A type 2 Ferrier rearrangement-based synthesis of d-myo-inositol 1,4,5-trisphosphate

The synthesis of d-myo-inositol 1,4,5-trisphosphate (InsP₃) from methyl α-d-glucopyranose, via a type 2 Ferrier rearrangement is reported. A key intermediate in this synthesis possesses orthogonal protecting groups at the 1-, 4- and 5-position, making it a versatile starting point for the synthesis of unnatural InsP₃ derivatives. Biological evaluation of the synthetic InsP₃ demonstrates that this compound evokes selective Ca²⁺ release via activation of InsP₃ receptors.     

Non-destructive bulk analysis of the Buggenum sword by neutron resonance capture analysis and neutron diffraction

Two neutron based techniques, neutron resonance capture analysis (NRCA) and time-of-flight neutron-diffraction (TOF-ND) have been used to determine the elemental composition and structure of a precious and very well preserved all-metal sword from the Bronze Age. This Buggenum sword was on loan from the National Museum of Antiquities (NMA) in Leiden (NL). NRCA and TOF-ND experiments have been carried out at a number of more or less identical positions of the sword. The tin-bronze ratio and the relative amounts of some minor elements (Sb, As, Ag, In) have been determined. The results of neutron diffraction measurements showed considerable tin-segregation, and clear indications of hardening on the edges of the blade. In addition, radiographs using Bremsstrahlung revealed the construction of the hilt–blade connection. The work was carried out at the EC Joint Research Centre IRMM in Geel (B) and at the ISIS facility of the Rutherford Appleton Laboratory (UK).     

Ultrafast and bias-free all-optical wavelength conversion using III-V-on-silicon technology

Using a 7.5 μm diameter disk fabricated with III-V-on-silicon fabrication technology, we demonstrate bias-free all-optical wavelength conversion for non-return-to-zero on-off keyed pseudorandom bit sequence (PRBS) data at the speed of 10 Gbits/s with an extinction ratio of more than 12 dB. The working principle of such a wavelength converter is based on free-carrier-induced refractive index modulation in a pump-probe configuration. We believe it to be the first bias-free on-chip demonstration of all-optical wavelength conversion using PRBS data. All-optical gating measurements in the pump-probe configuration with the same device have revealed that it is possible to achieve wavelength conversion beyond 20 Gbits/s.     

Pseudo-likelihood methodology for partitioned large and complex samples

Large data sets, either coming from a large number of independent replications, or because of hierarchies in the data with large numbers of within-unit replication, may pose challenges to the data analyst up to the point of making conventional inferential methods, such as maximum likelihood, prohibitive. Based on general pseudo-likelihood concepts, we propose a method to partition such a set of data, analyze each partition member, and properly combine the inferences into a single one. It is shown that the method is fully efficient for independent partitions, while with dependent sub-samples efficiency is sometimes but not always equal to one. It is argued that, for important realistic settings, efficiency is often very high. Illustrative examples enhance insight in the method’s operation, while real-data analysis underscores its power for practice.     

SNARE derived peptide mimic inducing membrane fusion

SNARE proteins mediate membrane fusion between synaptic vesicles and the plasma membrane. A minimized peptide SNARE model system with reduced complexity was introduced combining the native SNARE transmembrane (TMD) and linker domains with artificial coiled-coil forming peptides. Specific membrane fusion initiated by coiled-coil recognition was shown by lipid and content mixing vesicle assays.     

Spins of198Au levels from the (n, γ) reaction using polarized neutrons and polarized197Au nuclei

The¹⁹⁷Au(n, γ) reaction was studied with the aid of polarized thermal neutron beams. Two kinds of experimental data were obtained: i) circular polarization of gamma rays of high energy due to capture of polarized neutrons by unoriented¹⁹⁷Au nuclei, and ii) angular distribution of such gamma rays observed after capture of polarized neutrons by polarized¹⁹⁷Au nuclei. Spins of several levels of¹⁹⁸Au could be uniquely assigned or could be restricted. The sign of the hyperfine field of Au in AuFe has been determined to be negative.     

Highly sensitive differential pulse amperometric detection of second generation anti-tumor platinum compounds in HPLC effluents

Summary A highly sensitive on-line amperometric detection of platinum compounds in HPLC effluents was possible with the use of a polarographic detector. For TNO-1 (=cis-1,1-di(aminomethyl)-cyclohexane Pt(II)chloride) a linear dynamic range of at least three decades could be obtained (0.034–108g TNO-1/ml) with a detection limit of three times the noise signal at 0.7 ng TNO-1 (20ng Pt/ml). The sensitivity was 0.1 nA/ng TNO-1 (0.2nA/ng Pt). The within-day presicion was 1.1% at a concentration of 10.8g TNO-1/ml (n=10). With this system the compatibility was measured of TNO-6 with infusion fluids. In 0.15 M NaCl, TNO-6 (=cis-1,1-di(aminomethyl)-cyclohexanePt(II)sulphate) was converted into TNO-1 within 40 minutes. Molecular changes of TNO-6 were also observed in a 5% aqueous glucose solution.     

The 51V(n, γ)52V reaction studied with polarized neutrons and polarized vanadium nuclei

Circular polarization of γ- radiation following capture of polarized thermal neutrons by unoriented nuclei and the angular distribution of such radiation, using polarized neutrons and polarized nuclei, made it possible to assign spins to 13 levels of ⁵²V. In addition the admixtures of spin-3 and spin-4 reaction channels could be derived for 20 primary γ-ray transitions. With this information interference phenomena in the ⁵¹V(n, γ) reaction were studied. The low-lying levels of ⁵²V are compared with shell-model calculations. The capture mechanism is discussed in terms of a doorway-state model.