Coated silica nanoparticles in Nakhla iddingsite veins: implications for waterrock interaction within the Martian crust

No abstract available

Carbonates replacing plagioclase glass in the Martian meteorite ALH84001

No abstract available

The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations

Five-membered secondary amine heterocycles containing an α-heteroatom were prepared and shown to be ineffective as catalysts for the iminium ion catalysed Diels–Alder reaction between cinnamaldehyde and cyclopentadiene. Their six-membered counterparts proved to be highly active catalysts. In stark contrast, the catalytic activity observed when comparing the non α-heteroatom cyclic amines proline methyl ester and methyl pipecolinate showed the five-membered ring amine was significantly more active. Concurrent density functional theoretical calculations suggest a rationale for the observed trends in reactivity, highlighting that LUMO activation through an iminium ion intermediate plays a key role in catalytic activity

Solution phase, solid state, and theoretical investigations on the MacMillan imidazolidinone

A combination of soln. phase NMR, X-ray crystallog. studies, and DFT calcns. provide a consistent structural conformation for iminium ions derived from the MacMillan imidazolidinone

Aryldiazonium tetrafluoroborate salts as green and efficient coupling partners for the Suzuki-Miyaura reaction : from optimisation to mole scale

The use of aryldiazonium tetrafluoroborate salts as coupling partners in the Suzuki-Miyaura reaction was investigated from a process chemistry perspective including safety evaluation, solvent and catalyst screening and multi-variate factor optimization. Optimised conditions were applied to a range of substrates to evaluate the scope and limitations of the reaction and one example was carried out on mole-scale to demonstrate the practicality and scalability of the proces

Crystal structures and proton dynamics in potassium and cesium hydrogen bistrifluoroacetate salts with strong symmetric hydrogen bonds

The crystal structures of potassium and cesium bistrifluoroacetates were determined at room temperature and at 20 K and 14 K, respectively, with the single crystal neutron diffraction technique. The crystals belong to the I2/a and A2/a monoclinic space groups, respectively, and there is no visible phase transition. For both crystals, the trifluoroacetate entities form dimers linked by very short hydrogen bonds lying across a centre of inversion. Any proton disorder or double minimum potential can be rejected. The inelastic neutron scattering spectral profiles in the OH stretching region between 500 and 1000 cm^{-1} previously published [Fillaux and Tomkinson, Chem. Phys. 158 (1991) 113] are reanalyzed. The best fitting potential has the major characteristics already reported for potassium hydrogen maleate [Fillaux et al. Chem. Phys. 244 (1999) 387]. It is composed of a narrow well containing the ground state and a shallow upper part corresponding to dissociation of the hydrogen bond.Comment: 31 pages, 7 figure

Relationships between digit ratio (2D:4D) and basketball performance in Australian men

Objective To investigate relationships between the digit ratio (2D:4D) and competitive basketball performance in Australian men. Methods Using an observational cross‐sectional design a total of 221 Australian basketball players who competed in the Olympic Games, International Basketball Federation World Championships/Cup, Australian National Basketball League, Central Australian Basketball League or socially had their 2D:4Ds measured. Analysis of variance was used to assess differences in mean 2D:4Ds between men playing at different competitive standards, with relationships between 2D:4Ds and basketball game‐related statistics assessed using Pearson\u27s product moment correlations in men playing at a single competitive standard. Results There were significant differences between competitive standards for the left 2D:4D following Bonferroni correction, but not for the right 2D:4D, with basketballers who achieved higher competitive standards tending to have lower left 2D:4Ds. No important correlations between 2D:4D and basketball game‐related statistics were found, with correlations typically negligible. Conclusions This study indicated that the 2D:4D can discriminate between basketballers competing at different standards, but not between basketballers within a single competitive standard using objective game‐related statistics

Drug–excipient interactions in ketoprofen: A vibrational spectroscopy study

Ketoprofen (3-benzoyl-alpha-methylbenzeneacetic acid) is a widely used nonsteroidal anti-inflammatory drug (NSAID), always administered in the form of drug-excipient physical mixtures (PMs). The occurrence of possible interactions between ketoprofen and two commonly used excipients-lactose (LAC) and polyvinylpyrrolidone (PVP)-was evaluated, through vibrational spectroscopy techniques [both Raman and Inelastic Neutron Scattering (INS)]. Spectral evidence of drug:excipient close contacts, which were enhanced by aging, was verified for the (1:1) (w:w) (ketoprofen:PVP) and (ketoprofen:LAC) PMs, both by Raman and INS. These interactions were found to involve mainly the central carbonyl and the terminal methyl-carboxylic moieties of the ketoprofen molecule, this being reflected in particular vibrational modes, such as the methyl torsion, the out-of-plane C-OH bending, and the inter-ring C=O stretching

Utility of international normative 20 m shuttle run values for identifying youth at increased cardiometabolic risk

The purpose of this study was to examine the ability of international normative centiles for the 20 m shuttle run test (20mSRT) to identify youth at increased cardiometabolic risk. This was a cross-sectional study involving 961 children aged 10–17 years (53% girls) from the United Kingdom. Receiver operating characteristic (ROC) curves determined the discriminatory ability of cardiorespiratory fitness percentiles for predicting increased cardiometabolic risk. ROC analysis demonstrated a significant but poor discriminatory accuracy of cardiorespiratory fitness in identifying low/high cardiometabolic risk in girls (AUC = 0.58, 95% CI: 0.54–0.63; p = 0.04), and in boys (AUC = 0.59, 95% CI: 0.54–0.63; p = 0.03). The cardiorespiratory fitness cut-off associated with high cardiometabolic risk was the 55th percentile (sensitivity = 33.3%; specificity = 84.5%) in girls and the 60th percentile (sensitivity = 42.9%; specificity = 73.6%) in boys. These 20mSRT percentile thresholds can be used to identify children and adolescents who may benefit from lifestyle intervention. Nonetheless, further work involving different populations and cardiometabolic risk scores comprising of different variables are needed to confirm our initial findings