Redetermination of di-μ-sulfido-bis­{[(2R)-2-acet­oxy-2-amino­ethane-1-thiol­ato-κ2 N,S]oxidomolybdenum(V)}

The structure of the title compound, [Mo2(C4H8NO2S)2O2S2], has been redetermined. Besides obvious differences between the original [Drew & Kay (1971 ▶). J. Chem. Soc. A, pp. 1851–1854] and the current unit-cell parameters, some packing features of the structure are also different; these findings are the result of significant improvements in the precision and accuracy of the present structure analysis. The two Mo atoms in the dimeric complex have very similar distorted trigonal–bipyramidal environments. Each Mo atom is bonded to an S atom and to an N atom of an l-cysteine ester ligand, to a terminal O atom and to two S atoms which bridge to the adjacent Mo atom [Mo⋯Mo separation = 2.8191 (2) Å]. N—H⋯Ocarbon­yl and N—H⋯Oterminal hydrogen-bonding inter­actions consolidate the crystal packing. During the synthesis, the originally employed l-cysteinate ligand has been converted to the l-cysteinate methyl ester ligand. Since this reaction does not take place without tin(IV) chloride, it is clear that tin(IV) chloride acts as a catalyst for the reaction

Research and development for accuracy improvement of neutron nuclear data on minor actinides

To improve accuracy of neutron nuclear data on minor actinides, a Japanese nuclear data project entitled “Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)” has been implemented. Several independent measurement techniques were developed for improving measurement precision at J-PARC/MLF/ANNRI and KURRI/LINAC facilities. Effectiveness of combining the independent techniques has been demonstrated for identifying bias effects and improving accuracy, especially in characterization of samples used for nuclear data measurements. Capture cross sections and/or total cross sections have been measured for Am-241, Am-243, Np-237, Tc-99, Gd-155, and Gd-157. Systematic nuclear data evaluation has also been performed by taking into account the identified bias effect. Highlights of the AIMAC project are outlined

Dynamics of human replication factors in the elongation phase of DNA replication

In eukaryotic cells, DNA replication is carried out by coordinated actions of many proteins, including DNA polymerase δ (pol δ), replication factor C (RFC), proliferating cell nuclear antigen (PCNA) and replication protein A. Here we describe dynamic properties of these proteins in the elongation step on a single-stranded M13 template, providing evidence that pol δ has a distributive nature over the 7 kb of the M13 template, repeating a frequent dissociation–association cycle at growing 3′-hydroxyl ends. Some PCNA could remain at the primer terminus during this cycle, while the remainder slides out of the primer terminus or is unloaded once pol δ has dissociated. RFC remains around the primer terminus through the elongation phase, and could probably hold PCNA from which pol δ has detached, or reload PCNA from solution to restart DNA synthesis. Furthermore, we suggest that a subunit of pol δ, POLD3, plays a crucial role in the efficient recycling of PCNA during dissociation–association cycles of pol δ. Based on these observations, we propose a model for dynamic processes in elongation complexes

Comparison between adhesion properties of adhesive bonding and adhesive-free adhesion for heat-assisted plasma-treated polytetrafluoroethylene (PTFE)

Heating during plasma treatment, known as heat-assisted plasma treatment, has recently reported to positively affect the adhesion properties of polytetrafluoroethylene (PTFE). In the present study, the adhesion properties of adhesive bonding and adhesive-free adhesion were compared for plasma-treated PTFE with different plasma treatment times and with or without heating during the plasma treatment. The relations among adhesion strength, plasma treatment time, radical density ratio, surface morphology, and surface hardness were investigated. No correlation was found between the adhesion strength and the radical density ratio or between the adhesion strength and the oxygen-containing-functional-group ratio. In contrast, correlation was observed between the adhesion strength and the surface hardness. In addition, the heat-assisted plasma treatment time affected the recovery of the weak boundary layer on the PTFE surface. Adhesive-free adhesion was found to require a longer heat-assisted plasma treatment time than adhesive bonding in order to achieve a high adhesion strength such as 1 N/mm

Cation-Cation Interaction between NpVO2+ and Li+ in a Concentrated LiCl Solution

Hydrated neptunyl ions of Np(V) and Np(VI) in aqueous solutions are known to have a pentagonal-bipyramidal geometry of NpO2(H2O)5 n+ (n: 1 or 2) [1]. Two axial oxygen atoms (Oax) bound to Np to form NpO2 n+ and five oxygen atoms (Oeq) of hydrated water molecules are arranged in the equatorial plane. Neptunyl ion of Np(V), NpVO+, is possible to contact with co-existed cations in solutions. The cation-cation interaction (CCI), which is a mutual coordination ofactinyl ions, was firstly found in a complexation of Np(V)-U(VI) [2]. Following the finding, the CCIs between NpVO2 + and various cations or oxo-cations have been investigated (see references in [3]). These counter cations are multiply charged cations of heavy elements, and the CCI between Np(V) and monovalent light cations has not been reported. In the present study, we report the CCI between Li+ and NpVO+ in a concentrated LiCl solution

Effect of rubber compounding agent on adhesion strength between rubber and heat-assisted plasma-treated polytetrafluoroethylene (PTFE)

Although heat-assisted plasma treatment enables drastic improvement of the adhesion property of polytetrafluoroethylene (PTFE), plasma-treated PTFE does not strongly adhere to any adherend. To clarify which rubber compounding agents positively affect the adhesion strength of a plasma-treated PTFE/rubber assembly, six types of unvulcanised rubbers were prepared and thermally compressed to a plasma-treated PTFE sheet. Thus, it was found that SiO 2 addition to rubber drastically increased the adhesion strength of a plasma-treated PTFE/rubber assembly and cohesion failure of rubber occurred with large fractions of SiO 2 although no adhesives were used. To confirm the reaction between plasma-treated PTFE and SiO 2 powder, X-ray photoelectron spectroscopy (XPS) measurements were performed for the thermally compressed SiO 2 /PTFE assembly after repeated washing. The XPS results indicated that hydrophilic SiO 2 powder strongly adhered to the plasma-treated PTFE, whereas hydrophobic SiO 2 powder did not adhere to the PTFE. In this paper, a model was proposed for a possible mechanism of strong adhesion of a PTFE/rubber assembly through both hydrogen and covalent bonds between silanol groups of the SiO 2 powder surface in the rubber and hydroxyl or carboxyl groups on the plasma-treated PTFE

Cherenkov counting of 90Sr and 90Y in bark and leaf samples collected around Fukushima Daiichi Nuclear Power Plant

The radioactivity of 90Sr and 137Cs in environmental samples, bark and leaf, collected around the Fukushima Daiichi Nuclear Power Plant in May 2013 was determined with the aim of investigating the migration of both nuclides using their radioactivity ratio. The radioactivity of 90Sr was determined by using Cherenkov counting of 90Y after purification using Sr resin and that of 137Cs was determined by -spectrometry. Quench correction in Cherenkov counting was investigated by measurements of samples spiked with purified 90Y revealed that the radioactivity could be evaluated without quench correction. The radioactivity ratio of 90Sr to 137Cs in bark samples of 4.2×10-3 and 1.2×10-2 was compared with the results from soil samples collected in July 2011 to show that the migration of 90Sr was slower than 137Cs in bark and tree