a combined study of alpha-decay and alpha-particle scattering at energies near the Coulomb barrier should give a very precise determination of the barrier height and radius, although there is a more uniquely defined separation distance some way beyond the barrier. (orig.)

  6. /sup 12/C(/sup 16/O,. cap alpha. )/sup 24/Mg( reaction in the energy region E/sub c. m. / = 26. 6 to 42. 9 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bechara, M.J.; Lazzarini, A.J.; Ledoux, R.J.; Cosman, A.E.R.

    1983-04-01

    The /sup 12/C+ /sup 16/O resonance structure in the /sup 28/Si nucleus is examined by means of the /sup 12/C(/sup 16/O,..cap alpha..)/sup 2r/Mg reaction excitation functions in the energy range E/sub c.m./ = 26.6 to 42.9 MeV in 430 keV steps at theta/sub lab/ = 7.5/sup 0/. We could identify 64 discrete states in /sup 24/Mg up to 31.7 MeV of excitation energy. The excitation functions show abundant structure over the entire energy range. The summed excitation functions, which tend to average out statistical fluctuations, show pronounced intermediate structure enhancement in the cross section at E/sub c.m./approx. =29.5, 32.2, and 35 MeV and indicate the presence of a smaller peak at 37.3 MeV. The widths of these structures are about 1 MeV, which is intermediate between the value expected from ion-ion potential resonances and statistical fluctuations. The nonstatistical character of these structures is reinforced by some statistical tests and by the correlations in energy and width found in several exit channels. Our data also suggest a possible structural relationship between the /sup 28/Si resonances and certain /sup 24/Mg final states.

  7. Alpha decay of At-194

    OpenAIRE

    Andreev, Andrei; Antalic, S; Ackermann, D.; Bianco, L.; Franchoo, S.; S. Heinz; F. P. Hessberger; Hofmann, S.; Huyse, Marc; Kojouharov, I.; Kindler, B.; Lommel, B.; Mann, R.; Nishio, K; R.D.Page

    2009-01-01

    Detailed alpha-decay studies of the neutron-deficient isotope At-194 have been performed in the complete fusion reaction Fe-56+Pr-141 -> At-194+3n at the velocity filter SHIP. Two alpha-decaying isomeric states with half-lives of T-1/2(At-194(m1))=310(8) ms and T-1/2(At-194(m2))=253(10) ms were identified in this nucleus. Their complex decays to the states in the daughter nucleus Bi-190 are discussed in the article. We propose that similar to the case of the neighboring At-191,At-192,At-193,A...

  8. Synthesis and reactivity of {alpha}-phenylseleno-{beta}-substituted styrenes: preparation of (Z)-allyl alcohols, (E)-{alpha}-phenyl-{alpha},{beta}-unsaturated aldehydes and {alpha}-aryl acetophenones

    Energy Technology Data Exchange (ETDEWEB)

    Lenardao, Eder J.; Jacob, Raquel G.; Silva, Thiago B. da [Universidade Federal de Pelotas, RS (Brazil). Dept. de Quimica Analitica e Inorganica]. E-mail: lenardao@ufpel.edu.br; Cella, Rodrigo [Santa Maria Univ., RS (Brazil). Dept. de Quimica; Perin, Gelson [Universidade Federal de Pelotas, RS (Brazil). Dept. de Quimica Organica

    2006-09-15

    A new and efficient method was developed to prepare {alpha}-phenylseleno-{beta}-substituted styrenes by reaction of diethyl {alpha}-phenylseleno benzylphosphonate with NaH and aldehydes. Selenium-lithium exchange by reaction with n-BuLi yielded the vinyl lithium species, which were captured with several electrophiles, like aldehydes and DMF, affording exclusively (Z)-allyl alcohols, and (E)-{alpha}-phenyl-{alpha}-{beta}-unsaturated aldehydes, respectively in good yields. The hydrolysis of the vinyl selenides in presence of TiCl{sub 4} allowed the corresponding {alpha}-aryl acetophenones. (author)

  9. Enzymatic synthesis of l-menthyl alpha-maltoside and l-menthyl alpha-maltooligosides from l-menthyl alpha-glucoside by cyclodextrin glucanotransferase.

    Science.gov (United States)

    Do, Hiroyuki; Sato, Toshiyuki; Kirimura, Kohtaro; Kino, Kuniki; Usami, Shoji

    2002-01-01

    l-Menthyl alpha-D-glucopyranosyl-(1-->4)-alpha-d-glucopyranoside (alpha-MenG2), a novel glycoside of l-menthol, was synthesized enzymatically and its physicochemical properties were characterized. Production of alpha-MenG2 from l-menthyl alpha-d-glucopyranoside (alpha-MenG) was attempted since we had already succeeded in the high-yield production of alpha-MenG using a Xanthomonas campestris enzyme (Nakagawa H., et al. J. Biosci. Bioeng., 89, 138-144, 2000). Through production tests on enzymes, it was confirmed that cyclodextrin glucanotransferase (CGTase) from Bacillus macerans produced l-menthyl alpha-D-maltooligosides (alpha-MenG(n)), containing alpha-MenG2, from alpha-MenG and soluble starch. When 10 ml of a 10 mM citrate-10 mM phosphate buffer (pH 6.0) containing 150 mg of alpha-MenG, 3 g of soluble starch and CGTase was shaken at 70 degrees C for 24 h, a total of 81.8% alpha-MenG was reacted. The molar conversion yields of alpha-MenG2 and alpha-MenG(n) with alpha-glucose degrees of polymerization of 3-18, based on the amount of alpha-MenG supplied, reached 16.1% and 65.7%, respectively. For efficient production of alpha-MenG2, the reaction mixture was treated with alpha-amylase of Aspergillus oryzae, and alpha-MenG(n) were mainly converted into alpha-MenG2: finally, the molar conversion yield of alpha-MenG2 reached 74.2% based on the amount of alpha-MenG supplied. alpha-MenG2 was purified and its molecular structure was confirmed by 13C-NMR, 1H-NMR and two-dimensional HMBC (heteronuclear multiple-bond coherence). alpha-MenG2 and its aqueous solution tasted bitter and a little sweet at first, but in a few minutes, a refreshing flavor and sweetness spread. At 20 degrees C the solubility of alpha-MenG2 in pure water was 29.6 g/100 ml, approximately 1570-fold that of alpha-MenG. PMID:16233280

  10. Diabetes and alpha lipoic acid

    OpenAIRE

    IssyLaher

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  11. Diabetes and Alpha Lipoic Acid

    OpenAIRE

    Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  12. Reactions with light exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenthäler, R.; Faria, P.N. de; Pires, K.C.C.; Lepine-Szily, A.; Guimaraes, V.; Mendes Junior, D.R.; Assuncao, M.; Barioni, A.; Morcelle, V.; Morais, M.C.; Camargo Junior, O.; Alcantara Nuñez, J. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Moro, A.M. [Departamento de FAMN, Universidad de Sevilla, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Rodriguez-Gallardo, M. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)

    2014-07-01

    Experimental cross sections for the {sup 6}He+{sup 120}Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections. (author)

  13. Dynamical Screening Effect on $\\alpha$-$\\alpha$ Resonant Scattering and Thermal Nuclear Scattering Rate

    CERN Document Server

    Yao, Xiaojun; Müller, Berndt

    2016-01-01

    We study the dynamical screening effect in the QED plasma on the $\\alpha$-$\\alpha$ scattering at the $^8$Be resonance. Dynamical screening leads to an imaginary part of the potential which results in a thermal width for the resonance and dominates over the previously considered static screening effect. As a result, both the resonance energy and width increase with the plasma temperature. Furthermore, dynamical screening can have a huge impact on the $\\alpha$-$\\alpha$ thermal nuclear scattering rate. For example, when the temperature is around $10$ keV, the rate is suppressed by a factor of about $900$. We expect similar thermal suppressions of nuclear reaction rates to occur in nuclear reactions dominated by an above threshold resonance with a thermal energy. Dynamical screening effects on nuclear reactions can be relevant to cosmology and astrophysics.

  14. Catalytic Mechanism of Human Alpha-galactosidase

    Energy Technology Data Exchange (ETDEWEB)

    Guce, A.; Clark, N; Salgado, E; Ivanen, D; Kulinskaya, A; Brumer, H; Garman, S

    2010-01-01

    The enzyme {alpha}-galactosidase ({alpha}-GAL, also known as {alpha}-GAL A; E.C. 3.2.1.22) is responsible for the breakdown of {alpha}-galactosides in the lysosome. Defects in human {alpha}-GAL lead to the development of Fabry disease, a lysosomal storage disorder characterized by the buildup of {alpha}-galactosylated substrates in the tissues. {alpha}-GAL is an active target of clinical research: there are currently two treatment options for Fabry disease, recombinant enzyme replacement therapy (approved in the United States in 2003) and pharmacological chaperone therapy (currently in clinical trials). Previously, we have reported the structure of human {alpha}-GAL, which revealed the overall structure of the enzyme and established the locations of hundreds of mutations that lead to the development of Fabry disease. Here, we describe the catalytic mechanism of the enzyme derived from x-ray crystal structures of each of the four stages of the double displacement reaction mechanism. Use of a difluoro-{alpha}-galactopyranoside allowed trapping of a covalent intermediate. The ensemble of structures reveals distortion of the ligand into a {sup 1}S{sub 3} skew (or twist) boat conformation in the middle of the reaction cycle. The high resolution structures of each step in the catalytic cycle will allow for improved drug design efforts on {alpha}-GAL and other glycoside hydrolase family 27 enzymes by developing ligands that specifically target different states of the catalytic cycle. Additionally, the structures revealed a second ligand-binding site suitable for targeting by novel pharmacological chaperones.

  15. Measurement of Excitation Functions of 64Zn (n,p) 64Cu, 64Zn(n, Zn) 63Zn, 51V(n,alpha) 48Sc and 48Ti(n,p) 48Sc Reactions, Around 14-MeV Energy

    International Nuclear Information System (INIS)

    The cross-sections of the reactions 64Zn (n,p) 64Cu, 64Zn(n,Zn) 63Zn, 51V(n,alpha)48Sc and 48Ti (n,p) 48Sc around 14-MeV show large discrepancies in the literature. Accurate measurements of these excitation functions were made in the energy range 13.63-14.73 MeV applying the neutron activation technique using a neutron generator. Results were obtained with a statistical error less than 7%. These measured excitation functions were used to check the statistical multistep compound/ statistical multistep direct (SMC/SMD) reaction models using EXIFON code. The calculations are in good agreement with the measurements, specially for the (n,Zn) reactions

  16. Study of the /sup 50/V nucleus with the (/sup 3/He,d), (/sup 3/He,. cap alpha. ), (/sup 3/He,p), and (/sup 3/He,p. gamma. ) reactions. [Angular distribution, 13 and 22 MeV, analog states, DWBA, J,. pi. , spectroscopic factors, angular momentum, transitions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J W

    1971-06-01

    The nucleus /sup 50/V with a ground-state configuration (..pi..f/sub 7/2/)/sup 3/(..nu..f/sub 7/2/)/sup -1/ was studied with the /sup 49/Ti(/sup 3/He,d)/sup 50/V, /sup 51/V)/sup 3/He,..cap alpha..)/sup 50/V, and /sup 48/Ti(/sup 3/He,p)/sup 50/V, and /sup 48/Ti(/sup 3/He,p..gamma..)/sup 50/V reactions induced by the /sup 3/He/sup + +/ beam from the tandem Van de Graaff at the Argonne National Laboratory. The angular distributions from (/sup 3/He,d), (/sup 3/He,..cap alpha..), and (/sup 3/He,p) reactions induced by 22-MeV /sup 3/He were studied with overall energy resolution widths of 20, 30, and 42 keV, respectively. The reactions (/sup 3/He,p) and (/sup 3/He,p..gamma..) were also studied at an incident energy of 13 MeV to obtain the ..gamma.. decay of /sup 50/V levels (including two 0/sup +/ isobaric analog states) in which the neutron-proton pair is transferred with zero angular momentum. The angular distributions of the charged-particle reactions were analyzed with the distorted-wave Born approximation (DWBA), and spectroscopic factors have been extracted for the one-nucleon transfer reactions. The two-nucleon transfer reaction (/sup 3/He,p) was analyzed with the DWBA on the assumption that the neutron-proton pair is transferred as a deuteron. The angular momentum L/sub np/ of the transferred deuteron is established for most of the levels, and the possibility that several levels might have spin and parity 1/sup +/ is discussed.

  17. Faddeev calculation of 3 alpha and alpha alpha Lambda systems using alpha alpha resonating-group method kernel

    CERN Document Server

    Fujiwara, Y; Kohno, M; Suzuki, Y; Baye, D; Sparenberg, J M

    2004-01-01

    We carry out Faddeev calculations of three-alpha (3 alpha) and two-alpha plus Lambda (alpha alpha Lambda) systems, using two-cluster resonating-group method kernels. The input includes an effective two-nucleon force for the alpha alpha resonating-group method and a new effective Lambda N force for the Lambda alpha interaction. The latter force is a simple two-range Gaussian potential for each spin-singlet and triplet state, generated from the phase-shift behavior of the quark-model hyperon-nucleon interaction, fss2, by using an inversion method based on supersymmetric quantum mechanics. Owing to the exact treatment of the Pauli-forbidden states between the clusters, the present three-cluster Faddeev formalism can describe the mutually related, alpha alpha, 3 alpha and alpha alpha Lambda systems, in terms of a unique set of the baryon-baryon interactions. For the three-range Minnesota force which describes the alpha alpha phase shifts quite accurately, the ground-state and excitation energies of 9Be Lambda are...

  18. Contributions to the study of heavy and superheavy nuclei stability in alpha-decay

    International Nuclear Information System (INIS)

    Alpha-decay is treated in this work on the complete analogy of transfer reactions by means of nuclear shell models with continuous spectrum nucleons. Certain phenomenologically obtained or microscope evaluated data on low energy interactions between alpha-particles and nuclei, when related to nuclear structure data within the unified theory of nuclear reactions, allow of an improved accuracy in determining the alpha-particle wave function as well as of an estimation of alpha-probabilities in good keeping with experimental ones. The problem of alpha lifetimes thus narrows to the resolution of some homogeneous and inhomogeneous differential equations systems including the optic potential and the alpha formfactors. (author)

  19. Preparation of Mo, CoMo and NiMo/gamma-Al2O3 Hydrodesulfurization Catalysts via Reaction of alpha-Boehmite with Molybdena, Co and Ni Carbonates during Paste Processing

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Zdražil, Miroslav

    - : -, 2007, P9-4. [EuropaCat VIII. Turku/Aho (FI), 26.08.2007-31.08.2007] R&D Projects: GA ČR(CZ) GP104/06/P034 Institutional research plan: CEZ:AV0Z40720504 Keywords : alpha-boehmite * solvent-assisted spreading * hydrodesulfurization Subject RIV: CF - Physical ; Theoretical Chemistry

  20. The alloantigenic sites of alpha3alpha4alpha5(IV) collagen: pathogenic X-linked alport alloantibodies target two accessible conformational epitopes in the alpha5NC1 domain.

    Science.gov (United States)

    Kang, Jeong Suk; Kashtan, Clifford E; Turner, A Neil; Heidet, Laurence; Hudson, Billy G; Borza, Dorin-Bogdan

    2007-04-01

    Anti-glomerular basement membrane (GBM) antibody nephritis is caused by an autoimmune or alloimmune reaction to the NC1 domains of alpha3alpha4alpha5(IV) collagen. Some patients with X-linked Alport syndrome (XLAS) develop post-transplant nephritis mediated by pathogenic anti-GBM alloantibodies to collagen IV chains present in the renal allograft but absent from the tissues of the patient. In this work, the epitopes targeted by alloantibodies from these patients were identified and characterized. All XLAS alloantibodies recognized conformational epitopes in the NC1 domain of alpha5(IV) collagen, which were mapped using chimeric alpha1/alpha5 NC1 domains expressed in mammalian cells. Allograft-eluted alloantibodies mainly targeted two conformational alloepitopes mapping to alpha5NC1 residues 1-45 and 114-168. These regions also encompassed the major epitopes of circulating XLAS alloantibodies, which in some patients additionally targeted alpha5NC1 residues 169-229. Both kidney-eluted and circulating alloantibodies to alpha5NC1 distinctively targeted epitopes accessible in the alpha3alpha4alpha5NC1 hexamers of human GBM, unlike anti-GBM autoantibodies, which targeted sequestered alpha3NC1 epitopes. The results identify two immunodominant alpha5NC1 epitopes as major alloantigenic sites of alpha3alpha4alpha5(IV) collagen specifically implicated in the pathogenesis of post-transplant nephritis in XLAS patients. The contrast between the accessibility of these alloepitopes and the crypticity of autoepitopes indicates that distinct molecular forms of antigen may initiate the immunopathogenic processes in the two forms of anti-GBM disease. PMID:17293596

  1. Review of alpha_s determinations

    CERN Document Server

    Pich, Antonio

    2013-01-01

    The present knowledge on the strong coupling is briefly summarized. The most precise determinations of alpha_s, at different energies, are reviewed and compared at the Z mass scale, using the predicted QCD running. The impressive agreement achieved between experimental measurements and theoretical predictions constitutes a beautiful and very significant test of Asymptotic Freedom, establishing QCD as the fundamental theory of the strong interaction. The world average value of the strong coupling is found to be alpha_s(M_Z^2)= 0.1186 \\pm 0.0007.

  2. Effects of deuterium substitution alpha and beta to the reaction centre, 18O substitution in the leaving group, and aglycone acidity on hydrolyses of aryl glucosides and glucosyl pyridinium ions by yeast alpha-glucosidase. A probable failure of the antiperiplanar-lone-pair hypothesis in glycosidase catalysis.

    Science.gov (United States)

    Hosie, L; Sinnott, M L

    1985-03-01

    Neither kcat. nor kcat./Km for five aryl alpha-D-glucopyranosides correlates with aglycone pKa, and isotope effects, described according to the convention used by Cleland [(1982) CRC Crit. Rev. Biochem. 13, 385-428], of 18(V) = 1.002 +/- 0.008, alpha D(V) = 1.01 +/- 0.04 and alpha D(V/K) = 0.969 +/- 0.035 are observed for p-nitrophenyl, and one of beta D(V) = 1.02 +/- 0.04 for phenyl alpha-D-glucopyranoside; kcat. but not kcat./Km, correlates with aglycone pKa for five alpha-D-glucopyranosyl pyridinium ions with a Brønsted coefficient of -0.61 +/- 0.06, and isotope effects of alpha D(V) = 1.22 +/- 0.02, beta D(V) = 1.13 +/- 0.01 and alpha D(V/K) = 1.018 +/- 0.046 for the 4-bromoisoquinolinium, and alpha D(V) = 1.15 +/- 0.02 and beta D(V) = 1.085 +/- 0.011 for the pyridinium salts are observed. These data require that a non-covalent event, fast in the case of the N-glycosides but slow in the case of the O-glycosides, precedes bond-breaking, and that bond-breaking involves substantial charge development on the glycone and near-perpendicularity of the C2-H bond to the planar oxocarbonium ion system. A model meeting these requirements is that the non-covalent event is a conjoint change of protein and substrate conformation which puts the pyranose ring in the 2,5B conformation of the bond-breaking transition state. This model also explains the contrast between the powerful inhibition of the enzyme by deoxynojirimycin (Ki = 23 +/- 3 microM) and feeble inhibition by castanospermine [Saul, Chambers, Molyneux & Elbein (1983) Arch. Biochem. Biophys. 221, 593-597], but is directly contrary to the predictions of Deslongchamps' 'Theory of Stereoelectronic Control' [Deslongchamps (1975) Tetrahedron 31, 2463-2490; (1983) Stereoelectronic Effects in Organic Chemistry, p. 39, Pergamon Press, Oxford]. PMID:3888191

  3. Deletion of alpha-synuclein decreases impulsivity in mice

    OpenAIRE

    Peña-Oliver, Y; Buchman, V L; Dalley, J W; Robbins, T.W; Schumann, G; Ripley, T. L.; King, S L; Stephens, D. N.

    2012-01-01

    The presynaptic protein alpha-synuclein, associated with Parkinson's Disease (PD), plays a role in dopaminergic neurotransmission and is implicated in impulse control disorders (ICDs) such as drug addiction. In this study we investigated a potential causal relationship between alpha-synuclein and impulsivity, by evaluating differences in motor impulsivity in the 5-choice serial reaction time task (5-CSRTT) in strains of mice that differ in the expression of the alpha-synuclein gene. C57BL/6JO...

  4. Non-adiabatic dynamics in 10Be with the microscopic alpha+alpha+n+n model

    CERN Document Server

    Ito, M

    2006-01-01

    The alpha+6He low-energy reactions and the structural changes of 10Be in the microscopic alpha+alpha+n+n model are studied by the generalized two-center cluster model with the Kohn-Hulthen-Kato variation method. It is found that, in the inelastic scattering to the alpha+6He(2+) channel, characteristic enhancements are expected as the results of the parity-dependent non-adiabatic dynamics. In the positive parity state, the enhancement originates from the no-adiabatic eigenstate generated by the radial excitation of the relative motion between two alpha-cores. On the other hand, the enhancement in the negative parity state is induced by the Landau-Zener level-crossing. These non-adiabatic processes are discussed in connection to the formation of the inversion doublet in the compound system of 10Be.

  5. Review of alpha_s determinations

    OpenAIRE

    Pich, Antonio

    2013-01-01

    The present knowledge on the strong coupling is briefly summarized. The most precise determinations of alpha_s, at different energies, are reviewed and compared at the Z mass scale, using the predicted QCD running. The impressive agreement achieved between experimental measurements and theoretical predictions constitutes a beautiful and very significant test of Asymptotic Freedom, establishing QCD as the fundamental theory of the strong interaction. The world average value of the strong coupl...

  6. World Summary of $\\alpha_s$ (2015)

    CERN Document Server

    Bethke, Siegfried; Salam, Gavin P

    2015-01-01

    This is a preliminary update of the measurements of α s and the determination of the world average value of α s (M Z 2 ) presented in the 2013/2014 edition of the Review of Particle Properties [1]. A number of studies which became available since late 2013 provide new results for each of the (previously 5, now) 6 subclasses of measurements for which pre-average values of $\\alpha_s (M_Z^2)$ are determined.

  7. Human alpha 2-adrenergic receptor subtype distribution: widespread and subtype-selective expression of alpha 2C10, alpha 2C4, and alpha 2C2 mRNA in multiple tissues.

    Science.gov (United States)

    Eason, M G; Liggett, S B

    1993-07-01

    At present, molecular cloning and pharmacological studies have delineated three human alpha 2-adrenergic receptor (alpha 2AR) subtypes, alpha 2C10, alpha 2C4, and alpha 2C2. Assignment of the alpha 2AR subtypes to specific functions has been limited by an unclear definition of tissue alpha 2AR expression outside of the central nervous system. It has been suggested that alpha 2C4 expression is confined to the brain, that alpha 2C2 expression is only in the liver and kidney, and that there is nearly ubiquitous expression of alpha 2C10. However, this is based on studies of a limited number of rat tissues or on studies using non-species-specific approaches. Therefore, to define alpha 2C10, alpha 2C4, and alpha 2C2 tissue expression, we used reverse transcription of total RNA isolated from 20 human tissues, followed by amplification of alpha 2AR cDNA using the polymerase chain reaction. This technique provided two advantages: high sensitivity and, with the use of subtype-specific oligonucleotide primers and probes, differentiation between the alpha 2AR subtypes. The tissues studied were aorta, vena cava, heart (epicardium and endocardium), lung, skeletal muscle, liver, pancreas (head and tail), fat (perinephric and subcutaneous), kidney (cortex and medulla), prostate, stomach, ileum, jejunum, colon, adrenal gland, and spleen. We found that the majority of these tissues expressed alpha 2C10, with the exceptions being the head of the pancreas, subcutaneous fat, colon, and spleen. In marked distinction to other studies, however, we found a prolific expression of the alpha 2C4 and alpha 2C2 subtypes. Expression of alpha 2C4 was found in all tissues with the exception of liver, fat, stomach, and colon, and a virtually ubiquitous expression of alpha 2C2 was found, with the exception of epicardium. Of all tissues studied, only colon and subcutaneous fat expressed a single alpha 2AR subtype, which was alpha 2C2. Thus, the alpha 2AR subtypes do not have a confined expression but

  8. Nuclear Reactions at Intermediate Energies

    CERN Document Server

    Shyam, Radhey

    2015-01-01

    In the domain of Nuclear reactions at intermediate energies, the QCD coupling constant $\\alpha_s$ is large enough ($\\sim$ 0.3 - 0.5) to render the perturbative calculational techniques inapplicable. In this regime the quarks are confined into colorless hadrons and it is expected that effective field theories of hadron interactions via exchange of hadrons, provide useful tools to describe such reactions. In this contribution we discuss applications of one such theory, the effective Lagrangian model, in describing the hadronic reactions at intermediate energies whose measurements are the focus of a vast international experimental program.

  9. Erratum to 'Study of the vibrational nucleus sup 1 sup 0 sup 0 Ru by the sup 9 sup 8 Mo(alpha,2n gamma) and sup 9 sup 9 Ru(n,gamma) reactions' [Nucl. Phys. A 662 (2000) 3-43

    CERN Document Server

    Genilloud, L; Corminboeuf, F; Doll, C; Drissi, S; Jentschel, M; Jolie, J; Kern, J; Lehmann, H; Warr, N

    2000-01-01

    The nuclear structure of sup 1 sup 0 sup 0 Ru was investigated using the sup 9 sup 9 Ru(n,gamma) and sup 9 sup 8 Mo(alpha,2n gamma) reactions. In the in-beam spectroscopy study, the use of a coincidence system equipped with five Compton-suppression spectrometers allowed to place 207 transitions in the decay scheme. Spin and parity assignments of the states were determined using angular distribution analysis together with the excitation function slopes and side-feeding intensities. The photons following the neutron capture were observed using curved crystal and pair spectrometers. Using the results of both reactions, the level scheme was extended by 36 new levels. The interpretation of the resulting level scheme was performed in the framework of the spdf interacting boson model.

  10. C-H ACTIVATION REACTIONS BY YTTRIUM AND LUTETIUM HYDRIDE COMPLEXES - H/D EXCHANGE VS METALATION OF HYDROCARBONS - IMPORTANCE OF THE HYBRIDIZATION STATE AT THE ALPHA-CARBON

    NARCIS (Netherlands)

    DEELMAN, BJ; TEUBEN, JH; MACGREGOR, SA; EISENSTEN, O

    1995-01-01

    Extended Huckel (EHT) calculations have been used to discuss the two alternative sigma-bond C-H metathesis reactions which occur with organo-lanthanide (Ln = Y, Lu) compounds. The two reactions lead either to H/H (H/D) exchange or to metalation and have been modelled by studying the interaction of a

  11. Lyman Alpha Control

    CERN Document Server

    Nielsen, Daniel Stefaniak

    2015-01-01

    This document gives an overview of how to operate the Lyman Alpha Control application written in LabVIEW along with things to watch out for. Overview of the LabVIEW code itself as well as the physical wiring of and connections from/to the NI PCI-6229 DAQ box is also included. The Lyman Alpha Control application is the interface between the ALPHA sequencer and the HighFinesse Wavelength Meter as well as the Lyman Alpha laser setup. The application measures the wavelength of the output light from the Lyman Alpha cavity through the Wavelength Meter. The application can use the Wavelength Meter’s PID capabilities to stabilize the Lyman Alpha laser output as well as switch between up to three frequencies.

  12. New ALPHA-2 magnet

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    On 21 June, members of the ALPHA collaboration celebrated the handover of the first solenoid designed for the ALPHA-2 experiment. The magnet has since been successfully installed and is working well.   Khalid Mansoor, Sumera Yamin and Jeffrey Hangst in front of the new ALPHA-2 solenoid. “This was the first of three identical solenoids that will be installed between now and September, as the rest of the ALPHA-2 device is installed and commissioned,” explains ALPHA spokesperson Jeffrey Hangst. “These magnets are designed to allow us to transfer particles - antiprotons, electrons and positrons - between various parts of the new ALPHA-2 device by controlling the transverse size of the particle bunch that is being transferred.” Sumera Yamin and Khalid Mansoor, two Pakistani scientists from the National Centre for Physics in Islamabad, came to CERN in February specifically to design and manufacture these magnets. “We had the chance to work on act...

