Η αντιοξειδωτική προετοιμασία πριν από μείζονες ηπατεκτομές

Σκοπός: Σκοπός του πειράματος είναι να εκτιμηθεί κατά πόσον η αντιοξειδωτική προετοιμασία με δεφεροξαμίνη μπορεί να ελαττώσει τον τραυματισμό της ισχαιμίας/επαναιμάτωσης του ήπατος που σχετίζεται με εκτεταμένη ηπατεκτομή σε χοίρους. Μέθοδοι: Δεκαοκτώ χοίροι χωρίστηκαν τυχαία σε ομάδες: Δεφεροξαμίνης (DFO) και Χειρουργείου μόνο (SO). Οι χοίροι υποβλήθηκαν σε λαπαροτομία, προσωρινό αποκλεισμό των δεξιών και μέσων ηπατικών αγγείων και ηπατικού πόρου και ακολούθως σε αριστερή ηπατεκτομή. Η ομάδα DFO έλαβε IV δεφεροξαμίνη πριν από την πρόκληση ισχαιμίας του ήπατος. Η παρακολούθηση πραγματοποιήθηκε για 6 ώρες και τα δείγματα (Protein carbonyls (PC), Thiobarbituric acid reactive substances (TBARS), Ιστολογία, ALT, AST, Lactic acid και WBC) συλλέχθηκαν στα 0, 60 και 360 λεπτά. Αποτελέσματα: Οι αντιοξειδωτικοί δείκτες PC και TBARS είχαν σημαντικά χαμηλότερη συγκέντρωση και υψηλότερα ποσοστά μείωσης στον ορό και τον ηπατικό ιστό της ομάδας DFO. Η ιστολογική εξέταση του ήπατος έδειξε λιγότερη φλεγμονή και νέκρωση στην ομάδα DFO. Τα ηπατικά ένζυμα και οι μετρήσεις γαλακτικού οξέος έδειξαν υψηλότερο ρυθμό μείωσης στην ομάδα DFO στο τέλος του πειράματος. Συμπεράσματα: Αυτή η πειραματική μελέτη τεκμηριώνει ένα πρώιμο προστατευτικό αποτέλεσμα της χορήγησης δεφεροξαμίνης σε μείζονες ηπατεκτομές έναντι της βλάβης ισχαιμίας/επαναιμάτωσης στο ήπαρ.Purpose: The purpose of the experiment is to evaluate whether antioxidant preconditioning with Deferoxamine can attenuate liver ischemia reperfusion injury associated with extended hepatectomy in swine. Methods: Eighteen swine were randomly assigned to two groups: Deferoxamine (DFO) and Surgery Only (SO). The porcine in both groups were subjected to laparotomy, prolonged temporary occlusion of right and middle hepatic pedicles and subsequent left hepatectomy. DFO group received IV deferoxamine prior to induction of liver ischemia. Monitoring was performed for 6 hours and samples (Protein carbonyls, Thiobarbituric acid reactive substances, Histology, ALT, AST, Lactic acid and WBC) were drawn at 0, 60 and 360 mins. Results: Protein carbonyls and Thiobarbituric acid reactive substances had significantly lower concentration and higher reduction rates in serum and liver tissue of DFO group. The histological examination of liver tissue showed less inflammation and necrosis in DFO group. Hepatic enzymes and lactic acid measurements showed higher reduction rate in DFO group by the end of the experiment. Conclusions: This experimental study documents an early protective effect of deferoxamine administration in major hepatectomies against liver ischemia/reperfusion injury

8Li+alpha decay of 12B and its possible astrophysical implications

The 12B excitation energy spectrum has been obtained from coincidence measurements of the 9Be+7Li -> 2alpha+8Li reaction at E{0}=52 MeV. The decay of the states at excitations between 10 and 16 Mev into alpha$+8Li has been observed for the first time. Observed alpha-decay indicates possible cluster structure of the 12B excited states. The influence of these states on the cross section of the astrophysically important 8Li(alpha,n)11B and 9Be+t reactions is discussed and the results are compared with existing results.Comment: accepted for publication in Europhysics Letter

