Towards the Limits of Existence of Nuclear Structure: Observation and First Spectroscopy of the Isotope

The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: ^{31}K. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of ^{28}S+3p and the respective decay vertices. The energies of the previously unknown ground and excited states of ^{31}K have been determined. This provides its 3p separation energy value S_{3p} of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed ^{31}K states have been derived from distributions of the measured decay vertices.

Observation and Spectroscopy of New Proton-Unbound Isotopes ³°Ar and ²9Cl: An Interplay of Prompt Two-Proton and Sequential Decay.

Previously unknown isotopes (30)Ar and (29)Cl have been identified by measurement of the trajectories of their in-flight decay products (28)S+p+p and (28)S+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of (30)Ar and (29)Cl were found at 2.25(-0.10)(+0.15) and 1.8±0.1 MeV above the two- and one-proton thresholds, respectively. The lowest states in (30)Ar and (29)Cl point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the (30)Ar ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of (30)Ar*(2(+)) has been obtained by detecting two decay branches into the ground and first-excited states of the (28)S fragment.

Two-proton correlations in the decay of 45Fe.

The decay of extremely neutron-deficient 45Fe has been studied in detail by means of a novel type of a gaseous detector employing digital imaging to record tracks of charged particles. The two-proton radioactivity channel was clearly identified. For the first time, the angular and energy correlations between two protons emitted from the nuclear ground state were determined, indicating the genuine three-body character of this decay. The half-life of 45Fe was found to be 2.6+/-0.2 ms and the observed 2p decay branching ratio is 70+/-4%.

Observation of proton radioactivity of the (21+) high-spin isomer in 94Ag.

We have observed direct one-proton decay of the (21+) isomer in the N=Z nuclide 94Ag into high-spin states in 93Pd by detecting protons in coincidence with gamma-gamma correlations and applying gamma gates based on known 93Pd levels. Two decay branches have been identified, with proton energies of 0.79(3) and 1.01(3) MeV and branching ratios of 1.9(5)% and 2.2(4)%, respectively. The corresponding partial half-life values are 21(6) and 18(4) s. The Q value of the direct proton decay of the (21+) isomer was found to be 5.78(3) MeV. The very small reduced widths of the observed proton decays might reflect dominating collective configurations in the (21+) isomer, and the fine structure of the proton spectrum might indicate a strong deformation of this state.

Fine structure in proton emission from 145Tm discovered with digital signal processing.

Fine structure in proton emission from the 3.1(3) mus activity of 145Tm was discovered by using a novel technique of digital processing of overlapping recoil implantation and decay signals. Proton transitions to the ground state of 144Er and to its first excited 2(+) state at 0.33(1) MeV with a branching ratio I(p)(2(+))=9.6+/-1.5% were observed. The structure of the 145Tm wave function and the emission process were analyzed by using particle-core vibration coupling models.

Discovery of doubly magic 48Ni

In an experiment at the SISSI/LISE3 facility of GANIL, we used the projectile fragmentation of a primary 58Ni26+ beam at 74.5 MeV/nucleon with an average current of 3 &mgr;A on a natural nickel target to produce very neutron-deficient isotopes. In a 10-day experiment, 287 42Cr isotopes, 53 45Fe isotopes, 106 49Ni isotopes, and 4 48Ni isotopes were unambiguously identified. The doubly magic nucleus 48Ni, observed for the first time, is the most proton-rich isotope ever identified with an isospin projection T(z) = -4. It is probably the last doubly magic nucleus with "classical" shell closures accessible for present-day facilities. Its observation allows us to deduce a lower limit for the half-life of 48Ni of 0.5 &mgr;s.

Vanadium complexes of the N(CH2CH2S)3(3-) and O(CH2CH2S)2(2-) ligands with coligands relevant to nitrogen fixation processes.