  13. Alpha Shapes and Proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Sterner, Henrik; Sterner, Peter

    We provide a unified description of (weighted) alpha shapes, beta shapes and the corresponding simplicialcomplexes. We discuss their applicability to various protein-related problems. We also discuss filtrations of alpha shapes and touch upon related persistence issues.We claim that the full...... potential of alpha-shapes and related geometrical constructs in protein-related problems yet remains to be realized and verified. We suggest parallel algorithms for (weighted) alpha shapes, and we argue that future use of filtrations and kinetic variants for larger proteins will need such implementation....

  14. Alpha-thalassemia mutations in Gilan Province, North Iran.

    Science.gov (United States)

    Hadavi, Valeh; Jafroodi, Maryam; Hafezi-Nejad, Nima; Moghadam, Sousan Dehnadi; Eskandari, Fatemeh; Tarashohi, Shahin; Pourfahim, Hamideh; Oberkanins, Christian; Law, Hai-Yang; Najmabadi, Hossein

    2009-01-01

    One hundred and three patients from Gilan Province, Iran, presenting with hypochromic and microcytic anemia parameters without iron deficiency were included in this study. Using gap-polymerase chain reaction (gap-PCR), reverse hybridization StripAssay and DNA sequencing, we detected a total of 113 alpha-globin mutations in 94 (91.3%) of these patients. Most prevalent of the 16 different alpha-thalassemia (alpha-thal) alleles was -alpha(3.7) (42.5%), followed by the polyadenylation signal (poly A2) (AATAAA>AATGAA) (12.4%), Hb Constant Spring [Hb CS, alpha142, Term-->Gln (TAA>CAA in alpha2] (10.6%), --(MED) (8.8%), IVS-I donor site [GAG GTG AGG>GAG G-----, alpha(-5 nt) (-TGAGG)] (7.1%), -alpha(4.2) (4.4%) and poly A1 (AATAAA>AATAAG) (3.5%). An additional nine mutations were observed at frequencies below 2%. We also found two novel alpha1 gene mutations: alpha(-9) (HBA1: c.-9 G>C) and alpha(IVS-I-4) (HBA1: c.95+4 A>G). Our new findings will be valuable for improving targeted thalassemia screening and prevention strategies in this area. PMID:19657838

  15. $\\alpha$-cluster ANCs for nuclear astrophysics

    CERN Document Server

    Avila, M L; Koshchiy, E; Baby, L T; Belarge, J; Kemper, K W; Kuchera, A N; Santiago-Gonzalez, D

    2014-01-01

    Background. Many important $\\alpha$-particle induced reactions for nuclear astrophysics may only be measured using indirect techniques due to small cross sections at the energy of interest. One of such indirect technique, is to determine the Asymptotic Normalization Coefficients (ANC) for near threshold resonances extracted from sub-Coulomb $\\alpha$-transfer reactions. This approach provides a very valuable tool for studies of astrophysically important reaction rates since the results are practically model independent. However, the validity of the method has not been directly verified. Purpose. The aim of this letter is to verify the technique using the $^{16}$O($^6$Li,$d$)$^{20}$Ne reaction as a benchmark. The $^{20}$Ne nucleus has a well known $1^-$ state at excitation energy of 5.79 MeV with a width of 28 eV. Reproducing the known value with this technique is an ideal opportunity to verify the method. Method. The 1$^-$ state at 5.79 MeV is studied using the $\\alpha$-transfer reaction $^{16}$O($^6$Li,$d$)$^...

  16. Targeted Alpha Therapy: From Alpha to Omega

    International Nuclear Information System (INIS)

    This review covers the broad spectrum of Targeted Alpha Therapy (TAT) research in Australia; from in vitro and in vivo studies to clinical trials. The principle of tumour anti-vascular alpha therapy (TAVAT) is discussed in terms of its validation by Monte Carlo calculations of vascular models and the potential role of biological dosimetry is examined. Summmary of this review is as follows: 1. The essence of TAT 2. Therapeutic objectives 3. TAVAT and Monte Carlo microdosimetry 4. Biological dosimetry 5. Preclinical studies 6. Clinical trials 7. What next? 8. Obstacles. (author)

  17. An evaluation of alpha particle clustering in heavy nuclei

    International Nuclear Information System (INIS)

    In recent years, the pre-equilibrium models of nuclear reactions have been used to analyze many experiments involving the emission of alpha particles. The results of these analyses have been used as the basis for a calculation of the extent of alpha particle clustering in heavy nuclei. Calculations are presented of the rate of nucleon-nucleon and nucleon-alpha interactions in nuclear matter. Normalizing these to the preformation factors found in reaction studies, the number of alpha clusters in several complex nuclei has been obtained. It is suggested that the number of such performed alpha clusters in nuclei having A = 50, 90, 141, 202, and 232 are, respectively, 2.1, 3.6, 5.2, 6.9, and 7.8. (orig.) 891 FKS/orig. 892 MB

  18. A twin ionization chamber setup as detector for light charged particles with energies around 1 MeV applied to the sup 1 sup 0 B(n, alpha) sup 7 Li reaction

    CERN Document Server

    Göpfert, A; Bax, H

    2000-01-01

    The setup and operating conditions of a gridded twin ionization chamber with sample change facility to study light charged particle properties in the 1 MeV region is described. Detailed studies of different grid geometries in connection with the choice of an eligible counting gas mixture and the applied high voltage have been performed. Due to the high overall amplification of the small electrical chamber signals obtained from such low-energy particles, special filters have been developed in order to increase the signal-to-noise ratio. Timing properties of the chamber signals are discussed in detail. Information available from chamber signals and encoding methods are elucidated by spectra of alpha particles created by sup 2 sup 3 sup 4 sup , sup 2 sup 3 sup 5 U spontaneous alpha decay. The detector permits the independent and simultaneous measurement of energy and angular distribution of particles in both sides of the chamber. Finally, preliminary results and related analysis methods will be presented for the...

  19. 19F nuclear magnetic resonance analysis of the carbamate reaction of alpha-fluoro-beta-alanine (FBAL), the major catabolite of fluoropyrimidines. Application to FBAL carbamate determination in body fluids of patients treated with 5'-deoxy-5-fluorouridine

    International Nuclear Information System (INIS)

    alpha-Fluoro-beta-alanine (FBAL), the major catabolite of the antineoplastic fluoropyrimidines, is an amino acid which is in equilibrium with its carbamate derivative in weakly alkaline aqueous solutions containing carbonate. In both water and control biological fluids (urine, plasma) spiked with FBAL (and sodium bicarbonate, in some cases), 19F NMR was used: (i) to determine the pH range over which FBAL carbamate is present (pH greater than or equal to 7), the maximum concentration formed occurring around pH 9, (ii) to show that the amino group of FBAL interacts very slowly with a non-protein plasma component to form a compound X, unstable in acid medium. The presumed structure of X is RCONHCH2CHFCOOH, with R different from an alkyl group but still unidentified. The behavior of FBAL in urine and plasma of rats treated with FBAL or 5'-deoxy-5-fluorouridine (5'-dFUrd), a prodrug of 5-fluorouracil, and from patients treated with 5'-dFUrd was investigated. FBAL carbamate was not present in acid medium and was therefore absent in acidic human urine. However, it was found in alkaline rat urine. FBAL carbamate was found in plasma along with the compound X. The 19F NMR spectra of FBAL and derivatives are complex since alpha-fluoro-beta-ureido-propionic acid, the precursor of FBAL in the catabolic pathway of antineoplastic fluoropyrimidines, produces a signal overlapping that of FBAL carbamate, and very close to that of compound X

  20. Alpha-particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  1. Imaging alpha particle detector

    Science.gov (United States)

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  2. Chapter 19 (Part 3): Enolate Reactions

    OpenAIRE

    Christiansen, Mike A

    2012-01-01

    In this video I'll continue teaching you about various reactions (with mechanisms) that we can do using carbonyl compounds, due to the acidities of their alpha-hydrogens. These reactions include the aldol reaction, the Claisen condensation, the Robinson annulation, acid-catalyzed decarboxylation, and the malonic ester synthesis. --Dr. Mike Christiansen from Utah State University

  3. (n, {alpha}) cross section measurement of light nuclei using gridded ionization chamber and gaseous sample

    Energy Technology Data Exchange (ETDEWEB)

    Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Yamazaki, Tetsuro; Sato, Jun; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan)

    1998-03-01

    We have developed a measuring method of (n, {alpha}) cross section by using gaseous sample in a gridded ionization chamber. In this study, we measured the {sup 12}C(n, {alpha}{sub 0}) and the {sup 16}O(n, {alpha}{sub 0}), (n, {alpha}{sub 123}) cross sections for En=11.5 and 12.8 MeV neutrons. We also deduced the {sup 12}C(n, x{alpha}) spectrum and analyzed the data by a kinematic calculation combined with the reaction data of the {sup 12}C(n, n`3{alpha}). (author)

  4. Alpha-synuclein expression in the developing human brain.

    Science.gov (United States)

    Raghavan, Ravi; Kruijff, Loes de; Sterrenburg, Monique D; Rogers, Beverly B; Hladik, Christa L; White, Charles L

    2004-01-01

    Alpha (alpha)-synuclein is a presynaptic protein, abnormal expression of which has been associated with neurodegenerative and neoplastic diseases. It is abundant in the developing vertebrate central nervous system (CNS), but less is known about its developmental expression in the human CNS. Immunohistochemical expression of alpha-synuclein was studied in 39 fetal, perinatal, pediatric, and adolescent brains. Perikaryal expression of alpha-synuclein is observed as early as 11-wk gestation in the cortical plate. Several discrete neuronal groups in the hippocampus, basal ganglia, and brain stem express perikaryal alpha-synuclein by 20-wk gestation, persisting through the first few years of life. In the cerebellum, alpha-synuclein is present by 21-wk gestation and persists into adult life as a coarse granular neuropil reaction product in the internal granular layer, and as a diffuse neuropil "blush" in the molecular layer. The germinal matrix, glia, endothelial cells, external granular layer, Pukinje cells, and dentate neurons are consistently negative for alpha-synuclein. We conclude that alpha-synuclein is expressed very early in human gestation, and that its distribution and temporal sequence of expression varies in discrete neuronal groups. Perikaryal alpha-synuclein starts disappearing from the neuronal cytosol in early childhood, and only the neuropil retains immunoreactivity into adulthood. The reappearance of alpha-synuclein in the adult neuronal cytosol in certain disease processes may represent reemergence of cues from an earlier developmental stage as part of a stress response. PMID:15547775

  5. Histamine suppresses gene expression and synthesis of tumor necrosis factor alpha via histamine H2 receptors

    OpenAIRE

    1991-01-01

    Histamine and tumor necrosis factor alpha (TNF-alpha) can each contribute to the pathogenesis of allergic reactions and chronic inflammatory diseases. We now report the effect of histamine on gene expression and total cellular synthesis of TNF-alpha. Lipopolysaccharide (LPS)-induced synthesis of TNF-alpha in peripheral blood mononuclear cells (PBMC) from 18 healthy donors was suppressed by histamine concentrations from 10(-6) to 10(-4) M, levels comparable with those measured in tissues after...

  6. Local versus nonlocal $\\alpha\\alpha$ interactions in $3\\alpha$ description of $^{12}$C

    CERN Document Server

    Suzuki, Y; Descouvemont, P; Fujiwara, Y; Matsumura, H; Orabi, M; Theeten, M

    2008-01-01

    Local $\\alpha \\alpha$ potentials fail to describe $^{12}$C as a $3\\alpha$ system. Nonlocal $\\alpha \\alpha$ potentials that renormalize the energy-dependent kernel of the resonating group method allow interpreting simultaneously the ground state and $0^+_2$ resonance of $^{12}$C as $3\\alpha$ states. A comparison with fully microscopic calculations provides a measure of the importance of three-cluster exchanges in those states.

  7. Chapter 19 (Part 1): Enolate Reactions

    OpenAIRE

    Christiansen, Mike A

    2012-01-01

    In this video I'll teach you why alpha-hydrogens are so acidic, and how we can use that property to do some cool organic reactions. I'll talk about keto-enol tautomerism, LDA (lithium diisopropyl amine), alpha-halogenation, alkylation, acylation, beta-alkylation, the aldol reaction, the Claisen condensation, the Robinson annulation, decarboxylation, and the malonic ester synthesis. --Dr. Mike Christiansen from Utah State University

  8. Bremsstrahlung in $\\alpha$ Decay

    CERN Document Server

    Takigawa, N; Hagino, K; Ono, A; Brink, D M

    1999-01-01

    A quantum mechanical analysis of the bremsstrahlung in $\\alpha$ decay of $^{210}$Po is performed in close reference to a semiclassical theory. We clarify the contribution from the tunneling, mixed, outside barrier regions and from the wall of the inner potential well to the final spectral distribution, and discuss their interplay. We also comment on the validity of semiclassical calculations, and the possibility to eliminate the ambiguity in the nuclear potential between the alpha particle and daughter nucleus using the bremsstrahlung spectrum.

  9. Unified model for alpha-decay and alpha-capture

    International Nuclear Information System (INIS)

    A unified model for alpha-decay and alpha-capture is discussed. Simultaneously the half-lives for alpha-transition between ground states as well as ground and excited states and alpha-capture cross-sections by spherical magic or near-magic nuclei are well described in the framework of this model. Using these data the alpha-nucleus potential is obtained. The simple empirical relations for handy evaluation of the half-lives for alpha-transition, which take into account both the angular momentum and parity of alpha-transition, are presented

  10. ALPHA-2: the sequel

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    While many experiments are methodically planning for intense works over the long shutdown, there is one experiment that is already working at full steam: ALPHA-2. Its final components arrived last month and will completely replace the previous ALPHA set-up. Unlike its predecessor, this next generation experiment has been specifically designed to measure the properties of antimatter.   The ALPHA team lower the new superconducting solenoid magnet into place. The ALPHA collaboration is working at full speed to complete the ALPHA-2 set-up for mid-November – this will give them a few weeks of running before the AD shutdown on 17 December. “We really want to get some experience with this device this year so that, if we need to make any changes, we will have time during the long shutdown in which to make them,” says Jeffrey Hangst, ALPHA spokesperson. “Rather than starting the 2014 run in the commissioning stage, we will be up and running from the get go.&...

  11. Alpha methyldopa induced hepatotoxicity in pregnancy

    Directory of Open Access Journals (Sweden)

    Padmasri Ramalingappa

    2014-06-01

    Full Text Available We report a case of gestational hepatitis due to alpha-methyldopa and briefly review the literature on alpha-methyldopa-induced hepatotoxicity in pregnancy. A 32 year old woman, primigravida with 34 weeks of gestation with pre eclampsia, presented with symptoms of nausea, dark coloured urine and jaundice. She was on alpha methyldopa (Aldomet 250 mg thrice a day since the last five weeks. Laboratory investigations revealed raised bilirubin, serum aspartate transaminases and serum alanine transaminases. Platelets were normal. Peripheral smear did not show haemolysis. With the exclusion of viral, haemolytic and obstructive causes, drug induced jaundice was considered as a differential diagnosis. Alpha methyldopa was withdrawn and replaced with nifedipine for her pre eclampsia treatment. Her repeat bilirubin level done two weeks later showed a drop. She went into labour at 38 weeks and delivered vaginally. In postpartum follow up her liver tests returned to normal in two weeks, about six weeks after stopping methyldopa. Hepatotoxicity should be considered as one of the adverse drug reaction of alpha methyldopa. It is not possible at present to predict which patients will develop liver disease following the administration of this drug. An awareness of the possibility of methyldopa induced hepatotoxicity should be present in the clinician's mind and liver function tests should be done at regular intervals. The occasional occurrence of this harmful side effect is not a contraindication to the use of this antihypertensive agent. [Int J Reprod Contracept Obstet Gynecol 2014; 3(3.000: 805-807

  12. Alpha Resonant States in 13C

    International Nuclear Information System (INIS)

    The 9Be(6Li,d)13C reaction was used to investigate alpha resonant states in 13C up to 15 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. An energy resolution of 50 keV was obtained. Several narrow alpha resonant states not previously measured were detected, in particular the one at the (3α+n) threshold populated by an L = 2 transfer, revealing a 9Be+α component for the 1/2- cluster state candidate at this threshold. Experimental angular distributions are presented in comparison with DWBA predictions.

  13. Resting alpha activity predicts learning ability in alpha neurofeedback

    OpenAIRE

    Wenya eNan; Feng eWan; Mang I eVai; Agostinho eRosa

    2014-01-01

    Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the tr...

  14. Alpha particles in fusion research

    International Nuclear Information System (INIS)

    This collection of 39 (mostly view graph) presentations addresses various aspects of alpha particle physics in thermonuclear fusion research, including energy balance and alpha particle losses, transport, the influence of alpha particles on plasma stability, helium ash, the transition to and sustainment of a burning fusion plasma, as well as alpha particle diagnostics. Refs, figs and tabs

  15. alpha-thalassemia mutations in Khuzestan Province, Southwest Iran.

    Science.gov (United States)

    Zandian, Khodamorad; Nateghi, Jamal; Keikhaie, Bijan; Pedram, Mohammad; Hafezi-Nejad, Nima; Hadavi, Valeh; Oberkanins, Christian; Azarkeivan, Azita; Law, Hai-Yang; Najmabadi, Hossein

    2008-01-01

    Although alpha-thalassemia (alpha-thal) is the most common hereditary hemoglobin (Hb) disorder in Iran, no comprehensive data are so far available on the prevalence of the disease in the province of Khuzestan in Southwest Iran. This study investigates the spectrum of alpha-thal mutations in this region. One hundred and twenty-one subjects from Khuzestan Province, Iran, were initially tested for the three most common Iranian alpha-thal mutations (- alpha3.7, -alpha4.2, and --MED) by gap-polymerase chain reaction (gap-PCR). Reverse hybridization test strips and DNA sequencing were used to identify additional alpha-globin mutations. A total of 131 mutated alpha-globin alleles were identified in these patients. Of the 13 mutations that were detected in Khuzestan Province, Iran, the - alpha3.7 single gene deletion was the most frequently identified variant, representing 62.6% of the total; we also observed significant numbers of individuals with compound heterozygous mutations. On the basis of our results, we strongly recommend screening for the most common mutations to improve the molecular diagnosis of anemia in this region. PMID:19065332

  16. Study of semi-conductor spectrometers for high counting rates. Application to the study of the reaction {sup 31}P (p, {alpha}{sub 0}): E{sub p} < 2 MeV; Etude de spectrometres a semi-conducteurs pour forts taux de comptage application a l'etude de la reaction {sup 31}P (p, {alpha}0): E{sub p} < 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Ligeon, E. [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1967-10-01

    The study of nuclear reactions involving particles of low charge (E < 2 MeV) calls for spectrometers of high resolving power. In many experiments however, the counting rate is high because of Coulomb scattering at the target: this results in a distortion of the experimental spectra and a loss of resolving power in the detection equipment. The first part of the work is devoted to an evaluation of the resolving power obtained with silicon-detector spectrometers. A study of the elastic scattering of protons by {sup 31}P shows which are the factors limiting the resolving power. In the second part we examine the various types of spectrometer which can be used in the case of a high count-rate. We have built an apparatus which can be used for carrying out spectrometry on particles produced by nuclear reactions, for a total, count-rate of 10{sup 5} counts/sec. (author) [French] L'etude des reactions nucleaires avec particules chargees a basse energie (E < 2 MeV) exige des spectrometres de haute resolution. Cependant, dans de nombreuses experiences le taux de comptage est eleve, par suite de la diffusion coulombienne sur la cible; on observe alors une distorsion des spectres experimentaux et une perte de resolution de l'ensemble de detection. La premiere partie de ce travail est consacree a l'evaluation de la resolution obtenue avec des spectrometres utilisant des detecteurs au silicium. L'etude de la diffusion elastique des protons sur le {sup 31}P montre quels sont les facteurs qui limitent la resolution. Dans une deuxieme partie, nous etudions les differents types de spectrometres que l'on peut utiliser dans le cas d'un taux de comptage eleve. Nous avons construit un appareil qui permet de faire la spectrometrie de particules, provenant de reactions nucleaires, pour un taux de comptage total de 10{sup 5} c/s. (auteur)

  17. Pulse radiolytic study of alpha-tocopherol radical mechanisms in ethanolic solution

    Energy Technology Data Exchange (ETDEWEB)

    Jore, D.; Patterson, L.K.; Ferradini, C.

    1986-01-01

    Pulse radiolytic studies of alpha-tocopherol (alpha TH) oxidation-reduction processes were carried out with low doses (5 Gy) of high-energy electrons in O/sub 2/-, N/sub 2/-, and air-saturated ethanolic solutions. Depending on the concentration of oxygen in solution, two different radicals, A . and B ., were observed. The first, A ., was obtained under N/sub 2/ and results from alpha TH reaction with solvated electron (k alpha TH + e-solv = 3.4 X 10(8) mol-1 liter s-1) and with H/sub 3/C-CH-OH, (R.) (k alpha TH + R. = 5 X 10(5) mol-1 liter s-1). B., observed under O/sub 2/, is produced by alpha TH reaction with RO/sub 2/ . peroxyl radicals (k alpha TH + RO/sub 2/ . = 9.5 X 10(4) mol-1 liter s-1).

  18. Pulse radiolytic study of alpha-tocopherol radical mechanisms in ethanolic solution

    International Nuclear Information System (INIS)

    Pulse radiolytic studies of alpha-tocopherol (alpha TH) oxidation-reduction processes were carried out with low doses (5 Gy) of high-energy electrons in O2-, N2-, and air-saturated ethanolic solutions. Depending on the concentration of oxygen in solution, two different radicals, A . and B ., were observed. The first, A ., was obtained under N2 and results from alpha TH reaction with solvated electron (k alpha TH + e-solv = 3.4 X 10(8) mol-1 liter s-1) and with H3C-CH-OH, (R.) (k alpha TH + R. = 5 X 10(5) mol-1 liter s-1). B., observed under O2, is produced by alpha TH reaction with RO2 . peroxyl radicals (k alpha TH + RO2 . = 9.5 X 10(4) mol-1 liter s-1)

  19. Evidence for Alpha Receptors in the Human Ureter

    Science.gov (United States)

    Madeb, Ralph; Knopf, Joy; Golijanin, Dragan; Bourne, Patricia; Erturk, Erdal

    2007-04-01

    An immunohistochemical and western blot expression analysis of human ureters was performed in order to characterize the alpha-1-adrenergic receptor distribution along the length of the human ureteral wall. Mapping the distribution will assist in understanding the potential role alpha -1-adrenergic receptors and their subtype density might have in the pathophysiology of ureteral colic and stone passage. Patients diagnosed with renal cancer or bladder cancer undergoing nephrectomy, nephroureterectomy, or cystectomy had ureteral specimens taken from the proximal, mid, distal and tunneled ureter. Tissues were processed for fresh frozen examination and fixed in formalin. None of the ureteral specimens were involved with cancer. Serial histologic sections and immunohistochemical studies were performed using antibodies specific for alpha-1-adrenergic receptor subtypes (alpha 1a, alpha 1b, alpha 1d). The sections were examined under a light microscope and scored as positive or negative. In order to validate and quantify the alpha receptor subtypes along the human ureter. Western blotting techniques were applied. Human ureter stained positively for alpha -1-adrenergic receptors. Immunostaining appeared red, with intense reaction in the smooth muscle of the ureter and endothelium of the neighboring blood vessels. There was differential expression between all the receptors with the highest staining for alpha-1D subtype. The highest protein expression for all three subtypes was in the renal pelvis and decreased with advancement along the ureter to the distal ureter. At the distal ureter, there was marked increase in expression as one progressed towards the ureteral orifice. The same pattern of protein expression was exhibited for all three alpha -1-adrenergic receptor subtypes. We provide preliminary evidence for the ability to detect and quantify the alpha-1-receptor subtypes along the human ureter which to the best of our knowledge has never been done with

  20. Comparative Analysis of Eubacterial DNA Polymerase Ⅲ Alpha Subunits

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qian Zhao; Jian-Fei Hu; Jun Yu

    2006-01-01

    DNA polymerase Ⅲ is one of the five eubacterial DNA polymerases that is responsible for the replication of DNA duplex. Among the ten subunits of the DNA polymerase Ⅲ core enzyme, the alpha subunit catalyzes the reaction for polymerizing both DNA strands. In this study, we extracted genomic sequences of the alpha subunit from 159 sequenced eubacterial genomes, and carried out sequencebased phylogenetic and structural analyses. We found that all eubacterial genomes have one or more alpha subunits, which form either homodimers or heterodimers.Phylogenetic and domain structural analyses as well as copy number variations of the alpha subunit in each bacterium indicate the classification of alpha subunit into four basic groups: polC, dnaE1, dnaE2, and dnaE3. This classification is of essence in genome composition analysis. We also consolidated the naming convention to avoid further confusion in gene annotations.

  1. Probing clustering in excited alpha-conjugate buclei

    CERN Document Server

    Borderie, B; Ademard, G; Rivet, M F; De Filippo, E; Geraci, E; Neindre, N Le; Alba, R; Amorini, F; Cardella, G; Chatterjee, M; Guinet, D; Lautesse, P; La Guidara, E; Lanzalone, G; Lanzano, G; Lombardo, I; Lopez, O; Maiolino, C; Pagano, A; Papa, M; Pirrone, S; Politi, G; Porto, F; Rizzo, F; Russotto, P; Wieleczko, J P

    2016-01-01

    The fragmentation of quasi-projectiles from the nuclear reaction $^{40}$Ca+$^{12}$C at 25 MeV per nucleon bombarding energy was used to produce $\\alpha$-emission sources. From a careful selection of these sources provided by a complete detection and from comparisons with models of sequential and simultaneous decays, evidence in favor of $\\alpha$-particle clustering from excited $^{16}O$, $^{20}Ne$ and $^{24}Mg$ is reported.

  2. Alpha particle induced reactions on natCr up to 39 MeV: Experimental cross-sections, comparison with theoretical calculations and thick target yields for medically relevant 52gFe production

    International Nuclear Information System (INIS)

    Thin natCr targets were obtained by electroplating, using 23.75 μm Cu foils as backings. In five stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross sections for production of 52gFe, 49,51cumCr, 52cum,54,56cumMn and 48cumV in Cr and 61Cu,68Ga in Cu were measured up to 39 MeV incident α-particle energy. Reduced uncertainty is obtained by simultaneous remeasurement of the natCu(α,x)67,66Ga monitor reactions over the whole energy range. Comparisons with the scarce literature values and results from the TENDL-2013 on-line library, based on the theoretical code family TALYS-1.6, were made. A discussion of the production routes for 52gFe with achievable yields and contamination rates was made

  3. ALPHA MIS: Reference manual

    Energy Technology Data Exchange (ETDEWEB)

    Lovin, J.K.; Haese, R.L.; Heatherly, R.D.; Hughes, S.E.; Ishee, J.S.; Pratt, S.M.; Smith, D.W.

    1992-02-01

    ALPHA is a powerful and versatile management information system (MIS) initiated and sponsored and by the Finance and Business Management Division of Oak Ridge National Laboratory, who maintain and develop it in concert with the Business Systems Division for its Information Center. A general-purpose MIS, ALPHA allows users to access System 1022 and System 1032 databases to obtain and manage information. From a personal computer or a data terminal, Energy Systems employees can use ALPHA to control their own report reprocessing. Using four general commands (Database, Select, Sort, and Report) they can (1) choose a mainframe database, (2) define subsets within it, (3) sequentially order a subset by one or more variables, and (4) generate a report with their own or a canned format.

  4. Alpha-amylase gene transcription in tissues of normal dog.

    OpenAIRE

    Mocharla, H; Mocharla, R; Hodes, M E

    1990-01-01

    We studied the distribution of alpha-amylase mRNA in normal dog tissues by northern blotting (NB) and reverse transcription-polymerase chain reaction (RT-PCR) with human pancreatic (AMY2) and salivary (AMY1) alpha-amylase cDNA-specific primers. Analysis of poly(A+) RNA from various normal tissues by NB indicated the presence of detectable levels of alpha-amylase mRNA transcripts only in pancreas. Dot-blot analysis of DNA amplified with primers common to both (human) isoamylase mRNAs showed pr...

  5. Diabetes and alpha lipoic acid

    Directory of Open Access Journals (Sweden)

    IssyLaher

    2011-11-01

    Full Text Available Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E and glutathione. It also boosts antioxidant defense system through Nrf2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that a lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.

