Asymmetric epoxidation of some arylalkenyl sulfones using a modified Juliá-Colonna procedure

A modified procedure for performing the Juliá-Colonna epoxidation reaction effects the oxidation of some vinyl sulfones to generate the corresponding epoxides 5-8 in good to excellent optical purity.     

A natural-product-inspired photonic logic gate based on photoinduced electron-transfer-generated dual-channel fluorescence

[structure: see text] Modified 1-benzylisoquinoline N-oxides can operate as molecular logic gates. The combination of dual-channel fluorescence emissions and the preferred interaction for selected chemical inputs allows one to design multifunction and self-reprogrammable molecular logic gates.     

Flux difference splitting for 1D open channel flow equations

An upwind finite difference scheme based on flux difference splitting is presented for the solution of the equations governing unsteady open channel hydraulics. An approximate Jacobian needed for splitting the flux differences is defined that satisfies the conditions required to construct a first-order upwind conservative discretization of the equations. Added limited second-order corrections make the resulting scheme robust and accurate for the computation of all regimes of open channel flow. Some numerical results and comparisons with other classical schemes under exacting conditions are presented.     

Shock mechanisms by ultrahigh laser accelerated plasma blocks in solid density targets for fusion

Ignition of nuclear fusion flames in solid state density fuel following Chu?s model of 1972 is evaluated using now available plasma blocks from ultrahigh acceleration with laser pulses of picosecond (ps) duration and power up to and beyond petawatt (PW). A new numerical approach is reported where genuine two-fluid hydrodynamics is used in order to study the shock mechanism of the generated fusion flame, its propagation velocities above 1000 km/s$1000\text{km}/\text{s}$, and fusion efficiencies for deuterium–tritium needing an energy flux of 10⁸ J/cm²${10}^8\text{J}/{\text{cm}}^2$. The results of the built-up of the shock process are reported showing a basic difference between the ps and nanosecond (ns) properties.     

The factor group splitting phenomenon: a vibrational spectroscopy approach to assess polymer crystallinity and crystalline density

This paper gathers a number of relevant recent findings where Raman spectroscopy has been successfully applied by the author and coworkers to gain a unique structural picture about the crystalline phase present in isotropic and cold-drawn polyethylenes and in a range of aliphatic polyketone materials. In these semicrystalline polymers a relatively well-known spectroscopic phenomenon called factor group splitting (or correlation field splitting) is thought to occur. By careful analysis of the behaviour of this splitting phenomenon, chiefly in the -CH₂- bending range of the spectrum and in terms of alterations in band intensity and position, a valid approach to asses crystallinity content and morphology, crystalline polymorphism, and crystalline density is displayed. The potential of this spectroscopic phenomenon to yield information about the crystalline phase present in these polymers can therefore be regarded as analogous to that gained by wide-angle X-ray scattering.     

FT-Raman spectroscopic studies of guarana and some extracts

The Raman spectrum of guarana, an important product of the Amazonian rain forest, has been investigated; the therapeutic properties of guarana and it's extracts have been realised for some time and have been attributed to guaranine, which could be a complex of caffeine and tannins or to a new xanthine natural product. The purpose of this study is two-fold: firstly, to provide molecular structural information about guarana seeds and their extracts and, secondly, to test the viability of using the technique as a method of verification of genuine guarana extracts from synthetic composites. Raman spectroscopy shows that the composition of the guarana is very similar for the whole seed and for the outer and inner portions of the dissected seed, which are closely similar also to the ground commercial powders produced in the Amazon for the distributors. The results indicate that Fourier-transform Raman spectroscopy could be used for the monitoring of quality control of guarana products in the phytopharmaceutical industry.