Publications by authors named "K E H Penkman"

Article Synopsis
  • Corals and mollusks create aragonite structures using proteins that are rich in aspartic acid and glycine, which play a crucial role in biomineralization.
  • Research shows that aspartic acid, glycyl-l-aspartic acid, and tetra-aspartic acid all inhibit aragonite precipitation, while glycine does not have this effect.
  • The study finds that aspartic acid is particularly effective in reducing precipitation rates and influencing crystal structure, suggesting its key role in shaping coral skeletons and controlling mineral formation.
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Rationale: Alkylresorcinols (AR) are cereal-specific biomarkers and have recently been found in archaeological pots. However, their low concentrations and high susceptibility to degradation make them difficult to detect using conventional gas chromatography mass spectrometry (GC/MS). Here we describe the development of a more sensitive liquid chromatography mass spectrometry (LC/MS) method to detect these compounds.

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Article Synopsis
  • Understanding how temperature, pH, biomolecules, and mineral growth rates affect biogenic CaCO3 is key for developing palaeoproxies, and this study focuses on optimizing aragonite precipitation from seawater to simulate coral calcification conditions.
  • The research finds that low levels of aspartic acid enhance aragonite formation, while high levels inhibit it, impacting mineral structure and morphology significantly.
  • Additionally, variations in organic content of coral skeletons can alter the Raman spectra of aragonite, complicating interpretations of saturation states in calcification fluids.
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Despite the vast array of different geochronological tools available, dating the Paleolithic remains one of the discipline's greatest challenges. This review focuses on two different dating approaches: trapped charge and amino acid geochronology. While differing in their fundamental principles, both exploit time-dependent changes in signals found within crystals to generate a chronology for the material dated and hence, the associated deposits.

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Evolution on islands, together with the often extreme phenotypic changes associated with it, has attracted much interest from evolutionary biologists. However, measuring the rate of change of phenotypic traits of extinct animals can be challenging, in part due to the incompleteness of the fossil record. Here, we use combined molecular and fossil evidence to define the minimum and maximum rate of dwarfing in an extinct Mediterranean dwarf elephant from Puntali Cave (Sicily).

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