  6. Alpha particle induced reactions on {sup nat}Cr up to 39 MeV: Experimental cross-sections, comparison with theoretical calculations and thick target yields for medically relevant {sup 52g}Fe production

    Energy Technology Data Exchange (ETDEWEB)

    Hermanne, A.; Adam Rebeles, R. [Cyclotron Laboratory, Vrije Universiteit Brussel, Brussel 1090 (Belgium); Tárkányi, F.; Takács, S. [Institute of Nuclear Research, Hungarian Academy of Science, 4026 Debrecen (Hungary)

    2015-08-01

    Thin {sup nat}Cr targets were obtained by electroplating, using 23.75 μm Cu foils as backings. In five stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross sections for production of {sup 52g}Fe, {sup 49,51cum}Cr, {sup 52cum,54,56cum}Mn and {sup 48cum}V in Cr and {sup 61}Cu,{sup 68}Ga in Cu were measured up to 39 MeV incident α-particle energy. Reduced uncertainty is obtained by simultaneous remeasurement of the {sup nat}Cu(α,x){sup 67,66}Ga monitor reactions over the whole energy range. Comparisons with the scarce literature values and results from the TENDL-2013 on-line library, based on the theoretical code family TALYS-1.6, were made. A discussion of the production routes for {sup 52g}Fe with achievable yields and contamination rates was made.

  7. Producing a compound Nucleus via Inelastic Scattering: The 90Zr(alpha,alpha')90Zr* Case

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Dietrich, F S

    2008-05-23

    In a Surrogate reaction a compound nucleus is produced via a direct reaction (pickup, stripping, or inelastic scattering). For a proper application of the Surrogate approach it is necessary to predict the resulting angular momentum and parity distribution in the compound nucleus. A model for determining these distributions is developed for the case of inelastic alpha scattering off a spherical nucleus. The focus is on obtaining a first, simple description of the direct-reaction process that produces the compound nucleus and on providing the basis for a more complete treatment of the problem. The approximations employed in the present description are discussed and the extensions required for a more rigorous treatment of the problem are outlined. To illustrate the formalism, an application to {sup 90}Zr({alpha},{alpha}{prime}){sup 90}Zr* is presented.

  8. alpha-Amanitin induced apoptosis in primary cultured dog hepatocytes.

    Directory of Open Access Journals (Sweden)

    Adam Szelag

    2010-06-01

    Full Text Available Amatoxin poisoning is caused by mushroom species belonging to the genera Amanita, Galerina and Lepiota with the majority of lethal mushroom exposures attributable to Amanita phalloides. High mortality rate in intoxications with these mushrooms is principally a result of the acute liver failure following significant hepatocyte damage due to hepatocellular uptake of amatoxins. A wide variety of amatoxins have been isolated; however, alpha-amanitin (alpha-AMA appears to be the primary toxin. Studies in vitro and in vivo suggest that alpha-AMA does not only cause hepatocyte necrosis, but also may lead to apoptotic cell death. The objective of this study was to evaluate the complex hepatocyte apoptosis in alpha-AMA cytotoxicity. All experiments were performed on primary cultured canine hepatocytes. The cells were incubated for 12 h with alpha-AMA at a final concentration of 1, 5, 10 and 20 microM. Viability test (MTT assay, apoptosis evaluation (TUNEL reaction, detection of DNA laddering and electron microscopy were performed at 6 and 12 h of exposure to alpha-AMA. There was a clear correlation between hepatocyte viability, concentration of alpha-AMA and time of exposure to this toxin. The decline in cultured dog hepatocyte viability during the exposure to alpha-AMA is most likely preceded by enhanced cellular apoptosis. Our results demonstrate that apoptosis might contribute to pathogenesis of the severe liver injury in the course of amanitin intoxication, particularly during the early phase of poisoning.

  9. Alpha and evangelical conversion

    OpenAIRE

    Stout, A.; Dein, S.

    2013-01-01

    A semi-structured interview study was conducted among 11 ‘Born Again’ Christians eliciting their conversion narratives. Informants emphasised the importance of embodying the Holy Spirit and developing a personal relationship with Christ in the process of conversion. The Alpha Course played an important role in this process.

  10. Alpha-mannosidosis

    DEFF Research Database (Denmark)

    Borgwardt, Line; Stensland, Hilde Monica Frostad Riise; Olsen, Klaus Juul;

    2015-01-01

    the three subgroups of genotype/subcellular localisation and the clinical and biochemical data were done to investigate the potential relationship between genotype and phenotype in alpha-mannosidosis. Statistical analyses were performed using the SPSS software. Analyses of covariance were performed to...

  11. The $\\alpha_S$ Dependence of Parton Distributions

    OpenAIRE

    Martin, A. D.; Stirling, W. J.; Roberts, R G

    1995-01-01

    We perform next-to-leading order global analyses of deep inelastic and related data for different fixed values of $\\alpha_S (M_Z^2)$. We present sets of parton distributions for six values of $\\alpha_S$ in the range 0.105 to 0.130. We display the $(x, Q^2)$ domains with the largest parton uncertainty and we discuss how forthcoming data may be able to improve the determination of the parton densities.

  12. [The interaction of human alpha 1-antitrypsin with human plasmin].

    Science.gov (United States)

    Sakurama, S

    1984-01-01

    The interaction of alpha 1-antitrypsin (alpha 1-AT) with plasmin was investigated, and the molecular weight of the inhibitor was also re-evaluated. The value of molecular weight of alpha 1-AT determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method showed a difference depending on the presence or absence of the reducing agent, resulting in 72,000 dalton before reduction and 59,000 dalton after reduction. Conclusively, the molecular weight of alpha 1-AT was appropriate to be 59,000 dalton from considering the molecular shape of the protein. The interaction of alpha 1-AT with plasmin was analysed by SDS-PAGE method. Unreduced analysis revealed that two kinds of complexes with different molecular weight (the major of 155,000 dalton and the minor of 140,000 dalton) were formed time dependently, suggesting that the former was a native complex and the latter was a degraded product. Reduced analysis disclosed that the light chain of plasmin involved the complex formation with the inhibitor, and a peptide of 16,000 dalton appeared during the reaction. From these observations, the mechanism of action was summarized as follows. First, alpha 1-AT inhibited all of the plasmin activities by forming a 1: 1 stoichiometric complex with the enzyme, presumably with the active center of the enzyme, whose complex is undissociable in the presence of denaturing or reducing agents or both. Secondly, the native complex broke into a degraded product and a released peptide by limited proteolysis with the free plasmin which existed in the reaction mixture even with an excess of alpha 1-AT due to the reaction of complex formation being time consuming. The clinical significance of alpha 1-AT on fibrinolysis was also subject for discussion. PMID:6232193

  13. Genetics Home Reference: alpha thalassemia

    Science.gov (United States)

    ... for Disease Control and Prevention Centre for Genetics Education (Australia) Cooley's Anemia Foundation: Fact sheet about alpha thalassemia Disease InfoSearch: Alpha-Thalassemia Genomics Education Programme (UK) Information Center for Sickle Cell and ...

  14. $\\alpha$-minimal Banach spaces

    CERN Document Server

    Rosendal, Christian

    2011-01-01

    A Banach space with a Schauder basis is said to be $\\alpha$-minimal for some countable ordinal $\\alpha$ if, for any two block subspaces, the Bourgain embeddability index of one into the other is at least $\\alpha$. We prove a dichotomy that characterises when a Banach space has an $\\alpha$-minimal subspace, which contributes to the ongoing project, initiated by W. T. Gowers, of classifying separable Banach spaces by identifying characteristic subspaces.

  15. Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

    Energy Technology Data Exchange (ETDEWEB)

    Glaus, M. A.; Loon, L. R. Van

    2008-11-15

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}-isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, either at 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx}50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

  16. Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

    Energy Technology Data Exchange (ETDEWEB)

    Glaus, M. A.; Loon, L. R. Van

    2009-05-15

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}- isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx} 50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

  17. Resting alpha activity predicts learning ability in alpha neurofeedback

    Directory of Open Access Journals (Sweden)

    Wenya eNan

    2014-07-01

    Full Text Available Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback.

  18. Alpha scintillation radon counting

    International Nuclear Information System (INIS)

    Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222Rn and 226Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

  19. Rossi Alpha Method

    International Nuclear Information System (INIS)

    The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-α is no longer an α-eigenvalue

  20. Analysis of uncertainties in alpha-particle optical-potential assessment below the Coulomb barrier

    CERN Document Server

    Avrigeanu, V

    2016-01-01

    Background: Recent high-precision measurements of alpha-induced reaction data below the Coulomb barrier have pointed out questions of the alpha-particle optical-model potential (OMP) which are yet open within various mass ranges. Purpose: The applicability of a previous optical potential and eventual uncertainties and/or systematic errors of the OMP assessment at low energies can be further considered on this basis. Method: Nuclear model parameters based on the analysis of recent independent data, particularly gamma-ray strength functions, have been involved within statistical model calculation of the (alpha,x) reaction cross sections. Results: The above-mentioned potential provides a consistent description of the recent alpha-induced reaction data with no empirical rescaling factors of the and/or nucleon widths. Conclusions: A suitable assessment of alpha-particle optical potential below the Coulomb barrier should involve the statistical-model parameters beyond this potential on the basis of a former analysi...

  1. Alpha decay of {sup 181}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Davids, C.N.; Henderson, D.J.; Hermann, R. [and others

    1995-08-01

    The {alpha}-decay energy of {sup 181}Pb was measured as 7211(10) keV and 7044(15). In the first study the isotope was produced in {sup 90}Zr bombardments of {sup 94}Mo and, after traversing a velocity filter, implanted in a position-sensitive Si detector; no half life for {sup 181}Pb was reported. In the second study the isotope was produced in {sup 40}Ca bombardments of {sup 144}Sm and transported to a position in front of a Si(Au) surface barrier detector with a fast He-gas-jet capillary system; an estimate of 50 ms was determined for the {sup 181}Pb half life. Recently we investigated {sup 181}Pb {alpha} decay at ATLAS as part of a survey experiment in which a l-pnA beam of 400-MeV {sup 92}Mo was used to irradiate targets of {sup 89}Y, {sup 90,92,94}Zr, and {sup 92}Mo to examine yields for one- and two-nucleon evaporation products from symmetric cold-fusion reactions. Recoiling nuclei of interest were passed through the Fragment Mass Analyzer and implanted in a double-sided silicon strip detector for {alpha}-particle assay. With the {sup 90}Zr target we observed a group at 7065(20) keV which was correlated with A = 181 recoils and had a half life of 45(20) ms. Our new results for {sup 181}Pb therefore agreed with those of the second study. There was no indication in the {sup 90}Zr + {sup 92}Mo data of the 7211(10)-keV {alpha} particles seen by Keller et al. The interested reader is referred to the 1993 atomic mass evaluation wherein the input {alpha}-decay energies and resultant masses of the light Pb isotopes (including {sup 181}Pb) are discussed.

  2. Combining Alphas via Bounded Regression

    Directory of Open Access Journals (Sweden)

    Zura Kakushadze

    2015-11-01

    Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

  3. Asthma induction in mice leads to appearance of alpha2-3- and alpha2-6-linked sialic acid residues in respiratory goblet-like cells

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Jensen, Niels-Erik Viby; Mandel, Ulla;

    2008-01-01

    demonstrate binding of lectins and antibodies that detect alpha2-3- and alpha2-6-linked sialic acid residues. After sensitization and challenge, the histology of the lung changed markedly, and goblet-like cells appeared, most likely caused by Clara cell metaplasia. Normal Clara cells showed no reaction after...... incubation with the sialic acid detecting agents, while the goblet-like cells expressed both alpha2-3- and alpha2-6-linked sialic acid residues in the asthmatic animals. The lectins but not the antibodies reacted with intestinal goblet cells. Instead, an antibody recognizing a disialoganglioside, stained...

  4. New alpha particle counter based on micro-pixel avalanche photodiode

    International Nuclear Information System (INIS)

    Full text : The main goal of this work is study of possibility to detect alpha particles with micro-pixel avalanche photodiode which has very thin active volume. The obtained results show that alpha detectors based on the micro-pixel avalanche photodiodes can be used as alpha particle counter in many experiments : public security, radioactive contamination monitoring in various environments and detection of charged particles from nuclear reactions

  5. Alpha-globin loci in homozygous beta-thalassemia intermedia.

    Science.gov (United States)

    Triadou, P; Lapoumeroulie, C; Girot, R; Labie, D

    1983-01-01

    Homozygous beta-thalassemia intermediate (TI) differs from thalassemia major (TM) in being less severe clinically. Associated alpha-thalassemia could account for the TI phenotype by reducing the alpha/non-alpha chain imbalance. We have analyzed the alpha loci of 9 TI and 11 TM patients by restriction endonuclease mapping. All the TM and 7 of the TI patients have the normal complement of four alpha-globin genes (alpha alpha/alpha alpha). One TI patient has three alpha-globin genes (alpha alpha/-alpha), and another TI patient has five alpha genes (alpha alpha/alpha alpha alpha). PMID:6305827

  6. Cross Section Measurement of 9Be(\\gamma,n)8Be and Implications for \\alpha+\\alpha+n -> 9Be in the r-Process

    CERN Document Server

    Arnold, C W; Iliadis, C; Karwowski, H J; Rich, G C; Tompkins, J R; Howell, C R

    2011-01-01

    Models of the r-process are sensitive to the production rate of 9Be because, in explosive environments rich in neutrons, \\alpha(\\alpha n,\\gamma)9Be is the primary mechanism for bridging the stability gaps at A=5 and A=8. The \\alpha(\\alpha n,\\gamma)9Be reaction represents a two-step process, consisting of \\alpha+\\alpha -> 8Be followed by 8Be(n,\\gamma)9Be. We report here on a new absolute cross section measurement for the 9Be(\\gamma,n)8Be reaction conducted using a highly-efficient, 3He-based neutron detector and nearly-monoenergetic photon beams, covering energies from E_\\gamma = 1.5 MeV to 5.2 MeV, produced by the High Intensity \\gamma-ray Source of Triangle Universities Nuclear Laboratory. In the astrophysically important threshold energy region, the present cross sections are 40% larger than those found in most previous measurements and are accurate to +/- 10% (95% confidence). The revised thermonuclear \\alpha(\\alpha n,\\gamma)9Be reaction rate could have implications for the r-process in explosive environme...

  7. Selective effects of alpha interferon on human T-lymphocyte subsets during mixed lymphocyte cultures

    DEFF Research Database (Denmark)

    Hokland, M; Hokland, P; Heron, I;

    1983-01-01

    Mixed lymphocyte reaction (MLR) cultures of human lymphocyte subsets with or without the addition of physiological doses of human alpha interferon (IFN-alpha) were compared with respect to surface marker phenotypes and proliferative capacities of the responder cells. A selective depression on the T...

  8. Global alpha-particle optical potentials

    International Nuclear Information System (INIS)

    A search for a global optical potential for alpha-particles is described. It did not prove possible to find such a potential valid for a wide range of energies and nuclei, even treating the absorbing potential as an adjustable parameter for each nucleus. For practical purposes the best that can be done is to define an average potential, and such a potential is compared with a wide range of experimental data. Its energy variation is determined by fitting the total reaction cross-section. (author). 7 refs, 15 figs, 1 tab

  9. Identification alpha and gamma quantum at the pulse shape of the scintillates splash

    Directory of Open Access Journals (Sweden)

    V. I. Kornaga

    2008-05-01

    Full Text Available The methods of different scintillates splash alpha and gamma quantum at the pulse shape have been considered in experiment researches of the core's structure and mechanisms of the nuclear reaction.

  10. Unfolding domains of recombinant fusion alpha alpha-tropomyosin.

    OpenAIRE

    Ishii, Y; Hitchcock-DeGregori, S.; Mabuchi, K; Lehrer, S S

    1992-01-01

    The thermal unfolding of the coiled-coil alpha-helix of recombinant alpha alpha-tropomyosin from rat striated muscle containing an additional 80-residue peptide of influenza virus NS1 protein at the N-terminus (fusion-tropomyosin) was studied with circular dichroism and fluorescence techniques. Fusion-tropomyosin unfolded in four cooperative transitions: (1) a pretransition starting at 35 degrees C involving the middle of the molecule; (2) a major transition at 46 degrees C involving no more ...

  11. Bi209 alpha activity

    International Nuclear Information System (INIS)

    The study for measuring Bi209 alpha activity is presented. Ilford L4 nuclear emulsion pellicles loaded with bismuth citrate to obtain a load of 100 mg/cm3 of dry emulsion, were prepared. Other pellicles were prepared with the same. Ilford L4 gel to estimate the background radiation. To observe 'fading' effect, pellicles loaded with bismuth were submitted to neutrons of high energy, aiming to record recoil proton tracks. The pellicles were confined in nitrogen atmosphere at temperature lower than -100C. The Bi209 experimental half-life was obtained and compared with the estimated theoretical data. (M.C.K.)

  12. Background canceling surface alpha detector

    International Nuclear Information System (INIS)

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs

  13. Alpha activity measurement with lsc

    International Nuclear Information System (INIS)

    Recently, we showed that the alpha activity in liquid samples can be measured using a liquid scintillation analyzer without alpha/beta discrimination capability. The purpose of this work was to evaluate the performances of the method and to optimize the procedure of the sample preparation. A series of tests was performed to validate the procedure of alpha emitting radionuclides extraction in aqueous samples with Actinide Resin, especially regarding to the contact time required to extract all alpha nuclides. The main conclusions were that a minimum 18 hours stirring time is needed to achieve a percent recovery of the alpha nuclides grater than 90% and that the counting efficiency of alphas measurements with LSC is nearly 100%. (authors)

  14. Nuclear Reactions

    OpenAIRE

    Bertulani, C. A.

    2009-01-01

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay of compound nuclei;...

  15. Robust Estimation of Cronbach's Alpha

    OpenAIRE

    Christmann, A.; Van Aelst, Stefan

    2002-01-01

    Cronbach’s alpha is a popular method to measure reliability, e.g. in quantifying the reliability of a score to summarize the information of several items in question- naires. The alpha coefficient is known to be non-robust. We study the behavior of this coefficient in different settings to identify situations, which can easily occur in practice, but under which the Cronbach’s alpha coefficient is extremely sensitive to violations of the classical model assumptions. Furthermore,...

  16. Mouse egg integrin alpha 6 beta 1 functions as a sperm receptor.

    Science.gov (United States)

    Almeida, E A; Huovila, A P; Sutherland, A E; Stephens, L E; Calarco, P G; Shaw, L M; Mercurio, A M; Sonnenberg, A; Primakoff, P; Myles, D G; White, J M

    1995-06-30

    Binding between sperm and egg plasma membranes is an essential step in fertilization. Whereas fertilin, a mammalian sperm surface protein, is involved in this crucial interaction, sperm receptors on the egg plasma membrane have not been identified. Because fertilin contains a predicted integrin ligand domain, we investigated the expression and function of integrin subunits in unfertilized mouse eggs. Polymerase chain reactions detected mRNAs for alpha 5, alpha 6, alpha v, beta 1, beta 3, and beta 5. Immunofluorescence revealed alpha 6 beta 1 and alpha v beta 3 on the plasma membrane. GoH3, a function-blocking anti-alpha 6 monoclonal antibody, abolished sperm binding, but a nonfunction-blocking anti-alpha 6 monoclonal antibody, a function-blocking anti-alpha v beta 3 polyclonal antibody, and an RGD peptide had no effect. Somatic cells bound sperm avidly, but only if they expressed alpha 6 beta 1. A peptide analog of the fertilin integrin ligand domain inhibited sperm binding to eggs and alpha 6 beta 1+ cells and diminished GoH3 staining of eggs. Our results indicate a novel role for the integrin alpha 6 beta 1 as a cell-cell adhesion receptor that mediates sperm-egg binding. PMID:7600577

  17. First direct measurement of resonance strengths in 17O({\\alpha}, {\\gamma})21Ne

    CERN Document Server

    Best, A; Couder, M; deBoer, R; Falahat, S; Kontos, A; LeBlanc, P J; Li, Q; O'Brien, S; Sonnabend, K; Talwar, R; Uberseder, E; Wiescher, M

    2011-01-01

    The reaction 17O({\\alpha},{\\gamma})21Ne has been measured by in-beam gamma spectroscopy for the first time in the energy range E{\\alpha} = 750 keV to 1650 keV using highly enriched anodized Ta2(17O)5 targets. Resonances were found at E({\\alpha}) = 1002 keV, 1386 keV and 1619 keV. Their strengths and primary gamma-ray branchings are given. The new results exclude the low reaction rate of Descouvemont and support the rate of Caughlan and Fowler. Implications for the neutron poisoning efficiency of 16O in the weak s process are discussed.

  18. Engineering of hydrolysis reaction specificity in the transglycosylase cyclodextrin glycosyltransferase

    OpenAIRE

    Leemhuis, H; Dijkhuizen, L.

    2003-01-01

    Cyclodextrin glycosyltransferase (CGTase) is a member of the alpha-amylase family, a large group of enzymes that act on alpha-glycosidic bonds in starch and related compounds. Over twenty different reaction and product specificities have been found in this family. Although three-dimensional structure elucidation and the biochemical characterization of site-directed mutants have yielded a detailed insight into the mechanism of bond cleavage, the variation in reaction and product specificity is...

  19. Alpha glucosidase inhibitors.

    Science.gov (United States)

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  20. Insurance - Piper Alpha ''et al''

    International Nuclear Information System (INIS)

    This paper opens with some brief information about the Piper Alpha loss, how the loss was handled and its final cost. More importantly, it discusses the effect of the Piper Alpha loss on the world insurance market including the oil insurance captives such as O.I.L Limited. Finally, the insurance market current status and prognosis for the future are considered. (Author)

  1. Long-range alpha detector

    International Nuclear Information System (INIS)

    Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of ∼30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive

  2. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 (211At) and natural bismuth-212 (212Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 (223Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  3. The Lyman alpha reference sample

    DEFF Research Database (Denmark)

    Hayes, M.; Östlin, G.; Schaerer, D.; Verhamme, A.; Mas-Hesse, J.M.; Adamo, A.; Atek, H.; Cannon, J.M.; Duval, F.; Guaita, L.; Herenz, E.C.; Kunth, D.; Laursen, Peter; Melinder, J.; Orlitová, I.; Otí-Floranes, H.; Sandberg, A.

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028

  4. Low energy alpha particle spectroscopy using CR-39 detector

    CERN Document Server

    Izerrouken, M; Ilic, R

    1999-01-01

    The possibility of using CR-39 to measure the depth profile of sup 1 sup 0 B in Si is analysed. The measuring technique exploits the sup 1 sup 0 B(n, alpha) sup 7 Li nuclear reaction. For this reason the track parameters (size, optical properties) of low energy alpha-particles (<1.47 MeV) were studied. The results showed that an energy resolution of about 100 keV could be obtained by an appropriate selection of etching conditions. The profile of sup 1 sup 0 B in Si at a depth as small as 1 mu m can be measured.

  5. Dynamical alpha-type correlations in deformed superfluid nuclei

    International Nuclear Information System (INIS)

    By including an adequate four-particle interaction, correlations between the proton and neutron fluids in deformed nuclei are induced. As a result, superfluidities of the two nuclear systems may be generated by one another and the phase structure is enriched by a new superfluid phase dominated by alpha-type correlations. Among the consequences upon the nuclear structure and dynamics figure the prediction of new bands of elementary excitations and the increase of superfluid enhancement factors for alpha and pair transfer reactions. (author). 18 refs, 2 figs, 1 tab

  6. Alpha Schottky junction energy source

    Science.gov (United States)

    Litz, Marc S.; Fan, Zhaoyang; Carroll, James J.; Bayne, Stephen

    2012-06-01

    Isotope batteries offer solutions for long-lived low-power sensor requirements. Alpha emitting isotopes have energy per decay 103 times that of beta emitters. Alpha particles are absorbed within 20 μm of most materials reducing shielding mitigation. However, damage to materials from the alphas limits their practical use. A Schottky Barrier Diode (SBD) geometry is considered with an alpha emitting contact-layer on a diamond-like crystal semiconductor region. The radiation tolerance of diamond, the safety of alpha particles, combined with the internal field of the SBD is expected to generate current useful for low-power electronic devices over decades. Device design parameters and calculations of the expected current are described.

  7. Alpha-clustering and molecular structure of medium weight and heavy nuclei. Chapter 1. Introduction

    International Nuclear Information System (INIS)

    Since discovery of the nucleus by E. Rutherford, alpha particle has been one of the key particles in understanding the structure and reactions of nuclei. The alpha particle model is one of the oldest nuclear models. A number of alpha particle model (alpha cluster model) studies of nuclei in the 1960s and 1970s revealed that concept of alpha clustering is essential for understanding the structure of light nuclei. The relation between the alpha cluster model and the shell model was also theoretically clarified. However, successful is the alpha cluster model in light nuclei, is status cannot be raised to that of a universal nuclear model -- like the shell model and the collective model -- unless it is shown to work through out the Periodic Table. Many experimental studies has been carried out in order to investigate the alpha cluster properties of nuclei in the fp-shell region. The existence of the alpha cluster parity doublet band in both 44-Ti and 40-Ca prompts is to understand more fully the clustering aspects at the beginning of the fp-shell, as compared with those in the 16-O to 20-Ne region. Much progress has also been made recently in understanding of alpha clustering in heavy nuclei. It has been shown that the alpha-decay properties of heavy nuclei can be systematically explained within a phenomenological model taking into account alpha clustering in these nuclei. Ordinary nuclear matter has played an essential role in laying the foundations of independent particle model of nuclei. Similarly, alpha cluster matter plays a central role in the understanding of roots of the alpha cluster model. (G.K.)

  8. High precision $^{113}$In($\\alpha,\\alpha$)$^{113}$In elastic scattering at energies around the Coulomb barrier for the astrophysical $\\gamma$ process

    CERN Document Server

    Kiss, G G; Fülöp, Zs; Rauscher, T; Gyürky, Gy; Szücs, T; Halász, Z; Somorjai, E; Ornelas, A; Yalcin, C; Güray, R T; Özkan, N

    2013-01-01

    The $\\gamma$ process in supernova explosions is thought to explain the origin of proton-rich isotopes between Se and Hg, the so-called $p$ nuclei. The majority of the reaction rates for $\\gamma$ process reaction network studies has to be predicted in Hauser-Feshbach statistical model calculations using global optical potential parameterizations. While the nucleon+nucleus optical potential is fairly known, for the $\\alpha$+nucleus optical potential several different parameterizations exist and large deviations are found between the predictions calculated using different parameter sets. By the measurement of elastic $\\alpha$-scattering angular distributions at energies around the Coulomb barrier a comprehensive test for the different global $\\alpha$+nucleus optical potential parameter sets is provided. Between 20$^{\\circ}$ and 175$^{\\circ}$ complete elastic alpha scattering angular distributions were measured on the $^{113}$In \\textit{p} nucleus with high precision at E$_{c.m.}$ = 15.59 and 18.82 MeV. The elast...

  9. ALPHA freezes antiprotons

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Laboratories like CERN can routinely produce many different types of antiparticles. In 1995, the PS210 experiment formed the first antihydrogen atoms and a few years later, in 2002, ATRAP and ATHENA were already able to produce several thousand of them. However, no experiment in the world has succeeded in ‘trapping’ these anti-atoms in order to study them. This is the goal of the ALPHA experiment, which has recently managed to cool down the antiprotons to just a few Kelvin. This represents a major step towards trapping the anti-atom, thus opening a new avenue into the investigation of antimatter properties.   Members of the ALPHA collaboration working on the apparatus in the Antiproton Decelerator experimental hall at CERN. Just like the atom, the anti-atom is neutral. Unlike the atom, the anti-atom is made up of antiprotons (as opposed to protons in the atom) and positrons (as opposed to electrons). In order to thoroughly study the properties of the anti-atoms, scien...

  10. Measurement of $\\alpha_{s}$ with Radiative Hadronic Events

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, G; Anagnostou, G; Anderson, K J; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, R J; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, S; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; Dallavalle, M; de Roeck, A; De Wolf, E A; Desch, K; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, F; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, J; Gruwé, M; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Herten, G; Heuer, R D; Hill, J C; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krasznahorkays, A Jr; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Mashimo, T; Mättig, P; McKenna, J; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schiecks, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, J; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2008-01-01

    Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z0 boson with the OPAL detector at LEP. The strong coupling alpha S is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies ranging from 24 GeV to 78 GeV, and the energy dependence of alpha S is studied. Our results are consistent with the running of alpha S as predicted by QCD and show that within the uncertainties of our analysis event shapes in hadronic Z0 decays with hard and isolated photon radiation can be described by QCD at reduced centre-of-mass energies. Combining all values from different event shape observables and energies gives alpha S (Mz)=0.1182 pm 0.0015(stat.) pm 0.0101(syst.).

