In-beam γ-ray spectroscopy on56Ni

Yrast levels in the doubly-magic nucleus⁵⁶Ni have been studied by in-beam gg-spectroscopy with the reaction⁵⁴Fe(α, 2n)⁵⁶Ni. A cascade of five γ -transitions is established. A shell model calculation of 2p2h, T=0 states, using empirical matrix elements, suggests the assignments 8⁺ and 10⁺ for the two highest levels.     

Influence of pH on the Molecular Weight of Poly-3-hydroxybutyric Acid (P3HB) Produced by Recombinant Escherichia coli

The production of ultrahigh molecular weight poly-3-hydroxybutyric acid (P3HB) from carbohydrates by recombinant Escherichia coli harboring genes from Ralstonia eutropha was evaluated. In shaken-flask experiments, E. coli XL1 Blue harboring plasmid pSK::phaCAB produced P3HB corresponding to 40 and 27 % of cell dry weight from glucose and xylose, respectively. Cultures in bioreactor using glucose as the sole carbon source at variable pH values (6.0, 6.5, or 7.0) allowed the production of P3HB with molecular weight varying between 2.0 and 2.5 MDa. These figures are significantly higher than the values often obtained by natural bacterial strains (0.5–1.0 MDa). Contrary to reports of other authors, no influence of pH was observed on the molecular weight of the polymer produced. Using xylose, P3HB with high molecular weight was also produced, indicating the possibility to produce these polymers from lignocellulosic materials.     

Level structure of proton-richN=83 Nuclei150Ho and152Tm

The yrast levels of theN=83 odd-odd nuclei¹⁵⁰Ho and¹⁵²Tm have been studied byγ-ray spectroscopy following reactions induced by 240–250 MeV⁶⁰Ni ions. Isomers have been identified in¹⁵⁰Ho at 1.096, 2.625 and ～8.0 MeV and in¹⁵²Tm at 2.555 and ～ 6.3 MeV, and the level schemes of both nuclei have been established up to 2.6 MeV. The level spectra are interpreted using the shell model in terms of the coupling of anf _7/2,h _9/2 or i_13/2 valence neutron to the yrast excitations of the neighboring N=82 nuclei.     

A stereospecific phosphonium ylide-salt coupling reaction

The stereospecific formation of a phosphonium ylide-salt via the stereospecific coupling of an allylic phosphonium ylide with the corresponding phosphonium salt is described.     

Aspects of organic analysis

Summary Kairoline (1-methyl-1,2,3,4-tetrahydroquinoline) is proposed as a powerful solvent in the Zerewitinoff determination of active hydrogen in highly insoluble organic compounds.

---

Zusammenfassung Kairolin (1-Methyl-1,2,3,4-tetrahydrochinolin) wird als hervorragendes Lösungsmittel für die Bestimmung von aktivem Wasserstoff in sehr schwer löslichen organischen Substanzen nach Zerewitinoff vorgeschlagen.

---

Résumé Les auteurs proposent la kairoline (methyl-1-tetrahydroquinoléine-1,2,3,4) comme solvant de haute efficacité pour les composés organiques particulièrement insolubles lors de la détermination de l'hydrogène actif par la méthode de Zerewitinoff.

---

---

Part V: S. Afr. Industr. Chemist6, 274 (1952).     

Effectiveness of palladium as a chemical modifier for the determination of lead in biological materials and foodstuffs by graphite furnace atomic absorption spectrometry

Summary A combination of 6 g palladium and 15 g magnesium nitrate is proposed as chemical modifier for lead determinations in biological materials and foodstuffs. The applicability of this modifier was investigated by the analysis of several types of samples, as compared to the classical NH₄H₂PO₄ and Mg(NO₃)₂ modifier. Direct determinations of lead against aqueous standard solutions can be performed in 3-fold diluted urine, 2-fold diluted milk and 6-fold diluted blood, when the proposed modifier is added. A method for lead determinations in potatoes using the combined palladium and magnesium nitrate modifier, after a microwave acid digestion, is described. The optimum GFAAS pyrolysis temperature remains dependent on the matrix and should be determined for each type of sample. A wider linear range of the calibration curve is observed when the proposed Pd modifier is used.     

Decays of(vh_{11/2} ^n )^{10 + } and(\pi d_{5/2} vh_{11/2} ^n )^{25/2 + } isomers in even-A Sn and odd-A Sb nuclei

Isomeric decays in^{116, 118, 120}Sn and^{119, 120}Sb have been studied by measurements of delayedγ-rays following reactions of 26–40 MeV⁷Li ions on Cd targets. A 6.3 μs isomer of \((vh_{11/2} ^n )^{10 + } \) character in¹²⁰Sn is reported. The experimental variation inB(E2, 10⁺ → 8⁺) between \(vh_{11/2} ^n \) states in^{116, 118, 120, 128, 130}Sn is compared with the expected dependence on vh^11/2 subshell occupation number. Isomerism in Sb nuclei is also discussed, and a known high-spin isomer in¹¹⁹Sb is assigned the same seniority-three configuration \((\pi d_{5/2} vh_{11/2} ^n )^{25/2 + } \) as a well-established 340 μs isomer in¹¹⁷Sb.     

Quantitative mass spectrometric identification of isomers applying coherent laser control

Mass spectrometry (MS) is one of the oldest and most trusted analytical methods for chemical identification. Advances in biology, such as metabolic analysis and proteomics, have fueled a growing number of refinements in this method. Unfortunately, isomers, for example, o- and p-xylene, are seldom identifiable by MS because they produce identical spectra. Time-consuming and less sensitive multidimensional methods are subsequently required for structural determination. The sensitivity of MS coupled with shaped femtosecond laser pulses that control molecular fragmentation and ionization results in a new, fast, and reproducible method for molecular identification which is used here to distinguish positional and geometric isomer compounds and quantify their relative concentration in mixtures.     

Properties of the _{69}^{150}{\text{T}}{{\text{m}}_{81}} 6− β-decaying isomer

Decay experiments for ¹⁴⁸Ho 6^? and ¹⁵⁰Tm 6^? were carried out at the GSI On-line mass separator using 5 MeV/A ⁵⁸Ni-beams on ⁹⁴Mo and ⁹⁶Ru targets. Gammaγ-and γX-coincidences established the ¹⁵⁰Tm 6^? decay scheme, and e^? gave firm I^π assignments for ¹⁴⁸Dy and ¹⁵⁰Er levels fed in the decays. It was found that the previously unknown \(6_1^ -\) state in ¹⁵⁰Er receives significant β-strength, which strongly suggests \(\pi {h_{11/2}}\nu s_{1/2}^{ - 1}\) character for the ¹⁵⁰Tm 6^? isomer. The results are discussed in terms of the expected GT strength function. Shell model calculations for the \(\pi h_{11/2}^4\) yrast states are presented.