Search

Introduction: Dental calculus is a mineralized microbial dental plaque biofilm that forms throughout life by precipitation of salivary calcium salts. Successive cycles of dental plaque growth and calcification make it an unusually well-preserved, long-term record of host-microbial interaction in the archaeological record. Recent studies have confirmed the survival of authentic ancient DNA and proteins within historic and prehistoric dental calculus, making it a promising substrate for investigating oral microbiome evolution via direct measurement and comparison of modern and ancient specimens. Objective: We present the first comprehensive characterization of the human dental calculus metabolome using a multi-platform approach. Methods: Ultra performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) quantified 285 metabolites in modern and historic (200 years old) dental calculus, including metabolites of drug and dietary origin. A subset of historic samples was additionally analyzed by high-resolution gas chromatography–MS (GC–MS) and UPLC–MS/MS for further characterization of metabolites and lipids. Metabolite profiles of modern and historic calculus were compared to identify patterns of persistence and loss. Results: Dipeptides, free amino acids, free nucleotides, and carbohydrates substantially decrease in abundance and ubiquity in archaeological samples, with some exceptions. Lipids generally persist, and saturated and mono-unsaturated medium and long chain fatty acids appear to be well-preserved, while metabolic derivatives related to oxidation and chemical degradation are found at higher levels in archaeological dental calculus than fresh samples. Conclusions: The results of this study indicate that certain metabolite classes have higher potential for recovery over long time scales and may serve as appropriate targets for oral microbiome evolutionary studies.

Ethical dilemmas in organisations can arise due to situational circumstances, the decision making process and the conditions in which they are made. Academic literature offers some insights into analysing ethical decision making; these include guidelines on how to deal with ethical dilemmas (e.g. Abramson, 1985; Loewenberg and Dolgoff, 1996; Reamer, 1990). Recently, several prominent corporate scandals have been reported in the media. These include News International Limited, Barclays and BP. According to business ethics scholars, one of the causes for the escalating incidents of corporate scandals is triggered by the weaknesses in the leaders' decision making process. For example, Giacalone and Jurkiewicz (2003) claim that ethical decision making studies have been focused mostly on ethical codes, cultures, and leadership styles. Scholars have shown that ethical codes on its own cannot be relied on to decrease unethical behaviour (e.g. Somers, 2001) and that leadership fails to promote ethical behaviour always (e.g. Victor and Cullen, 1988). More focus is called into looking into the "individual character, personality, and belief systems that may influence ethical cognitions as precursors to behaviour" (Giacalone and Jurkiewicz, 2003, p. 86). One such individual focused approach to improve ethical decision making is based on spiritual leadership.

presented at the 2nd International Conference on Social Responsibility, Ethics, and Sustainable Business Bournemouth, UK, September 5 & 6, 2013.

While various scholars have proposed different spiritual leadership models, only a few have examined the similarities and differences between these models with a view to understanding the themes driving the spiritual leadership discourse. The purpose of this review paper is twofold. The first is to examine the key contributions shaping the literature on spiritual leadership by identifying key spiritual leadership models and the major themes represented by these models. Second, this paper aims to further examine these themes to explore the links between spiritual leadership and other organisational and individual level attributes such as success, performance and commitment. The paper concludes by discussing future research opportunities.