  11. Novel chemistry of alpha-tosyloxy ketones: applications to the solution- and solid-phase synthesis of privileged heterocycle and enediyne libraries

    DEFF Research Database (Denmark)

    Nicolaou, K C; Montagnon, T; Ulven, T; Baran, P S; Zhong, Y-L; Sarabia, F

    2002-01-01

    -functional nucleophiles furnishes annulated heterocyclic systems. In addition, the reactions of carbon-centered nucleophiles with alpha-tosylyloxy ketones are also explored. The collated data for all these nucleophiles provide compelling evidence for the proposal that different reaction pathways are followed when alpha...

  12. What Powers Lyman alpha Blobs?

    OpenAIRE

    Ao, Y.; Matsuda, Y; Beelen, A.; Henkel, C.; Cen, R.; De Breuck, C.; Francis, P; Kovacs, A.; Lagache, G.; Lehnert, M.; Mao, M; Menten, K. M.; Norris, R; Omont, A.; Tatemastu, K.

    2015-01-01

    Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array (ATCA) observations of the 20 cm radio emission and Herschel PACS and SPIRE measurements of the far-infrared (FIR) emission towards the four LABs in the protocluster J2143-4423 at z=2.38. Among the four LABs, B6 and B7 are detected in the rad...

  13. Sparse Coding for Alpha Matting

    OpenAIRE

    Johnson, Jubin; Varnousfaderani, Ehsan Shahrian; Cholakkal, Hisham; Rajan, Deepu

    2016-01-01

    Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measur...

  14. Catalytic, enantioselective, vinylogous aldol reactions.

    Science.gov (United States)

    Denmark, Scott E; Heemstra, John R; Beutner, Gregory L

    2005-07-25

    In 1935, R. C. Fuson formulated the principle of vinylogy to explain how the influence of a functional group may be felt at a distant point in the molecule when this position is connected by conjugated double-bond linkages to the group. In polar reactions, this concept allows the extension of the electrophilic or nucleophilic character of a functional group through the pi system of a carbon-carbon double bond. This vinylogous extension has been applied to the aldol reaction by employing "extended" dienol ethers derived from gamma-enolizable alpha,beta-unsaturated carbonyl compounds. Since 1994, several methods for the catalytic, enantioselective, vinylogous aldol reaction have appeared, with which varying degrees of regio- (site), enantio-, and diastereoselectivity can be attained. In this Review, the current scope and limitations of this transformation, as well as its application in natural product synthesis, are discussed. PMID:15940727

  15. Di-tert-butylsilylene-directed alpha-selective synthesis of 4-methylumbelliferyl T-antigen.

    Science.gov (United States)

    Imamura, Akihiro; Ando, Hiromune; Ishida, Hideharu; Kiso, Makoto

    2005-09-29

    [reaction: see text] We have succeeded in the facile synthesis of 4-methylumbelliferyl T-antigen as a substrate for endo-alpha-N-acetylgalactosaminidase by exploiting the combination of the di-tert-butylsilylene effect and the Mitsunobu reaction. PMID:16178547

  16. Synthesis of graphene oxide-intercalated alpha-hydroxides by metathesis and their decomposition to graphene/metal oxide composites

    OpenAIRE

    Nethravathi, C; Rajamathi, Michael; Ravishankar, N.; Basit, Lubna; FELSER, CLAUDIA

    2010-01-01

    Graphene oxide-intercalated alpha-metal hydroxides were prepared using layers from the delaminated colloidal dispersions of cetyltrimethylammonium-intercalated graphene oxide and dodecylsulfate-intercalated alpha-hydroxide of nickel/cobalt as precursors. The reaction of the two dispersions leads to de-intercalation of the interlayer ions from both the layered solids and the intercalation of the negatively charged graphene oxide sheets between the positively charged layers of the alpha-hydroxi...

  17. Measurement of differential (n,x{alpha}) cross section using 4{pi} gridded ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Sanami, Toshiya; Baba, Mamoru; Matsuyama, Shigeo; Kiyosumi, Takehide; Nauchi, Yasushi; Saito, Keiichiro; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Kawano, Toshihiko

    1997-03-01

    We carried out the measurements of high resolution {alpha} emission spectra of {sup 58}Ni and {sup nat}Ni between 4.5 and 6.5 MeV, and {sup 12}C(n,x{alpha}) cross section using a 4{pi} gridded ionization chamber. In Ni measurement, overall energy resolution was improved to around 200 keV by optimizing a sample thickness and a neutron source width. Measured alpha spectra showed separate peaks corresponding to the ground and low-lying excited states of the residual nucleus ({sup 55}Fe). These results were compared with another direct measurement and statistical model calculations. In {sup 12}C measurement, GIC was applied for (n,x{alpha}) reactions of light nuclei. This application is difficult to (n,x{alpha}) cross sections of light nuclei, because of the influences of large recoil energy and multi-body break-up. We developed new methods which eliminate the effects of recoil nuclei and multi-body break-up and applied them to {sup 12}C(n,x{alpha}) reaction at En=14.1 MeV. In our experiment, the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be angular differential cross section and {sup 12}C(n,n`3{alpha}) cross section were obtained. (author)

  18. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  19. Reaction mechanisms

    International Nuclear Information System (INIS)

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported

  20. Dynamic fibrils in Ly alpha

    CERN Document Server

    Koza, J; Vourlidas, A

    2008-01-01

    The solar chromosphere and transition region are highly structured regimes of large complexity. A recent breakthrough concerns the identification of dynamic fibrils seen in Halpha. An aim is to find out whether dynamic fibrils are also observable in Ly alpha. We use a brief sequence of four high-resolution Ly alpha filtergrams of the solar limb taken by the Very high Angular resolution ULtraviolet Telescope (VAULT) to identify 50 dynamic fibrils, measure their top trajectories, and fit these with parabolas. Most fibril tops move supersonically. Their decelerations vary from sub- to superballistic. About half show outward acceleration, which may be an artifact from the poor sampling. The similarity between these dynamic fibrils observed in Ly alpha and the ones observed in Halpha suggests that the magnetoacoustic shock excitation proposed for the Halpha dynamic fibrils is also valid for the Ly alpha ones.

  1. Almost Redundant Components in the 3 alpha Faddeev Equation for the Buck, Friedlich and Wheatly alpha alpha Potential

    CERN Document Server

    Fujiwara, Y; Kohno, M

    2004-01-01

    The 3 alpha orthogonality condition model using the Pauli-forbidden bound states of the Buck, Friedlich and Wheatly alpha alpha potential can yield a compact 3 alpha ground state with a large binding energy, in which a small admixture of the redundant components can never be eliminated.

  2. Alpha thalassaemia in British people.

    OpenAIRE

    Higgs, D R; Ayyub, H.; Clegg, J B; Hill, A V; Nicholls, R D; Teal, H; Wainscoat, J.S. (James S.); Weatherall, D. J.

    1985-01-01

    Although alpha thalassaemia is rare in north Europeans, it has been identified in British people with no known foreign ancestry. Twelve such patients were studied, of whom eight shared a distinctive molecular defect, which was clearly different from defects seen in subjects of Mediterranean or South East Asian origin. A rare but specific form of alpha thalassaemia is therefore present in the British population. In addition, two patients from families of mixed racial origin were encountered wh...

  3. Alpha-resonant states in {sup 13}C

    Energy Technology Data Exchange (ETDEWEB)

    Borello-Lewin, T.; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A.; Miyake, H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy); Istituto Nazionali di Fisica Nucleare (INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculty of Psychology

    2010-07-01

    Full text: The research program in progress aims to achieve a better understanding of the alpha-clustering phenomenon in light (x{alpha} + {nu}) nuclei. The {sup 9}Be({sup 6}Li,d){sup 13}C reaction was used in the present work to investigate alpha resonant states in {sup 13}C up to 15 MeV of excitation. The data have been taken at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. The plates covered 100 cm along the focal surface and spectra were measured at seven scattering angles, between 3 deg and 20 degrees in the laboratory frame. The resolution of 50 keV allowed for the separation of the resonant contributions to the known 7/2{sup -} at 10.753 MeV and (5/2{sup -}) at 10.818 MeV {sup 13}C states. Particularly interesting is the the narrow alpha resonance seen at E{sub x} = 12.3 MeV close the (3{alpha} + n) threshold, not previously measured, populated by an L = 2 transfer. Detected, near this threshold by alpha inelastic scattering, a large E0 isoscalar transition, the signature of a spatially developed 1/2{sup -} cluster-state, was reported by T. Kawabata. The L = 2 transfer agrees with the 1/2{sup -} attribution. The present work is underway. Taking the benefit of the use of the emulsion plates and applying the track selective reading methodology, at least other three narrow alpha resonances in {sup 13}C up to 15 MeV of excitation, not previously measured, were detected. (author)

  4. Alpha Particle Emission in Fission

    International Nuclear Information System (INIS)

    Soon after it was discovered that alpha particles are occasionally emitted in fission, it was concluded, on the basis of the energy and angular distributions of these particles, that they are emitted from the space between the fragments at times close to that of the snapping of the neck that connects them. It is shown that, independent of any (still unknown) dynamic features of the alpha-particle ejection process, the energy required to emit alpha particles from between the fragments at the indicated time is barely available. Presumably the rareness of alpha particles in fission, and the apparent absence of still heavier ''third'' particles, is associated with the marginal energy supply at the time of actual fragment division. The fact that the total kinetic energy release in so-called ternary fission is roughly equal to that in normal binary fission instead of being about 20 MeV larger is shown to imply that the mean fragment separation at the division time is larger in ternary fission. This is interpreted to indicate that alpha particles are emitted with greatest probability n those fissions where ample energy happens to be provided through the stretching of an abnormally long neck between the fragments before they actually divide. It is suggested that the release of the alpha particles is a sudden rather than adiabatic process. (author)

  5. Alpha particle physics for ITER

    International Nuclear Information System (INIS)

    The paper is devoted to the analysis of a variety of physical processes which, in the ITER EDA configuration, determine the nature of alpha particle heating in the plasma interior and alpha particle losses to the first wall. The paper consists of results from the alpha particle toroidal field (TF) ripple loss calculations and an analysis of alpha particle collective effects including Alfven modes, sawtooth stabilization, etc. It is shown that the ripple loss in the present ITER configuration is only a few per cent, which cannot directly affect the achievement of ignition. In spite of the up-down asymmetry, the loss fraction does not strongly depend on the toroidal drift direction. However, the heat load is highly localized and can be as high as 1 MW/m2 on the top of the protective limiters. Preliminary calculations of toroidicity induced Alfven eigenmode (TAE) stability indicate that high n numbers may be unstable, but the computational tools, needed for reliable quantitative predictions, are still in a state of development. The likelihood of appreciable alpha particle loss will depend on whether TAE modes produce stochastic alpha particle diffusion or not. The effect of fast particles on the m = 1 mode is also discussed. (author). 15 refs, 2 figs, 1 tab

  6. Gas phase hydrogen permeation in alpha titanium and carbon steels

    Science.gov (United States)

    Johnson, D. L.; Shah, K. K.; Reeves, B. H.; Gadgeel, V. L.

    1980-01-01

    Commercially pure titanium and heats of Armco ingot iron and steels containing from 0.008-1.23 w/oC were annealed or normalized and machined into hollow cylinders. Coefficients of diffusion for alpha-Ti and alpha-Fe were determined by the lag-time technique. Steady state permeation experiments yield first power pressure dependence for alpha-Ti and Sievert's law square root dependence for Armco iron and carbon steels. As in the case of diffusion, permeation data confirm that alpha-titanium is subject to at least partial phase boundary reaction control while the steels are purely diffusion controlled. The permeation rate in steels also decreases as the carbon content increases. As a consequence of Sievert's law, the computed hydrogen solubility decreases as the carbon content increases. This decreases in explained in terms of hydrogen trapping at carbide interfaces. Oxidizing and nitriding the surfaces of alpha-titanium membranes result in a decrease in the permeation rate for such treatment on the gas inlet surfaces but resulted in a slight increase in the rate for such treatment on the gas outlet surfaces. This is explained in terms of a discontinuous TiH2 layer.

  7. Anomalous Loss of DT Alpha Particles in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Hans W.

    1997-06-01

    Princeton's Tokamak Fusion Test Reactor (TFTR) is the first experimental fusion device to routinely use tritium to study the deuterium-tritium (DT) fusion reaction,allowing the first systematic study of DT alpha particles in tokamak plasmas. A crucial aspect of alpha-particle physics is the fraction of alphas that escape from the plasma, particularly since these energetic particles can do severe damage to the first wall of a reactor. An escaping alpha collector probe has been developed for TFTR's DT phase. Energy distributions of escaping alphas have been determined by measuring the range of alpha-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous "delayed" loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on alpha-particle loss has led to a better understanding of alpha-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing alpha-particles forced to move toward higher magnetic field during an inward major radius shift (i.e. compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90 degree lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an alpha-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized alpha

  8. Comparison of the effect of alpha1- and alpha2-adrenoceptor agonists and antagonists on muscle contractility of the rabbit abdominal aorta in vitro.

    Science.gov (United States)

    Gnus, Jan; Rusiecka, Agnieszka; Czerski, Albert; Zawadzki, Wojciech; Witkiewicz, Wojciech; Hauzer, Willy

    2013-01-01

    The aim of the study was to demonstrate the effect of selected agonists and antagonists of alpha-adrenergic receptors on muscle contractility of the rabbit abdominal aorta in vitro with particular emphasis on alpha2-adrenergic receptor subtypes. The study was conducted on 30 New Zealand breed rabbits from which specimens of the abdominal aorta were collected. The sections were set up in an automatic water bath in a Krebs-Henseleit buffer at 37 degrees C. The experiments showed that alpha1-adrenergic receptors played the main role in the contractile response ofthe rabbit abdominal aorta. Stimulation of alpha1-adrenergic receptor by administration ofphenylephrine resulted in an increase in smooth muscle tonus ofthe rabbit abdominal aorta by an average of 4.75 mN. The reaction after stimulation of alpha2-adrenergic receptors by similar doses of their agonists was much weaker. Prolonged tissue response time and time needed to reach maximum tonus for alpha2-adrenergic receptor agonists were observed. The obtained results confirm the thesis that the alpha1-adrenergic receptor is the most important factor controlling the contractility of the rabbit abdominal aorta, but the alpha2-adrenergic receptor is also involved in maintaining muscle tissue tonus. PMID:23767297

  9. Systematics of Alpha-Radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Perlman, I.; Ghiorso, A.; Seaborg, G.T.

    1949-09-12

    Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. Using most of the even-even nuclei to define 'normal nuclear radius' calculations are now able to show the shrinkage in the regions of lead and of 126 neutrons to amount to about 10%. The much greater change in 'effective radius' for bismuth isotopes can be dissociated into the effects of odd nucleons superimposed on the actual decrease in nuclear radius. The simple expression r = 1.48 A{sup 1/3} {center_dot} 10{sup -13} cm seems to fit the data for the even-even nuclei outside of the region of 126 neutrons better than more complex functions.

  10. Two-nucleon transfer reactions uphold supersymmetry in atomic nuclei

    OpenAIRE

    Barea, J.; Bijker, R.; Frank, A.

    2004-01-01

    The spectroscopic strengths of two-nucleon transfer reactions constitute a stringent test for two-nucleon correlations in the nuclear wave functions. A comparison between the recently measured 198Hg(d,alpha)196Au reaction and the predictions from the nuclear quartet supersymmetry lends further support to the validity of supersymmetry in nuclear physics.

  11. $\\alpha $ -Skew $\\pi $ -McCoy Rings

    OpenAIRE

    Areej M. Abduldaim; Chen, Sheng

    2013-01-01

    As a generalization of $\\alpha $ -skew McCoy rings, we introduce the concept of $\\alpha $ -skew $\\pi $ -McCoy rings, and we study the relationships with another two new generalizations, $\\alpha $ -skew ${\\pi }_{1}$ -McCoy rings and $\\alpha $ -skew ${\\pi }_{2}$ -McCoy rings, observing the relations with $\\alpha $ -skew McCoy rings, $\\pi $ -McCoy rings, $\\alpha $ -skew Armendariz rings, $\\pi $ -regular rings, and other kinds of rings. Also, we investigate conditions such that $\\alpha $ -skew ${...

  12. Bovine intermediate pituitary alpha-amidation enzyme: preliminary characterization

    International Nuclear Information System (INIS)

    A secretory granule-associated enzymatic activity that converts mono-[125I]-D-Tyr-Val-Gly into mono-[125I]-D-Tyr-Val-NH2 has been studied. The activity is primarily soluble and shows optimal activity at pH 7 to pH 8. Amidation activity was stimulated 9-fold by addition of optimal amounts of copper (3 microM). In the presence of optimal copper, ascorbate stimulated the reaction 7-fold; none of the other reduced or oxidized cofactors tested was as effective. Taking into account the dependence of the reaction on ascorbate and molecular oxygen and the production of glyoxylate [2], it is suggested that the alpha-amidation enzyme is a monooxygenase. Lineweaver Burk plots with D-Tyr-Val-Gly as the varied substrate demonstrated Michelis-Menten type kinetics with the values of K/sub m/ and V/sub max/ increasing with the addition of ascorbate to the assay. A variety of peptides ending with a COOH-terminal Gly residue act as inhibitors of the reaction. Two synthetic peptides, gamma 2MSH and ACTH(1-14), with carboxyl termini similar to the presumed physiological substrates for the enzyme, act as competitive inhibitors with similar K1 values. It is likely that this secretory granule alpha-amidation activity is involved in the physiological biosynthetic alpha-amidation of a wide range of bioactive peptides

  13. Real-time operating mode with DSSSD detector to search for short correlation ER-alpha chains

    CERN Document Server

    Tsyganov, Yury

    2015-01-01

    Real-time PC based algorithm is developed for DSSSD detector. Complete fusion nuclear reaction natYb+48Ca->217Th is used to test this algorithm at 48Ca beam. Example of successful application of a former algorithm for resistive strip PIPS detector in 249Bk+48Ca nuclear reaction is presented too. Case of alpha-alpha correlations is also under brief consideration.

  14. Systematic measurements of proton- and alpha-capture cross sections relevant to the modelling of the p process

    Energy Technology Data Exchange (ETDEWEB)

    Harissopulos, S. [Inst. of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Spyrou, A. [Inst. of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Lagoyannis, A. [Inst. of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Zarkadas, Ch. [Inst. of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece); Becker, H.-W. [Inst. fuer Experimentalphysik III, Ruhr-Universitaet Bochum, 44801 Bochum (Germany); Rolfs, C. [Inst. fuer Experimentalphysik III, Ruhr-Universitaet Bochum, 44801 Bochum (Germany); Strieder, F. [Inst. fuer Experimentalphysik III, Ruhr-Universitaet Bochum, 44801 Bochum (Germany); Hammer, J.W. [Institut fuer Strahlenphysik, Universitaet Stuttgart, 70569 Stuttgart (Germany); Dewald, A. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Zell, K.-O. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Brentano, P. von [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany); Julin, R. [Department of Physics, University of Jyvaeskylae, 40014 Jyvaeskylae (Finland); Demetriou, P. [IAA, Universite Libre de Bruxelles, CP226, 1050 Brussels (Belgium); Goriely, S. [IAA, Universite Libre de Bruxelles, CP226, 1050 Brussels (Belgium)

    2005-07-25

    Several in-beam cross section measurements of proton- as well as {alpha}-capture reactions in the Se-Sb region have been carried out to obtain global input parameters for Hauser-Feshbach (HF) calculations. In total, 20 (p,{gamma}) and 7 ({alpha}, {gamma}) reactions were measured. We compare some of these results with Hauser-Feshbach calculations using various optical model potentials and nuclear level densities.

  15. Alpha-glucosidase promotes hemozoin formation in a blood-sucking bug: an evolutionary history.

    Directory of Open Access Journals (Sweden)

    Flávia Borges Mury

    Full Text Available BACKGROUND: Hematophagous insects digest large amounts of host hemoglobin and release heme inside their guts. In Rhodnius prolixus, hemoglobin-derived heme is detoxified by biomineralization, forming hemozoin (Hz. Recently, the involvement of the R. prolixus perimicrovillar membranes in Hz formation was demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: Hz formation activity of an alpha-glucosidase was investigated. Hz formation was inhibited by specific alpha-glucosidase inhibitors. Moreover, Hz formation was sensitive to inhibition by Diethypyrocarbonate, suggesting a critical role of histidine residues in enzyme activity. Additionally, a polyclonal antibody raised against a phytophagous insect alpha-glucosidase was able to inhibit Hz formation. The alpha-glucosidase inhibitors have had no effects when used 10 h after the start of reaction, suggesting that alpha-glucosidase should act in the nucleation step of Hz formation. Hz formation was seen to be dependent on the substrate-binding site of enzyme, in a way that maltose, an enzyme substrate, blocks such activity. dsRNA, constructed using the sequence of alpha-glucosidase gene, was injected into R. prolixus females' hemocoel. Gene silencing was accomplished by reduction of both alpha-glucosidase and Hz formation activities. Insects were fed on plasma or hemin-enriched plasma and gene expression and activity of alpha-glucosidase were higher in the plasma plus hemin-fed insects. The deduced amino acid sequence of alpha-glucosidase shows a high similarity to the insect alpha-glucosidases, with critical histidine and aspartic residues conserved among the enzymes. CONCLUSIONS/SIGNIFICANCE: Herein the Hz formation is shown to be associated to an alpha-glucosidase, the biochemical marker from Hemipteran perimicrovillar membranes. Usually, these enzymes catalyze the hydrolysis of glycosidic bond. The results strongly suggest that alpha-glucosidase is responsible for Hz nucleation in the R. prolixus

  16. Gaseous alpha emitter diffusion studies using alpha track method

    International Nuclear Information System (INIS)

    Using a very accurate and sensitive analysis method such as alpha track method, the SSNTD group was able to undertake studies on the atomic and molecular processes taking place at low speed and/or very low concentrations, such as diffusion of gaseous alpha radionuclides in gaseous media. For practical application reasons, we began to study the diffusion in air for gaseous alpha radionuclides and aerosols carrying solid alpha radionuclides. The used alpha radionuclides were: Rn-222, as gaseous radionuclide and its solid descendants genetically related, attached to different particles from air, as radioactive aerosols. The source was included into an air tight device with a very well known volume. After 40 days, the radioactive equilibrium was established for all descendants, so that in the device there were the Rn-222 and its descendants, each of them having the same activity. The relative amount/activity ratio of each decay product, at any duration, for any initial mass of Ra-226 parent radionuclide, were calculated using the code UURASE, based on the Bateman general equations, for computing the U-238 radioactive series gamma accumulation. This was adapted for alpha accumulation as ALFAURASE programme. The device which contains the Ra-226 source can be coupled to the calibration system or to the diffusion system, without destroying the radioactive equilibrium. At this coupling, only the radioactive concentration is changed due to the variation of the volume. First of all the device was used for calibrating the CR-39 track detectors for both Rn-222 gaseous radionuclide and aerosol concentration measurements using, in the coupled calibration system, a special 'detector-container' equipped/or not with a filter used for radioactive aerosol stopping. The track detectors CR-39 were etched in NaOH 30%, for 7 hours at 70 deg. C and their studies were performed by optical microscopy using a stereo-microscope Wild M7S and a binocular Zeiss Jena microscope. (authors)

  17. Contribution to the study of the alpha-alpha interaction

    International Nuclear Information System (INIS)

    The new variable energy cyclotron at Berkeley that can accelerate an alpha beam up to an energy of 130 MeV and the mass production of lithium diffused junctions have enabled us to perform 2 series of measurement, in the first one we use alpha beams with an energy ranging between 50 and 120 MeV to study alpha-alpha forces in the second one we use the flexibility of the variable energy cyclotron the resonances around 40 MeV, region that can not yet be reached by tandem accelerators. This work is divided into 6 chapters. The first chapter is dedicated to the formalism of partial wave analysis and the theory of the compound nucleus. In the second chapter the author presents the 88 cyclotron at Berkeley and the diffusion chamber, the alpha detectors are lithium diffused junctions made of silicon. The third chapter deals with the experimental methods used and the issue of the reduction of the volume of data. In the fourth chapter the results obtained in the upper part of the energy range are described in terms of complex shifts that allow the description of the α-α interaction at high energy. The very low impact parameter has enabled us to find 2 new components (l=6 and l=8) of the rotational spectrum and to define a more accurate phenomenological potential. The fifth chapter is dedicated to the narrow resonances we have found between 12 and 27 MeV. We present in the last chapter a calculation of the binding energy of C12 in which we have considered the 12C nucleus as formed by 3 alpha particles interacting with each other through the phenomenological potential defined above

  18. Effects of Alpha- Tocopherol on the Velocity of Low Density Lipoprotein Oxidation by Cupric Ions

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Ghaffari

    2010-10-01

    Full Text Available We studied the effect of different concentrations of alpha-tocopherol on in vitro cupric ions induced oxidation of low density lipoproteins (LDL. Human native LDL (50 µg protein/ml oxidation was induced by 10 µmol/L of CuSO4. Conjugated dienes were measured spectrophotometrically for up to 440 minutes. The length of the lag phase (Tlag, maximum velocity of the reaction (Vmax and the maximum amount of generated dienes were obtained from kinetic data. Alpha-tocopherol increased Tlag and decreased Vmax with a dependence upon concentration (0-100 µmol/L. There was no difference between the Dmax obtained with cupric ions alone or in the presence of the various concentrations of alpha-tocopherol. The results suggest that alpha-tocopherol may decrease free radicals presence in LDL and thus decrease velocity of LDL oxidation by cupric ions. This mechanism may be a reason for alpha-tocopherol effect in ameliorating atherosclerosis.

  19. Workshop on Precision Measurements of $\\alpha_s$

    Energy Technology Data Exchange (ETDEWEB)

    Bethke, Siegfried; /Munich, Max Planck Inst.; Hoang, Andre H.; /Vienna U.; Kluth, Stefan; /Munich, Max Planck Inst.; Schieck, Jochen; /Munich U.; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

    2011-10-01

    These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

  20. Fokker Planck kinetic modeling of suprathermal alpha-particles in a fusion plasma

    OpenAIRE

    Peigney, Benjamin-Edouard; Larroche, Olivier; Tikhonchuk, Vladimir

    2014-01-01

    We present an ion kinetic model describing the ignition and burn of the deuterium-tritium fuel of inertial fusion targets. The analysis of the underlying physical model enables us to develop efficient numerical methods to simulate the creation, transport and collisional relaxation of fusion reaction products (alpha-particles) at a kinetic level. A two-energy-scale approach leads to a self-consistent modeling of the coupling between suprathermal alpha-particles and the thermal bulk of the impl...

  1. Evaluation of (alpha,n) Induced Neutrons as a Background for Dark Matter Experiments

    OpenAIRE

    Mei, D.-M.; C. Zhang; Hime, A.

    2008-01-01

    Neutrons from ($\\alpha$,n) reactions through thorium and uranium decays are important sources of background for direct dark matter detection. The neutron yields and energy spectra from a range of materials that are used to build dark matter detectors are calculated and tabulated. In addition to thorium and uranium decays, we found that $\\alpha$ particles from samarium, often the dopant of the window materials of photomultiplier tubes (PMT), are also an important source of neutron yield. The r...

  2. Alpha-particle clustering in excited expanding self-conjugate nuclei

    CERN Document Server

    Borderie, B; Ademard, G; Rivet, M F; De Filippo, E; Geraci, E; Neindre, N Le; Cardella, G; Lanzalone, G; Lombardo, I; Lopez, O; Maiolino, C; Pagano, A; Pirrone, S; Politi, G; Rizzo, F; Russotto, P

    2016-01-01

    The fragmentation of quasi-projectiles from the nuclear reaction 40Ca + 12C at 25 MeV/nucleon was used to produce alpha-emission sources. From a careful selection of these sources provided by a complete detection and from comparisons with models of sequential and simultaneous decays, strong indications in favour of $\\alpha$-particle clustering in excited 16O, 20Ne and 24}Mg are reported.

