Synthesis of 3, 4, 4a, 5, 6, 7, 8, 8a α-Octahydro-4a β, 8α-Dimethyl-2(1H)-Naphthalenones from the Wieland-Miescher Ketone

Conversion of the Wieland-Miescher ketone to a bicyclic dienophile capable of providing the AB rings of the picrasane skeleton of the guassinoids required the introduction of a C-8α methyl group in a 2-decalone. Among the routes explored, the conversion of the Wieland-Miescher ketone to a 4,4a,5,6,7,8-hexahydro-4aβ-methyl-8-methylene-2(3H)-napthalenone and subsequent reduction to a 3,4,4a,5,6,7,8,8aα-octahydro-4aβ,8α-dimethyl-2(1H)-napthalenone proved most useful.     

Multifocal multiphoton endoscope

We report a miniaturized resonant/non-resonant multi-fiber raster scanner that is paired with a gradient-index lens assembly to achieve a compact and flexible multifocal multiphoton endoscope capable of longitudinal parallel image acquisition. Multiphoton images are obtained simultaneously at three axial depths, separated by ≥4.8 μm, by incorporating three axially offset double clad optical fibers into the miniaturized scanner. The fabricated endoscope has an outer diameter of 3 mm, a rigid length of 4 cm, and acquires images at 4 frames/s per focal plane, with lateral and axial resolutions for two-photon imaging of 0.8 and 10 μm, respectively.     

Deposition measurement of particulate matter in connection with corrosion studies

A new passive particle collector (inert surrogate surface) that collects particles from all directions has been developed. It was used to measure particle deposition at 35 test sites as part of a project that examined corrosion of materials in order that variation in particulate material could be used in development of dose–response functions in a modern multi-pollutant environment. The project, MULTI-ASSESS, was funded by the EU to examine the effects of air pollution on cultural heritage. Passive samplers were mounted rain-protected, and both in wind-protected and wind-exposed positions, to match the exposure of the samples for corrosion studies. The particle mass and its chemical content (nitrate, ammonium, sulfate, calcium, sodium, chloride, magnesium and potassium) were analysed. The loss of light reflectance on the surrogate surface was also measured. Very little ammonium and potassium was found, and one or more anions are missing in the ion balance. There were many strong correlations between the analysed species. The mass of analysed water-soluble ions was fairly constant at 24% of the total mass. The particle mass deposited to the samplers in the wind-protected position was about 25% of the particles deposited to an openly exposed sampler. The Cl⁻/Na⁺ ratios indicate a reaction between HNO₃ and NaCl. The deposited nitrate flux corresponds to the missing chloride. The Ca²⁺ deposition equals the deposition and the anion deficiency. The deposition most likely originates from SO₂ that has reacted with basic calcium-containing particles either before or after they were deposited. The particle depositions at the urban sites were much higher than in nearby rural sites. The deposited mass correlated surprisingly well with the PM₁₀ concentration, except at sites very close to traffic.     

Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions

We study the sensitivity of our recent MSTW 2008 NLO and NNLO PDF analyses to the values of the charm- and bottom-quark masses, and we provide additional public PDF sets for a wide range of these heavy-quark masses. We quantify the impact of varying m _c and m _b on the cross sections for W, Z and Higgs production at the Tevatron and the LHC. We generate 3- and 4-flavour versions of the (5-flavour) MSTW 2008 PDFs by evolving the input PDFs and α _S determined from fits in the 5-flavour scheme, including the eigenvector PDF sets necessary for calculation of PDF uncertainties. As an example of their use, we study the difference in the Z total cross sections at the Tevatron and LHC in the 4- and 5-flavour schemes. Significant differences are found, illustrating the need to resum large logarithms in $Q^{2}/m_{b}^{2}$ by using the 5-flavour scheme. The 4-flavour scheme is still necessary, however, if cuts are imposed on associated (massive) b-quarks, as is the case for the experimental measurement of $Zb\bar{b}$ production and similar processes.     

Highly selective zeolite-catalysed mono-N-alkylation of arylenediamines by dialkyl carbonates

Arylenediamines are mono-N-alkylated by dialkyl carbonates in the presence of NaY zeolite catalyst in a regioselective and nontoxic process.     

Face-to-face arene-arene binding energies: dominated by dispersion but predicted by electrostatic and dispersion/polarizability substituent constants

Parallel face-to-face arene-arene complexes between benzene and substituted benzenes have been investigated at the MP2(full)/6-311G** and M05-2X/6-311G** levels of theory. A reasonably good correlation was found between the binding energies and the ∑|σ(m)| values of the substituted aromatics. It is proposed that a substituent |σ(m)| value informs on both the aromatic substituent dispersion/polarizability and the effect the substituent has on the aromatic electrostatics. Supporting this hypothesis, a combination of electrostatic (∑σ(m)) and dispersion/polarizability (∑M(r)) substituent constant terms gives an excellent, and statistically significant, correlation with the benzene-substituted benzene binding energy. Symmetry adapted perturbation theory energy decomposition calculations show the dominant attractive force is dispersion; however, the sum of all nonelectrostatic forces is essentially a constant, while the electrostatic component varies significantly. This explains the importance of including an electrostatic term when predicting benzene-substituted benzene binding energies.     

Microfluidic sorting system based on optical force switching

We report a versatile, and automatic method for sorting cells and particles in a three dimensional polydimethylsiloxane (PDMS) structure consisting of two cross-microchannels. As microspheres or yeast cells are fed continuously into a lower channel, a line shaped focused laser beam is applied (perpendicular to the direction of flow) at the crossing junction of the two channels. The scattering force of the laser beam was employed to push microparticles matching specific criteria upwards from one channel to another. The force depends on the intrinsic properties of the particles such as their refractive index and size, as well as the laser power and the fluid flow speed. The combination of these parameters gives a tunable selection criterion for the effective and efficient sorting of the particles. The introduction of the cylindrical lens into the optical train allows for simultaneous manipulation of multiple particles which has significantly increased the efficiency and throughput of the sorting. A high aspect ratio microchannel (A.R.=1.6) was found to enhance the sorting performance of the device. By careful control of the microparticle flow rate, near 100% sorting efficiency was achieved.     

Supercontinuum radiation for applications in chemical sensing and microscopy

The advent of compact, high brightness supercontinuum radiation sources employing solid core photonic crystal fibres is beginning to make an impact across the field of applied spectroscopy research. In this article we focus on the use of supercontinuum sources to construct novel instrumentation for chemical sensing. A brief overview is given on the mechanisms of supercontinuum generation in solid core photonic crystal fibres, and then we review recent, and present new, results from our own research. We present examples on gas phase sensing applications, permitting wide bandwidth molecular spectra to be gathered at ultrahigh speed. Furthermore we demonstrate the design and construction of a wide bandwidth microscope for wavelength flexible hyperspectral confocal imaging. We conclude with an outlook and a summary of where and how we think the field may develop over coming years. PACS  07.07.Df; 42.62.Fi; 87.64.mk; 87.64.-t