John S. Buckleton

132,173-cyclopheophorbide enol, the first porphyrin isolated from a sponge

Abstract 132,173-Cyclopheophorbide enol (1) a non-metalated chlorophyll A derivative has been isolated from Darwinella oxeata (Bergquist) and its structure determined by physical and X-ray measurements.

Empirical testing of estimated DNA frequencies

Direct empirical testing of forensic DNA micro-probabilities has proved difficult. Substantial support for the population genetic models on which these micro-probabilities are based has come from powerful but indirect means. However for many people empirical testing rather than models remains the ideal. Following the example set by Weir and Evett we report here a large-scale empirical test of a population genetic model incorporating substructure and relatedness. Given that all models represent simplifications of reality the fit of observed and prediction is remarkable and gives substantial support to the reliability of current methods.

Crystal structure and anion-dependent variations in the vibrational spectra of 4,4′-bipyridinium cations

Abstract The crystal structure of 4,4′-bipyridinium nitrate has been determined. Crystal data: C 10 H 10 N 4 O 6 , M r =282.18, a =23.334 (3), b =27.653 (6), c =3.6687 (5) A, V =2367.2 A 3 , orthorhombic, space group Fdd 2; Z =8, D m =1.59, D x =1.57 g cm −3 , Mo K α, λ=0.71069 A,μ=1.43 cm −1 , F (000) = 1168, T =292.5 ± 1 K, R =0.041, R w =0.042 for 847 ( I >2.5σ) reflections. The dihedral angle between the two planar rings of the cation is 39.0°. The Raman and IR spectra of the dinitrate salt confirm the existence of relatively strong hydrogen bonding (N + ··O − distance, 2.674 A) and reflect the lower cation symmetry ( D 2 ) associated with non-coplanar rings.

The development of a fully regiocontrolled synthesis of (±)-12a,12b-monosecocolchicine using a synthetic equivalent for the 7-methoxy-3-troponyl anion

The lithio-species (6) acts as a synthetic equivalent for the 7-methoxy-3-troponyl anion (3) and has been employed in a fully regiocontrolled synthesis of the title compound (2).

The Probabilistic Genotyping Software STRmix: Utility and Evidence for its Validity

Forensic DNA interpretation is transitioning from manual interpretation based usually on binary decision‐making toward computer‐based systems that model the probability of the profile given different explanations for it, termed probabilistic genotyping (PG). Decision‐making by laboratories to implement probability‐based interpretation should be based on scientific principles for validity and information that supports its utility, such as criteria to support admissibility. The principles behind STRmix™ are outlined in this study and include standard mathematics and modeling of peak heights and variability in those heights. All PG methods generate a likelihood ratio (LR) and require the formulation of propositions. Principles underpinning formulations of propositions include the identification of reasonably assumed contributors. Substantial data have been produced that support precision, error rate, and reliability of PG, and in particular, STRmix™. A current issue is access to the code and quality processes used while coding. There are substantial data that describe the performance, strengths, and limitations of STRmix™, one of the available PG software.