  3. Microscopic study of the isoscalar excitations by the alpha inelastic scattering

    International Nuclear Information System (INIS)

    Alpha particle with zero spin and isospin is a very good projectile to study isoscalar excited states by direct reaction. We have performed analyzing the alpha inelastic scattering on stable targets 12C and 208Pb to discuss about characteristics of isoscalar excitation. The feature of 0+2 state in 12C was presented. Otherwise, the existence of 2+2 state in 12C was discussed more detail. The isoscalar strength distribution in 208Pb was showed. (author)

  4. Space Station alpha joint bearing

    Science.gov (United States)

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

    1987-01-01

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

  5. ALPHA: antihydrogen and fundamental physics

    Science.gov (United States)

    Madsen, Niels

    2014-02-01

    Detailed comparisons of antihydrogen with hydrogen promise to be a fruitful test bed of fundamental symmetries such as the CPT theorem for quantum field theory or studies of gravitational influence on antimatter. With a string of recent successes, starting with the first trapped antihydrogen and recently resulting in the first measurement of a quantum transition in anti-hydrogen, the ALPHA collaboration is well on its way to perform such precision comparisons. We will discuss the key innovative steps that have made these results possible and in particular focus on the detailed work on positron and antiproton preparation to achieve antihydrogen cold enough to trap as well as the unique features of the ALPHA apparatus that has allowed the first quantum transitions in anti-hydrogen to be measured with only a single trapped antihydrogen atom per experiment. We will also look at how ALPHA plans to step from here towards more precise comparisons of matter and antimatter.

  6. Preparation of MoO3/gamma-Al2O3 Catalyst by the Reaction of alpha-Boehmite with MoO3/H2O Slurry - Dual Role of MoO3 as Active Phase and Texture Stabilizer during Calcination

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Zdražil, Miroslav

    2005-01-01

    Roč. 85, č. 2 (2005), s. 391-398. ISSN 0133-1736 R&D Projects: GA AV ČR(CZ) IAA4072306 Institutional research plan: CEZ:AV0Z40720504 Keywords : alpha- boehmite * alumina * molybdena catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.670, year: 2005

  7. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

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

  8. Angular correlation measurements for 4-{alpha} decaying states in {sup 16}O

    Energy Technology Data Exchange (ETDEWEB)

    Wuosmaa, A.H.; Back, B.B.; Betts, R.R. [and others

    1995-08-01

    Previous measurements of the {sup 12}C({sup 12}C,{sup 8}Be){sup 16}O{sup *}(4 {alpha}) reaction identified discrete levels in {sup 16}O which decay by breakup into 4 {alpha} particles through a number of different decay sequences, including {sup 16}O{sup *} {yields} {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C (O{sub 2}{sup +}). These states are observed in a range of excitation energies where resonances are observed in inelastic {alpha} + {sup 12}C scattering leading to the {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C final states. These resonances were associated with 4 {alpha}-particle chain configurations in {sup 16}O. Should the states populated in the {sup 12}C + {sup 12}C reaction possess this same extended structure, it would serve as an important piece of evidence supporting the idea that even more deformed structures are formed in the {sup 24}Mg compound system. In order to more firmly make this association, it is important to determine the spins of the states populated in the {sup 12}C + {sup 12}C reaction.

  9. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  10. Solar He-3: Information from nuclear reactions in flares

    Science.gov (United States)

    Ramaty, R.; Kozlovsky, B.

    1974-01-01

    Information on solar He-3 from nuclear reactions in flares was considered. Consideration was also given to the development of models for these reactions as well as the abundance of He-3 in the photosphere. Data show that abundances may be explained by nuclear reactions of flare acceleration protons and alpha particles with the ambient atmosphere, provided that various assumptions are made on the directionality of the interacting beams and acceleration of the particles after production.

  11. Chemical vapor deposition (CVD) of uranium for alpha spectrometry

    International Nuclear Information System (INIS)

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  12. Influence of the repulsive coefficient {alpha} and approximate corresponding states in Mie {alpha}-6 and exponential {alpha}-6 fluids

    Energy Technology Data Exchange (ETDEWEB)

    Galliero, Guillaume [Universite de Marne-la-Vallee, Laboratoire d' Etude des Transferts d' Energie et de Matiere (EA 2546), Bat. Lavoisier, Cite Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallee Cedex 2 (France)], E-mail: galliero@univ-mlv.fr; Boned, Christian; Baylaucq, Antoine [Universite de Pau et des Pays de l' Adour, Laboratoire des Fluides Complexes (UMR-5150), BP 1155, F-64013 Pau Cedex (France); Montel, Francois [TOTAL, CSTJF, Avenue Larribau, F-64018 Pau (France)

    2007-03-30

    Non-equilibrium molecular dynamics (NEMD) simulations of the Mie {alpha}-6 and the exponential {alpha}-6 (exp {alpha}-6) fluids have been carried out for 42 thermodynamic states. Various repulsive coefficients have been studied, {alpha} ranging from 9 to 14 for the Mie {alpha}-6 potentials and from 11 to 16 for the exp {alpha}-6 ones, which corresponds to a total of 603 points of simulation of stable phases. The simulations have shown that, for a given set of reduced temperature and density (using an appropriate scaling procedure), the reduced pressure varies linearly with {radical}({alpha}-6) for the Mie {alpha}-6 potentials and with {radical}({alpha}-7) for the exp {alpha}-6 potentials. Concerning the viscosity, it is shown that, for both potential families, the variation is linear with {alpha}. Thus, an approximate corresponding states scheme exists on pressure and on viscosity for fluids modelled by both potentials families, but only for each property separately. In addition, it appears that, approximate corresponding states exist between fluids modelled by a Mie {alpha}-6 potential and an exp ({alpha} + 2)-6 one for pressure, and between fluids modelled by a Mie {alpha}-6 potential and an exp ({alpha} + 2.5)-6 one for viscosity. So, despite obvious similarities, the influence of the shape of the potential on pressure and on viscosity is not strictly the same. Hence, a complete perfect corresponding states scheme (including both the pressure and the viscosity) seems hardly feasible between fluids modelled by the Mie {alpha}-6 and the exp {alpha}-6 potential families.

  13. Nuclear reactions

    International Nuclear Information System (INIS)

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

  14. Biotransformation of alpha- and 6beta-santonin by fungus and plant cell cultures.

    Science.gov (United States)

    Yang, L; Dai, J; Sakai, J-I; Ando, M

    2006-06-01

    One fungus, Abisidia coerulea IFO 4011, and suspended cell cultures of one plant, Asparagus officinalis, were employed to bioconvert alpha- and 6beta-santonin. Incubation of alpha-santonin with the cell cultures of the fungus afforded two products, 11beta-hydroxy-alpha-santonin (1, in 76.5% yield) and 8alpha-hydroxy-alpha-santonin (2, in 2.0% yield). And from 6beta-santonin, four major products (3, 4, 5 and 6) and four minor products (7, 8, 9 and 10) were obtained, including 8alpha-hydroxylated products in trace yields. Very interestingly, a skeletal rearrangement occurred and a guaiane product (13) formed in a very low yield when alpha-santonin incubating with A.officinalis cell cultures, while not in the case of 6beta-santonin as substrate. Among the obtained 15 products, 2, 7, 8, 9, 10 and 12 are new compounds. The fact of 8alpha hydroxylation of santonin enables the formation of 8,12-eudesmanolide instead of 6,12-eudesmanolide and some useful modification at C-8 position. In addition, these reactions would provide evidence for the biogenesis between different types of eudesmane and/or guaiane compounds in the plants in nature. PMID:16864442

  15. Capture reactions on C-14 in nonstandard big bang nucleosynthesis

    Science.gov (United States)

    Wiescher, Michael; Gorres, Joachim; Thielemann, Friedrich-Karl

    1990-01-01

    Nonstandard big bang nucleosynthesis leads to the production of C-14. The further reaction path depends on the depletion of C-14 by either photon, alpha, or neutron capture reactions. The nucleus C-14 is of particular importance in these scenarios because it forms a bottleneck for the production of heavier nuclei A greater than 14. The reaction rates of all three capture reactions at big bang conditions are discussed, and it is shown that the resulting reaction path, leading to the production of heavier elements, is dominated by the (p, gamma) and (n, gamma) rates, contrary to earlier suggestions.

  16. What Powers Lyman alpha Blobs?

    CERN Document Server

    Ao, Y; Beelen, A; Henkel, C; Cen, R; De Breuck, C; Francis, P; Kovacs, A; Lagache, G; Lehnert, M; Mao, M; Menten, K M; Norris, R; Omont, A; Tatemastu, K; Weiss, A; Zheng, Z

    2015-01-01

    Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array (ATCA) observations of the 20 cm radio emission and Herschel PACS and SPIRE measurements of the far-infrared (FIR) emission towards the four LABs in the protocluster J2143-4423 at z=2.38. Among the four LABs, B6 and B7 are detected in the radio with fluxes of 67+/-17 microJy and 77+/-16 microJy, respectively, and B5 is marginally detected at 3 sigma (51+/-16 microJy). For all detected sources, their radio positions are consistent with the central positions of the LABs. B6 and B7 are obviously also detected in the FIR. By fitting the data with different templates, we obtained redshifts of 2.20$^{+0.30}_{-0.35}$ for B6 and 2.20$^{+0.45}_{-0.30}$ for B7 which are consistent with the redshift of the lyman alpha emission within uncertainties, indicating that both ...

  17. Alcoholism, Alpha Production, and Biofeedback

    Science.gov (United States)

    Jones, Frances W.; Holmes, David S.

    1976-01-01

    Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

  18. Alpha Testing Escape from Diab

    Science.gov (United States)

    Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...

  19. Inclusive-jet photoproduction at HERA and determination of alphas

    CERN Document Server

    Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Aushev, V; Aushev, Y; Bachynska, O; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartosik, N; Bartsch, D; Basile, M; Behnke, O; Behr, J; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bindi, M; Blohm, C; Bokhonov, V; Bold, T; Bondarenko, K; Boos, E G; Borras, K; Boscherini, D; Bot, D; Brock, I; Brownson, E; Brugnera, R; Brummer, N; Bruni, A; Bruni, G; Brzozowska, B; Bussey, P J; Bylsma, B; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; D'Agostini, G; Corso, F Dal; del Peso, J; Dementiev, R K; De Pasquale, S; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dolinska, G; Doyle, A T; Drugakov, V; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Fang, S; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Forrest, M; Foster, B; Gach, G; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gizhko, A; Gladilin, L K; Gladkov, D; Glasman, C; Gogota, O; Golubkov, Yu A; Gottlicher, P; Grabowska-Bold, I; Grebenyuk, J; Gregor, I; Grigorescu, G; Grzelak, G; Gueta, O; Guzik, M; Gwenlan, C; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Hilger, E; Hochman, D; Hori, R; Horton, K; Huttmann, A; Ibrahim, Z A; Iga, Y; Ingbir, R; Ishitsuka, M; Jakob, H -P; Januschek, F; Jones, T W; Jungst, M; Kadenko, I; Kahle, B; Kananov, S; Kanno, T; Karshon, U; Karstens, F; Katkov, I I; Kaur, M; Kaur, P; Keramidas, A; Khein, L A; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kondrashova, N; Kononeko, O; Kooijman, P; Korol, Ie; Korzhavina, I A; Kotanski, A; Kotz, U; Kowalski, H; Kuprash, O; Kuze, M; Lee, A; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Ling, T Y; Lisovyi, M; Lobodzinska, E; Lohmann, W; Lohr, B; Lohrmann, E; Long, K R; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Maeda, J; Magill, S; Makarenko, I; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Mattingly, M C K; Melzer-Pellmann, I -A; Mergelmeyer, S; Miglioranzi, S; Idris, F Mohamad; Monaco, V; Montanari, A; Morris, J D; Mujkic, K; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nigro, A; Ning, Y; Nobe, T; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Oliver, K; Olkiewicz, K; Onishchuk, Yu; Papageorgiu, K; Parenti, A; Paul, E; Pawlak, J M; Pawlik, B; Pelfer, P G; Pellegrino, A; Perlanski, W; Perrey, H; Piotrzkowski, K; Plucinski, P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Reisert, B; Ren, Z; Repond, J; Ri, Y D; Robertson, A; Roloff, P; Rubinsky, I; Ruspa, M; Sacchi, R; Samson, U; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schonberg, V; Schorner-Sadenius, T; Schwartz, J; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Singh, I; Skillicorn, I O; Slominski, W; Smith, W H; Sola, V; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Stefaniuk, N; Stern, A; Stewart, T P; Stifutkin, A; Stopa, P; Suchkov, S; Susinno, G; Suszycki, L; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tapper, A D; Tassi, E; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tomaszewska, J; Trusov, V; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Vazquez, M; Verbytskyi, A; Viazlo, O; Vlasov, N N; Walczak, R; Abdullah, W A T Wan; Whitmore, J J; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zabiegalov, O; Zarnecki, A F; Zawiejski, L; Zenaiev, O; Zeuner, W; Zhautykov, B O; Zhmak, N; Zhou, C; Zichichi, A; Zolkapli, Z; Zotkin, D S

    2012-01-01

    Inclusive-jet cross sections have been measured in the reaction ep->e+jet+X for photon virtuality Q2 17 GeV and -1 < etajet < 2.5. In addition, measurements of double-differential inclusive-jet cross sections are presented as functions of ETjet in different regions of etajet. Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low ETjet and high etajet. The influence of non-perturbative effects not related to hadronisation was studied. Measurements of the ratios of cross sections using different jet algorithms are also presented; the measured ratios are well described by calculations including up to O(alphas2) terms. Values of alphas(Mz) were extracted from the measurements and the energy-scale dependence of the coupling was determined. The value of alphas(Mz) extracted from the measurements based on the kT jet algorithm is alphas(Mz) = 0.1206 +0.0023 -0.0022 (exp.) +0.0042 -0.0035 (th.); the results from the anti-kT and SIScone algorithms are compat...

  20. A synopsis of collective alpha effects and implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Sigmar, D.J.

    1990-10-01

    This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.

  1. How Is Alpha-1 Antitrypsin Deficiency Diagnosed?

    Science.gov (United States)

    ... Alpha-1 Antitrypsin Deficiency Diagnosed? Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you develop a ... related to the condition. Your doctor may suspect AAT deficiency if you have signs or symptoms of ...

  2. How Is Alpha-1 Antitrypsin Deficiency Treated?

    Science.gov (United States)

    ... Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but its related lung ... pulmonary disease). If you have symptoms related to AAT deficiency, your doctor may recommend: Medicines called inhaled ...

  3. What Causes Alpha-1 Antitrypsin Deficiency?

    Science.gov (United States)

    ... this page from the NHLBI on Twitter. What Causes Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) ... develop. The most common faulty gene that can cause AAT deficiency is called PiZ. If you inherit ...

  4. Calibration of sources for alpha spectroscopy systems

    International Nuclear Information System (INIS)

    This paper describes the calibration methodology for measuring the total alpha activity of plane and thin sources with the Alpha Spectrometer for Silicon Detector in the Nuclear Measures and Dosimetry laboratory at IEAv/CTA. (author)

  5. Monitor for alpha beta contamination of hands

    International Nuclear Information System (INIS)

    The following specifications of hands alpha beta contamination monitor are presented: the position of the hands, the detection and separation of alpha and beta, the information processing, the programming, the results presentation and general characteristics. (A.L.B.)

  6. \\alpha $ $^m $ Continuous Maps in Topological Spaces

    OpenAIRE

    Mathew, Milby; Parimelazhagan, R.; S Jafari

    2016-01-01

    The main aim of the present paper is to introduce new classes of functions called $ \\alpha $ $^m $ continuous maps and $ \\alpha $ $^m $ irresolute maps. We obtain some characterizations of these classes and properties are studied.

  7. T-cell receptor V sub. alpha. and C sub. alpha. alleles associated with multiple sclerosis and myasthenia gravis

    Energy Technology Data Exchange (ETDEWEB)

    Oksenberg, J.R.; Cavalli-Sforza, L.L.; Steinman, L. (Stanford Univ., CA (USA)); Sherritt, M.; Bernard, C.C. (LaTrobe Univ., Victoria (Australia)); Begovich, A.B.; Erlich, H.A. (Cetus Corporation, Emeryville, CA (USA))

    1989-02-01

    Polymorphic markers in genes encoding the {alpha} chain of the human T-cell receptor (TcR) have been detected by Southern blot analysis in Pss I digests. Polymorphic bands were observed at 6.3 and 2.0 kilobases (kb) with frequencies of 0.30 and 0.44, respectively, in the general population. Using the polymerase chain reaction (PCR) method, the authors amplified selected sequences derived from the full-length TcR {alpha} cDNA probe. These PcR products were used as specific probes to demonstrate that the 6.3-kb polymorphic fragment hybridizes to the variable (V)-region probe and the 2.0-kb fragment hybridizes to the constant (C)-region probe. Segregation of the polymorphic bands was analyzed in family studies. To look for associations between these markers and autoimmune diseases, the authors have studied the restriction fragment length polymorphism distribution of the Pss I markers in patients with multiple sclerosis, myasthenia gravis, and Graves disease. Significant differences in the frequency of the polymorphic V{sub {alpha}} and C{sub {alpha}} markers were identified between patients and healthy individuals.

  8. Role and mechanism of uncoupling protein 2 on the fatty acid-induced dysfunction of pancreatic alpha cells in vitro

    Institute of Scientific and Technical Information of China (English)

    SU Jie-ying; LI Hong-liang; YANG Wen-ying; XIAO Jian-zhong; DU Rui-qin; SHEN Xiao-xia; CAI Zhe; ZHANG Lan; SHU Jun

    2010-01-01

    Background Uncoupling protein (UCP) 2 is related to the dysfunction of beta cells induced by fatty acids. However,whether UCP2 has similar effects on alpha cell is still not clear. This study aimed to investigate the effects of UCP2 and its possible mechanisms in lipotoxicity-induced dysfunction of pancreatic alpha cells.Methods The alpha TC1-6 cells were used in this study to evaluate the effects of palmitate and/or UCP2 inhibit factors on the glucagon secretory function, glucagon content, the glucagon mRNA level and the nitrotyrosine level in the supernatant. Meantime, the expression levels of UCP2 and peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1 alpha) were measured by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Furthermore, the possible relationship between UCP2 and insulin signal transduction pathway was analyzed.Results Palmitate stimulated alpha cell glucagon secretion and the expression of UCP2 and PGC-1 alpha, which could be partially decreased by the inhibition of UCP2. Palmitate increased nitrotyrosine level and suppressed insulin signal transduction pathway in alpha cells. Inhibition of UCP2 influenced the effects of free fatty acid on alpha cells and may relate to glucagon secretion.Conclusion UCP2 played an important role on alpha cell dysfunction induced by free fatty acid in vitro, which may be related to its effects on oxidative stress and insulin signal transduction pathway.

  9. Enzyme replacement therapy for alpha-mannosidosis

    DEFF Research Database (Denmark)

    Borgwardt, Line Gutte; Dali, Christine I.; Fogh, J;

    2013-01-01

    Alpha-mannosidosis (OMIM 248500) is a rare lysosomal storage disease (LSD) caused by alpha-mannosidase deficiency. Manifestations include intellectual disabilities, facial characteristics and hearing impairment. A recombinant human alpha-mannosidase (rhLAMAN) has been developed for weekly intrave...... intravenous enzyme replacement therapy (ERT). We present the preliminary data after 12 months of treatment....

  10. Chain reaction

    International Nuclear Information System (INIS)

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  11. Cationization of Alpha-Cellulose to Develop New Sustainable Products

    Directory of Open Access Journals (Sweden)

    Ana Moral

    2015-01-01

    Full Text Available Papermaking has been using high quantities of retention agents, mainly cationic substances and organic compounds such as polyamines. The addition of these agents is related to economic and environmental issues, increasing contamination of the effluents. The aim of this work is to develop a cationic polymer for papermaking purposes based on the utilization of alpha-cellulose. The cationization of mercerized alpha-cellulose with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC is governed by a pseudo-second-order reaction. The initial amorphous fraction of cellulose is reacted with CHPTAC until the equilibrium value of nitrogen substitution is reached. Nitrogen is incorporated as a quaternary ammonium group in the polymer. Also, the kinetic constant increased with decreasing crystallinity index, showing the importance of the previous alkalization stage. The use of modified natural polysaccharides is a sustainable alternative to synthetic, nonbiodegradable polyelectrolytes and thus is desirable with a view to developing new products and new processes.

  12. Invited Commentary: Alpha-Gal Allergy: Tip of the Iceberg to a Pivotal Immune Response.

    Science.gov (United States)

    Commins, Scott P

    2016-09-01

    The syndrome of delayed allergic reactions to the carbohydrate galactose-alpha-1,3-galactose ("alpha-gal") has become increasingly recognized in allergy and immunology clinics regionally throughout the southeastern USA. Due to the increasing awareness of this unique food allergy, cases have been identified in the northeastern and central USA as well as in Central and South America, Europe, Asia, Scandinavia, and Australia. Clinically, alpha-gal allergy is characterized by reactions to non-primate mammalian meat (e.g., beef, pork, lamb) that occur 3-6 h following exposure. The IgE response to alpha-gal is thought to develop after tick bites and can result in the loss of tolerance to foods that have been safely consumed for years. Although the initial description of alpha-gal allergy in 2009 was limited to red meat, this epitope is now identified in an expanded number of products, medications and foods-both labeled and unlabeled. Moreover, we are beginning to recognize that alpha-gal food allergy is the tip of the iceberg for this immune response. PMID:27520937

  13. Damped Lyman-Alpha Galaxies

    CERN Document Server

    Turnshek, D A; Lane, W; Monier, E M; Nestor, D; Bergeron, J; Briggs, F; Smette, A

    2000-01-01

    Some results from an imaging program to identify low-redshift (0.09alpha (DLA) galaxies are presented. The standard paradigm that was widely accepted a decade ago, that DLA galaxies are the progenitors of luminous disk galaxies, is now being seriously challenged. The indisputable conclusion from imaging studies at low redshift is that the morphological types of DLA galaxies are mixed and that they span a range in luminosities and surface brightnesses.

  14. $Gamma(H\\to b\\bar{b})$ to order $\\alpha\\alpha_s$

    CERN Document Server

    Mihaila, Luminita; Steinhauser, Matthias

    2015-01-01

    We compute the decay rate of the Standard Model Higgs boson to bottom quarks to order $\\alpha\\alpha_s$. We apply the optical theorem and calculate the imaginary part of three-loop corrections to the Higgs boson propagator using asymptotic expansions in appropriately chosen mass ratios. The corrections of order $\\alpha\\alpha_s$ are of the same order of magnitude as the ${\\cal O}(\\alpha_s^3)$ QCD corrections but have the opposite sign.

  15. Photoreduction of alkylmethylviologens with {alpha}-tocopherol in dioctadecyldimethylammonium chloride vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, M.; Baglioni, P.; Kevan, L. [Univ. of Houston, TX (United States)

    1992-03-19

    Electron spin resonance (ESR) spectroscopy is used to detect the photoreduction yield of alkylmethylviologens (AV{sup 2+}) in rapidly frozen dioctadecyldimethylammonium chloride (DODAC) vesicles containing concentrations of {alpha}-tocopherol (major component of vitamin E) from 0 to 23 mol %. The observed radicals are alkylmethylviologen cation radicals (AV{sup +}) from photoirradiated AV{sup 2+} in DODAC vesicles without {alpha}-tocopherol. For 1-3 mol % {alpha}-tocopherol, the major radical is AV{sup +} and the minor radical is a neutral free radical of {alpha}-tocopherol (EO) which is formed by photoinduced conversion from the {alpha}-tocopherol cation radical (EH{sup +}) with DODAC vesicles acting as proton scavengers. The total ESR intensity increases with an increase of the alkyl chain length of AV{sup 2+}. The AV{sup +} intensity increases slightly with increasing {alpha}-tocopherol concentration. For over 9 mol % {alpha}-tocopherol, the major radical becomes EO, and at 17 mol % EO alone is observed. This is explained by acceleration of the photoreduction of AV{sup 2+} to AV{sup +} by electrons released from {alpha}-tocopherol and further photoreduction of AV{sup +} to AV, which is not detected by ESR spectroscopy. The photoyield for 23 mol % {alpha}-tocopherol in DODAC vesicles without AV{sup 2+} is about 2-fold more than that in hexane solution. This enhancement of photoyield suggests that DODAC may act as a proton scavenger and compartmentalize {alpha}-tocopherol to minimize back electron reaction. 26 refs., 8 figs.

  16. Diagnosis of alpha-1-antitrypsin deficiency by DNA analysis of children with liver disease

    Directory of Open Access Journals (Sweden)

    De TOMMASO Adriana Maria Alves

    2001-01-01

    Full Text Available Background - Alpha-1-antitrypsin deficiency is a genetic disorder which is transmitted in a co-dominant, autosomal form. Alpha-1-antitrypsin deficiency affects mainly the lungs and the liver leading, in the latter case, to neonatal cholestasis, chronic hepatitis or cirrhosis. A precise diagnosis of Alpha-1-antitrypsin deficiency may be obtained by biochemical or molecular analysis. Objective - The purpose of this study was to use DNA analysis to examine the presence of an alpha-1-antitrypsin deficiency in 12 children suspected of having this deficiency and who showed laboratory and clinical characteristics of the disease. Patients and Methods - Twelve patients, aged 3 months to 19 years, who had serum alpha-1-antitrypsin levels lower than normal and/or had hepatic disease of undefined etiology were studied. The mutant alleles S and Z of the alpha-1-antitrypsin gene were investigated in the 12 children. Alpha-1-antitrypsin gene organization was analyzed by amplification of genoma through the polymerase chain reaction and digestion with the restriction enzymes Xmnl (S allele and Taq 1 (Z allele. Results - Seven of the 12 patients had chronic liver disease of undefined etiology and the other five patients had low serum levels of alpha-1-antitrypsin as well as a diagnosis of neonatal cholestasis and/or chronic liver disease of undefined etiology. Five of the 12 patients were homozygous for the Z allele (ZZ and two had the S allele with another allele (*S different from Z. Conclusion - These results show that alpha-1-antitrypsin deficiency is relatively frequent in children with chronic hepatic disease of undefined etiology and/or low alpha-1-antitrypsin levels (41.6%. A correct diagnosis is important for effective clinical follow-up and for genetic counseling.

  17. The application of alpha spectrometry to the discovery of new elements heavy-ion beam bombardment

    Science.gov (United States)

    Nitschke, J. M.

    1984-06-01

    Starting with polonium in 1898, alpha spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, alpha spectra have proven simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the "natural" alpha decay series led to the very powerful method of "genetically" linking the decay of new elements to the well-established alpha emission of "daughter" and "granddaughter" nuclei. This technique has been used for all recent discoveries of new elements, including Z = 101, thin samples suitable for alpha spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators, new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in helium gas. Subsequent electrical deposition or a helium jet technique yielded samples that were not only thin enough for alpha spectrometry, but also for alpha and beta-recoil experiments. Many variations of these methods have been developed and will be covered in this paper. For the synthesis of element 106, an aerosol-based recoil transport technique was devised. In this most recent experiments, alpha spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 -1-10 0s for helium jets and 10 1-10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyse them with These latest techniques. Again, alpha spectrometry will play a major role, since the expected signature for the decay of a SHE is a sequence of alpha decays followed by spontaneous fission.

  18. Alpha voltaic batteries and methods thereof

    Science.gov (United States)

    Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)

    2011-01-01

    An alpha voltaic battery includes at least one layer of a semiconductor material comprising at least one p/n junction, at least one absorption and conversion layer on the at least one layer of semiconductor layer, and at least one alpha particle emitter. The absorption and conversion layer prevents at least a portion of alpha particles from the alpha particle emitter from damaging the p/n junction in the layer of semiconductor material. The absorption and conversion layer also converts at least a portion of energy from the alpha particles into electron-hole pairs for collection by the one p/n junction in the layer of semiconductor material.

  19. Innovations in Los Alamos alpha box design

    International Nuclear Information System (INIS)

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented

  20. Innovations in Los Alamos alpha box design

    Energy Technology Data Exchange (ETDEWEB)

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented.

