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A radiochemical method for producing 82Se sources with an ultra-low level of contamination of natural radionuclides (40K, decay products of 232Th and 238U) has been developed based on cation-exchange chromatographic purification with reverse removal of impurities. It includes chromatographic separation (purification), reduction, conditioning (which includes decantation, centrifugation, washing, grinding, and drying), and 82Se foil production. The conditioning stage, during which highly dispersed elemental selenium is obtained by the reduction of purified selenious acid (H2SeO3) with sulfur dioxide (SO2) represents the crucial step in the preparation of radiopure 82Se samples. The natural selenium (600 g) was first produced in this procedure in order to refine the method. The technique developed was then used to produce 2.5 kg of radiopure enriched selenium (82Se). The produced 82Se samples were wrapped in polyethylene (12 μm thick) and radionuclides present in the sample were analyzed with the BiPo-3 detector. The radiopurity of the plastic materials (chromatographic column material and polypropylene chemical vessels), which were used at all stages, was determined by instrumental neutron activation analysis. The radiopurity of the 82Se foils was checked by measurements with the BiPo-3 spectrometer, which confirmed the high purity of the final product. The measured contamination level for 208Tl was 8–54 μBq/kg, and for 214Bi the detection limit of 600 μBq/kg has been reached.

Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray telescope Fermi/LAT. No statistically significant excess has been observed, thus upper limits on the neutrino fluences have been derived and compared to the predictions by models. Constraints have been put on the ratio of proton to electron luminosity in the jets.

This work presents a new search for magnetic monopoles using data taken with the ANTARES neutrino telescope over a period of 10 years (January 2008 to December 2017). Compared to previous ANTARES searches, this analysis uses a run-by-run simulation strategy, with a larger exposure as well as a new simulation of magnetic monopoles taking into account the Kasama, Yang and Goldhaber model for their interaction cross-section with matter. No signal compatible with the passage of relativistic magnetic monopoles is observed, and upper limits on the flux of magnetic monopoles with β=v/c≥0.55, are presented. For ultra-relativistic magnetic monopoles the flux limit is ∼7×10−18 cm−2s−1sr−1.

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A formal [2 + 2] cycloaddition of 2-amidoacrylates with monosubstituted donor olefins, including its asymmetric version, is described. The stereoselectivity of this reaction can be modulated by the use of sterically hindered aluminum aryloxides or methylaluminoxane as Lewis acids. The reaction was applied to the synthesis of both stereoisomers of 2-benzyloxycyclobutane-α-amino acid, which are protected serine analogues c4Ser(OBn).

Summary.: An efficient and easily applicable method for the synthesis of a variety of hydroxy-α-amino acids analogues of serine and phenylalanine has been established. The method involves the stereoselective intramolecular conjugate addition of the benzamide group to cyclohexenone promoted by Lewis acid. Subsequent transformations of functional groups pro-vide the conformationally constrained 2-hydroxy- and 2,4-dihydroxy-6-phenylcyclohexane-α-amino acids.

Abstract: A prospective nonrandomized study was made of 17 basketball players with fractures of the proximal third of the shaft of the fifth metatarsal. Eight had acute fractures, which were treated with a cast without weight-bearing, and the other nine had stress fractures for which percutaneous compression screwing was initially used. In the first group, union was obtained in four cases in an average of 9 weeks, with resumption of sport by12 weeks. Three had a good outcome and the fourth was fair. The other four cases, which had not healed after 12 weeks of immobilization, were subsequently treated using compression screws. Resumption of sport was achieved 20–24 weeks after the fracture. Two of these had a good result; in the other two the results were fair. Of the nine patients with stress fractures in which a screw was inserted, all healed between 8 and 14 weeks and returned to sport within 7–12 weeks. Seven had a good result and the other two only fair. There was one intraoperative complication, but no postoperative complications, such as nonunion or refracture, were observed. Even if the non-operative treatment is able to provide a good result, immobilization without weight-bearing does not guarantee healing. In this series, percutaneous screw fixation was able to achieve successful healing in a short period of time. Thus, this procedure seems to be preferable for primary treatment of this lesion in athletes.

This report describes the behavior of 4hetaryliden and 4aryliden54Hoxazolones as dienophiles in the DielsAlder reaction with several dienes. The application of this reaction to the synthesis of different conformationally constrained cyclic analogues of natural amino acids of pharmacological interest is also described.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

We report the results of a search for the neutrinoless double-β decay (Oνββ)of 100Mo, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg·y, no evidence for the Oνββ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T1/2(0νββ) > 1.1 x 1024 years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of (mν) < 0.3-0.9 eV (90% C.L.). Constraints on other lepton number violating mechanisms of Oνββ decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2-10] MeV is observed for an exposure of 47 kg · y. [ABSTRACT FROM AUTHOR]

A novel low-energy neutrino-oscillation experiment NOSTOS, combining a strong tritium source and a high pressure spherical TPC detector (10 m in radius) has been recently proposed. The goal of the experiment is to measure the mixing angle , the neutrino magnetic moment and the Weinberg angle at low energy. The same apparatus, filled with high pressure Xenon, exhibits a high sensitivity as a Super Nova neutrino detector with extra galactic sensitivity. Results of a first prototype will be shown and a short-term experimental program will be discussed. [Copyright &y& Elsevier]