Vanadium(III) and vanadium(V) complexes derived from the tris(2-thiolatoethyl)amine ligand [(NS3)3-] and the bis(2-thiolatoethyl)ether ligand [(OS2)2-] have been synthesized with the aim of investigating the potential of these vanadium sites to bind dinitrogen and activate its reduction. Evidence is presented for the transient existence of (V(NS3)(N2)V(NS3), and a series of mononuclear complexes containing hydrazine, hydrazide, imide, ammine, organic cyanide, and isocyanide ligands has been prepared and the chemistry of these complexes investigated. [V(NS3)O] (1) reacts with an excess of N2H4 to give, probably via the intermediates (V(NS3)(NNH2) (2a) and (V(NS3)(N2)V(NS3) (3), the V(III) adduct [V(NS3)(N2H4)] (4). If 1 is treated with 0.5 mol of N2H4, 0.5 mol of N2 is evolved and green, insoluble [(V(NS3))n] (5) results. Compound 4 is converted by disproportionation to [V(NS3)(NH3)] (6), but 4 does not act as a catalyst for disproportionation of N2H4 nor does it act as a catalyst for its reduction by Zn/HOC6H3Pri2-2,6. Compound 1 reacts with NR1(2)NR2(2) (R1 = H or SiMe3; R2(2) = Me2, MePh, or HPh) to give the hydrazide complexes [V(NS3)(NNR2(2)] (R2(2) = Me2, 2b; R2(2) = MePh, 2c; R2(2) = HPh, 2d), which are not protonated by anhydrous HBr nor are they reduced by Zn/HOC6H3Pri2-2,6. Compound 2b can also be prepared by reaction of [V(NNMe2)(dipp)3] (dipp = OC6H3Pri2-2,6) with NS3H3. N2H4 is displaced quantitatively from 4 by anions to give the salts [NR3(4)][V(NS3)X] (X = Cl, R3 = Et, 7a; X = Cl, R3 = Ph, 7b; X = Br, R3 = Et, 7c; X = N3, R3 = Bu(n), 7d; X = N3, R3 = Et, 7e; X = CN, R3 = Et, 7f). Compound 6 loses NH3 thermally to give 5, which can also be prepared from [VCl3(THF)3] and NS3H3/LiBun. Displacement of NH3 from 6 by ligands L gives the adducts [V(NS3)(L)] (L = MeCN, nu CN 2264 cm-1, 8a; L = ButNC, nu NC 2173 cm-1, 8b; L = C6H11NC, nu NC 2173 cm-1, 8c). Reaction of 4 with N3SiMe3 gives [V(NS3)(NSiMe3)] (9), which is converted to [V(NS3)(NH)] (10) by hydrolysis and to [V(NS3)(NCPh3)] (11) by reaction with ClCPh3. Compound 10 is converted into 1 by [NMe4]OH and to [V(NS3)NLi(THF)2] (12) by LiNPri in THF. A further range of imido complexes [V(NS3)(NR4)] (R4 = C6H4Y-4 where Y = H (13a), OMe (13b), Me (13c), Cl (13d), Br (13e), NO2 (13f); R4 = C6H4Y-3, where Y = OMe (13g); Cl (13h); R4 = C6H3Y2-3,4, where Y = Me (13i); Cl (13j); R4 = C6H11 (13k)) has been prepared by reaction of 1 with R4NCO. The precursor complex [V(OS2)O(dipp)] (14) [OS2(2-) = O(CH2CH2S)2(2-)] has been prepared from [VO(OPri)3], Hdipp, and OS2H2. It reacts with NH2NMe2 to give [V(OS2)(NNMe2)(dipp)] (15) and with N3SiMe3 to give [V(OS2)(NSiMe3)(dipp)] (16). A second oxide precursor, formulated as [V(OS2)1.5O] (17), has also been obtained, and it reacts with SiMe3NHNMe2 to give [V(OS2)(NNMe2)(OSiMe3)] (18). The X-ray crystal structures of the complexes 2b, 2c, 4, 6, 7a, 8a, 9, 10, 13d, 14, 15, 16, and 18 have been determined, and the 51V NMR and other spectroscopic parameters of the complexes are discussed in terms of electronic effects.

[Dissecting aneurysm of the ascending aorta as a late complication of the treatment of acquired defects of the aortic and mitral valves]. / Tetniak rzekomy aorty wstepujacej jako pózne powiklanie w przebiegu pooperacyjnego leczenia wady nabytej zastawki aortalnej i mitralnej.

A diffuse aneurysm of the ascending aorta was observed five months after prosthetic valve implantation in to mitral and aortic orifices because of the acquired valvular heart disease. The main factor predisposing to the formation of a false aneurysm was an infection of the endocardium and ascending aortal wall which were observed previously during cardiac surgery. The diagnosis, based on the clinical symptoms and non-invasive investigations, was later confirmed with aortography and intra-operatively.

[The protective effect of an EDTA-sodium-extract-vaccine obtained from swine-pathogenic E. coli in a field trial. 1. Communication: Direct and indirect immunization of suckling piglets (author's transl)]. / Die Schutzwirkung von EDTA-Na-Extraktimpfstoffen aus schweinepathogenen E. coli-Bakterien in Feldversuchen. 1. Mitteilung: Direkte und indirekte Immunisierung von Saugferkeln.