Nuclear Astrophysics in Storage Rings

Nuclear reaction cross sections are usually very small in typical astrophysical environments. It has been one of the major challenges of experimental nuclear astrophysics to assess the magnitude of these cross sections in the laboratory. For a successful experiment high luminosity beams are needed. Increasing the target width, one also increases the reaction yields. But, this is of limited use due to multiple scattering in the target. Storage rings are a very good way to overcome these difficulties. In principle, they can be tuned to large luminosities, and have the advantage of crossing the interaction region many times per second (typically one million/s), compensating low density internal gas targets, or low reaction rates in beam-beam collisions. Storage rings are also ideal tools for precise measurements of masses and beta-decay lifetimes of nuclei of relevance for astrophysics.Comment: 14 pages, LaTeX, figures available upon reques

Solving the large discrepancy between inclusive and exclusive measurements of the 8Li+4He→11B+n{}^8{\rm Li}+{}^4{\rm He}\to{}^{11}{\rm B}+n reaction cross section at astrophysical energies

A solution of the large discrepancy existing between inclusive and exclusive measurements of the ${}^8{\rm Li}+{}^4{\rm He}\to{}^{11}{\rm B}+n$ reaction cross section at $E_{cm} <3$ MeV is evaluated. This problem has profound astrophysical relevance for this reaction is of great interest in Big-Bang and r-process nucleosynthesis. By means of a novel technique, a comprehensive study of all existing ${}^8{\rm Li}+{}^4{\rm He}\to{}^{11}{\rm B}+n$ cross section data is carried out, setting up a consistent picture in which all the inclusive measurements provide the reliable value of the cross section. New unambiguous signatures of the strong branch pattern non-uniformities, near the threshold of higher ${}^{11}{\rm B}$ excited levels, are presented and their possible origin, in terms of the cluster structure of the involved excited states of ${}^{11}{\rm B}$ and ${}^{12}{\rm B}$ nuclei, is discussed.Comment: 5 pages, 4 figures, 1 tabl

Beta-decay in odd-A and even-even proton-rich Kr isotopes

Beta-decay properties of proton-rich odd-A and even-even Krypton isotopes are studied in the framework of a deformed selfconsistent Hartree-Fock calculation with density-dependent Skyrme forces, including pairing correlations between like nucleons in BCS approximation. Residual spin-isospin interactions are consistently included in the particle-hole and particle-particle channels and treated in Quasiparticle Random Phase Approximation. The similarities and differences in the treatment of even-even and odd-A nuclei are stressed. Comparison to available experimental information is done for Gamow-Teller strength distributions, summed strengths, and half-lives. The dependence of these observables on deformation is particularly emphasized in a search for signatures of the shape of the parent nucleus.Comment: 29 pages, 16 figure

A compilation of charged-particle induced thermonuclear reaction rates

Low-energy cross section data for 86 charged-particle induced reactions involving light (1 less than or equal to Z less than or equal to 14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 10(6) K to 10(10) K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that the target states are thermally populated following a Maxwell-Boltzmann distribution, except in some cases involving isomeric states. Adopted values complemented with lower and upper limits of the rates are presented in tabular form. Analytical approximations to the adopted rates, as well as to the inverse/direct rate ratios, are provided. (C) 1999 Elsevier Science B.V. All rights reserved

Low-Energy Direct Capture in the 8Li(n,gamma)9Li and 8B(p,gamma)9C Reactions

The cross sections of the 8Li(n,gamma)9Li and 8B(p,gamma)9C capture reactions have been analyzed using the direct capture model. At low energies which is the astrophysically relevant region the capture process is dominated by E1 transitions from incoming s-waves to bound p-states. The cross sections of both mirror reactions can be described simultaneously with consistent potential parameters, whereas previous calculations have overestimated the capture cross sections significantly. However, the parameters of the potential have to be chosen very carefully because the calculated cross section of the 8Li(n,gamma)9Li reaction depends sensitively on the potential strength.Comment: 6 pages, 5 figures, Phys. Rev. C, accepte