  1. Alpha particles detection in nitrocellulose

    International Nuclear Information System (INIS)

    The method for the manufacturing of the detection films follows these steps: preparation of the mass which includes nitrocellulose in the form of cotton as raw material ethyl acetate, cellosolve acetate, isopropyl and butyl alcohols as solvents and dioctyl phtalate as plasticiser; dilution of the paste; pouring of the diluted mass; and drying of the detection films. The results obtained experimentally are: The determination of the development times of the different thicknesses of the manufactured films. Response linearity of the detectors, variation of the number of tracks according to the distance of the source to the detector. Sizes of the diameter of the tracks depending of the distance detector-alpha emmission source. As a conclusion we can say the the nitrocellulose detectors are specific for alpha radiation; the more effective thicknesses in uranium prospecting works were those of 60 microns, since for the laboratory works the thicknesses of 30 to 40 microns were the ideal; the development technique of the detection films is simple and cheap and can be realized even in another place than the laboratory; this way of the manufacturing of nitrocellulose detection film sensitive to alpha nuclear radiation is open to future research. (author)

  2. Theoretical Calculations and Analysis for n+59Co Reaction up to 20 MeV

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>All cross-sections of neutron-induced reactions, angular distributions, double differential cross sections, and energy spectra for neutron, proton, deuteron, triton, helium and alpha-particle emissions are

  3. The Behaviour of Varying-Alpha Cosmologies

    CERN Document Server

    Barrow, John D; Magueijo, J

    2002-01-01

    We determine the behaviour of a time-varying fine structure 'constant' $\\alpha (t)$ during the early and late phases of universes dominated by the kinetic energy of changing $\\alpha (t)$, radiation, dust, curvature, and lambda, respectively. We show that after leaving an initial vacuum-dominated phase during which $\\alpha$ increases, $\\alpha$ remains constant in universes like our own during the radiation era, and then increases slowly, proportional to a logarithm of cosmic time, during the dust era. If the universe becomes dominated by negative curvature or a positive cosmological constant then $\\alpha$ tends rapidly to a constant value. The effect of an early period of de Sitter or power-law inflation is to drive $\\alpha$ to a constant value. Various cosmological consequences of these results are discussed with reference to recent observational studies of the value of $\\alpha$ from quasar absorption spectra and to the existence of life in expanding universes.

  4. Improved information on electron screening in {sup 7}Li(p,{alpha}){alpha} using the Trojan-horse method

    Energy Technology Data Exchange (ETDEWEB)

    Aliotta, M.; Rolfs, C.; Strieder, F. [Inst. fuer Physik mit Ionenstrahlen, Ruhr-Universitaet Bochum (Germany); Spitaleri, C.; Lattuada, M.; Musumarra, A.; Pizzone, R.G. [Dipt. di Metodologie Fisiche e Chimiche per l' Ingegneria, Univ. di Catania (Italy); Tumino, A. [Catania Univ. (Italy). Ist. di Astronomia

    2000-12-01

    The available astrophysical S(E) factor data for the reaction {sup 7}Li(p,{alpha}){alpha} at 10=}100 keV, while at lower energies this calculated S{sub b}(E) factor curve for bare nuclides drops below the data, which in turn represent the case of electron-shielded nuclides, i.e. the electron-shielded S{sub s}(E) factor. The comparison between S{sub b}(E) and S{sub s}(E) leads to an electron-screening potential energy U{sub e}=350 eV, which is much higher than the adiabatic limit of 175 eV and not understood at present. The deduced value of S{sub b}(0) is considerably smaller than the previously adopted value of 59 keV b, significantly increasing the calculated abundance of {sup 7}Li in big-bang nucleosynthesis. The Trojan-horse method was applied to the reaction {sup 7}Li(p,{alpha}){alpha} to determine the energy dependence of the S{sub b}(E) factor for 10

  5. Identification of noncollagenous sites encoding specific interactions and quaternary assembly of alpha 3 alpha 4 alpha 5(IV) collagen: implications for Alport gene therapy.

    Science.gov (United States)

    Kang, Jeong Suk; Colon, Selene; Hellmark, Thomas; Sado, Yoshikazu; Hudson, Billy G; Borza, Dorin-Bogdan

    2008-12-12

    Defective assembly of alpha 3 alpha 4 alpha 5(IV) collagen in the glomerular basement membrane causes Alport syndrome, a hereditary glomerulonephritis progressing to end-stage kidney failure. Assembly of collagen IV chains into heterotrimeric molecules and networks is driven by their noncollagenous (NC1) domains, but the sites encoding the specificity of these interactions are not known. To identify the sites directing quaternary assembly of alpha 3 alpha 4 alpha 5(IV) collagen, correctly folded NC1 chimeras were produced, and their interactions with other NC1 monomers were evaluated. All alpha1/alpha 5 chimeras containing alpha 5 NC1 residues 188-227 replicated the ability of alpha 5 NC1 to bind to alpha3NC1 and co-assemble into NC1 hexamers. Conversely, substitution of alpha 5 NC1 residues 188-227 by alpha1NC1 abolished these quaternary interactions. The amino-terminal 58 residues of alpha3NC1 encoded binding to alpha 5 NC1, but this interaction was not sufficient for hexamer co-assembly. Because alpha 5 NC1 residues 188-227 are necessary and sufficient for assembly into alpha 3 alpha 4 alpha 5 NC1 hexamers, whereas the immunodominant alloantigenic sites of alpha 5 NC1 do not encode specific quaternary interactions, the findings provide a basis for the rational design of less immunogenic alpha 5(IV) collagen constructs for the gene therapy of X-linked Alport patients. PMID:18930919

  6. Analysis of radiation risk from alpha particle component of soalr particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The Solar Particle Events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and Linear Energy Transfer (LET) spectra in shielding are discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  7. Measurement of the branching ratio for beta-delayed alpha decay of 16N

    CERN Document Server

    Refsgaard, J; Dijck, E A; Fynbo, H O U; Lund, M V; Portela, M N; Raabe, R; Randisi, G; Renzi, F; Sambi, S; Sytema, A; Willmann, L; Wilschut, H W

    2015-01-01

    While the 12C(a,g)16O reaction plays a central role in nuclear astrophysics, the cross section at energies relevant to hydrostatic helium burning is too small to be directly measured in the laboratory. The beta-delayed alpha spectrum of 16N can be used to constrain the extrapolation of the E1 component of the S-factor; however, with this approach the resulting S-factor becomes strongly correlated with the assumed beta-alpha branching ratio. We have remeasured the beta-alpha branching ratio by implanting 16N ions in a segmented Si detector and counting the number of beta-alpha decays relative to the number of implantations. Our result, 1.49(5)e-5, represents a 25% increase compared to the accepted value and implies an increase of 14% in the extrapolated S-factor.

  8. Antisymmetry and channel coupling contributions to the absorption for $p + \\alpha /d + ^{3}He$

    CERN Document Server

    Cooper, S G

    1997-01-01

    To understand recently established empirical p + alpha potentials, RGM calculations followed by inversion are made to study contributions of the d + 3He reaction channels and deuteron distortion effects to the p + alpha potential. An equivalent study of the d + 3He potential is also presented. The contributions of exchange non-locality to the absorption are simulated by including an phenomenological imaginary potential in the RGM. These effects alone strongly influence the shape of the imaginary potentials for both p + alpha and d + 3He. The potentials local-equivalent to the fully antisymmetrised-coupled channels calculations have a significant parity-dependence in both real and imaginary components, which for p + alpha is qualitatively similar to that found empirically. The effects on the potentials of the further inclusion of deuteron distortion are also presented. The inclusion of a spin-orbit term in the RGM, adds additional terms to the phase-equivalent potential, most notably the comparatively large im...

  9. Changes of lipid peroxides and alpha-tocopherol in rats with experimentally induced myocardial necrosis.

    Directory of Open Access Journals (Sweden)

    Higuchi,Yoshimi

    1982-04-01

    Full Text Available Myocardial necrosis was produced in rats by injection of isoproterenol (80 mg per kg body weight. Lipid peroxides were measured by the thiobarbituric acid reaction. alpha-Tocopherol was assayed by fluorometric analysis. Immediately after isoproterenol injections, serum lipid peroxides increased and serum alpha-tocopherol decreased, then gradually returned to the pre-injection levels. Lipid peroxides increased more rapidly in the heart and liver than in serum. Alpha-Tocopherol decreased in the heart and liver, then gradually returned to the pre-injection levels. These results indicate that increase in serum lipid peroxides reflects production of peroxides in myocardial tissue and in liver. The decrease in alpha-tocopherol may be due to consumption as anti-oxidants in the vascular system and organs.

  10. Analysis of radiation risk from alpha particle component of solar particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  11. Multifractal scaling analysis of autopoisoning reactions over a rough surface

    CERN Document Server

    Chaudhari, A; Lee, S L

    2003-01-01

    Decay type diffusion-limited reactions (DLR) over a rough surface generated by a random deposition model were performed. To study the effect of the decay profile on the reaction probability distribution (RPD), multifractal scaling analysis has been carried out. The dynamics of these autopoisoning reactions are controlled by the two parameters in the decay function, namely, the initial sticking probability (P sub i sub n sub i) of every site and the decay rate (m). The smaller the decay rate, the narrower is the range of alpha values in the alpha-f(alpha) multifractal spectrum. The results are compared with the earlier work of DLR over a surface of diffusion-limited aggregation (DLA). We also considered here the autopoisoning reactions over a smooth surface for comparing our results, which show clearly how the roughness affects the chemical reactions. The q-tau(q) multifractal curves for the smooth surface are linear whereas those for the rough surface are nonlinear. The range of alpha values in the case of a ...

  12. Expression of an alpha-galactosidase from Saccharomyces cerevisiae in Aspergillus awamori and Aspergillus oryzae.

    Science.gov (United States)

    Murphy, R A; Power, R F G

    2002-02-01

    A gene encoding alpha-galactosidase activity was isolated by polymerase chain reaction (PCR) from Saccharomyces cerevisiae NCYC686 and separately placed under the control of transcriptional elements regulating alpha-amylase expression in Aspergillus oryzae and glucoamylase expression in A. awamori. Following transformation of both A. oryzae and A. awamori with their respective expression vectors, induction of heterologous alpha-galactosidase from positively selected clones was effected through the addition of soluble starch (10% wt/vol) to the growth medium. Upon induction in A. oryzae, a transcriptional instability resulted in degradation of mRNA encoding heterologous alpha-galactosidase, thus preventing expression of the active enzyme. The use of a gene fusion strategy in A. awamori overcame this instability and resulted in stable expression of S. cerevisiae alpha-galactosidase. Subsequent to initial (shake flask) experiments, a series of scale-up and optimisation studies led to heterologous expression of the recombinant enzyme in batch fermentation at 51 U mg(-1) total extracellular protein. This was higher than previously published works, which reported extracellular levels of heterologous alpha-galactosidase up to 38 U mg(-1) total protein. Analysis of crude extracts of the fermentation medium revealed significant differences between the activity parameters reported previously in the literature for this enzyme and those observed here. The recombinant enzyme exhibited thermostability properties not previously reported for S. cerevisiae alpha-galactosidase, a trait which would make it suitable for use in processes requiring high temperatures. PMID:12074058

  13. Measurement of $\\alpha$-particle quenching in LAB based scintillator in independent small-scale experiments

    CERN Document Server

    von Krosigk, B; Hans, S; Junghans, A R; Kögler, T; Kraus, C; Kuckert, L; Liu, X; Nolte, R; O'Keeffe, H M; Tseung, H S Wan Chan; Wilson, J R; Wright, A; Yeh, M; Zuber, K

    2015-01-01

    The $\\alpha$-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, $\\alpha$-particles were produced in the scintillator via $^{12}$C($n$,$\\alpha$)$^9$Be reactions. In the second approach, the scintillator was loaded with 2% of $^{\\mathrm{nat}}$Sm providing an $\\alpha$-emitter, $^{147}$Sm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants $^{222}$Rn, $^{218}$Po and $^{214}$Po provided the $\\alpha$-particle signal. The behavior of the observed $\\alpha$-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter $kB$ ranges from $(0.0071\\pm0.0003)$ cm/MeV to $(0.0076\\pm0.0003)$ cm/MeV. In the first approach, the $\\alpha$-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proto...

  14. High efficiency charged-particle spectrometer using gridded ionization chamber for fast-neutron induced reactions

    International Nuclear Information System (INIS)

    A high efficiency charged particle spectrometer for fast neutron induced reactions has been developed using a gridded-ionization chamber taking advantage of its large solid angle and capability of energy-angle determination. It is characterized by high stopping-power and low background to be applicable for alpha-particles emitted by 15 MeV neutrons and protons for MeV incident neutrons. The spectrometer has been applied successfully for (n, alpha) and (n, p) reactions. (orig.)

  15. Enantioconvergent synthesis by sequential asymmetric Horner-Wadsworth-Emmons and palladium-catalyzed allylic substitution reactions

    DEFF Research Database (Denmark)

    Pedersen, Torben Møller; Hansen, E. Louise; Kane, John;

    2001-01-01

    A new method for enantioconvergent synthesis has been developed. The strategy relies on the combination of an asymmetric Horner-Wadsworth-Emmons (HWE) reaction and a palladium-catalyzed allylic substitution. Different $alpha@-oxygen-substituted, racemic aldehydes were initially transformed by...... asymmetric HWE reactions into mixtures of two major $alpha@,$beta@-unsaturated esters, possessing opposite configurations at their allylic stereocenters as well as opposite alkene geometry. Subsequently, these isomeric mixtures of alkenes could be subjected to palladium-catalyzed allylic substitution...

  16. $\\alpha_s$ extractions from CMS (status and plans)

    CERN Document Server

    Rabbertz, Klaus

    2015-01-01

    Numerous extractions of the strong coupling constant have been performed at hadron colliders, in particular from jet cross sections. The latest results achieved by the experiments at the $ep$ collider HERA, at the $p\\bar{p}$ collider Tevatron, and at the $pp$ collider LHC are reported with emphasis on the CMS experiment for the latter. Future prospects for precision determinations of $\\alpha_s(M_Z)$ and for testing the running of the strong coupling beyond the TeV range are discussed.

  17. Phenylalanine Aminomutase-Catalyzed Addition of Ammonia to Substituted Cinnamic Acids : a Route to Enantiopure alpha- and beta-Amino Acids

    NARCIS (Netherlands)

    Szymanski, Wiktor; Wu, Bian; Weiner, Barbara; Wildeman, Stefaan de; Feringa, Ben L.; Janssen, Dick B.

    2009-01-01

    An approach is described for the synthesis of aromatic alpha- and beta-amino acids that Uses phenylalanine aminomutase to catalyze a highly enantioselective addition of ammonia to substituted cinnamic acids. The reaction has a broad scope and yields Substituted alpha- and beta-phenylalanines with ex

  18. Palladium-Catalyzed alpha-Arylation of Tetramic Acids

    DEFF Research Database (Denmark)

    Storgaard, Morten; Dorwald, F. Z.; Peschke, B.;

    2009-01-01

    A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2...... effect on their reactivity: both electron-rich and electron-poor aryl chlorides and bromides or triflates led to good yields. Ortho-substituted aryl halides and heteroaryl halides, however, did not undergo the title reaction....

  19. Measurement of Alpha Emitters Concentration in Imported Cigarettes

    International Nuclear Information System (INIS)

    The aime of this study was to measured the alpha emitters concentration of (15) different kinds of imported cigarettes. the nuclear reaction used U-235(n, f) obtained by the bombardment of U-235 with thermal neutrons from (AmBe)neutron source with thermal flux of(5*103 n.cm-2.s-1). The Results obtained showed the values of the Uranium concentration, and varies from (0.041 ppm) in five stares kind to (2.374ppm) in Machbeth (chocolate) 100's kind. All the result obtained are within the limit levels as given by UNSCAR data

  20. Side-chain-anchored N(alpha)-Fmoc-Tyr-OPfp for bidirectional solid-phase synthesis

    DEFF Research Database (Denmark)

    Olsen, Christian A; Jørgensen, Malene; Hansen, Steen H; Witt, Matthias; Jaroszewski, Jerzy W; Franzyk, Henrik

    2005-01-01

    [reaction: see text] A mild resin-immobilization strategy employing a readily prepared trityl bromide resin for anchoring building blocks via a phenol group has been developed. With N(alpha)-Fmoc-Tyr-OPfp as a starter building block, it was possible to prepare asymmetrically substituted hybrids o...

  1. Quantum chemical calculations on the Peterson olefination with alpha-silyl ester enolates

    DEFF Research Database (Denmark)

    Gillies, Malcolm Bjørn; Tønder, Janne E.; Tanner, David Ackland;

    2002-01-01

    The reaction of stabilized Peterson reagents (alpha-silyl ester enolates) with ketones has been studied theoretically and experimentally. Enolate geometry was studied by trapping experiments and NMR spectroscopy and was found to differ markedly with the nature of the base (LiHMDS vs LDA vs KHMDS...

  2. The Resonance Theory of Proton and Alpha Decay from Hot Sources

    CERN Document Server

    Karpeshin, F F; Vardaci, E; Brondi, A; Moro, R; Abramovich, S N; Serov, V I; Vardaci, Emanuele; Brondi, Augusto; Moro, Renata

    2005-01-01

    The consecutive microscopic solution is presented of the problem of tunneling of a particle through a potential barrier. The method is applied to the alpha and proton decay of compound systems formed in fusion reaction. Appearance of the peaks in the spectrum of emitted particles is predicted. The peaks correspond to quasistationary states inside the potential barrier.

  3. The 2009 Wolrd Average of $\\alpha_s (M_Z)$

    CERN Document Server

    Bethke, Siegfried

    2009-01-01

    Measurements of $\\alpha_s$, the coupling strength of the Strong Interaction between quarks and gluons, are summarised and an updated value of the world average of $\\alpha_s (M_Z)$ is derived. Building up on previous reviews, special emphasis is laid on the most recent determinations of $\\alpha_s$. These are obtained from $\\tau$-decays, from global fits of electroweak precision data and from measurements of the proton structure function $\\F_2$, which are based on perturbative QCD calculations up to $O(\\alpha_s^4)$; from hadronic event shapes and jet production in $\\epem$ annihilation, based on $O(\\alpha_s^3) $ QCD; from jet production in deep inelastic scattering and from $\\Upsilon$ decays, based on $O(\\alpha_s^2) $ QCD; and from heavy quarkonia based on unquenched QCD lattice calculations. Applying pragmatic methods to deal with possibly underestimated errors and/or unknown correlations, the world average value of $\\alpha_s (M_Z)$ results in $\\alpha_s (M_Z) = 0.1184 \\pm 0.0007$. The measured values of $\\alpha...

  4. Three-Dimensional Conformal Radiotherapy in Prostate Cancer Patients: Rise in Interleukin 6 (IL-6) but not IL-2, IL-4, IL-5, Tumor Necrosis Factor-{alpha}, MIP-1-{alpha}, and LIF Levels

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Lopes, Carlos [Universidade do Vale do Paraiba, Centro de Oncologia Radioterapica do Vale do Paraiba, Universidade do Vale do Paraiba Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Sao Jose dos Campos, Sao Paulo (Brazil); Callera, Fernando, E-mail: fcallera@gmail.com [Centro de Hematologia Onco-hematologia e Transplantes de Medula Ossea do Vale do Paraiba, Sao Paulo (Brazil)

    2012-03-15

    Purpose: To investigate the effect of radiotherapy (RT) on serum levels of interleukin-2 (IL-2), IL-4, IL-5, IL-6, tumor necrosis factor alpha (TNF-{alpha}), macrophage inflammatory protein-1-alpha (MIP-1-{alpha}) and leukemia inhibitory factor (LIF) in patients with prostate cancer. Methods and Materials: Forty eight patients with prostate cancer received three-dimensional conformal blocking radiation therapy with a linear accelerator. IL-2, IL-4, IL-5, IL-6, TNF-{alpha}, MIP-1-{alpha}, and LIF levels were measured by the related immunoassay kit 1 day before the beginning of RT and during RT at days 15 and 30. Results: The mean IL-2 values were elevated before and during the RT in contrast with those of IL-4, IL-5, IL-6, TNF-{alpha}, MIP-1-{alpha}, and LIF, which were within the normal range under the same conditions. Regarding markers IL-2, IL-4, IL-5, TNF-{alpha}, MIP-1-{alpha}, and LIF, comparisons among the three groups (before treatment and 15 and 30 days during RT) did not show significant differences. Although values were within the normal range, there was a significant rise in IL-6 levels at day 15 of RT (p = 0.0049) and a decline at day 30 to levels that were similar to those observed before RT. Conclusions: IL-6 appeared to peak after 15 days of RT before returning to pre-RT levels. In contrast, IL-2, IL-4, IL-5, TNF-{alpha}, MIP-1-{alpha}, and LIF levels were not sensitive to irradiation. The increased levels of IL-6 following RT without the concurrent elevation of other cytokines involved in the acute phase reaction did not suggest a classical inflammatory response to radiation exposure. Further studies should be designed to elucidate the role of IL-6 levels in patients with prostate cancer treated with RT.

  5. Targeted alpha therapy for cancer

    Science.gov (United States)

    Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John

    2004-08-01

    Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 µCi in human

  6. The Alpha Magnetic Spectrometer (AMS)

    CERN Document Server

    Alcaraz, J; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Babucci, E; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bizzaglia, S; Blasko, S; Bölla, G; Boschini, M; Bourquin, Maurice; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cecchi, C; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Chuang, Y L; Cindolo, F; Commichau, V; Contin, A; Crespo, P; Cristinziani, M; Cunha, J P D; Dai, T S; Deus, J D; Dinu, N; Djambazov, L; Dantone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, P; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Huang, M A; Hungerford, W; Ionica, M; Ionica, R; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kenny, J; Kim, W; Klimentov, A; Kossakowski, R; Koutsenko, V F; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lee, S C; Levi, G; Levchenko, P M; Liu, C L; Liu, H T; Lopes, I; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mourao, A; Mujunen, A; Palmonari, F; Papi, A; Park, I H; Pauluzzi, M; Pauss, Felicitas; Perrin, E; Pesci, A; Pevsner, A; Pimenta, M; Plyaskin, V; Pozhidaev, V; Postolache, V; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Röser, U; Roissin, C; Sagdeev, R; Sartorelli, G; Schwering, G; Scolieri, G; Seo, E S; Shoutko, V; Shoumilov, E; Siedling, R; Son, D; Song, T; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Ulbricht, J; Urpo, S; Usoskin, I; Valtonen, E; Vandenhirtz, J; Velcea, F; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, Gert M; Vitè, Davide F; Gunten, H V; Wallraff, W; Wang, B C; Wang, J Z; Wang, Y H; Wiik, K; Williams, C; Wu, S X; Xia, P C; Yan, J L; Yan, L G; Yang, C G; Yang, M; Ye, S W; Yeh, P; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B

    2002-01-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m sup 2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  7. The Alpha Magnetic Spectrometer (AMS)

    International Nuclear Information System (INIS)

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS

  8. The Alpha Magnetic Spectrometer (AMS)

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Azzarello, P.; Babucci, E.; Baldini, L.; Basile, M.; Barancourt, D.; Barao, F.; Barbier, G.; Barreira, G.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Bene, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bizzaglia, S.; Blasko, S.; Boella, G.; Boschini, M.; Bourquin, M.; Brocco, L.; Bruni, G.; Buenerd, M.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Camps, C.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cecchi, C.; Chang, Y.H.; Chen, H.F.; Chen, H.S.; Chen, Z.G.; Chernoplekov, N.A.; Chiueh, T.H.; Chuang, Y.L.; Cindolo, F.; Commichau, V.; Contin, A. E-mail: contin@bo.infn.it; Crespo, P.; Cristinziani, M.; Cunha, J.P. da; Dai, T.S.; Deus, J.D.; Dinu, N.; Djambazov, L.; DAntone, I.; Dong, Z.R.; Emonet, P.; Engelberg, J.; Eppling, F.J.; Eronen, T.; Esposito, G.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P.H.; Fluegge, G.; Fouque, N.; Galaktionov, Yu.; Gervasi, M.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W.Q.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Huang, M.A.; Hungerford, W.; Ionica, M.; Ionica, R.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kenny, J.; Kim, W.; Klimentov, A.; Kossakowski, R.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lee, S.C.; Levi, G.; Levtchenko, P.; Liu, C.L.; Liu, H.T.; Lopes, I.; Lu, G.; Lu, Y.S.; Luebelsmeyer, K.; Luckey, D.; Lustermann, W.; Mana, C.; Margotti, A.; Mayet, F.; McNeil, R.R.; Meillon, B.; Menichelli, M.; Mihul, A.; Mourao, A.; Mujunen, A.; Palmonari, F.; Papi, A.; Park, I.H.; Pauluzzi, M.; Pauss, F.; Perrin, E.; Pesci, A.; Pevsner, A.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Postolache, V.; Produit, N.; Rancoita, P.G.; Rapin, D.; Raupach, F.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J.P.; Riihonen, E.; Ritakari, J.; Roeser, U.; Roissin, C.; Sagdeev, R.; Sartorelli, G.; Schultz von Dratzig, A.; Schwering, G.; Scolieri, G.; Seo, E.S.; Shoutko, V.

    2002-02-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m{sup 2}) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  9. Genomic organization of the bovine alpha-S1 casein gene.

    OpenAIRE

    Koczan, D; Hobom, G.; Seyfert, H.M.

    1991-01-01

    We report the sequence of the complete bovine alpha-s1 casein gene eludicating for the first time the genomic organization of an alpha-s type casein gene. Extending over 17508 bp the gene is split into 19 exons, ranging in size from 24 bp to 385 bp. Except for the translational stop codon not a single coding triplet of the alpha-s1 reading frame is disrupted by any of the splice junctions, which all confirm to known splice consensus sequences. Nine out of 16 coding exons begin with a 'GAX' co...

  10. Reaction Rate Sensitivity of the gamma-Process Path

    OpenAIRE

    Rauscher, T.

    2004-01-01

    The location of the (gamma,p)/(gamma,n) and (gamma,alpha)/(gamma,n) line at gamma-process temperatures is discussed, using recently published reaction rates based on global Hauser-Feshbach calculations. The results can directly be compared to previously published, classic gamma-process discussions. The nuclei exhibiting the largest sensitivity to uncertainties in nuclear structure and reaction parameters are specified.

  11. Alpha-interferon in the treatment of nodular lymphomas.

    Science.gov (United States)

    Urba, W J; Longo, D L

    1986-12-01

    Patients with nodular lymphoma initially respond to a number of therapies but relapse is common and inexorable with time, and despite further therapy, most patients will ultimately die of their lymphoma. The recent demonstration of their sensitivity to alpha-interferon is promising. The importance of this human antitumor effect is that it is presumably based on mechanisms different from conventional agents. Phase I trials of various doses and schedules of recombinant alpha-interferon have shown that effective serum levels can be obtained by intramuscular (IM), intravenous (IV), or subcutaneous (SC) routes. Virtually all patients experienced some degree of acute toxicity manifested by fever, chills, myalgia, and headache. Tolerance usually developed to acute adverse effects within the first few weeks of therapy, regardless of dose or schedule. Fatigue and anorexia were the most important adverse reactions, occurring during the first two weeks of treatment and generally persisting for the duration of therapy. Occasional adverse effects relating to the central nervous and cardiovascular systems have been reported. Primary laboratory abnormalities observed during treatment include decreases in hematologic parameters and elevations of liver function tests. The clinical efficacy of alpha-interferon, both natural and recombinant, has been demonstrated in both untreated and heavily pretreated patients with nodular lymphoma. The response rate has approached 50% in recent studies; however, less than half were complete responders. Future directions include combination of interferon with cytotoxic agents or other biological response modifiers and use as adjuvant therapy. PMID:3541218

  12. [Aspergillus niger alpha-N-acetylgalactosaminidase: isolation, purification and properties].

    Science.gov (United States)

    Borzova, N V; Varbanets, L D

    2006-01-01

    alpha-N-acetylgalactosaminidase has been isolated from liquid culture of micromycete Aspergillus niger and purified 600 times by ammonium sulphate precipitation followed by ion exchange and gel-filtration chromatography on TSK-gels with specific activity 10.5 U/mg of protein. The preparation was homogenic: its molecular mass by the data of gel-filtration on Sepharose 6B was 430 kDa, on PAAGE in the system of DDSNa--70 kDa. That gives every reason to suppose oligomeric structure of the enzyme molecule. The carbohydrate component, including mannose, galactose, glucosamine and two nonidentified hexosamines was observed in alpha-N-acetylgalactosaminidase. Thermo- and pH- optima were 60 degrees C and pH 3.5, respectively. The enzyme was thermo- and pH-stable, resistant in storage. The enzyme was found to exhibit strict specificity in respect ofglycon. It was shown that enzyme was competitively inhibited by substrate and reaction product. Km and Vmax with respect to nitrophenyl substrate were 1.25 mM and 10.5 mkmole/min/mg of protein. The activity of glycosidase tested was independent of the presence of metal ions. The presence of carboxylic group of C-terminal aminoacid and imidazol group of hystidine in active centre of molecule was established. A number of natural and synthetic substrates were able to activate (50-200%) production of A. niger alpha-N-acetylgalactosaminidase. PMID:17290780

  13. Nanodosimetry of radon alpha particles

    International Nuclear Information System (INIS)

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several open-quotes classicalclose quotes models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of open-quotes associated surfaceclose quotes (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea's associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation

  14. Nanodosimetry of radon alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Zaider, M. [Columbia Univ. New York, NY (United States); Varma, M.N. [U.S. Department of Energy, Washington, DC (United States)

    1992-12-31

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several {open_quotes}classical{close_quotes} models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of {open_quotes}associated surface{close_quotes} (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea`s associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation.