Pentavalent EDTA-Sodium-extract-vaccines and monovalent EDTA-Sodium-extract-vaccines obtained from swine-pathogenic E. coli and produced in Berlin-Buch were used in field trials to test their antiepizootic effect in industrial pig-farms in the district of Wroclaw. The pentavalent vaccine contained extracts from E. coli O138, O139, O141, O147, and O149, whereas extracts from O8, O115 and O149 were used as monovalent vaccines. The field trials were conducted as blind trials is closed stocks of pigs. We employed direct oral immunization of suckling piglets and indirect immunization via sow vaccination. Direct oral immunization was tested in 382 suckling piglets. 190 animals were vaccinated, 192 animals received placebo. Neither the pentavalent vaccine nor a monovalent vaccine obtained from an epizootie strain of this stock gave protection in terms of a decrease in the duration of disease or a reduction of morbidity and mortality. Direct oral-immunization of suckling piglets thus was ineffective. Indirect immunization of the suckling piglets via vaccination of sow was performed in 189 pregnant sows 18--15 days before farrowing. 84 sows received vaccines i.m., 105 were given placebo i.m. These sows farrowed 1717 pigs, 777 of which were immunized indirectly and 940 treated with placebos. With the pentavalent vaccine and with the monovalent vaccine obtained from an epizootic strain we achieved significant protection of the indirect vaccinated suckling piglets.

[The protective effect of an EDTA-sodium-extract-vaccine obtained from swine-pathogenic E. coli in a field trial. 2. Communication: Immunization of weanling piglets (author's transl)]. / Die Schutzwirkung von EDTA-Na-Extraktimpfstoffen aus schweinepathogenen E. coli-Bakterien im Feldversuch. 2. Mitteilung: Immunisierung von Absatzferkeln.

Pentavalent EDTA-Sodium-extract vaccines and monovalent EDTA-Sodium-extract vaccines obtained from swine-pathogenic E. coli were used to test their antiepizootic effect in industrial pig farms, 2929 piglets after weaning were included in this field trial, 1309 were immunized partly orally, partly i.m., 1620 piglets received placebos accordingly. By means of oral immunization the pentavalent vaccine was capable of reducing the morbidity of the vaccinated animals significantly. Intramuscular immunization with the pentavalent vaccines produced significant differences in morbidity too. A monovalent vaccine obtained from E. coli O149 and E. coli O8 was shown to be equally effective, whereas a monovalent vaccine obtained from E. coli O115 was ineffective. But in this stock there were infections with O149 but none with O115 or O8.

[Preliminary results of an atiepizootic field test using EDTA-Na extract vaccine from Escherichia coli strains pathogenic to swine in swine production industrial units]. / Erste Ergebnisse eines antiepizootischen Feldversuches mit einem EDTA-Na-Extraktimpfstoff aus schweinepathogenen Escherichia-coli-Stämmen in Anlagen der industriemässigen Schweineproduktion.

An anti-epizootic field test was applied to industrialised pig farms in the region of Wroclaw, Poland, to test the effectiveness of a pentavalent EDTA (calcium disodium edetate)--sodium vaccine extracted from Escherichia coli strains with pathogenicity to swine. The vaccine had been received from a centre in Berlin-Buch, GDR. The vaccine failed to provide any protection, when orally applied to nursed piglets. However, both morbidity and mortality were reduced and, thus, an anti-epizootic effect on nursed piglets produced, when the vaccine had been injected intramuscularly to the pregnant mother animals, prior to farrowing. In weaned piglets morbidity was sucessfully reduced by both oral as well as intramuscular administration.

[Rheumatoid arthritis and morbidity among wet spinning factory women workers]. / Zachorowalnosc i chorobowosc na reumatoidalne zapalenie stawów (R.Z.S.) u kobiet mokrej przedzalni zakladow lniarskich.

Two hundred ninety women employed in the wet spinning mill of the linen plants have been examined. Their average age and duration of employment were respectively 45 and 17,5 years. Examined women worked in specific microclimate including temperature from 24 degrees C to 25.3 degrees C and the moisture of air from 63,5 to 72,5%. Rheumatoid Arthritis in women working in wet spinning factory was the aim of this examination. It has been stated that these surroundings have no influence on that sort of disease.