69 research outputs found

    Beyond the neutron drip line: The unbound oxygen isotopes (25)O and (26)O

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    This is the publisher's version, and is also available electronically from http://journals.aps.org/prc/abstract/10.1103/PhysRevC.88.034313.The very neutron-rich oxygen isotopes 25O and 26O are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from 26F and 27F at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into 24O plus one or two neutrons, the 25O ground-state energy and width are determined, and upper limits for the 26O ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in 26O at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added

    PARTICIPATION OF APOLIPOPROTEIN E IN TRANSFER AND ABSORPTION OF FATTY ACIDS BY THE CELLS And CAUSING OF HYPERLIPOPROTEINEMIA

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    ApoE vector protein in association with apoB-100 directly transferring saturated and monounsaturated FA (SFA and MFA) in triglyceride form (composed of very low density lipoproteins (L)) to the cells which are assimilating FA by cooperative receptors of apoE. Only insulin dependent cells have apoe/B-l00 receptors on the cell membrane (skeletal myocytes, cardiac myocytes, periportal hepatocytes, adipocytes of subcutaneous fat and Kupffer's macrophages). Phylogenetically late apoE has a domain for protein-protein interaction unlike the other apos. Apo forms cooperative ligands: apoE/A-l, apoE/B-48 and apoE/B-100 while using this domain. At later stages of phylogenesis while apoE forms cooperative ligands it is also involved in cell transfer and absorption of polyunsatured essential fatty acids in high density L, SFA +MFA +unsatured FA in chylomicrons, SFA+MFA in very low density L. Phenotype E 33 appears to be regular. Phenotypes E2/2 and E4/4 are cause of hypertriglyceridemia of I and V types, which call destructive inflammation of arterial intima with atherothrombosis

    Systematic investigation of projectile fragmentation using beams of unstable B and C isotopes

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    Publisher's Version/PDFBackground: Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from [superscript 10,12−18]C and [superscript 10−15]B isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic [superscript 10,12−18]C and [superscript 10−15]B isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the EPAX code is not able to describe the data satisfactorily. Using ABRABLA07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease ABRABLA07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study

    ПАЛЬМИТИНОВАЯ, ОЛЕИНОВАЯ КИСЛОТЫ И ИХ РОЛЬ В ПАТОГЕНЕЗЕ АТЕРОСКЛЕРОЗА

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    On the basis of phylogenetic theory of general pathology, the cause of a noninfectious disease whose occurrence in a population is more than 5–7% is an impaired biological function or reaction to the environment. From the general biology viewpoint, high mortality rate related to cardio-vascular diseases and atherosclerosis (intercellular deficiency of polyenic fatty acids (PFA)) is just extinction of the Homo sapiens population upon adaptation to new environmental factors. The biological function of throphology (feeding) and biological reaction of exotrophy (external feeding) are impaired in several aspects, the major of which is nonphysiologically high dietary content of saturated fatty acids, primarily, of palmitic fatty acid (FA). The lipoprotein system formed at early stages of phylogenesis cannot transport and provide physiological deposition of great amounts of palmitic FA, which leads to the development of an adaption (compensatory) and accumulation disease. This results in hypermipidemia, impaired bioavailability of PFA to cells, compesatory production of humoral mediators from ω-9 eicosatrienoic mead FA, disorders in physiological parameters of cell plasma membrane and integral proteins, nonphysiological conformation of apoВ-100 in lipoproteins, formation of ligandless lipoproteins (biological litter) and impairments in the biological function of endoecology, utilization of ligandless lipoproteins in arterial intima by phylogenetically early macrophages that do not hydrolyze polyenic cholesterol esters, increase in the intensity of the biological reaction of inflammation, and destructive and inflammatory lesions in arterial intima of an atheromatosis or atherothrombosis type. Atheromatous masses are catabolites of PFA which were not internalized by phylogenetically late cells via receptor-mediated pathway.С позиций филогенетической теории общей патологии, если частота неинфекционного заболевания в популяции превышает 5–7%, причина кроется в нарушении биологических функций и биологических реакций in vivo в ответ на воздействие внешней среды. С позиций общей биологии высокий уровень смертности от сердечно-сосудистой патологии, атеросклероза (дефицита в клетках полиеновых жирных кислот (ПНЖК)) – это не более, чем вымирание части популяции Homo sapiens при адаптации к новым воздействиям внешней среды. Факторов нарушения биологической функции трофологии (питания), биологической реакции внешнего питания (экзотрофии) много, основным является афизиологично высокое содержание в пище насыщенных жирных кислот (ЖК), в первую очередь пальмитиновой. Образованная на ранних ступенях филогенеза система липопротеинов (ЛП) не в состоянии переносить к клеткам и физиологично депонировать столь большое количество пальмитиновой насыщенной ЖК; постепенно формируется болезнь адаптации (компенсации) и болезнь накопления. Это влечет за собой гиперлипидемию, нарушение биодоступности для клеток ПНЖК; компенсаторный синтез гуморальных медиаторов из ω-9 эйкозатриеновой мидовой ЖК; нарушение физиологичных параметров мембраны клеток, функции интегральных протеинов; афизиологичную конформацию апоВ-100 в ЛП, формирование безлигандных ЛП (биологического «мусора») и нарушение биологической функции эндоэкологии; утилизацию безлигандных ЛП в интиме артерий филогенетически ранними макрофагами, которые не гидролизуют полиеновые эфиры холестерина; повышение активности биологической реакции воспаления и деструктивно-воспалительное поражение интимы артерий по типу атероматоза или атеротромбоза. Атероматозные массы – катаболиты тех ПНЖК, которые не смогли рецепторным путем поглотить филогенетически более поздние клетки