  15. Contribution to the study of 6Li + 6Li et 6Li + 9Be reactions

    International Nuclear Information System (INIS)

    This research thesis reports measurements of coincidence between γ rays and particles charged in 6Li + 6Li and 6Li + 9Be reactions. These measurements have been repeated with some technical improvements which are described: discrimination between protons and alphas of 7Li* + 4He + p, simultaneous recording of fortuitous coincidences, assessment of the proportion of charged particles at a final state beyond the detection threshold. 'alpha-alpha' coincidences of the 6Li + 6Li → 3α reaction have also been recorded in conditions which better suited the rough study of the middle of the Dalitz diagram than the precise study of the burst into two energetic alphas. Some information have been obtained from 'alpha-p' coincidences of 7Li* + 4He + p and 7Li* + 4He + p. For these measurements, a multi-parametric installation has been developed for the recording of angular correlations at several simultaneous angles

  16. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, Alex; Franses, Philip Hans

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for ...

  17. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, A. J.; Franses, Ph.H.B.F.

    2003-01-01

    Coefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for significant ...

  18. Conformons in alpha-helical proteins

    CERN Document Server

    Atanasov, Victor

    2009-01-01

    We propose the conformon as a quantum of conformational change for energy transfer in alpha-helical proteins. The underlying mechanism of interaction between the quantum of excitation and the conformational degrees of freedom is nonlinear and leads to solitary wave packets of conformational energy. The phenomenon is specific to alpha-helices and not to beta-sheets in proteins due to the three strands of hydrogen bonds constituting the alpha-helical backbone.

  19. Mtp-40 and alpha antigen gene fragment amplification for the detection of Mycobacterium tuberculosis in Colombian clinical specimens

    OpenAIRE

    Alfonso Rosalba; Romero Rosa Elena; Patarroyo Manuel Elkin; Murillo Luis Angel

    2002-01-01

    In this study, the use of Mtp-40 and alpha antigen polymerase chain reaction (PCR) amplification fragments for the precise tuberculosis (TB) diagnosis was evaluated. One hundred and ninety two different samples were obtained from 113 patients with suspected TB. Mtp-40 and alpha antigen protein genes were amplified by the PCR technique and compared to both the "gold standard" (culture) test, as well as the clinical parameters (including a clinical record and X-ray film exam in 113 patients). T...

  20. Levels of eicosanoids (6-oxo-PGF1 alpha and 8-epi-PGF2 alpha) in human and porcine lymphatics and lymph.

    Science.gov (United States)

    Oguogho, A; Kaliman, J; Sinzinger, H

    1998-12-01

    Prostaglandin (PG)I2 is the primary eicosanoid synthesized by human lymphatics and 8-epi-PGF2 alpha, an isoprostane formed during free radical catalyzed peroxidation, is the most potent stimulator of lymphatic contraction tested thus far. We now examine the respective concentrations in the lymphatic wall of both human and porcine lymphatics and lymph fluid using specific immunoassays. Although both compounds are detectable in the lymphatic wall and lymph fluid, PGI2- (via its main metabolite 6-oxo-PGF1 alpha) is greater in the lymphatic wall whereas 8-epi-PGF2 alpha dominates in lymph fluid. Because inflammation is associated with oxidative injury, which in turn stimulates release of isoprostane, eicosanoid derivatives may modulate lymphatic tone during acute tissue reaction. PMID:9949390

  1. Quantum time scales in alpha tunneling

    CERN Document Server

    Kelkar, N G; Nowakowski, M

    2008-01-01

    The theoretical treatment of alpha decay by Gamow is revisited by investigating the quantum time scales in tunneling. The time spent by an alpha particle in front of the barrier and traversing it before escape is evaluated using microscopic alpha nucleus potentials. The half-life of a nucleus is shown to correspond to the time spent by the alpha knocking in front of the barrier. Calculations for medium and super heavy nuclei show that from a multitude of available tunneling time definitions, the transmission dwell time gives the bulk of the lifetime of the decaying state, in most cases.

  2. Prospects for alpha particle studies on TFTR

    International Nuclear Information System (INIS)

    TFTR is expected to produce approximately 5 MW of alpha heating during the D/T Q ≅ 1 phase of operation in 1990. At that point the collective confinement properties and the heating effects of alpha particles become accessible for study for the first time. This paper outlines the potential performance of TFTR with respect to alpha particle production, the diagnostics which will be available for alpha particle measurements, and the physics issues which can be studied both before and during D/T operation

  3. [Alpha-linolenic acid and cardiovascular diseases].

    Science.gov (United States)

    Ristić-Medić, Danijela; Ristić, Gordana; Tepsić, Vesna

    2003-01-01

    IMPORTANCE AND METABOLISM OF ALPHA-LINOLENIC ACID: Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken by food. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid. It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. POTENTIAL ROLE IN PATHOGENESIS OF CARDIOVASCULAR DISEASES: Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. DIETARY SOURCES AND NUTRITION RECOMMENDATIONS: Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid. PMID:15510909

  4. Alpha particle problems in shielded support systems

    International Nuclear Information System (INIS)

    Alpha particle confinement is considered in the case of internal conductor systems with magnetically shielded supports. The treatment includes problems of energy transfer to the background plasma, the balance between radiation losses and alpha particle heating, mirror confinement in the main poloidal field, the cut-off and shielding conditions at the supports, ambipolar electric fields, wall interaction, and support location. With a proper and technically realizable choice of parameter values, it should become possible to achieve alpha particle heating as well as to manage the reactor technological problems due to alpha particle interaction with the supports. (Auth.)

  5. Quantum Estimates of Alpha Emitter Life Time

    Directory of Open Access Journals (Sweden)

    B. Santoso

    2006-01-01

    Full Text Available Quantum estimates of several alpha radioactive life time have been made using the probability of quantum tunneling through the nuclear potential barrier. It is assumed that for a given nucleus with mass number A and isotopic number Z, there exists an alpha particle moving freely back and forth in the nucleus with mass and isotopic numbers A -4 and Z-2. If the probability of penetrating the nuclear potential barrier is Τ, then after N times (N=1/Τ hitting the barrier an alpha particle is emitted. To obtain the elapsed time for emitting an alpha particle requires N times τ0, where τ0 is the time travel for alpha across the nuclear diameter, which is dependent on alpha energy. It is assumed here that this kinetic energy is the same as the emitted energy. The emitting alpha kinetic energies here are calculated by the difference of the masses of the parent and daughter nuclei and the alpha particles. They are in closed agreement with the experimental observations. While the alpha radioactive life time are not the same order of magnitudes but give the same linearity on the logarithmic scale as function of the inverse square root of energy.

  6. Images of mycobacterium for nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Lima, C.T.S.; Crispim, V.R. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mails: clima@con.ufrj.br; verginia@con.ufrj.br; Souza, H.V.C. [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca, Rio de Janeiro, RJ (Brazil)]. E-mail: hvcsouza@gmail.com; Silva, M.G. [Universidade Federal do Rio de Janeiro UFRJ, Rio de Janeiro, RJ (brazil). Inst. de Microbiologia Prof. Paulo Goes]. E-mail: marlei_gomes@yahoo.com.br

    2007-07-01

    According to the World Health Organization (WHO) tuberculosis is responsible for 2.9 million deaths annually worldwide. The necessity for optimizing time to detect the tuberculosis bacillus (mycobacterium tuberculosis) in the sputum samples of affected individuals (TB patients) led to the development of a methodology based on the doping with boron of the bacillus, submission of the samples to thermal neutron beam and ionizing particles, generating nuclear reactions of the types: {sup 10}B (n,{alpha}){sup 7}Li and {sup 10} B({alpha}, p){sup 13}C. Images of these bacilli are obtained by means of the nuclear tracks produced in the CR-39 detector for particles products of these nuclear reactions, {alpha} and p. When the CR-39 is submitted to a chemical attack the traces are developed and the images of the microorganisms registered in the detector can be observed with a conventional light microscope, characterizing them by morphology. The use of this methodology results in images of the mycobacterium tuberculosis becoming more defined and enlarged than those obtained by bacilloscopy, in which the sample is submitted to the method of coloration of Ziehl-Neelsen (ZN) and observed in light microscopy. (author)

  7. SOURCES 4C : a code for calculating ([alpha],n), spontaneous fission, and delayed neutron sources and spectra.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W. B. (William B.); Perry, R. T. (Robert T.); Shores, E. F. (Erik F.); Charlton, W. S. (William S.); Parish, Theodore A.; Estes, G. P. (Guy P.); Brown, T. H. (Thomas H.); Arthur, Edward D. (Edward Dana),; Bozoian, Michael; England, T. R.; Madland, D. G.; Stewart, J. E. (James E.)

    2002-01-01

    SOURCES 4C is a computer code that determines neutron production rates and spectra from ({alpha},n) reactions, spontaneous fission, and delayed neutron emission due to radionuclide decay. The code is capable of calculating ({alpha},n) source rates and spectra in four types of problems: homogeneous media (i.e., an intimate mixture of a-emitting source material and low-Z target material), two-region interface problems (i.e., a slab of {alpha}-emitting source material in contact with a slab of low-Z target material), three-region interface problems (i.e., a thin slab of low-Z target material sandwiched between {alpha}-emitting source material and low-Z target material), and ({alpha},n) reactions induced by a monoenergetic beam of {alpha}-particles incident on a slab of target material. Spontaneous fission spectra are calculated with evaluated half-life, spontaneous fission branching, and Watt spectrum parameters for 44 actinides. The ({alpha},n) spectra are calculated using an assumed isotropic angular distribution in the center-of-mass system with a library of 107 nuclide decay {alpha}-particle spectra, 24 sets of measured and/or evaluated ({alpha},n) cross sections and product nuclide level branching fractions, and functional {alpha}-particle stopping cross sections for Z < 106. The delayed neutron spectra are taken from an evaluated library of 105 precursors. The code provides the magnitude and spectra, if desired, of the resultant neutron source in addition to an analysis of the'contributions by each nuclide in the problem. LASTCALL, a graphical user interface, is included in the code package.

  8. MUST2: A new generation array for direct reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Pollacco, E.; Atkin, E.; Baron, P.; Drouart, A.; Druillole, F.; Gillibert, A.; Lapoux, V.; Le Ven, V.; Lugiez, F.; Nalpas, L.; Paul, B.; Rouger, M.; Skaza, F. [CEA/DSM/DAPNIA/SPhN, Saclay, Gif-sur-Yvette Cedex (France); Beaumel, D.; Baronick, J.P.; Becheva, E.; Blumenfeld, Y.; Edelbruck, P.; Lavergne, L.; Leterrier, L.; Richard, A.; Vilmay, M.; Wanlin, E. [IPN Orsay, Orsay Cedex (France); Roussel-Chomaz, P.; Boujrad, A.; Gelin, M.; Houarner, Ch.; Leberthe, G.; Olivier, L.; Raine, B.; Saillant, F.; Tripon, M.; Wittwer, M. [GANIL (DSM/CEA, IN2P3/CNRS), BP 5027, Caen Cedex 5 (France)

    2005-09-01

    We have developed a new telescope array, dedicated to the study of direct reactions of exotic nuclei on light targets in inverse kinematics. This device, called MUST2, is briefly described, and the results of the first tests performed with an alpha source and Ni beams at 10 and 75 MeV/u on a CDH target are presented. (orig.)

  9. $\\alpha_{s}$ from the (revised) ALEPH data for $\\tau$ decay

    CERN Document Server

    Boito, Diogo; Maltman, Kim; Osborne, James; Peris, Santiago

    2014-01-01

    We present a new analysis of $\\alpha_s$ from hadronic $\\tau$ decays based on the recently revised ALEPH data. The analysis is based on a strategy which we previously applied to the OPAL data. We critically compare our strategy to the one traditionally used and comment on the main differences. Our analysis yields the values $\\alpha_s(m_\\tau^2)=0.296\\pm 0.010$ using fixed-order perturbation theory, and $\\alpha_s(m_\\tau^2)=0.310\\pm 0.014$ using contour-improved perturbation theory. Averaging these values with our previously obtained values from the OPAL data, we find $\\alpha_s(m_\\tau^2)=0.303\\pm 0.009$, respectively, $\\alpha_s(m_\\tau^2)=0.319\\pm 0.012$, as the most reliable results for $\\alpha_s$ from $\\tau$ decays currently available.

  10. Failure of isolated rat tibial periosteal cells to 5 alpha reduce testosterone to 5 alpha-dihydrotestosterone

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.T.; Bleiberg, B.; Colvard, D.S.; Keeting, P.E.; Evans, G.; Spelsberg, T.C. (Mayo Clinic, Rochester, MN (USA))

    1990-07-01

    Periosteal cells were isolated from tibiae of adult male rats after collagenase treatment. Northern blot analysis of total cytoplasmic RNA extracted from the isolated periosteal cells was positive for expression of genes encoding the osteoblast marker proteins osteocalcin (BGP) and pre-pro-alpha 2(I) chain of type 1 precollagen. The isolated periosteal cells were incubated with 1 nM (3H)testosterone (({sup 3}H)T) for up to 240 minutes and the reaction products separated by high-performance liquid chromatography. ({sup 3}H)5 alpha-dihydrotestosterone (({sup 3}H)DHT) was not detected in extracts of periosteal cell incubations. In contrast, ({sup 3}H)DHT was produced in a time-dependent manner by cells from seminal vesicles. These results suggest that testosterone 5 alpha-reductase activity is not expressed by osteoblasts in rat tibial periosteum and that the anabolic effects of androgens in this tissue are not mediated by locally produced DHT.

  11. Purification and properties of alpha-pinene oxide lyase from Nocardia sp. strain P18.3.

    OpenAIRE

    Griffiths, E T; Harries, P C; Jeffcoat, R; Trudgill, P W

    1987-01-01

    alpha-Pinene oxide is an intermediate in the degradation of alpha-pinene by Nocardia sp. strain P18.3 and some Pseudomonas strains. The epoxide is cleaved by a lyase which catalyzes a concerted reaction in which both rings of the bicyclic structure are cleaved with the formation of cis-2-methyl-5-isopropylhexa-2,5-dienal. The enzyme has been purified to homogeneity from Nocardia sp. strain P18.3. It was induced by growth with alpha-pinene and constituted 6 to 7% of the soluble protein of cell...

  12. $\\alpha$-curvatures and $\\alpha$-flows on low dimensional triangulated manifolds

    OpenAIRE

    Ge, Huabin; Xu, Xu

    2015-01-01

    In this paper, we introduce two discrete curvature flows, which are called $\\alpha$-flows on two and three dimensional triangulated manifolds. For triangulated surface $M$, we introduce a new normalization of combinatorial Ricci flow (first introduced by Bennett Chow and Feng Luo \\cite{CL1}), aiming at evolving $\\alpha$ order discrete Gauss curvature to a constant. When $\\alpha\\chi(M)\\leq0$, we prove that the convergence of the flow is equivalent to the existence of constant $\\alpha$-curvatur...

  13. alpha-nucleus potentials, alpha-decay half-lives, and shell closures for superheavy nuclei

    OpenAIRE

    Mohr, Peter

    2006-01-01

    Systematic alpha-nucleus folding potentials are used to analyze alpha-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict alpha-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured alpha-decay energies using the discontinuity of the volume integral at shell closures. ...

  14. Alpha-decay properties of {sup 261}Bh

    Energy Technology Data Exchange (ETDEWEB)

    Hessberger, F.P.; Ackermann, D.; Heinz, S.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R. [Helmholtzzentrum fuer Schwerionenforschung GmbH, GSI, Darmstadt (Germany); Antalic, S. [Comenius University Bratislava, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Hofmann, S. [Helmholtzzentrum fuer Schwerionenforschung GmbH, GSI, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany)

    2010-02-15

    The isotope {sup 261}Bh was produced in the reaction {sup 209}Bi({sup 54}Cr,2n){sup 261}Bh and its {alpha} decay has been remeasured. It was found that it populates by an unhindered transition of {approx} 10 MeV an excited level at E{sup *} >350 keV in the daughter nucleus {sup 257}Db. The latter decays by internal transitions either into the isomeric state or the ground state. A somewhat improved half-life value of T{sub 1/2}=11.8{sup +3.9} {sub -2.4} ms was obtained for {sup 261}Bh. The data support the previous assignment of the {alpha} activities {sup 257}Db (1) and {sup 257}Db (2) to the isomer and to the ground state, respectively. No evidence for an isomeric state in {sup 261}Bh decaying by {alpha} emission was found. Based on the experimental results and theoretical calculations a partial decay scheme of {sup 261}Bh including spin and parity assignments of the ground-state and excited levels in the daughter nucleus {sup 257}Db populated by the {alpha} decay and succeeding internal transitions have been suggested. {sup 261}Bh represents so far the heaviest nucleus for which such an attempt has been made. No spontaneous fission (SF) events that could be attributed to {sup 261}Bh were observed, resulting in an SF branching b{sub SF}< 0.05. The measured production cross-section is (64{+-}15) pb at E{sup *}=22 MeV. (orig.)

  15. Expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor in human alcoholic brain.

    Science.gov (United States)

    Lewohl, J M; Crane, D I; Dodd, P R

    1997-03-14

    The expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor was studied in the superior frontal and motor cortices of 10 control, 10 uncomplicated alcoholic and 7 cirrhotic alcoholic cases matched for age and post-mortem delay. The assay was based on competitive RT/PCR using a single set of primers specific to the alpha class of isoform mRNA species, and was normalized against a synthetic cRNA internal standard. The assay was shown to be quantitative for all three isoform mRNA species. Neither the patient's age nor the post-mortem interval significantly affected the expression of any isoform in either cortical area. The profile of expression was shown to be significantly different between the case groups, particularly because alpha 1 expression was raised in both groups of alcoholics of controls. The two groups of alcoholics could be differentiated on the basis of regional variations in alpha 1 expression. In frontal cortex, alpha 1 mRNA expression was significantly increased when uncomplicated alcoholics were compared with control cases whereas alcoholic-cirrhotic cases were not significantly different from either controls or uncomplicated alcoholic cases. In the motor cortex, alpha 1 expression was elevated only when alcoholic-cirrhotic cases were compared with control cases. There was no significant difference between case groups or areas for any other isoform. PMID:9098573

  16. The 59Co(n,α) reaction from threshold to 30 MeV

    International Nuclear Information System (INIS)

    Neutron-induced reactions that result in alpha-particle emission have been investigated for the target nucleus 59Co over the neutron energy range from threshold to 30 MeV with the spallation neutron source at WNR/LAMPF. Double-differential cross sections were measured at alpha-particle emission angles of 30, 60, 90 and 135 degree. Integrated cross sections agree well with activation data below 14 MeV where only the 59Co(n,α)56Mn reaction contributes to alpha-particle emission. At higher energies, the integrated alpha-particle emission cross section exceeds the activation data. The results will be interpreted in terms of statistical and pre-compound reaction mechanisms. The sensitivity to nuclear level density parameters will be discussed

  17. {alpha}-Pinene conversion by modified-kaolinitic clay

    Energy Technology Data Exchange (ETDEWEB)

    Volzone, C. [CETMIC-Centro de Tecnologia de Recursos Minerales y Ceramica-(CONICET-CIC), C.C. 49, Cno. Centenario y 506 (1897) M.B. Gonnet, Prov., Buenos Aires (Argentina)]. E-mail: volzcris@netverk.com.ar; Masini, O. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Comelli, N.A. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Grzona, L.M. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Ponzi, E.N. [CINDECA (CONICET-UNLP) calle 47 No. 257 (1900) La Plata, Prov., Buenos Aires (Argentina); Ponzi, M.I. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina)

    2005-10-15

    The isomerization of {alpha}-pinene using natural kaolinitic clay before and after different treatments was studied in this work. The kaolinite is a clay material constituted by phyllosilicate 1:1 layer (one sheet of tetrahedral silicon and one sheet of octahedral alumina). The clay was treated at different times using 6.0 N solution of sulfuric acid previous heating to 500 or 700 K. The materials were characterized by X-ray diffraction, by chemical analyses and acidity measurements. The catalytic reactions were carried out at 373 K in a reactor batch with condenser and stirrer. Samples were taken at regular intervals, and reactants and products were quantitatively analyzed with a gas chromatograph after separation of the individual compounds. Conversions of alpha pinene between 67 and 94%, and selectivities in camphene and in limonene of 65 and 23%, respectively, were obtained with the clay treated at different conditions. The structural and textural changes of the clay by the treatments influenced on catalytic reactions.

  18. On thermonuclear reaction rates

    OpenAIRE

    Hans J. Haubold; Mathai, Arak Mathai

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  19. A brief review of ultra-rare alpha decay detection technique

    International Nuclear Information System (INIS)

    Three approaches to the measurement of rare alpha decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long-lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy-time-position recoil-alpha sequences from 48Ca-induced nuclear reactions with actinide targets, like 242,244Pu, 245,248Cm, 243Am, and 249Cf. Namely with this technique it has became possible to provide a radical suppression of backgrounds in the full fusion (3-5n) reactions aimed at the synthesis of superheavy elements with Z = 113-118

  20. A Brief Review of Ultra-Rare Alpha Decay Detection Technique

    CERN Document Server

    Tsyganov, Yu S

    2006-01-01

    Three approaches to the measurement of a rare alpha decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long-lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy-time-position recoil-alpha sequences from $^{48}$Ca-induced nuclear reactions with actinide targets, like $^{242, 244}$Pu, $^{245,248}$Cm, $^{243}$Am, and $^{249}$Cf. Namely with this technique it has became possible to provide a radical suppression of backgrounds in the full fusion (3-5$n$) reactions aimed at the synthesis of superheavy elements with Z=113-118.

  1. Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume

    Science.gov (United States)

    Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.

    2015-01-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…

  2. Alpha-Synuclein Binds to the Inner Membrane of Mitochondria in an alpha-Helical Conformation

    NARCIS (Netherlands)

    Robotta, M.; Gerding, H.R.; Vogel, A.; Hauser, K.; Schildknecht, S.; Karreman, C.; Leist, M.; Subramaniam, V.; Drescher, M.

    2014-01-01

    The human alpha-Synuclein (alphaS) protein is of significant interest because of its association with Parkinson's disease and related neurodegenerative disorders. The intrinsically disordered protein (140 amino acids) is characterized by the absence of a well-defined structure in solution. It displa

  3. Matching coefficients for alpha_s and m_b to O(alpha_s^2) in the MSSM

    CERN Document Server

    Bauer, A; Salomon, J

    2009-01-01

    We compute the exact two-loop matching coefficients for the strong coupling constant alpha_s and the bottom-quark mass m_b within the Minimal Supersymmetric Standard Model (MSSM), taking into account O(alpha_s^2) contributions from Supersymmetric Quantum Chromodynamics (SQCD). We find that the explicit mass pattern of the supersymmetric particles has a significant impact on the predictions of alpha_s and m_b at high energies. Further on, the three-loop corrections exceed the uncertainty due to the current experimental accuracy. In case of the the running bottom-quark mass, they can reach in the large tan(beta) regime up to 30% from the tree-level value.

  4. Coal fly ash- and copper smelter dust-induced modulation of ex vivo production of tumor necrosis factor-alpha by murine macrophages: effects of metals and overload

    Energy Technology Data Exchange (ETDEWEB)

    Broeckaert, F.; Buchet, J.P.; Delos, M.; Yager, J.W.; Lison, D. [Universite Catholique de Louvain, Brussels (Belgium). School of Public Health, Industrial Toxicology and Occupational Medicine Unit

    1999-03-12

    The paper assesses the effect of two arsenic-containing particles, coal fly ash (FA) and copper smelter dust (CU), on lung integrity and on the ex vivo release of tumor necrosis factor alpha (TNF-alpha) by alveolar phagocytes. The results show that coal fly ash and copper smelter dust bear distinct inflammatory properties. At the end of the observation period (d 120), the high CU dose produced a fibrotic reaction whereas the high dose of FA particles generated a delayed and persistent lung inflammatory reaction associated with lymphoid noduli. Marked differences in TNF-alpha production were observed within the CU and FA groups. CU particles, conceivably through their metal content, decreased TNF-alpha production by alveolar phagocytes. Due to their low arsenic content, considerably higher FA particle doses needed to be administered to produce an inhibition of TNF-alpha production.

  5. The role of alpha particles in the dynamics of ring-stabilized devices

    International Nuclear Information System (INIS)

    The use of relativistic electron rings to stabilize plasmas against the interchange modes has been utilized in such devices as the Elmo Bumpy Torus (EBT) and the plugs of a Tandem Mirror device (STM). In the EBT case enhanced stability is reflected in higher betas (ratio of plasma to magnetic field pressures), while in the Tandem Mirror case symmetry in the plug magnetic geometry results in reduced particle diffusion across the magnetic field in the central cell. Regardless of the application, the question arises as to what effect would alpha particles generated by the Deuterium-Tritium (DT) reactions have on the stability of such ring-stabilized devices. In this paper the macroscopic stability of such systems is reexamined in order to assess the effect of alphas on the background interchange mode, the interacting interchange mode, and the high frequency compressional Alfven and coupled modes. A fluid description is used for the background plasma while a kinetic treatment is utilized for the hot electron species and alpha particles. It is shown that the alphas tend to mildly destabilize the interacting interchange while stabilizing the background interchange due to their sizeable Larmor radii. The destabilization is most pronounced at high alpha energies i.e., at birth, and near complete recovery of stability is achieved as these particles approach thermalization with the background ions. It is also shown that the alphas completely stabilize the high frequency modes. (orig.)

  6. Effect of alpha particles on the stability of Elmo Bumpy Torus (EBT) reactor. Final report

    International Nuclear Information System (INIS)

    The macroscopic stability of an ignited EBT reactor is investigated by studying the effects of the alpha particles generated by the Deuterium-Tritium (D-T) fusion reaction on the background interchange mode, the interacting interchange mode, and the high-frequency compressional Alfven and coupled modes. A fluid description is used for the background plasma while a kinetic treatment is utilized for the hot electron species and the alpha particles. It is shown that the alphas tend to mildly destabilize the interacting interchange while stabilizing the background interchange due to their sizable Larmor radii. The destabilization is most pronounced when the beta of the alpha particles in highest, i.e., at birth, and recovery of stabilization takes place as these particles slow down toward thermalization. It is also shown that the alphas completely stabilize the high frequency modes so that it can safely be concluded that fusion alphas present no detrimental effects on the stability of an EBT reactor that possesses an appropriate hot electron ring for macroscopic stability

  7. Ancient roots for polymorphism at the HLA-DQ. alpha. locus in primates

    Energy Technology Data Exchange (ETDEWEB)

    Gyllensten, U.B.; Erlich, H.A. (Cetus Corp., Emeryville, CA (USA))

    1989-12-01

    The genes encoding the human histocompatibility antigens (HLA) exhibit a remarkable degree of polymorphism as revealed by immunologic and molecular analyses. This extensive sequence polymorphism either may have been generated during the lifetime of the human species or could have arisen before speciation and been maintained in the contemporary human population by selection or, possibly, by genetic drift. These two hypotheses were examined using the polymerase chain reaction method to amplify polymorphic sequences from the DQ{alpha} locus, as well as the DX{alpha} locus, an homologous but nonexpressed locus, in a series of primates that diverged at known times. In general, the amino acid sequence of a specific human DQ{alpha} allelic type is more closely related to its chimpanzee or gorilla counterpart than to other human DQ{alpha} alleles. Phylogenetic analysis of the silent nucleotide position changes shows that the similarity of allelic types between species is due to common ancestry rather than convergent evolution. Thus, most of the polymorphism at the DQ{alpha} locus in the human species was already present at least 5 million years ago in the ancestral species that gave rise to the chimpanzee, gorilla, and human lineages. However, one of the DQ{alpha} alleles may have arisen after speciation by recombination between two ancestral alleles.

  8. Local Varying-Alpha Theories

    CERN Document Server

    Barrow, John D

    2014-01-01

    In a recent paper we demonstrated how the simplest model for varying alpha may be interpreted as the effect of a dielectric material, generalized to be consistent with Lorentz invariance. Unlike normal dielectrics, such a medium cannot change the speed of light, and its dynamics obey a Klein-Gordon equation. This work immediately suggests an extension of the standard theory, even if we require compliance with Lorentz invariance. Instead of a wave equation, the dynamics may satisfy a local algebraic relation involving the permittivity and the properties of the electromagnetic field, in analogy with more conventional dielectric (but still preserving Lorentz invariance). We develop the formalism for such theories and investigate some phenomenological implications. The problem of the divergence of the classical self-energy can be solved, or at least softened, in this framework. Some interesting new cosmological solutions for the very early universe are found, including the possibility of a bounce, inflation and e...

