Magnetic dipole moments near Sn: Measurement on isomeric 11/2 states in odd-A Te and Te by NMR/ON

On-line low temperature nuclear orientation (OLNO) experiments have been performed on the odd-A Te isotopes ¹³¹Te and ¹³³Te using the technique of nuclear magnetic resonance on oriented nuclei (NMR/ON). The magnetic moments of the isomeric 11/2⁻ states have been measured extending the known data on these states in the Te isotopes up to the neutron shell closure at N = 82. The contribution to the 11/2⁻ magnetic moment in ¹³³Te due to core polarisation is calculated using an RPA shell model as well as corrections to the magnetic dipole operator caused by mesonic exchange currents. The neutron number dependence of the magnetic moments of the 11/2⁻ isomers in heavy Te isotopes is discussed in terms of particle-core coupling model (PCM) calculations.     

Densitometric quantification of individual phospholipids. Improvement and evaluation of a method using molybdenum blue reagent for detection

A densitometric method for simultaneous quantification of individual phospholipids based on visualization with molybdenum blue reagent is presented. Previously reported problems concerning colour instability have been solved. The method is specific for phosphorus-containing compounds and independent of the degree of fatty acid unsaturation. The molar absorptivities of most analysed phospholipids do not differ more than 10% from that for phosphatidylcholine from egg yolk. For cases of greater deviation (sphingomyelin, lysophosphatidylcholine and phosphatidylserine), analysis is accomplished by use of appropriate standard mixtures. The between-series coefficient of variation is ca. 9%. The method is compared to a preparative thin-layer chromatographic assay and another commonly used densitometric method.     

Laser and radio-frequency spectroscopy of the 5d 36s 2 4 P 3/2,5/2 states in Ta I

The hyperfine structure of the metastable atomic states 5d ³6s ^{2 4} P _3/2 and⁴ P _5/2 in¹⁸¹Ta has been studied using high resolution laser spectroscopy and laser radio-frequency double-resonance methods.     

Studies towards the total synthesis of an epoxy isoprostane phospholipid,a potent activator of endothelial cells

We report studies toward the total synthesis of an epoxy isoprostane, namely the preparation of compound 9 which is an analogue of the elimination product 7 of the naturally occurring epoxy isoprostane 4 by a straightforward route using a three-component coupling, and have shown by several spectroscopic criteria that it closely resembles the natural material.     

Pellicular expanded bed matrix suitable for high flow rates

A new type of expanded bed matrix with a heavy core of stainless steel covered with an agarose layer was prepared. Two bead size fractions, the smaller one (32-75 microm diameter) having a single particle core and the larger (75-180 microm diameter) with an agglomerate of stainless steel particles constituting the core, were chosen for further characterisation. The dispersion behaviour was determined both in packed bed and expanded bed modes by the retention time distribution method (RTD) and compared with the Streamline matrix (Amersham Pharmacia Biotech). The comparison turned out in favour of the new matrix. Flow rates as high as 3000 cm/h were used with the larger fraction, giving stable expanded beds with good mass transfer properties. The matrices were mechanically stable without any tendency to crack or peal, even after prolonged use.     

All alkoxide route to manganate and coboltate perovskite films and powders: effects of processing parameters

Manganate and cobaltate perovskites having the general formula ABO₃ have many technologically important applications. Here we present all alkoxide based routes to manganate and coboltate perovskite films and nano-phase powders of the compositions; LCMO (La_0.67Ca_0.33MnO₃), LSMO (La_0.75Sr_0.25MnO₃), LNCMO (La_0.33Nd_0.33Ca_0.33MnO₃), LBSMO (La_0.75Ba_0.125Sr_0.125MnO₃) and LSCO (La_0.50Sr_0.50CoO₃). The Mn and Co (oxo) methoxy-ethoxide precursors were prepared by reaction of MnCl₂ or CoCl₂ with 2 Kmoe in methoxy-ethanol-toluene. After hydrolysis of the alkoxide solutions by atmospheric air all systems produced X-ray and electron diffraction amorphous gels of high elemental homogeneity, and the IR spectra showed that they consisted of hydrated oxo-carbonates. Heating in air resulted in similar weight-loss curves for all studied gels passing; loss of H₂O in the range 20–300 °C, decomposition of carbonate groups into oxide and CO₂ in the temperature range 300–700 °C, and in some cases loss of a small amount of oxygen in the temperature range 700–1,000 °C. The pure perovskites were obtained at 690–770 °C with heat rates of typically 5–20 °C min^?1 without annealing. Perovskites could also be obtained at 550 °C by annealing, but these perovskites are prone to be A-site ion inhomogeneous according to the TEM EDS studies, which was not the case for the perovskites heat-treated to at least the carbonate decomposition temperature. This A-site inhomogeneity is ascribed to sequential decomposition of carbonates due to their different thermal stabilities, which is probably a general feature also with other sol–gel precursors and low temperature annealing. High quality polycrystalline films were prepared on Si/SiO₂/TiO₂/Pt substrates with all compositions and high quality epitaxial films were prepared of LCMO (on 100 LaAlO₃) and LSCO (on 100 SrTiO₃). The colossal magneto resistance (CMR) of the epitaxial LCMO films of 32% (246 K) is in parity with PLD derived films. The conductivities of the epitaxial and polycrystalline LSCO films were 1.9 mΩcm (on STO) and 1.7 mΩcm (on α-Al₂O₃, respectively).     

Molecular structure of decamethylgermanocene in the solid state

The low temperature X-ray structure analysis of decamethylgermanocene reveals two independent molecules in the unit cell, both of which have a bent sandwich structure with angles between the planes of the two C₅Me₅ rings of 31.26(0.09)° and 31.55(0.10)°, respectively. The perpendicular germanium to ring distances are 220 pm, corresponding to Ge-C bond lengths ranging from 240 to 266 pm.     

Reaction of H-Phosphonate Diesters with Trityl Halides

Abstract

A study on the reaction of H-phosphonate diesten with trityl halides under different reaction conditions has been performed. The reactions were evaluated using 31P NMR spectroscopy. For the study we selected simple H-phosphonate diesters, i.r. diphenyl H-phosphonate and diethyl H-phosphonate. Depending on the reaction conditions used the products obtained differed substantially. Formation of C-phosphonate 1 vs 2 depended primarily on the kind of trityl derivative used for the reaction.     

Methodology for determination of <Superscript>89</Superscript>Sr and <Superscript>90</Superscript>Sr in radiological emergency: II. Method development and evaluation

In this work a method for the determination of both ⁸⁹Sr and ⁹⁰Sr is presented. The method can potentially be used in radiological emergency and deliver results shortly after an incident. The method development was based on theoretical calculations of potential interferences from other fission products and how these could be discriminated when applying different chemical separation schemes. Validation was done on reactor coolant water containing short-lived fission products, and on a reference material. The results indicate that correct results of ⁸⁹Sr and ⁹⁰Sr can be obtained 4 and 9 days, respectively, after an incident.