    Comparison of electromagnetic and nuclear dissociation of 17Ne^{17}\mathrm{Ne}

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    The Borromean drip-line nucleus ¹⁷Ne has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp-process, where the two-proton capture reaction ¹⁵O(2p,γ) ¹⁷Ne plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of the ¹⁷Ne structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u¹⁷Ne beam was directed toward lead, carbon, and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of ¹⁷Ne were disentangled. The relative populations of s and d states in ¹⁶F were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system ¹⁵O + 2p. The ¹⁷Ne EMD data were compared to current theoretical models. None of them, however, yields satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process

    Coulomb breakup of 17 Ne from the view point of nuclear astrophysics

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    6 pags., 5 figs. -- XII International Symposium on Nuclei in the Cosmos, August 5-12, 2012, Cairns, AustraliaBy the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p, γ) 17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section σCoul has been determined, which then will be converted into a photo-absorption cross section σphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress.This project was supported by the German Federal Ministry for Education and Research (BMBF), EU(EURONS), EMMI-GSI, and HIC for FAI

    Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics

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    By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress. \ua9 Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence

    Coulomb and nuclear excitations of narrow resonances in Ne-17

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    New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure

    Diverse mechanisms in proton knockout reactions from the Borromean nucleus 17Ne

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    Nucleon knockout experiments using beryllium or carbon targets reveal a strong dependence of the quenching factors, i.e., the ratio (R s) of theoretical to the experimental spectroscopic factors (C 2S), on the proton-neutron asymmetry in the nucleus under study. However, this dependence is greatly reduced when a hydrogen target is used. To understand this phenomenon, exclusive 1H (17Ne , 2p16F) and inclusive 12C(17Ne,2p16F)X , 12C (17Ne , 16F) X as well as 1H (17Ne , 16F) X (X-denotes undetected reaction products) reactions with 16F in the ground and excited states were analysed. The longitudinal momentum distribution of 16F and the correlations between the detached protons were studied. In the case of the carbon target, there is a significant deviation from the predictions of the eikonal model. The eikonal approximation was used to extract spectroscopic factor values C 2S . The experimental C 2S value obtained with C target is markedly lower than that for H target. This is interpreted as rescattering due to simultaneous nucleon knockout from both reaction partners, 17Ne and 12C

    Systematic investigation of projectile fragmentation using beams of unstable B and C isotopes

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    Background: Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from C10,12-18 and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the epax code is not able to describe the data satisfactorily. Using abrabla07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease abrabla07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study
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