  9. Kidney development and gene expression in the HIF2alpha knockout mouse.

    Science.gov (United States)

    Steenhard, Brooke M; Freeburg, Paul B; Isom, Kathryn; Stroganova, Larysa; Borza, Dorin-Bogdan; Hudson, Billy G; St John, Patricia L; Zelenchuk, Adrian; Abrahamson, Dale R

    2007-04-01

    The hypoxia-inducible transcription factor-2 (HIF2), a heterodimer composed of HIF2alpha and HIF1beta subunits, drives expression of genes essential for vascularization, including vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2, Flk-1). Here, we used a HIF2alpha/LacZ transgenic mouse to define patterns of HIF2alpha transcription during kidney development and maturation. Our results from embryonic heterozygotes showed HIF2alpha/LacZ expression by apparently all renal endothelial cells. At 4 weeks of age, glomerular mesangial and vascular smooth muscle cells were also positive together with endothelial cells. These expression patterns were confirmed by electron microscopy using Bluo-gal as a beta-galactosidase substrate. Small numbers of glomerular and tubular epithelial cells were also positive at all stages examined. Light and electron microscopic examination of kidneys from HIF2alpha null embryos showed no defects in renal vascular development or nephrogenesis. Similarly, the same amounts of Flk-1 protein were seen on Western blots of kidney extracts from homozygous and heterozygous HIF2alpha mutants. To examine responsiveness of HIF2alpha null kidneys to hypoxia, embryonic day 13.5 metanephroi were cultured in room air or in mild (5% O(2)) hypoxia. For both heterozygous and null samples, VEGF mRNA levels doubled when metanephroi were cultured in mild hypoxia. Anterior chamber grafts of embryonic HIF2alpha knockouts were morphologically indistinguishable from heterozygous grafts. Endothelial markers, platelet endothelial cell adhesion molecule and BsLB4, as well as glomerular epithelial markers, GLEPP1 and WT-1, were all expressed appropriately. Finally, we undertook quantitative real-time polymerase chain reaction of kidneys from HIF2alpha null embryos and wild-type siblings and found no compensatory up-regulation of HIF1alpha or -3alpha. Our results show that, although HIF2alpha was widely transcribed by kidney endothelium and vascular

  10. Confidence Intervals for Cronbach's Coefficient Alpha Values

    NARCIS (Netherlands)

    A.J. Koning (Alex); Ph.H.B.F. Franses (Philip Hans)

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, wh

  11. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  12. DT results of TFTR's alpha collector

    International Nuclear Information System (INIS)

    An escaping alpha collector probe has been developed for TFTR's DT phase to complement the results of the lost alpha scintillator detectors which have been operating on TFTR since 1988. Measurements of the energy distribution of escaping alphas have been made by measuring the range of alphas implanted into nickel foils located within the alpha collector. Exposed samples have been analyzed for 4 DT plasma discharges at plasma currents of 1.0 and 1.8 MA. The results at 1.0 MA are in good agreement with predictions for first orbit alpha loss at 3.5 MeV. The 1.8 MA results, however, indicate a large anomalous loss of partially thermalized alphas at an energy ∼30% below the birth energy and at a total fluence nearly an order of magnitude above expected first orbit loss. This anomalous loss is not observed with the lost alpha scintillator detectors in DT plasmas but does resemble the anomalous delayed loss seen in DD plasmas. Several potential explanations for this loss process are examined. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations

  13. ALPHA experiment facility and Prof. Jeffrey Hangst.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    Picture 01-07: General views of the ALPHA experiment Picture 5: Andrea Gutierrez, a PhD student from UBC, transfers liquid helium from a storage dewar into the cryostat containing the superconducting magnetic trap used by the ALPHA experiment.Picture 08-11: Jeffery Hangst, spokesperson for ALPHA Picture 12: The ALPHA silicon detector, which surrounds the trapping resion and is used for imaging antiproton annihilations (Credit University of Liverpool) Picture 13: Untrapped antihydrogen atoms annihilating on the inner surface of the ALPHA trap. These are measured by the ALPHA annihilation detector. The events are concentrated at the electrode radius of about 22.3 mm. The coordinates are defined in the Nature article, Figure 1b. Picture 14: The electrodes (gold) for the ALPHA Penning trap being inserted into the vacuum chamber and cryostat assembly. This is the trap used to combine or "mix" positrons and antiprotons to make antihydrogen. (Credit: Niels Madsen ALPHA/Swansea.) Picture 15: Top, a diagram of the...

  14. Single-field $\\alpha$-attractors

    CERN Document Server

    Linde, Andrei

    2015-01-01

    I describe a simple class of $\\alpha$-attractors, generalizing the single-field GL model of inflation in supergravity. The new class of models is defined for $0<\\alpha \\lesssim 1$, providing a good match to the present cosmological data. I also present a generalized version of these models which can describe not only inflation but also dark energy and supersymmetry breaking.

  15. Evaluation of (alpha,n) Induced Neutrons as a Background for Dark Matter Experiments

    CERN Document Server

    Mei, D -M; Hime, A

    2008-01-01

    Neutrons from ($\\alpha$,n) reaction through thorium and uranium decays are important sources of background for direct dark matter detection. Neutron yield and energy spectrum from a range of materials that are used to build dark matter detectors are calculated and tabulated. In addition to thorium and uranium decays, we found that $\\alpha$ particles from samarium that is often doped in the window material of photomultiplier (PMT) are also an important source of neutron yield. The results in this paper can be used as the input in the Monte Carlo simulation for many materials that will be used for next generation experiments.

  16. Relationship between alpha-1 antitrypsin deficient genotypes S and Z and lung cancer in Jordanian lung cancer patients

    International Nuclear Information System (INIS)

    Alpha-1 antitrypsin (alpha1-AT) is a secretory glycoprotein produced mainly in the liver and monocytes. It is the most abundant serine protease inhibitor in human plasma. It predominantly inhibits neutrophil elastase thus, it prevents the breakdown of lung tissue. The deficiency of alpha1-AT is an inherited disorder characterized by reduced serum level of alpha1-AT. Protease inhibitors Z (PiZ) and protease inhibitors S (PiS) are the most common deficient genotypes of alpha1-AT. The aim of this study is to test the relationship between alpha1-AT deficient genotypes S and Z and lung cancer in Jordanian lung cancer patients. We obtained the samples used in this study from 100 paraffin embedded tissue blocks of the lung cancer patients from Prince Iman Research Center and Laboratory Sciences at King Hussein Medical Center, Amman, Jordan. Analyses of the Z and S genotypes of alpha1-AT were performed by polymerase chain reaction and restriction fragment length polymorphism techniques at Jordan University of Science and Technology during 2003 and 2004. We demonstrated that all lung cancer patients were of M genotype, and no Z or S genotypes were detected. There is no relationship between alpha1-AT deficient genotypes S and Z and lung cancer in patients involved in this study. (author)

  17. {alpha}-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Jerzykiewicz, Maria, E-mail: Mariaj@wchuwr.pl [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland); Cwielag-Piasecka, Irmina; Witwicki, Maciej; Jezierski, Adam [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland)

    2011-05-26

    Graphical abstract: {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. Display Omitted Highlights: {yields} {alpha}-Tocopherol does not inhibit the oxidation of DMSO to {center_dot}CH{sub 3}. {yields} {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. {yields} {alpha}-Tocopherol does not inhibit the oxidation of PBN. {yields} The structures of observed spin adducts were theoretically confirmed. - Abstract: EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of {alpha}-tocopherol. Additionally, the mixtures of {alpha}-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. {alpha}-Tocopherol inhibited oxidation of the main decomposition product of DMSO, {center_dot}CH{sub 3} to {center_dot}OCH{sub 3} but did not prevent the transformation process of N-t-butyl-{alpha}-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  18. A low-energy determination of $\\alpha_s$ at three loops

    CERN Document Server

    Vairo, Antonio

    2015-01-01

    We review one of the most accurate low-energy determinations of $\\alpha_s$. Comparing at short distances the QCD static energy at three loops and resummation of the next-to-next-to leading logarithms with its determination in 2+1-flavor lattice QCD, we obtain $\\alpha_s(1.5~{\\rm GeV})=0.336^{+0.012}_{-0.008}$, which corresponds to $\\alpha_s(M_Z)=0.1166^{+0.0012}_{-0.0008}$. We discuss future perspectives.

  19. Practical alpha detectors for site characterization

    International Nuclear Information System (INIS)

    The authors have and are developing a series of practical alpha detectors for alpha characterization. These include soil surface monitors, pipe and duct monitors, air quality and radon monitors, tool monitors, and sample monitors. Two types of these monitors have been transferred to industry thus far for commercialization. Several of these systems have been fully field tested: for example, the soil surface monitor has been used to characterize 11 sites for 7 customers at 3 DOE facilities. Using a new but simple technology, these alpha detectors can be put to use in many areas where conventional alpha probes are impractical or insufficiently sensitive. Use of these alpha detectors in site characterization at the Uranium in Soil Integrated Demonstration at Fernald, at Los Alamos, and elsewhere will be discussed as well as their commercialization and possible further applications

  20. An Alpha Schottky Junction Power Source

    Science.gov (United States)

    Litz, Marc; Carroll, James; Henriquez, Stan

    2011-10-01

    Isotope batteries present solutions for long-lived low power sources. Compact sensors, and electronic circuit boards can be powered for the lifetime of infrastructure. Alpha sources are practical for safety reasons because of the limited distance before energy absorption in materials, and the high energy (~5MeV) per particle. Damage to materials from the alphas limits the practical use. A Schottky diode geometry is created from an alpha foil on a diamond-like crystal. A power source is proposed that takes advantage of the radiation damage tolerance of diamond, combined with the short range of the alpha radiation. The internal field of the Schottky barrier creates a current through the diode from electron-hole pairs created by alpha bombardment in the gap. Calculations of the expected current, circuit model results, and design parameters for a device are described.

  1. Folding model analysis of alpha radioactivity

    CERN Document Server

    Basu, D N

    2003-01-01

    Radioactive decay of nuclei via emission of $\\alpha$ particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the $\\alpha$-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the $\\alpha$ nucleus and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction has been used for calculating the nuclear interaction potential which has been supplemented by a zero-range pseudo-potential for exchange along with the density dependence. The nuclear microscopic $\\alpha$-nucleus potential thus obtained has been used along with the Coulomb interaction potential to calculate the action integral within the WKB approximation. This subsequently yields microscopic calculations for the half lives of $\\alpha$ decays of nuclei. The density dependence and the exchange effects have not been found to be very significant. These calculations...

  2. Exposure-sensitization relationship for alpha-amylase allergens in the baking industry.

    Science.gov (United States)

    Houba, R; Heederik, D J; Doekes, G; van Run, P E

    1996-07-01

    Fungal alpha-amylase is an important occupational allergen in the bakery industry. Epidemiologic studies focusing on the relationship between alpha-amylase allergen exposure and work-related respiratory allergy, however, have not been reported yet. In this cross-sectional study, sensitization to occupational allergens and work-related symptoms were studied in 178 bakery workers and related to allergen exposure. Alpha-amylase allergen concentrations were measured in personal dust samples, using a sandwich enzyme immunoassay. All workers were categorized into groups on the basis of their job histories and the alpha-amylase exposure levels of their job titles. Of all workers 25% had one or more work-related symptoms. As much as 9% of the bakery workers showed a positive skin prick test reaction to fungal amylase, and in 8% amylase-specific IgE was demonstrated. Alpha-amylase exposure and atopy appeared to be the most important determinants of skin sensitization, with prevalence ratios for atopy of 20.8 (95% CI, 2.74 to 158) and for medium and high alpha-amylase exposure groups of 8.6 (95% CI, 1.01 to 74) and 15.9 (95% CI, 1.95 to 129), respectively. Furthermore, a positive association was found between positive skin prick tests to alpha-amylase and work-related respiratory symptoms. In conclusion, this study has shown that there is a strong and positive relationship between alpha-amylase allergen exposure levels in bakeries and specific sensitization in bakery workers. PMID:8680668

  3. On the structure, function and biosynthesis of human inter-. alpha. inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Swaim, M.W.

    1989-01-01

    Human inter-{alpha} inhibitor (I{alpha}I) is a {approx}200-kD serum glycoprotein with serine proteinase-inhibitory activity whose physiologic role remains unclear. I{alpha}I is related to smaller inhibitors found in physiologic fluids and is a complex of {approx}40-kD light and {approx}90-kD heavy chains. I{alpha}I proteinase-inhibitory activity resides exclusively in the light chain, which has tandem Kunitz inhibitory domains with methionine and arginine residues, respectively, at position P{sub 1}. The inhibitory activity of the reactive centers was heretofore uncharacterized. Cis-dichlorodiammineplatinum (II) (cis-DDP) reacts with sulfur containing residues in a limited and selective fashion. In preliminary studies, cis-DDP was evaluated as a reagent to modify the methionine reactive centers of two other plasma proteinase inhibitors, {alpha}{sub 1}-antitrypsin and {alpha}{sub 2}-antiplasmin. Cis-DDP readily abolished the proteinase-inhibitory activity of both proteins. Methionine oxidation, papain digestion, and platinum binding assays showed that cis-DDP inactivates {alpha}-antitrypsin by binding exclusively to its reactive-center methionine. Cis-DDP partially eliminated I{alpha}I inhibitory activity against cathepsin G and neutrophil elastase but did not affect inhibition of trypsin or chymotrypsin. Conversely, reaction with the arginine-modifying reagent 2,3-butanedione afforded complete loss of activity against trypsin and chymotrypsin but partial loss of activity against cathepsin G and elastase. Employment of both reagents eliminated inhibition of cathepsin G and elastase. Thus eathepsin G and elastase are apparently inhibited at either reactive center. Trypsin and chymotrypsin are inhibited exclusively at the arginine reactive center.

  4. Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression

    Energy Technology Data Exchange (ETDEWEB)

    Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J

    1998-06-29

    Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

  5. Direct Alpha Analysis for Forensic Samples (DAAFS)

    International Nuclear Information System (INIS)

    The goal of the DAAFS project is to deliver a field deployable direct alpha sample spectrometry system. This system is designed to rectify current gaps in pure alpha emitting material detection. The system comprises, firstly, an evaluation of multiple innovative methods for rapid on-site sample collection of difficult to detect alpha RN contamination. Secondly, the incorporation of an experimental alpha spectrometry analysis software suite, 'ADAM', is provided for performing the required on-site deconvolution of the complex alpha spectra arising from the direct sample measurement. Software simulation of collected alpha spectra will be handled by 'AASI', which will simulate alpha spectra as a training and analysis verification tool. Thirdly, a Concept of Operations (ConOps) for the system implementation in RN field teams is included. This combination of the swipe methodology, advanced swipe treatment equipment, mobile field laboratories, and the state of the art analysis software suite will provide RN response teams with the capability to identify and rapidly (i.e., hours as opposed to days) quantify low activity and difficult to detect alpha emitters. Further expert analysis support is available to field teams by sharing of raw spectral data via email with off-site laboratories. The proposed system provides the solution to this identified capability gap, specifically, a field-deployable real-time alpha detection system. The system comprises: a non-destructive particle sampler, standardized swipe sampling methods, a self-contained field alpha spectrometry system and an integrated data management/communications tool allowing for real-time raw-data tracking and data sharing. This system also provides responders with the type/quantity of RN material for improved safeguards, forensics, and contamination mitigation applications. (author)

  6. Synthesis of aminophosphonate haptens for an aminoacylation reaction between methyl glucoside and a beta-alanyl ester.

    Science.gov (United States)

    Lintunen, T; Yli-Kauhaluoma, J T

    2000-08-01

    Two 2-aminophosphonate haptens derived from methyl alpha-D-glucopyranoside were synthesized to mimic the transition-state of a transesterification reaction between methyl alpha-D-glucopyranoside and 4-nitrophenylester of tert-BOC-beta-alanine. Two sets of monoclonal antibodies were generated against these haptens. PMID:10937739

  7. The Glyoxal Clock Reaction

    Science.gov (United States)

    Ealy, Julie B.; Negron, Alexandra Rodriguez; Stephens, Jessica; Stauffer, Rebecca; Furrow, Stanley D.

    2007-01-01

    Research on the glyoxal clock reaction has led to adaptation of the clock reaction to a general chemistry experiment. This particular reaction is just one of many that used formaldehyde in the past. The kinetics of the glyoxal clock makes the reaction suitable as a general chemistry lab using a Calculator Based Laboratory (CBL) or a LabPro. The…

  8. Human podocytes adhere to the KRGDS motif of the alpha3alpha4alpha5 collagen IV network.

    Science.gov (United States)

    Borza, Corina M; Borza, Dorin-Bogdan; Pedchenko, Vadim; Saleem, Moin A; Mathieson, Peter W; Sado, Yoshikazu; Hudson, Heather M; Pozzi, Ambra; Saus, Juan; Abrahamson, Dale R; Zent, Roy; Hudson, Billy G

    2008-04-01

    Podocyte adhesion to the glomerular basement membrane is required for proper function of the glomerular filtration barrier. However, the mechanism whereby podocytes adhere to collagen IV networks, a major component of the glomerular basement membrane, is poorly understood. The predominant collagen IV network is composed of triple helical protomers containing the alpha3alpha4alpha5 chains. The protomers connect via the trimeric noncollagenous (NC1) domains to form hexamers at the interface. Because the NC1 domains of this network can potentially support integrin-dependent cell adhesion, it was determined whether individual NC1 monomers or alpha3alpha4alpha5 hexamers support podocyte adhesion. It was found that, although human podocytes did not adhere to NC1 domains proper, they did adhere via integrin alphavbeta3 to a KRGDS motif located adjacent to alpha3NC1 domains. Because the KRGDS motif is a site of phosphorylation, its interactions with integrin alphavbeta3 may play a critical role in cell signaling in physiologic and pathologic states. PMID:18235087

  9. Practice Gaps: Drug Reactions.

    Science.gov (United States)

    Wolverton, Stephen E

    2016-07-01

    The term "drug reactions" is relevant to dermatology in three categories of reactions: cutaneous drug reactions without systemic features, cutaneous drug reactions with systemic features, and systemic drugs prescribed by the dermatologist with systematic adverse effects. This article uses examples from each of these categories to illustrate several important principles central to drug reaction diagnosis and management. The information presented will help clinicians attain the highest possible level of certainty before making clinical decisions. PMID:27363888

  10. Study of the 28Si(16O,20Ne)24Mg reaction

    International Nuclear Information System (INIS)

    In this work, measurements of elastic and inelastic angular distributions in the system 16O+ 20Si and in the alpha transfer reactions 20Si(16O,20Ne)24Mg were made in the angular range of 200 0 and the transfer reaction 20Si(16O,12C)32S in the angular range 160 0 at the energy of Ecm = 31.57 MeV. Optical potential parameters and β2 deformation parameters as well as spectroscopic factors were determined for the alpha transfer reactions. (A.C.A.S.)

  11. Lucid dreaming and alpha activity: a preliminary report.

    Science.gov (United States)

    Ogilvie, R D; Hunt, H T; Tyson, P D; Lucescu, M L; Jeakins, D B

    1982-12-01

    10 good dream recallers spent 2 nights in the sleep lab during which they were awakened 4 times per night from REM sleep, twice during their highest alpha activity in REM, and twice during low REM alpha. 5 were given alpha feedback training prior to sleep onset. Arousals from high alpha REM sleep yielded significantly higher lucidity ratings. Alpha feedback had no effect upon lucidity or REM alpha levels. Similarities between lucid dreams and meditative phenomena are discussed. PMID:7162915

  12. Osmotic fragility test in heterozygotes for alpha and beta thalassaemia.

    OpenAIRE

    Maccioni, L; Cao, A

    1985-01-01

    This study shows that the combination of heterozygous beta thalassaemia and deletion heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) alpha+ thalassaemia may result in the production of erythrocytes which have normal mean volume and haemoglobinisation but decreased osmotic fragility. Based on this finding and previous studies, which have shown that beta thalassaemia screening by the osmotic fragility test may miss a significant proportion of beta thalassaemia heterozygotes, we ...

  13. Cintichem modified process - {sup 99}Mo precipitation step: application of statistical analysis tools over the reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Rodrigo; Dias, Carla R.B.R.; Osso Junior, Joao A., E-mail: jaosso@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Fernandez Nunez, Eutimio Gustavo [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica

    2011-07-01

    Precipitation of {sup 99}Mo by {alpha}-benzoin oxime ({alpha}-Bz) is a standard precipitation method for molybdenum due the high selectivity of this agent. Nowadays, statistical analysis tools have been employed in analytical systems to prove its efficiency and feasibility. IPEN has a project aiming the production of {sup 99}Mo by the fission of {sup 235}U route. The processing uses as the first step the precipitation of {sup 99}Mo with {alpha}-Bz. This precipitation step involves many key reaction parameters. The aim of this work is based on the development of the already known acidic route to produce {sup 99}Mo as well as the optimization of the reactional parameters applying statistical tools. In order to simulate {sup 99}Mo precipitation, the study was conducted in acidic media using HNO{sub 3}, {alpha}Bz as precipitant agent and NaOH /1%H{sub 2}O{sub 2} as dissolver solution. Then, a Mo carrier, KMnO{sub 4} solutions and {sup 99}Mo tracer were added to the reaction flask. The reactional parameters ({alpha}-Bz/Mo ratio, Mo carrier, reaction time and temperature, and cooling reaction time before filtration) were evaluated under a fractional factorial design of resolution V. The best values of each reactional parameter were determined by a response surface statistical planning. The precipitation and recovery yields of {sup 99}Mo were measured using HPGe detector. Statistical analysis from experimental data suggested that the reactional parameters {alpha}-Bz/Mo ratio, reaction time and temperature have a significant impact on {sup 99}Mo precipitation. Optimization statistical planning showed that higher {alpha}Bz/Mo ratios, room temperature, and lower reaction time lead to higher {sup 99}Mo yields. (author)

  14. Lyman alpha radiation in external galaxies

    Science.gov (United States)

    Neufeld, David A.; Mckee, Christopher F.

    1990-01-01

    The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by galaxies is generated within regions of the interstellar medium which are photoionized by starlight. Conversely, much of the energy radiated by photoionized regions is carried by the Ly alpha line. Only hot, massive stars are capable of ionizing hydrogen in the interstellar medium which surrounds them, and because such stars are necessarily short-lived, Ly alpha emission traces regions of active star formation. Researchers argue that the strength of the Ly alpha emission observed from external galaxies may be used to estimate quantitatively the dust content of the emitting region, while the Ly alpha line profile is sensitive to the presence of shock waves. Interstellar dust particles and shock waves are intimately associated with the process of star formation in two senses. First, both dust particles and shock waves owe their existence to stellar activity; second, they may both serve as agents which facilitate the formation of stars, shocks by triggering gravitational instabilities in the interstellar gas that they compress, and dust by shielding star-forming molecular clouds from the ionizing and dissociative effects of external UV radiation. By using Ly alpha observations as a probe of the dust content in diffuse gas at high redshift, we might hope to learn about the earliest epochs of star formation.

  15. A potent effect of strong $\\bar{\\mbox{p}}-$p nuclear forces on the rate of the low-energy three-body protonium formation reaction: $\\bar{\\mbox{p}} + (\\mbox{p}\\mu^-)_{1s} \\rightarrow (\\bar{\\mbox{p}} \\mbox{p})_{\\alpha} + \\mu^-$

    CERN Document Server

    Sultanov, Renat A; Adhikari, Sadhan K

    2016-01-01

    The effect of the strong $\\bar{\\rm p}-$p nuclear interaction in a three-charge-particle system with arbitrary masses is investigated. Specifically, the ($\\bar{\\rm p},\\ \\mu^-$,\\ p) system is considered. A numerical computation in the framework of a detailed few-body approach is carried out for the following protonium (antiprotonic hydrogen) production three-body reaction: $\\bar{\\mbox{p}} +(\\mbox{p}\\mu^-)_{1s} \\rightarrow (\\bar{\\mbox{p}}\\rm{p})_{1s} + \\mu^-$. Here, p is a proton, $\\bar{\\mbox{p}}$ is an antiproton, $\\mu^-$ is a muon, and a bound state of $\\mbox{p}^+$ and its counterpart $\\bar{\\mbox{p}}$ is protonium: $Pn = (\\bar{\\mbox{p}}\\mbox{p})$. The low-energy cross sections and rates of the $Pn$ formation reaction are computed in the framework of a Faddeev-like equation formalism. The strong $\\bar{\\mbox{p}}-$p interaction is included in these calculations within a first order approximation. It was found, that the inclusion of this strong interaction results in a quite significant correction to the output of...

  16. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  17. Naturally-occurring alpha activity

    International Nuclear Information System (INIS)

    In view of the difficulties of assessing the significance of man-made radioactivity it is important to study for comparison the background of natural radioactivity against which the human race has evolved and lives. It is also important to define the present levels of activity so that it will be possible to detect and study as quickly as possible any changes which may occur owing to the release into the environment of new radioactive materials. Moreover, by the study of the behaviour of natural radioactivity light may be shed upon that of the artificially produced isotopes and a number of analogies traced between the two groups. These concepts have led to studies of naturally-occurring radioactive materials alongside a programme of research into fission products in food, water and air, as well as studies of the metabolism of both sets of materials in the human body. Since the last report there has been a useful increase in our knowledge of natural radioactivity in the biosphere, and its levels relative to the new man-made activities. These studies have necessitated technical developments, particularly in the methods of measuring and identifying alpha-ray emitters, to which group many of the more important natural radioactive materials belong

  18. Diagnostics for PLX-alpha

    Science.gov (United States)

    Gilmore, Mark; Hsu, Scott

    2015-11-01

    The goal of the Plasma Liner eXperiment PLX-alpha at Los Alamos National Laboratory is to establish the viability of creating a spherically imploding plasma liner for MIF and HED applications, using a spherical array of supersonic plasma jets launched by innovative contoured-gap coaxial plasma guns. PLX- α experiments will focus in particular on establishing the ram pressure and uniformity scalings of partial and fully spherical plasma liners. In order to characterize these parameters experimentally, a suite of diagnostics is planned, including multi-camera fast imaging, a 16-channel visible interferometer (upgraded from 8 channels) with reconfigurable, fiber-coupled front end, and visible and VUV high-resolution and survey spectroscopy. Tomographic reconstruction and data fusion techniques will be used in conjunction with interferometry, imaging, and synthetic diagnostics from modeling to characterize liner uniformity in 3D. Diagnostic and data analysis design, implementation, and status will be presented. Supported by the Advanced Research Projects Agency - Energy - U.S. Department of Energy.

  19. Growth behaviors in the range $e^{r^\\alpha}$

    OpenAIRE

    Brieussel, Jérémie

    2011-01-01

    For every $\\alpha \\leq \\beta$ in a left neighborhood $[\\alpha_0,1]$ of 1, a group $G(\\alpha,\\beta)$ is constructed, the growth function of which satisfies $\\limsup \\frac{\\log \\log b_{G(\\alpha,\\beta)}(r)}{\\log r}=\\alpha$ and $\\liminf \\frac{\\log \\log b_{G(\\alpha,\\beta)}(r)}{\\log r}=\\beta$. When $\\alpha=\\beta$, this provides an explicit uncountable collection of groups with growth functions strictly comparable. On the other hand, oscillation in the case $\\alpha < \\beta$ explains the existence of...

  20. 13C(alpha,n)16O background in a liquid scintillator based neutrino experiment

    CERN Document Server

    Zhao, Jie; Liu, Jianglai; Li, Xiaobo; Zhang, Feihong; Xia, Dongmei

    2013-01-01

    Alpha from natural radioactivity may interact with a nucleus and emit a neutron. The reaction introduces background to the liquid scintillator (LS) based neutrino experiments. In the LS detector, alpha comes from 238U, 232Th and 210Po decay chains. For Gadolinium-doped LS (Gd-LS) detector, alpha also comes from 227Ac. The nucleus 13C is a natural component of Carbon which is rich in the LS. The background rate and spectrum should be subtracted carefully from the neutrino candidates. This paper describes the calculation of neutron yield and spectrum with uncertainty estimated. The results are relevant for many existing neutrino experiments and future LS or Gd-LS based experiments.